BN 3035/90.80
Software Version 7.20
Operating Manual
BN 3035/98.32
9
Please direct all enquiries to your
local Wavetek Wandel Goltermann sales
company. The addresses are given at the
end of this handbook.
Copyrights
This product or parts of it are based upon
Recommendations and/or Standards of the
Standardization Sector of the International
Telecommunication Union - ITU-T and/or of the
European Telecommunications Standards Institute ETSI. These Recommendations and Standards are
subject to copyrights of these organizations. Without
written permission of the ITU-T and/or ETSI it is not
permitted to copy ITU-T Recommendations or ETSI
standards or parts thereof and/or make them available
to third parties.
1Main applications of the Broadband Analyzer/Generator
ATM is set to change the landscape in WANs and LANs in the coming years. Practically all
network operators view ATM as a key technology in enabling them to provide the required high
quality standard in future serv i ces.
With the Broadband Analyzer/Generator the right tool is provided to you for performing ATM
tests in a simply, reliably manner and with highest accuracy.
The tester is particularly suitable for
• commissioning,
• acceptance testing and
• in-service testing of ATM services, switches and networks.
This means that your network management is enhanced to provide performance tests that
guarantee the best possible “Quality of Service”. A special feature, the real-time function
supports the test, which also allows you to optimize the ATM traffic management.
Both SVCs (Switched Virtual Circuits) and PVCs (Permanent Virtual Circuits) are tested
precisely.
Testing of different ATM service categories will be supported directly by the Broadband
Analyzer/Generator.
A TM traffic contracts can be analyzed in detail and can therefore be guaranteed by means of an
acceptance test. The figure below shows the relationship between the ATM Forum and ITU-T
service categories, their traffic descriptions and the minimum guarantee corresponding to the
appropriate traffic contract.
Service
Category
CBR
DBR
nrt-VBR
CBR
ABR
UBR
Traffic
Description
PCR
and CDVT
PCR, SCR, MBS
CDVT
and CDVT
PCR, SCR, MBS
CDVT
and CDVT
PCR, MCR
and CDVT
PCR, MCR
and CDVT
PCR
BCR
PCR
BCR
PCR
PCR
PCR
Guarantees
Quality of Service
Bandwidth, min CLR
max CTD, CDV
Bandwidth, min CLR
max CTD, CDV
Bandwidth, min CLR
Bandwidth, low CLR for
conforming sources
No
peak-to-peak
peak-to-peak
Fig. I-1Features of ITU-T and ATM Forum traffic contracts
IntroductionI-1
Broadband Analyzer/GeneratorANT-20/ANT-20E
All the test applications have been developed in accordance with the latest information from the
standardization bodies ATM Forum and ITU-T to ensure that they are always up to date.
Your Wavetek Wandel Goltermann Sales Partner can supply the latest information about
software upgrades and new options to keep you abreast of the latest developments in A TM test
technology.
2Application concept
The Broadband Analyzer/Generator in the ANT-20/ANT-20E is an ATM tester that is equipped
with integrated interfaces. This ensures that the necessary interface is easily accessible when
you are on the move.
Fig. I-2Comprehensive choice of interfaces for the ANT-20/ANT-20E
The Broadband Analyzer/Generator operates in “Emulate” mode for an UNI interface for most
test applications. This configuration provides the test instrument with characteristics that are
similar to those of an ATM terminal. This configuration also allows signaling emulation to enable
you to make performance measurements using ATM switched virtual circuits. The function is
also used for testing the major characteristics of ATM switches.
ATM tests on SVCs can be performed faster and more effectively since you no longer need to
be concerned with setting up and clearing down the connection.
I-2Introduction
ANT-20/ANT-20EBroadband Analyzer/Generator
The diagram below illustrates the steps that the Broadband Analyzer/Generator performs
automatically, when a self-call was initiated:
1. Test circuit set up
2. Performance analysis over the test circ uit
Fig. I-3Automatic test sequence for switched virtual circuits
The receiver of the Broadband Analyzer/Generator can be used separately for troubleshooting
or analysis. The ANT-20/ANT-20E can be used with a “T” connector or optical power splitter for
this monitor type operating mode.
Fig. I-4ANT-20/ANT-20E monitor function
IntroductionI-3
Broadband Analyzer/GeneratorANT-20/ANT-20E
All test applications are supported by a practical application and channel database. In the
simplest scenario, an application is called up and started directly.
With the ATM channel editor a comfortable tool for the extension and handling of the ATM
channel database is available.
The results must be recorded, not just for acceptance tests. All the virtual instruments of the
Broadband Analyzer/Generator include a print function to allow you to produce hard copies that
can be used for presentations.
The Broadband Analyzer/Generator is particularly suitable for end to end or Multicall test
applications. The concept allows new connections, network nodes or network terminations to be
tested simply and reliably on the customer’s premises. These tests can also be automated if
they are performed using signaling and SVCs.
Fig. I-5Multicall applications using the Broadband Analyzer/Generator
Several Broadband Analyzer/Generators are calling a “Call-server”
OMC: Operation & Maintenance Center
I-4Introduction
ANT-20/ANT-20EBroadband Analyzer/Generator
3Test applications
3.1ATM performance analysis
The basic version of the tester supports analysis of the ATM layer “Quality of Service”.
Measurements are performed in conformance with ITU-T Recommendation O.191,
“SPECIFICATIONS OF MEASURING EQUIPMENT; Equipment to Assess ATM Layer Cell
Transfer Performance”.
This standard describes the currently most reliable ATM measurement method. It basically
defines test cell formats and evaluation algorithms such as a 4-byte sequence number, the
timestamp and a CRC16 check per cell.
By these definitions, test results in accordance to O.191 were registered, which can be
compared directly.
The following quality parameters are reliably and unambiguously determined from the test cell
data using the measurement algorithm:
• Error-related network performance parameters
– CER, Cell Error Ratio
– CLR, Cell Loss Ratio
– SECBR, Severely Errored Cell Block Ratio
– CMR, Cell Misinsertion Rate
• Availability-related network performance parameters
– LPAC, Loss of Performance Assessment Capability
Using this measurement method, particularly precise long term measurements are possible
which allow evidence of the constant high quality of a connection to be obtained.
3.2Traffic management tests
Various test functions assist you in testing the ATM traffic management functions or to optimize
their settings.
In particular, the tester supports the following:
• Definition and agreement of the ATM traffic contract for ATM circuits
• Tests using the “leaky bucket” algorithm (GCRA, generic cell rate algorithm)
• Simulations with traffic shaping
• Compliance and conformance simulations with ATM circuits and ATM sources
• Tests in connection with connection admission control
• Tests of UPC (usage parameter control) functions
• Analysis of cell loss priority control
• Tagging tests
• Explicit forward congestion analysis
In preparation:
• AAL-5 frame discard testing
IntroductionI-5
Broadband Analyzer/GeneratorANT-20/ANT-20E
3.3UNI signaling tests
The “Signaling Emulation” function allows you to test the signaling characteristics of UNIs.
Signaling emulation provides a rapid “go/no go” assessment of the following:
• Is it possible to set up a connection?
• What address format is supported?
• Which contract parameters can be negotiated?
• Which service categories can be used?
• Does the signaling process operate without problems?
3.4Analysis of ATM signals
The ATM Channel Explorer is used to analyze ATM signals. This tool, for example can perform
rapid diagnostics by finding the active ATM channels and displaying their bandwidth and AAL
distributions. A further application is the detection of defects and anomalies in the ATM signal.
3.5Other fields of application
The range of applications for the Broadband Analyzer/Generator is very wide and includes the
following fields:
• Function tests for ATM network elements and modules
• Performance management
• Remote-controlled measurement of demand
• ATM network monitoring
• Acceptance tests
• Commissioning of ATM network nodes and ATM connections
• Commissioning of new ATM services
I-6Introduction
ANT-20/ANT-20EBroadband Analyzer/Generator
4Using and setting up the Broadband Analyzer/Generator
The Broadband Analyzer/Generator is a flexible test concept for performing tests on the various
protocol layers.
The diagram shows the points of access that the ATM tester can use within the layer model. It
also shows the modular structure of the Windows user interface in conjunction with the
generator and receiver hardware.
Fig. I-6Hardware and software structure of the Broadband Analyzer/Generator
The modern operating concept and the user interface have been developed to allow you to
perform tests simply and reliably. The number of operating steps needed has been reduced to
a minimum:
1. Select the required instrument configuration
2. Select the test type
3. Select and edit the default test parameters where necessary
4. Start the measurement
The generator produces a test data stream in accordance with the selected test type and the
analyzer outputs the test results in optimized form.
If one of the pre-defined applications in the Application Manager matches your test
requirements exactly, it can be started immediately. This also applies to any applications that
will be defined or modified by yourself. Own applications are easily made by storing instrument
settings once with the Application Manager.
The stock of applications you create, together with the universal channel database allows the
ATM tester to be rapidly adapted to new, complex test situations.
IntroductionI-7
Broadband Analyzer/GeneratorANT-20/ANT-20E
5Overview: Virtual Instruments, “VIs”
To make it easier to locate and operate the large number of instrument functions, a user
interface was developed for the ANT-20 family of instruments that makes use of the concept of
virtual instruments or “VIs”. The VIs are designed so that each has a clearly defined set of tasks.
By selecting specific VIs, tools or “applications” can be developed and tailored to perform
particular measurement tasks. The VIs for the Broadband Analyzer/Generator are summarized
briefly below.
Virtual instrumentProtocol
IconName
ATM Test Control
ATM Test Results
ATM Channel Explorer
Table I-1Virtual instruments for the Broadband Analyzer/Generator
layer
Physical
•••
•••
•••
Function
ATM
Higher
Configure the test connection, signaling emulation and
protocol layers for ATM measurements. Define
measurement modes and virtual channels. Control traffic
generation. Insert errors in the ATM and higher layers.
Display and outpu t the results o f the A TM me asurements
made.
Characterize ATM traffic at the standard interfaces and
trace alarms in the ATM layer (up to 1000 channels).
Perform AAL layer analysis.
I-8Introduction
ANT-20/ANT-20EBroadband Analyzer/Generator
6Often used terminology
Application
An application consists of a suitable collection of virtual instruments (VIs for short) used to solve
a measurement task. In this way applications can be defined e.g. for physical layer or ATM layer
measurements.
Applications are configured and managed in the “ANT20 - <Application Title>” window
(Application Manager VI).
If an application is saved, the parameter settings for the VIs used will also be saved.
In the same way, the measurement results are also saved with the application.
When the application is loaded, the test equipment is automatically set to the same settings as
when the application was last used.
Test type
The “test type” is a concept used for ATM measurements. Test types are used to simply and
quickly configure the instrument and prevent operating errors, particularly if signaling emulation
is being used.
A test type consists of a measurement mode (only “ATM-Layer QoS” is available in this software
version) and a “connection mode”.
When a test type is selected, the instrument is pre-set for performing the measurement. A setup
dialog is provided for each test type so that you can make settings that are specific to the test
you want to perform.
The settings for all test types used are saved within an application. When an application is
loaded, the last test type used in the application will automatically be activated.
Example test types:
• ATM Layer QoS (PVC) - Point-to-point
• ATM Layer QoS ( SVC) - Calling
• ATM Layer QoS ( SVC) - Self-Call
Connection mode
The “connection mode” indicates the way that the virtual connection is switched through the
ATM layer.
Example connection modes:
• For permanent virtual connections (PVC):
– Point-to-point
– Looped
• For switched virtual connections SVC):
– Calling (switched point-to-point connection with calling instrument)
– Called (switched point-to-point connection with called instrument)
– Self-Call (switched connection with self-call)
IntroductionI-9
Broadband Analyzer/GeneratorANT-20/ANT-20E
Port configuration
The Port configuration (topology) describes the way in which the test equipment is connected to
the device under test on the physical layer.
Example topologies:
• Emulate
• Looped (between generator and receiver)
• Monitor (not yet supported)
Traffic type
The traffic type indicates the type of traffic contract. This term is defined by the ATM Forum. The
ITU equivalent term is “broadband bearer capability”.
A traffic type must be specified for each virtual channel defined in the Channel Editor of the
“ATM Test Control” VI.
Example traffic types:
• CBR (constant bit rate)
• VBR-nRT (variable bit rate, non real time)
• DBR (deterministic bit rate)
• SBR (statistical bit rate)
The CBR and DBR traffic types are identical in most respects. This is also true of the VBR-nRT
and SBR traffic types.
Switched Virtual Circuit (SVC)
• Forward is the direction from the “calling” device to the “called” device.
• Backward is the direction from the “called” device to the “calling” device.
Permanent Virtual Circuit (PVC)
• Forward is the send direction of the device.
• Backward is the receiving direction of the device
Device means: ANT-20/ANT-20E.
I-10Introduction
ANT-20/ANT-20EBroadband Analyzer/Generator
Operation
1ATM Test Control
1.1Introduction
Task
The “ATM Test Control” VI is used to select a test type and to configure the instrument for the
selected test type. You can also control the running of the test from this VI if the selected test
type allows for manual control (“Test - Online Control” dialog). Each test type generally includes
configuration of the generator and the receiver.
The instrument configuration covers selection of the port configuration (topology), setting the
various protocol layers, in particular the ATM layer and higher layers, as well as selection of the
type of connection, i.e. “permanent” or “switched”.
The “test types” available for selection are used to structure measurement types and connection
modes. These are arranged according to protocol layers, with only the ATM layer being
supported at present. Only those test types that are possible and practicable with the selected
instrument configuration are available for selection.
On-line control allows relevant test parameters to be altered during the traffic generation. This
is particularly useful for traffic parameters such as the peak cell rate or mean cell rate, allowing
rapid assessment of the effects of these parameters on the behavior of the device under test.
On-line control also allows errors (anomalies and defects) to be inserted into the test cell
stream.
The “A TM Test Control” VI is normally used together with the “A TM Test Results” VI. The latter
displays the test results as determined by the selected test type and corresponding instrument
configuration.
The settings made for a certain test type are saved within an “application” and are set again
automatically when the test is called up again. Bit error measurements in the physical layer are
not supported by the “ATM Test Control” VI.
Requirements
✓ The “Signal Structure” VI must also be loaded when performing ATM measurements. This is
used to control and configure the physical layer, e.g. select the bit rate, frame type, etc. The
instrument can also be configured for bit error measurements in the physical layer with the
“Signal Structure” VI. If the “ATM Test Control” VI is loaded, the “Signal Structure” VI can
only be accessed via the “Instrument Configuration” dialog of the “ATM Test Control” VI.
✓ To perform detailed tests in the physical layer, the “Anomaly/Defect Insertion” and “Anomaly/
Defect Analyzer” VIs should also be loaded. The “Anomaly/Defect Insertion” VI allows
insertion of a wide range of anomalies and defects in the physical layer. The “Anomaly/
Defect Analyzer” VI provides corresponding analysis of the anomalies and defects in the
physical layer.
OperationO-1
Broadband Analyzer/GeneratorANT-20/ANT-20E
Restrictions
The following virtual instruments cannot be used within a single application at the same time as
the “ATM Test Control” VI: “ATM Signal Structure”, “ATM Background Generator” and “ATM
Traffic Analyzer”
1.2“ATM Test Control” window layout and commands
The “ATM Test Control” main window appears after the VI is loaded. It basically consists of a
menu bar, toolbar and workspace containing the current configuration diagram. Most functions
can be executed via menu commands (text) or via the icons in the toolbar.
When you select a menu command or an icon, a dialog window for making further settings may
appear in the foreground.
Menu bar and toolbar
Configuration diagram/
workspace
Fig. O-1“ATM Test Control” main window
The “ATM Test Control” main window essentially consists of
• the menu bar and pull-down menus,
• the toolbar and
• the workspace with configuration diagram.
Menu bar
The menu bar contains a range of pull-down menus for selecting the following commands or
groups of commands:
InstrumentConfigure instrument
TestSelect test type, set test parameters (on-line, off-line),
insert errors and control traffic enable
OptionsSelect optional settings
ToolsDefine, handle and print out virtual channels
ViewCustomize the application window
HelpUse on-line help
O-2Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
Toolbar
The toolbar buttons provide direct access to the more important functions of the VI.
Meanings of icons, from left to right (equivalent menu command shown in brackets):
Select test type, set test parameters (Test - Setup ...)
Alter source parameters “on-line”(Test - Online Control ...)
Insert errors (Test - Error Insertion ...)
Enable test traffic (Test - Traffic Enable)
Define and handle virtual channels (Tools - Channel Editor ...)
Print list of virtual channels (Tools - Print Channel List ...)
Open on-line help (Help - Contents)
Table O-1Meanings of icons
Configuration diagram
The main window workspace always displays a pictogram of the actual measurement
configuration. If the configuration requires a second instrument, this will also be shown. Further
information describes the configuration and the instrument status in detail:
Fig. O-2Display of “Port configuration” (Main window “ATM Test Control” VI),
Example: “Emulate” and switched virtual circuit (SVC)
OperationO-3
Broadband Analyzer/GeneratorANT-20/ANT-20E
1.3Important dialog windows
The “Instrument Configuration” dialog
The “Instrument Configuration” dialog is used to set the port configuration or topology for the
measurement task and to match the instrument to the protocol layers used. You can also select
whether permanent (PVC) or switched (SVC) virtual connections are to be tested. If switched
virtual connections are selected, you can also configure the signaling emulation and set the
ATM address of the instrument in this dialog.
The dialog shows the selected configuration in graphical form along with push buttons that open
further dialogs for a given layer. This is also the case for the physical layer; the “Signal
Structure” VI is opened when the “PHYSICAL” button is clicked, assuming that the “Signal
Structure” VI has been loaded in the current application; see Sec. 4.4,Page O-19.
Fig. O-3“Instrument Configuration” dialog
The “Test Setup” dialog
The “Test Setup” dialog is used to select the appropriate test type for your measurement task.
Depending on the requirements and modifications with respect to the default setup, further
dialog windows can be called up to configure your test type.
Fig. O-4“Test Setup” dialog with available test types
O-4Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
The extended “Test Setup” dialog
The “Test Setup <...>” dialog is used to configure the test type and to match it to your
measurement task (see Sec. 5.9).
Fig. O-5The extended “Test Setup <...>” dialog
The “Channel Editor” dialog
The Channel Editor is used to define virtual channels and save them in a database;
Sec. 6,Page O-38. Push buttons and a list box in the dialog window header are used for
defining and handling the channels. When first used, the list contains a range of default virtual
channels for the usual types of traffic (CBR, VBR, etc.). These channels can be saved under a
new name and edited individually.
Fig. O-6The “Channel Editor” dialog
OperationO-5
Broadband Analyzer/GeneratorANT-20/ANT-20E
The “Test Online Control - <...>” dialog
The source parameters of interest for your measurement task can be altered using the “Test
Online Control - <...>” dialog as the test cell stream is being generated while a measurement is
running. Any changes made become effective immediately. The channels (A, B, etc.) are
controlled from separate index cards.
Fig. O-7The “Test Online Control <...>” dialog
The “Test Error Insertion <...>” dialog
The “Test - Error Insertion” dialog is used to insert test-specific errors (anomalies and defects)
into the test cell stream. The channels (A, B, etc.) are controlled from separate index cards.
Fig. O-8The “Test Error Insertion <...>” dialog
O-6Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
2ATM Test Results
2.1Introduction
Task
The “ATM Test Results” VI is used to display the results of measurements performed using the
“A TM Test Control” VI. The results windows are configured depending on the active “Test type”
set in the “ATM Test Control” VI. The following results windows may appear in the workspace of
the “ATM Test Results” main window:
• “Receiver Status” window; this gives an overview of the overall receiver status.
• “Quality of Service” window; this displays the ITU-T O.191 QoS performance parameters.
The results from a maximum of four test channels are displayed: Cell Error Ratio, Cell Loss
Ratio, Cell Misinsertion Rate, Mean Cell Transfer Delay, etc.
• “Signaling Analysis” window; this displays the results of signaling analysis.
Requirements
✓ The “ATM Test Results” VI is primarily intended for use with the “ATM Test Control” VI.
Restrictions
The following virtual instruments cannot be used within a single application at the same time as
the “ATM Test Results” VI: “ATM Signal Structure”, “ATM Background Generator” and “ATM
Traffic Analyzer”.
Tip:Detailed analysis of the physical layer is performed using the “Anomaly/Defect Analyzer”
VI which can be used at the same time as the “ATM Test Results” VI.
2.2“ATM Test Results” main window layout and commands
The “ATM Test Results” main window appears after the VI is loaded. The display area contains
separate windows for the receiver status, QoS results and signaling analysis.
The commands for selecting and arranging the results windows and for outputting data are
found in the menu bar. The main commands are also available as icon buttons in the toolbar.
The “ATM Test Results” main window essentially consists of
• the menu bar and pull-down menus,
• the toolbar and
• the workspace with results window.
OperationO-7
Broadband Analyzer/GeneratorANT-20/ANT-20E
Menu bar and toolbar
Result window/
workspace
Fig. O-9“ATM Test Results” main window
Menu bar
The menu bar contains a range of pulldown menus for selecting the following commands or
groups of commands:
OptionsSelect optional settings for the record file for signaling measurements.
PrintPrint out or export the results.
ViewCustomize the application window.
HelpUse on-line help.
Toolbar
The toolbar buttons provide direct access to the more important functions of the VI:
Functions for arranging the results windows, for printing out and exporting the results. Other
functions for customizing the screen display are found in the menu bar.
Meanings of icons, from left to right (equivalent menu command shown in brackets):
IconMeaning
Cascade the results windows (View - Cascade)
Display rece iver status (View - Receiver Status)
Display Quality of Service parameters (View - Quality Of Service)
After the measurement has been started, the measurement data are written continuously to the
display fields of the individual windows.
After the VI is loaded, the workspace contains the following result windows in their default
configuration:
“Receiver Status”
The “Receiver Status” results window gives a quick overview of the status of the receiver. This
window is always displayed in the workspace, regardless of the current type of test.
(continue)
Fig. O-10“Receiver Status” results window
“Quality Of Service”
The “Quality Of Service” results window (Fig. 11, Page 2-10) shows the ITU-T O.191 QoS
performance parameters. The index cards of the window show detailed, channel-specific
results. The right-hand section of the window is always visible and shows the alarm states for
all channels.
The VI displays the QoS performance parameters of up to four permanent virtual circuits (PVC)
or switched virtual circuits (SVC) simultaneously.
OperationO-9
Broadband Analyzer/GeneratorANT-20/ANT-20E
Fig. O-11“Quality Of Service” results window
“Signaling Analysis”
A record of the signaling is made and displayed in the “Signaling Analysis” window for each
measurement on switched virtual circuits (SVC). The record is saved in a Log File. If the “Log
QoS Parameters” option is activated, the results for the QoS parameters are also saved in the
log file when the circuit is teared down. The results of “ATM Layer QoS (SVC) <...>” type
measurements can be recorded completely in this way. This is particularly useful if an
instrument is operated in “Called” mode without supervision over a long period of time.
Fig. O-12“Signaling Analysis” results window
O-10Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
3ATM Channel Explorer
3.1Introduction
Task
The “ATM Channel Explorer” VI is a tool for observing and interactively analysing activity on an
ATM Link. The Channel Explorer provides various types of “Scans” and “Analyses” for this
purpose.
The selection of the Scan type determines the criteria that the instrument uses to investigate the
data stream that is present. Channels that match the corresponding criteria are recorded in the
VI database and displayed in a list of results.
“Activity” Scan
“Activity” Scan registers all existing virtual channels up to a maximum count of 1000. Important
attributes of the channels are determined, such as VPI/VCI value and various bandwidth
informations. The channels recorded in the database can be subjected to various analyses,
such as AAL type analysis.
“Trouble” Scan
“Trouble” Scan registers all virtual paths (VPs) and virtual channels (VCs) where an alarm state
(AIS or RDI) is present, up to a maximum count of 1000. VP (F4) and VC (F5) layer results are
listed separately.
Requirements
✓ To operate the “ATM Channel Explorer” VI, the “Signal Structure” VI must also be loaded so
that the instrument can be matched to the physical layer. The receiver of the instrument must
be configured for ATM operation to operate the Channel Explorer.
Restrictions
The following virtual instruments cannot be used at the same time as the “ATM Channel
Explorer” VI within an application (applies to ANT-20 only): “ATM Signal Structure”, “ATM
Background Generator” and “ATM Traffic Analyzer”.
The Channel Explorer can only be used if no other measurements have been started with the
Application Manager and no test traffic is enabled.
OperationO-11
Broadband Analyzer/GeneratorANT-20/ANT-20E
3.2“ATM Channel Explorer” window layout and commands
The “ATM Channel Explorer” main window with the result list appears after the VI is loaded.
The commands for configuring and starting the Scan functions are found in the menu bar. In
addition, there are commands to perform analyses, to sort the output and to output results. The
main commands are also available as icon buttons in the toolbar.
Menu bar and toolbar
Results window
e.g. Scan “Activity”
Fig. O-13“ATM Channel Explorer” main window with results list
The “ATM Channel Explorer” main window essentially consists of
• the menu bar and pull-down menus,
• the toolbar and
• the workspace with results window.
Menu bar
The menu bar contains a few simple pulldown menus for selecting the following commands or
groups of commands:
ScanSelect Scan type, start and stop Scan.
AnalyseSelect Analysis type and perform analysis.
SortSelect sort criterion.
OptionsSelect ATM interface.
PrintPrint out or export the Scan results.
ViewCustomise the application window.
HelpUse on-line help.
O-12Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
Toolbar
The toolbar buttons provide direct access to the more important functions of the VI:
• Triggering the Scan function
• Triggering AAL analysis
• Sorting
• Preselecting the interface
• Printing and exporting the results.
Meanings of icons, from left to right (equivalent menu command shown in brackets):
IconMeaning
Start and stop Scan (Scan - Start)
Analyse AAL type in the active channel (Analyse - AAL Type)
Display AAL Type Distribution as a pie chart (Analyse - AAL Type Distribution)
Sort channels by VPI/VCI values (Sort - VPI/VCI)
Sort channels by bandwidth (load) (Sort - Bandwidth)
Delete inactive channels (Options - Aging)
Select UNI (Options - UNI)
Select NNI (Options - NNI)
Print results (Print - Print ...)
Export results (Print - Export ...)
Open on-line help (Help - Contents)
Table O-3Meanings of icons
OperationO-13
Broadband Analyzer/GeneratorANT-20/ANT-20E
3.3Results window
After the Scan has been triggered, the results are saved in the result memory and displayed in
the appropriate results window according to the selected Scan type. The results memory can
store up to 1000 channels per Scan. The results window can only show about 10 channels at
once. The scroll bar at the side of the window can be used to view the remaining channels.
The order of the channels can be changed according to the Sort criterion selected in the “Sort”
menu. The “Print” menu commands allow you to print out and to export the data to other
programs for further processing.
Scan - Activity
The “Scan - Activity” investigates for active channels. The instrument detects every active
channel and enters it in the results list. The results list is expanded until no new channels are
detected or the maximum number of 1000 channels is reached. Each line corresponds to a
channel. The columns in the results list contain the specific attributes of the channel.
Analyse - AAL Type
Detects and displays the AAL types for the active ATM channels.
Analyse - AAL Type Distribution
Determines and displays the distribution of active ATM channels according to AAL type. The
“AAL Type Distribution” window appears showing the current distribution of active channels
according to AAL type:
• Dynamic overview as a pie-chart display
• Quantitative display as a table of percentage values
Fig. O-14“AAL Type Distribution” results window
O-14Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
Scan - Trouble
“Scan - Trouble” checks for channels that are in an alarm state. The instrument detects every
alarm message cell and enters the corresponding channel in the results list. There are two
results windows corresponding to the error management hierarchy:
• F4 window: OAM Flow 4 (VP level)
• F5 window: OAM Flow 5 (VC level)
Fig. O-15“Scan - Trouble” results display
OperationO-15
Broadband Analyzer/GeneratorANT-20/ANT-20E
4Port configurations (topologies) and
Instrument Configuration
VI: ATM Test Control
4.1Overview
To simplify the basic setting of the instrument for ATM measurements, all the fundamental
settings are made from a central dialog. This “Instrument Configuration” dialog handles the
following:
• Selecting the topology (port configuration)
• Configuring the physical layer
• Configuring the ATM layer
• Enabling and configuring signaling emulation
4.2The “Instrument Configuration” dialog
Port configuration
(topology)
Signaling for
switched virtual
circuits
The “Instrument Configuration” dialog is used to set the port configuration or topology for the
measurement task and to match the instrument to the protocol layers used. You can also select
whether permanent (PVC) or switched (SVC) virtual circuits are to be tested. If switched virtual
connections are selected, you can also configure the signaling emulation and set the ATM
address of the instrument in this dialog.
The dialog shows the selected configuration in graphical form along with push buttons that open
further dialogs for a given layer. This is also the case for the physical layer; the “Signal
Structure” VI is opened when the “PHYSICAL” button is clicked, assuming that the “Signal
Structure” VI has been loaded in the current application.
Configuration:
Signaling
Protocol layers
Fig. O-16The “Instrument Configuration” dialog; e.g. with “Emulate” topology and Signaling
O-16Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
The dialog contains the following sections:
SectionMeaning
Port configurationSet the topology (Sec. 4.3,Page O-17)
Tx/Rx ConfigurationMatch the instrument to the protocol layers (Sec. 4.4, Page O-19)
Signaling emulationActivate the signaling emulation
ButtonsConfirm configuratio n for all layers and closes the dialog
Table O-4“Instrument Conf igu r ati on” dia log sect ion s
4.3Port configuration
The radio buttons in the “Port configuration” field are used to set the way in which the instrument
is connected to the device under test (ATM DUT). The following topologies can be selected:
Emulate
The instrument's generator and receiver are connected to the same port of the device under
test. This topology allows emulation with permanent or switched virtual connections. The
“Emulate” topology must be used if signaling emulation is to be used. “Emulate” can only be
selected if the physical layer bit rate and mapping are the same for the generator and the
receiver and if an ATM mapping is selected.
Cancel configuration settings
Fig. O-17Dialog display, if “Emulate” topo logy is selected
OperationO-17
Broadband Analyzer/GeneratorANT-20/ANT-20E
Looped
The instrument's generator and receiver are connected to different ports, with the Tx signal
looped back to the receiver. Using this topology, it is possible to configure the physical layer for
different bit rates or mappings for the generator and receiver. An ATM mapping must, however,
be selected for the Tx and Rx sides.
Fig. O-18Dialog display, if “Looped” topology is selected
Disabled
Pseudo-topology indicating that ATM operation is disabled.
Fig. O-19Dialog display, if “Disabled” option is selected
O-18Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
4.4Tx/Rx Configuration
The buttons in the “Tx/Rx configuration” field are used to configure the individual protocol layers
for the Tx and Rx sides of the instrument.
The buttons have the following meanings:
ButtonMeaning
SERVICE
SIG
AAL
SAAL
ATM
PHYSICAL
1 Actually not implemented.
2 For Emulate topology with signaling emulation.
3 This button is present for both Tx and Rx for Looped topology. It is only present once for Emulate topology.
1
2
1
1
3
3
Configure the ATM service layer
Configure the signaling protocol (Sec.4.5.1,Page O-21)
Configure the ATM adaptation layer
Configure the signaling AAL
Configure the ATM layer (Sec. 4.4.1,Page O-19)
Configure the physical layer (Sec. 4.4.2,Page O-21)
Table O-5Meaning of action buttons
Note:The most important layer-specific settings are shown on each button area.
Buttons for non-relevant layers are disabled.
4.4.1The “ATM Layer” dialog
This sub dialog is used to configure the ATM layer.
a
Fig. O-20The “ATM Layer” sub dialog (“Emulate” topology)
b
c
OperationO-19
Broadband Analyzer/GeneratorANT-20/ANT-20E
The buttons and check boxes have the following meanings:
Radio buttons/Check boxesMeaning
Tx/(Rx) Settings (a)Generator (receiver) side parameters
InterfaceInterface type
Payload ScramblerActivate/deactivate payload scrambler
StuffingType of stuffing cells
Tx => RxCopy Tx settings to the receiver
Tx <= RxCopy Rx settings to the generator
Table O-7Additional buttons (“ATM Layer” sub dialog)
O-20Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
4.4.2“Edit Signal Structure”
The “PHYSICAL” button brings the “Signal Structure” VI to the front if it was previously loaded
using the Application Manager. The relevant parameters such as physical interface, bit rate,
frame structure or mapping, etc. are set from this VI.
This button is provided for both Tx and Rx sides in “Looped” topology. The buttons both perform
the same action.
When the “ATM Test Control” VI has been opened, settings in the “Signal Structure” VI can only
be made via the mentioned “PHYSICAL” button. Direct opening of the “Signal Structure” VI by
the Application Manager will cause disabling most of the edit boxes. This avoids undesired
effects during instrument settings.
Note:Overhead bytes of the physical frame can be configured with the separate “Overhead
Check box unchecked:Only allow permanent virtual connections (PVC).
Note:Signaling can only be activated if “Emulate” topology has been selected.
To configure the signaling, open the “Instrument configuration - Signaling Protocol”
dialog using the “SIG”-button.
4.5.1The “Signaling Protocol” dialog
This dialog is used to configure the signaling and to set the instrument ATM address (own call
address). You should normally always enter an instrument address. This address is used as the
called address in self-c all mo de.
a
b
c
Fig. O-21The “Signaling Protocol” sub dialog
OperationO-21
Broadband Analyzer/GeneratorANT-20/ANT-20E
The buttons and check boxes have the following meanings:
Button/Check BoxMeaning
Protocol (a)Combo box with protocol types: UNI 3.0, UNI 3.1, Q.2931
Associated SignalingCheck box for selecting “Associated Signaling”. This requires that the
Signaling Channel (b)Header value for the signaling channel.
Decimal, Hex.Input format
VPIVirtual path identifier
VCIVirtual channel identifier
RangeDisplay field for VPI/VCI range of values
Instrument Address (c)Address display and button for changing the instrument address
Accessed using the “Change Address” button. The dialog is used to set the instrument address
(own call address ) .
a
b
c
Fig. O-22The “Address Input” sub dialog
O-22Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
The buttons and check boxes have the following meanings:
Button/Check BoxMeaning
Format (a)Address format
Native E.164Option for E.164 format
NSAPOption for NSAP-format
Address (b)Change address for “Native E.164” format or “NSAP” format
Subaddress (c)Change sub-address
Table O-9Parts of “Address Input” dialog
The “Address Input - Native E.164” box
Button/Check BoxMeaning
Button for
Number type:Type of address
international- int ernational
national
1
network specific
subscriber
abbreviated
unknown
1
1
1
1
- national
- network-specific
- subscriber-specific
- abbreviated
- unknown
Numbering plan:Type of numbering plan
ISDN- ISDN standard plan
unknown
1
- unknown plan
Check Box for
E.164 address without prefix
2
edit box for address (without 0 prefix)
Length- Maximum number of characters
1 Not always available, depends on protocol.
2 Decimal.
Table O-10Parts of “Address Input” dialog
OperationO-23
Broadband Analyzer/GeneratorANT-20/ANT-20E
The “Address Input - NSAP” box (not displayed)
Button/Check BoxMeaning
Radio buttons for
AFI
1
Edit boxes for
2
IDI
HO-DSP
2
ESI
2
SEL
Display field
ICD- International Code Designator
DCC- Data Country Code
E.164- Public network code number, as per E.164
E.191- Public network code number (for Q.2931 only), as per E.191
2
Type of address (Authority and Format Identifier)
Initial Domain Identifier
High Order Specific Part
End System Identifier
Selector
LengthNumber of characters for the selected edit box e.g. 4 for ICD-IDI
1 NSAP address: AFI (2 characters) + IDI + HO-DSP + ESI + SEL (length = 40).
2 Hexadecimal.
Table O-11Parts of “Address Input” dialog
The “Sub-address” box (NSAP)
This box is used to set a sub-address.
BoxMeaning
Enable SubaddressEnables sub-address
Subaddress
1
LengthNumber of characters (40)
1 Hexadecimal
Table O-12Parts of “Address Input” dialog
Edit box for sub-address (hexadecimal string)
O-24Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
5Test Types
5.1Overview
“Test types” serve to structure the measurement modes and the so-called connection modes.
A “test type” comprises a measurement mode and a connection mode. The connection mode
defines how the virtual ATM connection is switched.
To allow precise line-up of traffic contracts, facilities must be provided to allow virtual
connections to be switched between two or more test instruments. Some test types are
designed for such configurations involving several test instruments. Software version 6.5
initially only provides support for the “A TM-layer Quality of Service” measurement mode; the
following connection modes are possible:
Connection ModeMeaning
For PVCs
Point-to-PointThe virtual connection is a point-to-point connection between two or more
instruments.
Looped The virtual connection is a looped-back point-to-point connection. The loop-
For SVCs
CallingThe virtual connection is a point-to-point connection between two or more
CalledThe virtual connection is a point-to-point connection between two or more
Self-CallThe virtual connecti on is a loop ed-back po int-to-poin t connect ion in th e ATM
Table O-13
Possible connection modes
back can be either in the ATM layer or in the physical layer.
instruments . The instrument initiates the call (calling instrument).
instruments. T he instrument takes the call (called instrument)
layer. The instrument generates a se lf-call.
The test type is selected in the “Test Setup” dialog of the “ATM Test Control” VI. The
configuration of the instrument determines which of the test types will be available for selection.
Only those test types that are possible and meaningful for the given configuration setting are
displayed for selection.
The table below indicates the test types that can be selected:
Test typeSignaling
activated
ATM Layer QoS - Looped TopologyNoLoopedOnly test type available for
ATM Layer QoS (SVC) - Self CallYesEmulateOnly possible on UNI.
Table O-14Übersicht der wählbaren Test types
activated
(continue)
5.2The “Test Setup” dialog: Settin g the Test Type
The “Test Setup” dialog (see Fig. 23) is used to select the appropriate test type (a) for your
measurement task. Click the “Configure Test” button (c) to configure the test. The extended
“Test Setup <...>” dialog win dow open s.
The “Virtual Channel Setup” box displays the current virtual connection mode as a pictogram
with the channel names as specified in the Channel Editor.
TopologyNotes
Only possible on UNI.
Only possible on UNI.
a
Fig. O-23The “Test Setup” dialog with available test types,
e.g. with types for switched virtual circuits (SVCs)
b
c
d
O-26Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
The “Test Setup” dialog consists of the following sections:
Section Meaning
Test type (a)List of test types, depends on the actual instrument configuration.
Virtual Channel
Setup (b)
Configure Test (c)Button for opening the “Test Setup - <...>” dialog to configure the test.
Action buttons(d)OK: Confirm the selected test type and/or parameter settings in the
1 Names as specified in the Channel Editor
Table O-15“Test Setup” dialog sections
Display of current virtual connection mode as a pic togram with t he channel
1
names
(Sec. 5.9,Page O-32)
“Test Setup - <...>” dialog and return to the main window.
Cancel: Cancel the settings
.
“Point-to-point”, “Calling” or “Called” connection
mode
“Looped” topology
“Looped” or “Self-Call” connection mode
5.3The “ATM Layer QoS - Looped Topology” test type
This test type is intended for ATM layer QoS measurements in Looped topology. This means
that the transmitter and receiver are connected to different ports of the device under test (DUT),
with the Tx signal looped back to the receiver.
Characteristics
• Measurement of permanent virtual connections
(PVC)
• Up to four virtual channels possible
• Cell delay measurements are possible
• Unidirectional or bi-directional channels can be
tested. The parameters for the backward direction are
ignored for bi-directional channels..
Basic instrument settings
• “Looped” topology
The pictogram shown opposite appears in the workspace
of the VI.
OperationO-27
Broadband Analyzer/GeneratorANT-20/ANT-20E
5.4The “ATM Layer QoS (PVC) - Point-to-point” test type
This test type is intended for ATM layer QoS measurements with permanent virtual connections
where channels are to be tested from end to end in both directions. This test is particularly
effective in determining adherence to traffic contracts. Two test instruments are required.
Characteristics
• Measurement of permanent virtual connections
(PVC)
• Up to four virtual channels possible
• Cell delay measurements are not possible
• Bi-directional, symmetrical or asymmetric channels
can be test ed.
Basic instrument settings
• “Emulate” topology
• Signaling emulation “off”
The pictogram shown opposite appears in the workspace
of the VI.
Tip: Configurations using more than two test
instruments are also possible.
O-28Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
5.5The “ATM Layer QoS (PVC) - Looped” test type
This test type is intended for ATM layer QoS measurements with permanent virtual connections
where the virtual channels are to be looped back in the DUT either in the physical layer or in the
ATM layer.
Loop-back in the physical layer
If you select unidirectional channels in the extended
“Test Setup <...>” dialog, this corresponds to a
loop-back in the DUT in the physical layer.
Tip:Only virtual channels with symmetrical
bandwidth can be used with this method.
Characteristics
• Measurement of permanent virtual connections
(PVC)
• Up to two virtual channels possible
• Cell delay measurements are possible
• Bi-directional, symmetrical channels can be tested.
From the point of view of the DUT, the channels are
bi-directional and symmetrical; from the test
instrument point of view, the connection is a
unidirectional loop.
Loop-back in the ATM layer
If you select bi-directional channels in the extended
“Test Setup <...>” dialog, this corresponds to a
loop-back in the DUT in the ATM layer.
Characteristics
• Measurement of permanent virtual connections
(PVC)
• Up to two virtual channels possible
• Cell delay measurements are possible
• Bi-directional, symmetrical or asymmetric
channels can be tested.
Basic instrument settings
• “Emulate” topology
• Signaling emulation “off”
The pictogram shown opposite appears in the
workspace of the VI.
OperationO-29
Broadband Analyzer/GeneratorANT-20/ANT-20E
5.6The “ATM Layer QoS (SVC) - Calling” test type
This test type is intended for ATM layer QoS measurements with switched virtual connections
where channels are to be tested from end to end in both directions. Two test instruments are
needed for the test, one acting as calling party and the other as called party. The instrument
configured with this test type is the calling party.
This test is particularly effective in determining adherence to traffic contracts.
Characteristics
• Measurement of switched virtual connections (SVC)
• Up to four virtual channels possible
• Cell delay measurements are not possible
• Bi-directional, symmetrical or asymmetric channels
can be test ed.
Basic instrument settings
• “Emulate” topology
• Signaling emulation “on”
The pictogram shown opposite appears in the workspace
of the VI.
Tip: Configurations using more than two test
instruments are also possible.
5.7The “ATM Layer QoS (SVC) - Called” test type
This test type is intended for ATM layer QoS measurements with switched virtual connections
where channels are to be tested from end to end in both directions. Two test instruments are
needed for the test, one acting as calling party and the other as called party. The instrument
configured with this test type is the called party.
This test is particularly effective in determining adherence to traffic contracts.
When the instrument accepts the call, it automatically configures its transmitter according to the
contract parameters contained in the incoming Setup Message. The instrument then starts
generating traffic (if traffic generation has been enabled by the user) and measuring the QoS
parameters. Traffic generation ceases after the call is cleared down.
The instrument can be called as often as is required, but it can accept a maximum of four calls
at one time. The calls can come from different (ANT-20) instruments at the far end operating in
“Calling” mode.
The signaling processes and connection states are saved in a log file and displayed in the “ATM
Test Results”. The measured QoS parameters can also be saved optionally in the log file.
O-30Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
Characteristics
• Measurement of switched virtual connections (SVC)
• Up to four virtual channels possible
• Cell delay measurements are not possible
• Bi-directional, symmetrical or asymmetric channels
can be tested.
Basic instrument settings
• “Emulate” topology
• Signaling emulation “on”
The pictogram shown opposite appears in the workspace
of the VI.
Tip:Configurations using more than two test
instruments are also possible.
5.8The “ATM Layer QoS (SVC) - Self Call” test type
This test type is intended for ATM layer QoS measurements with switched virtual connections.
It is a self call, with the connection being looped back in the DUT in the ATM layer.
Characteristics
• Measurement of switched virtual connections (SVC)
• Up to two virtual channels possible
• Cell delay measurements are possible
• Bi-directional, symmetrical or asymmetric channels
can be tested.
Basic instrument settings
• “Emulate” topology
• Signaling emulation “on”
The pictogram shown opposite appears in the workspace
of the VI.
OperationO-31
Broadband Analyzer/GeneratorANT-20/ANT-20E
5.9The “Test Set up <...>” dialog: Configure test type
The extended “Test Setup <...>” dialog is used to configure the test type and to match it to your
measurement task. The test channels are represented here by index cards, e.g. “Channel A”,
“Channel B”, etc. The index card labels are determined by the selected test type.
Virtual channels that you define in the “Channel Editor” are shown in a selection list. You can
assign certain virtual channels from this stock of channels to the test channels A, B, etc. When
you assign a virtual channel to a test channel in this way, all the corresponding parameters will
be assigned to the test channel on the current index card in a single step. The first time that you
open the dialog, the edit boxes on the index cards will be empty as no assignment has yet been
made. This status is indicated in the selection list by the item <disabled>.
As a large number of parameters are required for complete definition of a channel (contract
parameters, source parameters, etc.) only the most important parameters are shown on the
index cards. You can overwrite these parameter values directly, without altering the standard
definition of the channel in the “Channel Editor”. To view all the parameters for the virtual
channel, call up the “Channel Editor” by clicking on the “Channel Editor” button.
a
b
c
Fig. O-24Extended “Test Setup <...>” dialog
d
e
f
O-32Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
The “Test Setup <...>” dialog may include the following sections:
SectionMeaning
Select channel (a)Select pre-defined test channels (see Sec. 5.9.1)
Channel Editor ... (b)Push button: Open the Channel Edit or
Source Parameters (c)Set the source parameters
1
Header (d)
- or -
Called party address
- or -
Own instrument address
Multiplexer (e)Display field: Information about the ATM traffic multiplexer
CLOSE (f)Push button: Confirm the settings and returns to the
1 Input for PVCs
2 Input for SVCs in “Calling” mode
3 For SVCs in “Self Call” mode
Table O-16Section of the dialog “Test Setup <...>”
Set the cell header parameters
Display / set the called party address
Display field: Own instrument address
“Test Setup” dialog.
.
2
.
3
.
Certain relationships exist between parameters which depend on the current configuration. This
means that the choice of parameters will not always be the same. To preserve clarity, the index
cards only include the parameters that are relevant to the actual configuration or test type.
Parameters that cannot be edited, and which are for information only, are grayed out. In
particular,
• all index cards are empty in “Called” mode
• the index cards for the backward path are empty in “Self-Call” mode
• the index card for the backward path for the “A TM Layer QoS (PVC) - Looped” test type does
not include a “Selected channel” box.
Parameter settings can only be made if the test traffic is disabled (“Test - Traffic Enable” must
be deactivated).
5.9.1Select channel
The “Select channel” list box contains a selection of virtual channel types that can be used to
rapidly configure the test channels. The list is arranged in order of traffic type.
To preserve clarity, only those channel types that can be used with the current instrument
configuration are shown in the list box, e.g. if a test type for permanent virtual connections
(PVC) has been selected, no channels will be listed which are defined as switched virtual
connections (SVC).
Fig. O-25List box with pre-selected virtual channel types
OperationO-33
Broadband Analyzer/GeneratorANT-20/ANT-20E
5.9.2Header
The items in the list are arranged in alphabetical order of traffic type. The following traffic types
are available:
DisabledNo test channel assigned; test channel is disabled
CBRConstant bit rate traffic
VBR-RTReal-time variable bit rate traffic
VBR-nRTNon real-time variable bit rate traffic
DBRDeterministic bit rate traffic
SBRStatistical bit rate traffic
UBRUnspecified bit rate traffic
The “Header” field is used to define the test cell header for permanent virtual connections
(PVC). Generally, the header values for the Tx and Rx sides are set separately.
The edit boxes and radio buttons have the following meanings:
Button/BoxMeaning
FormatRadio buttons for selecting the VPI/VCI format
DecimalInput and display of the numerical values for Tx and Rx as decimal numbers
Hex.Input and display of the numerical values for Tx and Rx as hexa decimal numbers
TxTx side header values
UNI/NNIDisplay indicating the inter face to which the paramet ers apply
GFCGeneric Flow Control (for UNI only)
• for “Native E.164” format (Sec. 4.5.1, Page O-21)
• for “NSAP” format (Sec. 4.5.2, Page O-22)
Table O-18“Called party address” dialog sections
5.9.4Own instrument address
This field is used to display the instrument's own ATM address as set in the instrument
configuration. This address is used as the call address in self-call mode.
The “Source Parameters” field is used to set the source parameters. These determine the load
conditions for the channel (Peak Cell Rate, Mean Cell Rate) and the jitter and burst
characteristics. When you select a test channel, the source parameters will be initialized with
the default values pre-defined in the “Channel Editor”.
Each source parameter has its own increment / decrement buttons for entering the parameters.
The units are selected from the adjacent list boxes.
The “Source Parameters” field consists of the following sections:
:
SectionMeaning
Peak Cell RatePeak cell rate (load) in Mbps, kbps or cps (cells/s).
Mean Cell Rate
Cell JitterCell jitter in ms or µs.
Burst Size
Shape to contract
1
1
Mean cell rate (load) in Mbps, kbps or cps (cells/s).
Burst size in ms or µs.
2
Check box: Activate traffic shaper.
Set DefaultPush button: Sets the source parameters to the pre-defined values on the
Set Maximum
1 Not always available; depends on source type
2 Not always available; depends on conformance definition
Table O-20Source Parameters
2
“Traff ic Source” (Chan nel Editor) index card.
Push button: Sets the source parameters to their maximum possible values.
These are determined by the traffic contract.
With regard to the generated cell rate, the traffic generator has a high resolution range (for low
cell rates) and a low resolution range (for high cell rates). If the low resolution range is active,
the arrow keys for the lowest value digit of the increment / decrement keypad are highlighted in
yellow.
The source parameters are interdependent, i.e. you cannot set a mean cell rate that is higher
than the peak cell rate. Cell jitter and burst size are limited by the characteristics of the traffic
generator. If a parameter value cannot be set as required, this may be due to the set values of
other parameters. It is a good idea to set the parameters in the following order:
• Mean and peak cell rates
• Burst size
• Cell jitter
The maximum values for burst size and cell jitter are limited and depend on the settings of other
parameters. Where appropriate, the burst size and cell jitter settings will be reduced
automatically by the instrument.
O-36Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
5.9.6Multiplexer
The entries made in the “Multiplexer” field have the character of a preview (traffic prediction)
since the generator is not yet active during the setup. This makes it possible to set up the
generator exactly before starting the measure men t.
5.9.7Channel labeling
In
• Looped and
• Self Call
Connection Modes, the instrument generates traffic on up to two channels in both directions.
The channels are then labeled as follows on the index cards and in the Multiplexer field:
Channel A =>Channel A, forward direction
Channel A <=Channel A, backward direction
Channel B =>Channel B, forward direction
Channel B <=Channel B, backward direction
In the other Connection Modes, the instrument generates traffic on up to four channels in one
direction. The channels are labeled as follows:
Channel AChannel A
Channel BChannel B
Channel CChannel C
Channel DChannel D
OperationO-37
Broadband Analyzer/GeneratorANT-20/ANT-20E
6Defining Virtual Channels
VI: ATM Test Control
6.1Overview
Virtual channel
The term “virtual channel” is central to ATM technology. A virtual channel is basically
characterized by
• The type of virtual connection: switched (SVC) or permanent (PVC)
• The direction: unidirectional or bi-directional
• The virtual channel number (VPI/VCI) for permanent virtual connections or the ATM address
for switched virtual connections
• The traffic contract which is basically defined by the “Conformance Definition”, the “Traffic
Descriptor” and the “Quality of Service” class
• The AAL type
• For a measurement task it is usually also necessary to assign the channel to a traffic source
which is defined by the source type and the source parameters.
As can be seen, a large number of parameters are used to fully define a virtual channel. The
“Channel Editor” tool in the “ATM Test Control” VI has been provided to keep operations
involving virtual channels as simple as possible.
The “Channel Editor” allows you to define, modify and copy channels. Each channel definition
can be assigned a user-defined name.
Database
A channel database is included in the “Channel Editor”. This database is used to exchange
channel definitions between applications and instruments.
One database is available per instrument. When a channel is used in an application, a copy of
the channel is saved with the application. Each time the application is loaded, the instrument
checks that the copy is identical to the channel definition in the database, or if the channel is still
present in the database. If differences are found, the “Channel Import” dialog is displayed. This
allows you to remove any inconsistencies between the application and the database. As a copy
of each channel used is present in the application, the channels will automatically be exported
when an application is exported to another instrument. These channels can be included into the
database of the other instrument when the application is started there for the first time.
6.2The “Channel Editor” dialog
The Channel Editor is used to define virtual channels and save them in a database. Push
buttons and a list box in the dialog window header are used for defining and handling the
channels. When first used, the list contains a range of default virtual channels for the usual
types of traffic (CBR, VBR, etc.). These channels can be saved under a new name and edited
individually.
Access to the various parameter groups is by means of index cards.
O-38Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
a
b
c
Fig. O-26The “Channel Editor” dialog
The dialog contains the following sections:
SectionMeaning
Header (a)
ChannelList box
2
Save
NewCreates a new virtual channel.
DeleteDeletes the marked virtual channel from the database.
3
Check
Index cards (b)
General
Header/Address
Traffic Contract
Traffic Contract (con't)
Traffic Source
Buttons (c)
Help
CLOSE
1 Arranged in alphabetical order
2 Not available for write-protected virtual channels with names beginning with “W&G...”
3 A check is made to see if the channel can be assigned to a test channel in the current instrument configuration.
Saves the virtual channel in the database under the current name
Checks the channel for consistency with the current configuration.
For entering general channel parameters
For entering header information or addresses
For entering main traffic contract parameters
For entering further traffic contract parameters
For entering source parameters
Push button: Calls up on-line Help.
Push button: Closes the dialog.
1
listing all saved virtual channels.
Table O-21Sections of the “Channel Editor” dialog
OperationO-39
Broadband Analyzer/GeneratorANT-20/ANT-20E
6.3Parameter display and modification (index cards)
6.3.1The “General” index card
This index card defines the general parameters for the virtual channel selected in the “Channel”
list box.
a
b
Fig. O-27The “General” index card (Channel Editor)
c
d
e
The radio buttons have the following meanings:
ButtonMeaning
Traffic Type (a)Available traffic types (type of traffic contract)
CBR• constant bit rate
VBR - nRT• variable bit rate (non real time)
VBR - RT• variable bit rate (real time)
CBR• unspecified bit rate
UBR• deterministic bit rate
SBR• statistic al bit rate
Direction type (b)Available channels (forward / backward)
1 For PVCs only
2 Forward and backward parameters are identical (see “Traffic Contract”, “Traffic Contract (con´t)” and “Traffic
Source” index cards)
3 Only with switched connections
3
User defined• Setup message contains the inf orm atio n e lem en t “Use r defined
None• Setup message contains no AAL information element.
1
2
• unidirectional
• bidirectional (symmetrical)
Channel assignement to Adaptation Layer
AAL”.
Table O-22Radio buttons of the “General” index card
O-40Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
6.3.2The “Header/Address” index card
This index card defines the default header values or the default ATM address of the selected
channel, depending on whether a permanent (PVC) or a switched (SVC) channel is selected:
• PVC: Set default header
• SVC: Set default Called Party Address
You can overwrite the default values during configuration of the test type (in the “Test Setup”
dialog) to match them to your measurement task.
Default Header
a
cb
Fig. O-28The “Header/Address” index card when using permanent virtual circuits: Default Header
The radio buttons and edit boxes have the following meanings:
Button/BoxMeaning
Format (a)Radio buttons for selecting the VPI/VCI format.
DecimalTx and Rx numerical values entered and displayed as decimal numbers
Hex.Tx and Rx numerical values entered and displayed as hexadecimal numbers
(b)Tx (Rx) side header values
UNI/NNIInput of interface type
GFCGeneric Flow Control (for UNI only)
1
VPI
1
VCI
CICongestion Indicator
CLPCell Loss Priority (High = 1, Low = 0)
(c)Rx side header values
Separate RxCheck box for setting Rx side separately
UNI/NNIInput of interface type
1
VPI
1
VCI
RangeRange of values for GFC, VPI, VCI
1 If “Separate Rx” is not activated, the Tx values will be used
Address display and action button for editing the default called party
address of the channel.
• for “Native E.164” format (Sec. 4.5.2, Page O-22)
• for “NSAP” format (Sec. 4.5.2, Page O -22)
Table O-24Display fields and other operating elements of the “Header/Address” index card
You can only assign a channel in the “Test Setup” dialog if the set signaling protocol is
compatible with the actual instrument configuration; i.e. it is not possible to assign a channel
defined for Q.2931 if the instrument is configured for UNI 3.1.
O-42Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
6.3.3The “Traffic Contract” index card
This index card defines the channel traffic contract parameters. The possible entries depend on
the selected traffic type. The index card contains the following sections:
Fig. O-30The “Traffic Contract” index card (Channel Editor)
The index card contains the following sections:
SectionMeaning
Conformance Definition: Radio button for selecting the conformance definition
1
None
- No conformance definition
CBR.1, VBR.1 ...- Conformance definition, selection depends on traffic type
Info- Information window for conformance definition
Use MBSActivates / deactivates entry of maximum burst size parameter (in
cells) instead of burst tolerance.
Forward/Backward Traffic Des. Contract parameters for forward / backward direction
Peak Cell Rate- Peak cell rate
CDVT peak- Cell dela y variation tolerance, referred to the peak cell rate
Sustainable Cell Rate
Burst Tolerance
Maximum Burst Size
CDVT sustained
2
2
3
2
Additional action buttons for bi-directional asymmetric channels
- Sustainable cell rate
- Burst-tolerance
- Cell delay variation tolerance, referred to the sustainable cell ra te
4
Forward => BackwardCopies the forward parameters to the backward direction
Forward <= BackwardCopies the backward parameters to the forward direction
Forward<> BackwardExchanges the forward and backward direction parameters
1 For PVC only (SVC always require conformance definition)
2 Not always available, depends on traffic type
This box is only available instead of “Burst Tolerance” if “Use MBS” is activated.
3
4 See “General” index card; the buttons only affect the relevant index card.
Table O-25Sections of the “Traffic Contract” index card (Channel Editor)
OperationO-43
Broadband Analyzer/GeneratorANT-20/ANT-20E
6.3.4The “Traffic Contract” index card (continued)
This index card defines the extended part of the contract parameters for the channel. The
possible entries depend on the selected connection type (PVC, SVC).
Fig. O-31The “Traffic Contract (con’t)” index card (Channel Editor)
The index card contains the following sections:
SectionMeaning
Conformance Definition
CBR.1Display of selected conformance definition.
Forward/Backward QoS ParametersQuality of Service class for forward / backward direction
Class 0 - UnspecifiedClass 0: No quality of service specified
Class 1
Class 2
Class 3
Class 4
1
1
1
1
Additional action buttons for bi-directional asymmetric channels
Class 1
Class 2
Class 3
Class 4
2
Forward => BackwardCopies the forward parameters to the backward direction
Forward <= BackwardCopies the backward parameters to the forward direction
Forward<> BackwardExchanges the forward and backward direction parameters
1 For SVC only
2 See “General” index card; the buttons only affect the relevant index card
Table O-26Sections of the “Traffic Contract (con’t)” index card (Channel Editor)
O-44Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
6.3.5The “Traffic Source” index card
This index card is used to set the default source parameters for the channel.
a
b
Fig. O-32The “Traffic Source” index card (Channel Editor)
The index card contains the following sections:
:
SectionMeaning
Source type (a) Source type
On-Off- On / off source
Constant bit rate- Constant bit rate source
Forward/Backward Default
Source parameters for forward / backward direction
Parameters (b)
Peak Cell Rate- Peak cell rate
Cell Jitter- Cell delay variation tolerance, referred to the peak cell rate
Mean Cell Rate
Burst Size
1
1
Additional action buttons for bi-directional asymmetric channels
- Sustainable cell rate
- Burst-tolerance
2
Forward => BackwardCopies the forward parameters to the backward direction
Forward <= BackwardCopies the backward parameters to the forward direction
Forward<> BackwardExchanges the forward and backward direction parameters
1 Not always available, depends on source type
2 See “General” index card; the buttons only affect the relevant index card
Table O-27The sections of the “Traffic Source” index card (Channel Editor)
OperationO-45
Broadband Analyzer/GeneratorANT-20/ANT-20E
Notes:
O-46Operation
ANT-20/ANT-20EBroadband Analyzer/Generator
Application Guide
1The Application Manager
Starting point
The instrument has been started. After booting up, the “Application Manager” appears on the
screen (“ANT20 - <Application Title>” window). The “Application Title” window is the central
control for the instrument. It is used to control and manage the measurement applications and
the results that they generate, and to control the measurement sequence. Remember that the
various virtual instruments (VIs) can be selected and the desired maximum measurement time
can be set from here.
Fig. A-1The “ANT20 <Application Title>” window as “Minibar”
1.1Selecting the Instruments for ATM Applications
An ATM application consists of at least the following VIs in addition to the “Signal Structure” VI:
• ATM Test Control and ATM Test Results, or
• ATM Channel Explorer, or
• all three of the above instruments.
The “Signal Structure” VI is needed for making interface settings or measurements on the
physical layer (offset, level). It does not have to be saved along with the other VIs if this
information is not required or if the interface characteristics do not need to be altered.
To select the instruments for your application
1. Click the above icon in the “Toolbar” of the Application Manager.
The “Add & Remove Instruments” dialog window opens.
2. Click on the check box(es) in the “Instrument group” section, which no VI(s) shall be loaded
from. Consequently deactivate the “Physical Layer” (1) and “ATM Standard” (2) options for
your ATM applications. The “Instruments available” list box will contain a reduced, more
clearly arranged selection of “ATM Advanced” instruments.
3. Select the first VI (e.g. AT M Test Control) from the “Instruments available” list box.
4. Click the “Add>>” button.
The “ATM Test Control” VI is placed in the “Instruments used” list box.
5. Select the other VIs required as per steps 3 and 4.
6. Click the OK button.
The main windows of the three VIs are displayed on the screen and the corresponding
buttons are displayed in the Application Manager (Minibar).
Fig. A-2Application Manager after selection of VIs
Application GuideA-1
Broadband Analyzer/GeneratorANT-20/ANT-20E
Fig. A-3“Add & Remove Instruments” dialog after adding the desired virtual instruments
(Preselection: ATM Advanced)
1.2Starting and Stopping the Measurement
✓ Before starting the measurement, the traffic button in the Application Manager is set to
“green”.
Starting the measurement
⇒ Click on the traffic signal button.
– The measurement will be carried out with the parameters, set in the “Measurement
Settings” dialog (Application manager)
– The traffic button display will change from “green” to “red”
– The status display will change from <Stopped> to <Running>.
– The measurement will be stopped automatically after the Gate time run down.
A measurement can also be stopped manually.
Stopping a measurement manually
⇒ Click on the traffic signal button again.
The measurement will be stopped.
A-2Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
2ATM Layer Quality of Service Measurements (SVC)
2.1Overview: Basic operating sequence
The following section lists all the necessary steps, from loading the application, basic
configuration settings via defining the test traffic to the results display. Further information on
the operating sequences is found in the corresponding sub-sections (see the “More” column).
Please note the settings that apply to more than one VI. The VI icons used in the Application
Manager are shown in the left-hand column as an aid to orientation.
VIOperating stepMore information
1. Select the virtual instruments for the ATM application
(ATM Test Control, ATM Test Results, Signal Structure)
2. Configure instrument
Set topology, physical layer, ATM layer and, where appropriate,
signaling.
3. Select test type
4. Configure test type
Set test type,traffic type, source parameters, call address.
5. Enable/disable test traffic
6. Prepare results recording
• Arrange results windows
• Activate Log-file if necessary
7. Start measurementSec. 1.2,Page A-2
8. Displaying and recording results “online”
• Signaling informations
• QoS Performance parameters
• Receiver status
9. Change test parameters “on-line”
Alter source parameters and observe ef fects in the “A TM Test Resul ts”
window.
10. Insert errors
Insert errors and observe effects in the “ATM Test Results” window.
Sec. 1.1,Page A-1
Sec. 2.3.1,Page A-5
Sec. 2.3.2,Page A-9
Sec. 2.3.3,Page A-10
Sec. 2.4,Page A-12
Sec. 2.7.1,Page A-15
Sec. 2.7,Page A-15
Sec. 2.5,Page A-13
Sec. 2.6,Page A-14
11. Stop measurement Sec. 1.2,Page A-2
12. Final results
• evaluate
• store
• export
• print
Table A-1Overview: ATM Layer Quality of Service Measurement (SVC)
see
“ATM Test Results”
on-line help
Application GuideA-3
Broadband Analyzer/GeneratorANT-20/ANT-20E
2.2Test setup and description
Chapter 2 takes you step by step through the procedure for ATM layer QoS tests. The
procedure is based on a configuration with terminal emulation and signaling, to allow switched
virtual connections (SVCs) to be tested. The example selection of an end-to-end measurement
requires the use of a second instrument. The operating steps described apply to the left-hand
instrument in “Calling” mode.
Fig. A-4Test setup for switched point-to-point connection
2.3Application settings
VIs required
• ATM Test Control
• ATM Test Results
• Signal Structure
⇒ Add the VIs required to the list of VIs used in the Application Manager.
The Application Manager should include at least the following instruments (see Fig. A-5):
Fig. A-5“Application Manager” (Minibar) with ATM-Instruments
A-4Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
2.3.1Configuring the Instrument: “ATM Test Control” VI
⇒ Click on the icon button of the “ATM Test Control” VI in the minibar (Application Manager)
(see Fig. A-5).
The “ATM Test Control” main window appears on top (see Fig. A-6).
I
Fig. A-6“ATM Test Control” main windows with last setting
The “ATM Test Control” VI is used to configure the instrument and to select a test type and its
configuration (see Sec. 2.3.2).
The instrument configuration covers the selection of the connection configuration (topology),
settings for the various protocol layers - in particular of the ATM and higher layers - and the
selection of the connection type (“permanent” or “switched”).
To configure the instrument
⇒ Click this icon button
The “Instrument Configuration” dialog window opens.
A
B
C
D
E
Fig. A-7The “Instrument Configuration” dialog
Application GuideA-5
Broadband Analyzer/GeneratorANT-20/ANT-20E
A) To set the topology
⇒ Select the “Emulate” option in the “Port configuration” field to allow activation of signaling
emulation.
“Emulate” can only be selected if the physical layer is set to the same bit rate and mapping for
both generator and receiver; see D.
B) To enable signaling emulation
⇒ Check the “Signaling emulation” check box.
A check appears in the check box.
C) To configure the ATM layer
1. Click the “ATM” button.
The “Instrument Configuration - ATM Layer” dialog window opens.
2.
3.
4.
5.
Fig. A-8The “Instrument Configuration - ATM Layer” sub dialog
2. Select the interface corresponding to the actual measurement connection of the instrument
by means of the “Interface” option buttons. If signaling is used, only the UNI interface type
for terminal equipment is available.
3. Check the “Payload Scrambler” check box if the test cell payload is to be scrambled.
4. Select the type of justification cells using the “Stuffing” option buttons:
– “Idle Cells” or “Unassigned Cells”.
5. Click the CLOSE button to confirm the configuration of the ATM layer; this returns you to the
“Instrument Configuration” dialog.
D) To configure the physical layer: VI “Signal Structure”
Example: STM-1, C-4 mapping
✓ The “Instrument Configuration” dialog is open.
⇒ Click the “PHYSICAL” button.
The VI “Signal Structure” opens.
1.
Fig. A-9The “Signal Structure” main window
A-6Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
1. Click the toolbar icon or the “Edit - Signal Structure...” menu command
The “Edit Signal Structure” dialog window of the “Signal Structure” VI opens. The signal
structure is set column by column using the corresponding buttons.
2. 4.3.5.
Fig. A-10The “Signal Structure” window and “Edit Signal Structure - TX” dialog
2. Click the “TX” button to configure the transmitting side.
3. Set the signal structure, e.g. “ITU-T”, “Normal”, “STM-1”, “AU4”, “VC4” and “ATM” by clicking
the appropriate buttons.
4. Click the “TX=>RX” button.
This sets the receiving side to the same settings as the transmitting side.
5. Confirm the input by clicking “OK”. this returns you to the “Instrument Configuration” dialog.
E) To configure the signaling
✓ The “Instrument Configuration” dialog is open.
1. Click the “SIG” button.
The “Instrument Configuration - Signaling Protocol” dialog window opens.
2.
3.
4.
5.
Fig. A-11The “Instrument Configuration - Signaling Protocol” sub dialog
2. Select the required item, e.g. “Q.2931” in the “Protocol” list box.
3. Select the input format, e.g. “Decimal” using the option buttons.
4. Edit the VPI and VCI values in the entry boxes.
The available range is shown under “Range”.
Application GuideA-7
Broadband Analyzer/GeneratorANT-20/ANT-20E
Option “Change own address”
5. Click the “Change Address” button if you want to alter the address of the instrument.
The “Address Input” dialog window opens.
9.
6.
7.
9.
Fig. A-12The “Address Input” dialog
6. Select the address format, e.g. Native E.164.
7. Select the type of code number, e.g. International.
8. Select the type of numbering plan, e.g. ISDN.
9. Set the address or dialling number (without 0 prefix).
The maximum number of digits is shown under “Length”.
10.Click the CLOSE button to confirm the address.
This returns you to the “Signaling Protocol” or “Instrument Configuration” window.
8.
A-8Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
2.3.2Selecting the Test Type: “ATM Test Control” VI
The “Test types” available for selection are used to structure the measurement and connection
types or so-called “Connection modes”. They are arranged according to protocol layers, with
only the ATM layer currently supported. Only those test types that are possible and meaningful
for the selected instrument configuration are available for selection.
To select and configure the test type required for your measurement task
✓ The instrument is configured for Emulate topology with switched virtual connections (SVCs).
✓ The “ATM Test Control” main window is open.
⇒ Click on this icon button or select the “Test - Setup...” menu command.
The “Test Setup” dialog window opens.
1.
Fig. A-13The “Test Setup” dialog
1. Select the desired test type from the “Test type” list box,
e.g. “ATM Layer QoS (SVC) - Calling”
2. Click the “Configure Test” button.
The “Test Setup <...>” dialog window opens (see Sec. 2.3.3).
– or –
Click the OK button if the pre-defined test type is to be used.
This returns you to the main window.
2.
Fig. A-14The “ATM Test Control” main window
Application GuideA-9
Broadband Analyzer/GeneratorANT-20/ANT-20E
2.3.3Configuring the Test Type: “ATM Test Control” VI
To configure the test type required for your measurement task
✓ The first index card for “Channel A” has been selected
1. In the “Select channel” list, mark the virtual channel that you want
first
to assign to the
test channel:
e.g. with the designation “CBR_Voice” (constant bit rate voice traffic).
The corresponding parameter values are shown on the index card.
2. Click on the index card for the
second
channel, e.g. “Channel B”.
The index card moves to the front.
3. In the “Select channel” list, select the virtual channel that you want to assign to the second
test channel e.g. with the designation “CBR_Data” (constant bit rate data traffic).
The corresponding parameter values are shown on the index card.
2.
1.
3.
Fig. A-16Assigning virtual channels to your test type
Note:
• The “Select channel” list contains just a few standard channels when it is first opened.
• Virtual channels can be used more than once, i.e. on more than one index card.
A-10Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
B) Entering the address of the called instrument
✓ The “Test - Setup <...>” dialog is open.
✓ The instrument is configured for SVCs.
1. Click the “Change Address” button.
The “Address Input” dialog window opens.
2.
3.
Fig. A-17The “Address Input” dialog
5.
4.
2. Select the address format, e.g. Native E.164.
3. Select the type of code number, e.g. International.
4. Select the type of numbering plan, e.g. ISDN.
5. Set the address or dialling number (without 0 prefix).
The maximum number of digits is shown under “Length”.
6. Click the CLOSE button to confirm the address.
This returns you to the “Test - Setup <...>” window.
C) Changing the source parameters, e.g. Peak Cell Rate
a) Click the arrow key to increase the parameter value in decades.
– or –
b) Click the arrow key to decrease the parameter value in decades.
c) Open the list box if the units are to be changed, and select the appropriate list entry (e.g.
kbps).
a
b
Fig. A-18Changing the source parameter
c
Application GuideA-11
Broadband Analyzer/GeneratorANT-20/ANT-20E
Removing a test channel, if necessary
1. Click on the index card of the channel that you want to remove, e.g. “Channel B”.
The index card showing the current channel and traffic type will move to the front.
2. Click on “<disabled>” in the “Select channel” list.
“Channel B” will be removed from the current test traffic.
1.
2.
Fig. A-19Removing test channel
2.4Enabling and Disabling Test Traffic: “ATM Test Control” VI
✓ The “ATM Test Control” main window is open.
To enable the test cell stream
⇒ Click the above icon in the “Toolbar” .
– or –
⇒ Select the “Test - Traffic Enable” menu command.
Test traffic will be enabled.
To disable the test cell stream
⇒ Click the above icon in the “Toolbar” again.
– or –
⇒ Select the “Test - Traffic Enable” menu command again.
Test traffic will be disabled.
Note:Test traffic:
– For SVC: Only after the connection is set up
– For PVC: Immediately after clicking the “TRAF ON” button.
A-12Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
2.5Editing Test Parameters “On-Line”: “ATM Test Control” VI
Opening the “Online Control” dialog window
✓ The “A TM Test Control” main window is open.
⇒ Click the above icon button of the toolbar.
– or –
⇒ Select the “Test - Online Control” menu command.
The “Test Online Control - ATM Quality of Service...” dialog window opens.
The source parameters which can be altered during traffic generation can be accessed and
can be edited channel by channel: “Peak Cell Rate”, “Mean Cell Rate”, “Cell Jitter” and
“Burst Size”.
f
a
bcd
Fig. A-20“Test Online Control” dialog, eg. for test type
“ATM Quality of Service ATM Layer QoS (SVC) - Calling”
e
a) Click on the index tab of the virtual channel required (e.g. Channel A ...).
The test parameters for the channel are placed on top.
b) Change the parameter (e.g. Peak Cell Rate) continuously using the arrow keys.
– or –
c) Set the default parameter value by clicking the “Set Default” button.
– or –
d) Set the maximum parameter value by clicking the “Set Maximum” button.
e) Open the list box if the units are to be changed, and select the appropriate list entry (e.g.
kbps).
f) Activate the “Shape to contract” check box if the Traffic Shaper is to be activated.
Application GuideA-13
Broadband Analyzer/GeneratorANT-20/ANT-20E
2.6Inserting Errors: “ATM Test Control” VI
Opening the “Error Insertion” dialog window
✓ The “ATM Test Control” main window is open.
⇒ Click the above icon button of the toolbar.
– or –
⇒ Select the “Test - Error Insertion” menu command.
The “Test Error Insertion ATM Quality of Service” window opens.
The error criteria required for the measurement task can be inserted in each test channel
separately.
a
bc
Fig. A-21The “Test Error Insertion” dialog for ATM Quality of Service
a) Click on the tab index for the virtual channel required (e.g. Channel A ...).
The action buttons for the various error types are placed on top.
b) Insert an anomaly (e.g. “Severely Errored Cell Block) by clicking the “Insert” button (next to
“SECB”).
Each time the button is clicked, the anomaly will be inserted into the test cell stream.
c) Insert an alarm (e.g. “Virtual Path Remote Defect Indication”) by clicking the “OFF” button
(next to “VP-RDI”).
The alarm criterion is now set for the virtual channel and the button label changes from OFF
to ON (toggle function). Also, all alarms set for the channels are listed in the “Selected
alarms” box.
The alarm remains set until the test cell stream is switched off or the “ON” button is clicked
to turn the alarm OFF.
A-14Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
2.7Displaying the Results: “ATM Test Results” VI
Fig. A-22Application manager
⇒ Click the icon button for the “ATM Test Results” VI in the minibar.
The “Test Results” window is displayed on top.
After the VI has booted up, the work area contains the following results windows:
• Receiver Status: This window indicates the receiver status
• Quality of Service: This window indicates the QoS performance parameters as per ITU-T
O.191. The results are displayed for up to four test channels: Cell Error Ratio, Cell Loss
Ratio, Cell Misinsertion Rate, Mean Cell Transfer Delay, etc.
• Signaling Analysis: This window indicates the results of signaling analysis.
2.7.1Preparing to Record Results
Arranging the results windows for the application
Normally, the three results windows are displayed in a space-saving cascade arrangement.This
arrangement can be altered as required and restored at any time.
⇒ Click the above icon button of the toolbar.
– or –
⇒ Select the “View - Cascade” menu command.
The three results windows are displayed in the default arrangement.
Fig. A-23Results window “Signaling Analysis”
Application GuideA-15
Broadband Analyzer/GeneratorANT-20/ANT-20E
The “Signaling Analysis” is on top when the configuration selected is for switched virtual
connections (SVC). This allows you to follow the signaling sequence right from when the call is
being set up. The window is not displayed for configurations with permanent virtual connections
(PVC) since it has no meaning in this context.
After the measurement is started (Sec. 1.2,Page A-2), all data events are written continuously
as they occur to the display fields of the windows. The “Print” menu commands can be used
once the measurement has ended to print out the data or export it for further processing with
other programs.
2.7.2Displaying the Signaling Analysis
For each measurement involving switched virtual connections (SVC), a record of the signaling
is made and is displayed in the “Signaling Analysis” window. This record is also saved as a log
file. If the “Log QoS Parameters” option is activated, the QoS parameter results will also be
saved in the log file when the connection is cleared down. This permits the making of a
complete record for measurements of test types “ATM Layer QoS (SVC) <...>”. This is
particularly useful when an instrument in “Called” mode is operated without supervision over a
long period of time.
Putting the “Signaling Analysis” window on top
(where this is not already the case)
⇒ Click the above icon button of the toolbar.
– or –
⇒ Select the “View - Signaling Analyzer” menu command.
The “Signaling Analysis” window is displayed on top.
Fig. A-24The “Signaling Analysis” resu lts window
A-16Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
Channel Status
The “Channel Status” field indicates the circuit status of the test channels:
Red“disconnected”Circuit disconnected.
Yellow“connecting”Circuit in process of connecting.
Green“connected”Circuit connected (switched).
Signaling events
This display field indicates the progress of the signaling. The signaling events are shown
consecutively in separate lines, each with date and time information. Each time there is a
change in the status of the channel circuit, this is indicated in the display field. A channel can
assume any of the following states:
disconnectedCircuit disconnected
connectingCircuit in process of connecting
connectedCircuit connected (switched)
If the “Detailed” check box is marked, additional information will be shown for each change of
status.
for “disconnected”: Indication of reason for disconnection
for “connecting”:Address of called instrument and traffic contract
parameters (for called instrument only)
for “connected”:VPI/VCI values for the switched test channel and the
call set up time (for calling instrument only)
Display
The “Display” field allows you to select the signaling information to be displayed in the righthand display field and to control the display itself. The following check boxes and action buttons
are provided:
DetailedCheck box for selecting the degree of detail in the displayed
information:
“Detailed” off:Display of circuit status only (e.g. connected)
“Detailed” on:Display of additional information. If the “Log QoS Parameters” is
selected, the measured QoS parameters will also be displayed
All channelsCheck box for displaying all channels
A, B, ...Check box for displaying a specific test channel
Page:Display of the displayed page number and the total number of pages
<Action button for paging backwards
>Action button for paging forwards
Application GuideA-17
Broadband Analyzer/GeneratorANT-20/ANT-20E
2.7.3The “Quality Of Service” window
The “Quality Of Service” results window shows the ITU-T O.191 QoS performance parameters.
The index cards of the window show detailed, channel-specific results. The right-hand section
of the window is always visible and shows the alarm states for all channels.
The VI displays the QoS performance parameters of up to four permanent virtual circuits (PVC)
or switched virtual circuits (SVC) simultaneously. The index cards are labeled according to the
active test type. These are explained below under “Explanation”.
Putting the “Quality Of Service” window on top
⇒ Click the above icon button of the toolbar.
– or –
⇒ Select the “View - Quality Of Service” menu command.
The “Quality Of Service” window is displayed on top with the QoS parameters (left section)
and possible alarm events (right section).
Fig. A-25The “Quality Of Service” results window
QoS-Parameter
Error Related Parameters
The “Error Related Parameters” display field shows the performance parameters indicating
communication errors for the selected test channel.
The two leftmost columns show the “Total” results. The two rightmost columns show the
“Intermediate” results. The Total results are for the entire measurement period up to this point.
The Intermediate results are those for the last intermediate interval. The length of the
intermediate interval can be set in the Application Manager. The absolute value (Count) and the
Rate or Ratio are displayed for each parameter.
A-18Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
Delay Related Parameters
The “Delay Related Parameters” display field shows the performance parameters affecting the
cell transfer delay for the selected test channel. The overall results are shown under “Total”. The
intermediate results are shown under “Intermed.” The Total results are for the entire
measurement period up to this point. The Intermediate results are those for the last intermediate
interval. The length of the intermediate interval can be set in the Application Manager.
Min. CTDMinimum cell transfer delay
Max. CTDMaximum cell transfer delay
Mean CTDMean cell transfer delay
2-pt. CDVpp2-point cell delay variation
Activity
The “Activity” display field shows additional information about the performance of the analyzed
channel:
Analyzed CellsNumber of cells analyzed. The greater the number of cells evaluated, the
more reliable the values measured for the error- and delay-related
parameters
LPACIndication of “Defect Seconds” for which no performance parameters could
be measured (Loss of Performance Assessment Capability). This can be
due to an alarm in the physical layer, for example. LPAC is a measure of the
availability of the circuit. Each LPAC second is non-available time.
NCSIndication of “Defect Seconds” for which the test channel is not connected
(Not Connected Seconds). This indication is only relevant for switched
virtual circuits (SVC)..
Defect Seconds (QoS-Parameter)
The “Defect Seconds” display field shows the defect seconds for the following defects:
Alarms that have occurred (defects) are indicated by a set of LEDs for all test channels together.
Yellow“History”: On if the alarm occurred at least once during the entire
measurement interval.
Yellow and red“Current”: On when the alarm is active.
Application GuideA-19
Broadband Analyzer/GeneratorANT-20/ANT-20E
The alarm duration is shown separately for each channel on the corresponding index cards.
• The “Delay Related Parameters” are only displayed if one of the following test types was
selected in the “ATM Test Control” VI:
– ATM Layer QoS - Looped Topology, or
– ATM Layer QoS (PVC) - Looped, or
– ATM Layer QoS (SVC)- Self-Call
• The call set-up times are not shown in the “Quality Of Service” window. They are displayed
in the “Signaling Analysis” window.
2.7.4The “Receiver Status” window
The “Receiver Status” results window gives a quick overview of the status of the receiver. This
window is always displayed in the workspace, regardless of the current type of test.
Putting the “Receiver Status” window on top
⇒ Click the above icon button of the toolbar.
– or –
⇒ Select the “View - Receiver Status” menu comm and .
The “Receiver Status” window is displayed on to.
Fig. A-26The “Receiver Status” results window
Link
The “Link” display field shows information about the total load on the physical link. The load is
calculated over all virtual channels, regardless of the test channels that are set. The actual load
is averaged at intervals of 0.1 second.
Total Bandwidthin Mbps
Utilizationin %
A-20Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
HEC Error Counts
The “HEC Error Counts” display area shows the results of the receiver Header Error Check. The
values are cumulative for the entire measurement interval.
CorrectableTotal number of correctable header errors
UncorrectableTotal number of uncorrectable header error s
Defect Seconds
The “Defect Seconds” display field registers the defects (alarms) in the physical layer:
Loss of Cell Del.Loss of Cell Delineation
Phys. Layer Def.Physical Layer Defect. Alarm occurring as a result of an interruption in the
data stream in the physical layer.
The alarm status is shown by LEDs and the alarm duration is shown under “Defect Seconds”.
Yellow“History”: On if the alarm occurred at least once during the entire
measurement interval.
Yellow and red“Current”: On when the alarm is active.
Application GuideA-21
Broadband Analyzer/GeneratorANT-20/ANT-20E
3Detecting and analyzing ATM channels (Channel Explorer)
3.1Overview: Basic operating sequence
The following section lists all the necessary steps, from starting the application and selecting the
scan type through to the scan itself and on to sorting the results and recording them. Further
information on the operating sequences is found in the corresponding sub-sections (see the
“More” column). Please note the settings that apply to more than one VI. The VI icons used in
the “minibar” are shown in the left-hand column as an aid to orientation.
VIOperating stepMore infor m ation
1. Select the virtual instruments for the ATM application
“Signal Structure” VI and “ATM Channel Explorer” VI
2. Set the signal structure
Configure the physical layer and match it to the measurement task
3. Close the “Signal Structure” VI-
4. Select the scan type
• Select the “Activity” scan if active traffic channels are to be displayed
– or –
• Select the “Trouble” scan type if channels showing alarms are to
be displayed.
5. Select the options
• Select the interface at which the measurement is being made.
• Deselect the inactive channels.
6. Trigger the scan
The traffic check or alarm detection procedure starts. The required
channels are entered one after the other in the results window. The
scan runs until the 1000th channel is detected or until the scan is
stopped.
7. Perform AAL analysis (“Activity” scan type)
• Select “AAL Type” analysis if you want a ta bular evalu ation acc ording to AAL types.
– or –
• Select “AAL Type Distribution” analysis if you want a graphical
evaluation according to AAL types.
8. Sort the channels
9. Record and/or further process the results
• Print out the contents of the results window
– or –
• Export the contents of the results window.
Sec. 1.1,Page A-1
see D on
page A-6
Sec. 3.4.1,Page A-24
Sec. 3.4.4,Page A-27
Sec. 3.5,Page A-29
Sec. 3.5,Page A-29
Sec. 3.4.1,Page A-24
Sec. 3.4.4,Page A-27
Sec. 3.4.2,Page A-25
Sec. 3.4.3,Page A-26
Sec. 3.6,Page A-30
see
“Channel Explorer” online help
Table A-2Overview: Detecting and analyzing ATM channels
A-22Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
3.2Test setup and description
Chapter 3 describes the procedure for checking traffic and locating faults using the “Channel
Explorer”. This tool is used to interactively observe the events on an ATM link and to analyze
them. The various “Scan and analysis types” available are described.
Fig. A-27Test setup for traffic checking
3.3Application settings
VIs required
• ATM Channel Explorer
• Signal Structure
⇒ Add the VIs required to the list of VIs used in the Application Manager.
The Application Manager should include at least the following instruments (see Fig. A-28):
Fig. A-28Minibar (Application Manager) after selecting the VIs
Application GuideA-23
Broadband Analyzer/GeneratorANT-20/ANT-20E
3.4Measurement
3.4.1“Activity” Scan: Detect and Display Acti ve AT M Channels
“Scan - Activity” looks for active channels. The instrument detects every active channel and
enters it in to the results list. The “Activity” scan type is the default setting, as shown in the
header of the current results list.
⇒ Click on the icon button of the “ATM Channel Explorer” VI in the minibar (Application
Manager).
The “ATM Channel Explorer” main window appears on top.
To select “Activity” scan if this is not activated by default
The scan type is set and the scan is controlled from the “Scan” menu.
⇒ Click the item “Activity” in the “Scan” menu.
The selected functi on is marked with a dot.
Header “Scan - Activity”
Results list
(initially empty)
Fig. A-29The “Scan” menu with selected “Activity” scan type and corresponding results list
To start the scan
⇒ Click the above icon button of the toolbar or click “Start” in the “Scan” menu.
The scan starts. Channels detected are entered successively in the corresponding results
windows.
Results list
Scrollbar
Fig. A-30The “ATM Channel Explorer” with detected channels
A-24Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
Tip:To stop the scan click the icon button of the toolbar again or click “Start” in the “Scan”
menu again.
A scan can only be started or a test traffic can be generated, when no other measurements that
are started from the Application Manager are in progress. No other measurements can be
started or a test traffic can be generated, while a scan is in progress.
ColumnMeaning
No.Sequence number to assist orientation in the list
VPIVirtual Path Identifier. Displayed as a decimal number.
VCIVirtual Channel Identifier. Displayed as a decimal number.
CI-BWCongestion Indicator Bandwidth: Pro port ion o f c el ls w ith Co nge sti on Indication (CI) bit
CLP1-BWCell Loss Priority 1 Bandwidth: Proportion of cells with Cell Loss Priorit y (CLP) bit set.
AvBWAverage Bandwidth of the channel in Mbit/s. The displayed value is determined over
CuBWCurrent Bandwidth or channel lo ad in Mbit/s. Th e displaye d value is t he averag e for the
Table A-3Result list header for “Activity” scan type
set. The displayed percentage is determined over the entire duration of the scan.
The displayed percentage is determined over the entire duration of the scan.
the entire duration of the scan. All user and OAM cells are included in the calculation.
last seconds. All user and OAM cells are included in the calculation.
3.4.2Analyzing the AAL types of active ATM channels
Detect and analyze the AAL types in the detected ATM channels (Fig. A-30,Page A-24).
To start the analysis
⇒ Click the above icon button of the toolbar or click the item “AAL Type” in the “Analyse” menu.
A bargraph display appears indicating the progress of the analysis.
AAL attributes
Fig. A-31Analysis of AAL types
If a large number of channels are listed in the results window, AAL analysis may take a very long
time. You can interrupt the analysis at any time using the “Cancel” button. All the channels
listed, regardless of AAL status, are checked during an AAL analysis.
Application GuideA-25
Broadband Analyzer/GeneratorANT-20/ANT-20E
To stop the analysis
⇒ Click the “Cancel” button (e.g. if “Unchecked” entries appear in the list).
– or –
The analysis stops automatically when all channels are analyzed again.
AttributeMeaning
AAL 1Constant bit rate channel (AAL type 1, service class A)
AAL 3/4Data services channel (AAL type 3/4, service class C, D)
AAL 5Channel with simplified protocol for rapid data communications (AAL type 5, service
class C)
UncheckedThe channel was not checked for AAL type. Reason: User aborted analysis.
Undet.Channel cannot be analyzed or assigned to a particular AAL type. Reason: unknown
Table A-4 AAL type display after an AAL analysis
AAL type or no activity in channel.
3.4.3Displaying the AAL Type Distribution
Determine and display the distribution of active ATM channels according to AAL types.
To start the analysis
⇒ Click the above icon button of the toolbar or click the item “AAL Type Distribution” in the
“Analyse” menu.
The “AAL Type Distribution” window showing the current distribution of active channels
according to AAL types is displayed.
– The pie chart gives a dynamic overview
– The table lists percentage values to give a quantitative display
Pie chart
Table
Fig. A-32AAL type analysis
A-26Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
To stop the analysis
⇒ Click the “Cancel” button.
– or –
The analysis stops automatically when the analysis is complete (“Unchecked” = 0%).
When you perform an “AAL Type Distribution” analysis, an “AAL Type” analysis is automatically
also performed.
• If a large number of channels are listed in the results window, AAL analysis may take a very
long time. You can interrupt the analysis at any time using the “Cancel” button.
• If the analysis is aborted, the distribution of the channels analyzed so far will be displayed.
Pie chart
Graphic display of distribution according to AAL types. The yellow segment indicates the as yet
unchecked channels. It decreases in size as the analysis progresses.
Table
ColorLoad
(example)
blue19.00 %38Channels cannot be analyzed o r cannot be assigned to an
white17.00 %34Channel with AAL type 1
green22.00 %44Channel with AAL type 3/4
red22.00 %44Channel with AAL type 5
yellow20.00 %40Channels not yet checked for AAL type.
Tabelle E-5Column meanings (Example: Analysis of 200 channels)
Number of
channels
Meaning
AAL type. Cause: Unkno wn AAL type or c hannel currently
inactive.
“Cancel” button
Cancels the analysis as long as a yellow segment is visible or “Unchecked” > 0 %. The analysis
ends when the yellow segment disappears or “Unchecked” = 0 % and the “Cancel” button
changes to “OK”.
3.4.4Trouble Scan: Detecting and displaying ATM Channels where alar ms are present
“Scan - Trouble” searches for channels that exhibit an alarm state. The instrument detects every
alarm indication cell and enters the corresponding channel into the results list. There are two
results windows corresponding to the error management hierarchy:
• F4 window: OAM Flow 4 (VP layer)
• F5 window: OAM Flow 5 (VC layer)
The type of record and the scan type are set and the scan is controlled from the “Scan” menu.
Application GuideA-27
Broadband Analyzer/GeneratorANT-20/ANT-20E
To select “Trouble” scan
⇒ Click the item “Trouble” in the “Scan” menu.
The selected functi on is marked with a dot.
Header “Scan -Trouble”
Results lists
(initial ly empty)
Fig. A-33The “Scan” menu with selected “Trouble” scan type and corresponding results list
To start the scan
⇒ Click the above icon button of the toolbar or click “Start” in the “Scan” menu.
The scan starts. Channels detected are entered successively in the corresponding results
windows.
Tip: To stop the scan click the icon button again or click “Start” in the “Scan” menu again.
Results lists
Scrollbar
Fig. A-34The “ATM Channel Explorer” with detected channels
A scan can only be started, when no other measurements that are started form the Application
Manager are in progress or no test traffic is generated from the ATM Test Control VI. No other
measurements can be started or no test traffic can be generated, while a scan is in progress.
A-28Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
Results lists
Each line corresponds to a channel exhibiting a RDI and/or an AIS alarm. A current alarm is
indicated in upper-case letters (e.g. AIS). Previous alarms that are no longer active are indicated
in lower-case letters (e.g. ais).
ColumnMeaning
No.Sequence number to assist orientation in the list
VCIVirtual Channel Identifier. Displayed as a decimal number (only F5).
VPIVirtual Path Identifier. Displayed as a decimal number.
RDIRemote Defect Indication: Backward alarm.
AISAlarm Indication Signal: Forward alarm.
Table A-6Trouble scan res ult s lis t heade r
3.5Selecting Options
To select the interface where the measurement is to be made
The icon buttons shown above (toolbar) are used to select the interface before starting the
measurement. Each button corresponds to an interface type. Only one type can be selected, so
clicking one button releases the other (toggle function).
⇒ Click the “UNI” button to measure on the “User-Network Interface”.
– or –
⇒ Click the “NNI” button to measure on the “Network-Node Interface”.
To sort out the inactive channels
The icon button in the toolbar shown above is used to sort out the inactive channels during the
scan.
⇒ Click the “AGE” button to start the aging function.
All channels that remain inactive over a period of 30 seconds will be deleted.
This dynamic process gives you a better picture of the actual traffic situation. This is particularly
useful in an environment with switched virtual connections (SVC).
Application GuideA-29
Broadband Analyzer/GeneratorANT-20/ANT-20E
3.6Sorting Channels
To sort the channels
The icon buttons shown above (toolbar) are used to sort the channels, i.e. to determine the
order in which they are displayed in the result window. Each button corresponds to a sort
criterion. Only one criterion can be selected, so clicking one button releases the other (toggle
function).
⇒ Click the “VPI VCI” button to list the channels in ascending order of VPI/VCI values
– or –
⇒ Click the “BW” button to list the channels in ascending order of CuBW (Current Bandwidth)
values.
The “BW” (Bandwidth) sort criterion is not available for “Trouble” scan.
A-30Application Guide
ANT-20/ANT-20EBroadband Analyzer/Generator
Technical Background
1ATM Traffic Generation and Multiplexing
VI: ATM Test Control
1.1Overview
ATM test equipment takes on an important role in generating traffic profiles and multiplexing
several virtual channels due to the specific characteristics of ATM technology. The
requirements for a powerful test instrument are mainly concentrated in the following areas:
Traffic profile, source models
Suitable traffic profiles are needed to perform most of the tests required on A TM networks. This
is particularly true of the ATM layer quality of service test. Suitable source models must be
provided for the various types of traffic contract. These source models must be designed so that
users can easily see the relationship between the parameters of the traffic contract under test
and the parameters of the source model.
Multiplexer, traffic shaper
Since ATM does not use fixed (deterministic) bandwidth assignment, the individual virtual
channels affect each other. The characteristics of traffic in one virtual channel, and hence the
measurement results, do not just depend on the source settings, they are also dependent on
what is happening in other channels. The multiplexing method used by the instrument also
plays a part here. To ensure that adherence to the traffic contract can be guaranteed for each
channel, the instrument must be able to shape the traffic profile using so-called traffic shapers.
The type of traffic shaper used and its parameters depend on the characteristics of the traffic
contract itself.
Background traffic
Since statistical multiplexing is used in ATM networks and network elements, a realistic
measurement result is only obtained if background channels are also loaded in addition to the
virtual channels to be tested. In most cases, the characteristics of traffic generated on the
background channel must be precisely defined and known. This means that precisely controlled
traffic has to be generated on several channels simultaneously.
Technical BackgroundTB-1
Broadband Analyzer/GeneratorANT-20/ANT-20E
1.2Generator Principle
The traffic generator of the ANT-20 or of the Broadband Analyzer/Generator simultaneously
generates up to four test channels (software version 6.0). The generator produces quasistatistical traffic according to different source models and model parameters. It is deterministic
in the sense that the same instrument settings will always result in exactly the same traffic
profile. This means that measurements can be reproduced precisely at any time.
The multiplexing method used operates on a fixed priority principle. Each of the four channels
(A through D) is assigned a certain priority. This allows the channel that is to be most precisely
measured to be given the highest priority (channel A). The traffic profile of this channel is only
minimally influenced (some influence due to effects in the physical layer is unavoidable). Lower
priority channels (e.g. channel D) are best used for background loads or for measurements of
tolerant traffic contracts.
A traffic shaper can be activated for each of the four test channels if required. The traffic shaper
parameters are determined by the requirements of the traffic contract defined for the channel.
Auxiliary channels, such as are used for the signaling, do not affect the traffic profile of the test
channels. This is regardless of the bandwidth required for the auxiliary channels (as long as the
total bandwidth available for the physical link is not exceeded).
1.3Source Models
Two different source models are provided by the test instrument for the various ATM tests. each
channel defined in the Channel Editor (see Fig.TB-1) is assigned a traffic model (a) in the
“Traffic Source” index card. The default values for the source parameters (b) are set on the
same index card.
In the “Test Setup” dialog, you can select the channels generated in the Channel Editor and
assign them to the current test type. The source of the channel is initialized to its default values
when it is assigned.
a
b
Fig. TB-1The “Channel Editor” with activated “Traffic Source” index card
TB-2Technical Background
ANT-20/ANT-20EBroadband Analyzer/Generator
1.3.1“Constant Bit Rate” source model
The “Constant Bit Rate” source model generates test cells at equidistant intervals in time, with
fill cells inserted in the spaces (see Fig.TB-2). The desired traffic profile can be affected using
the following parameters:
• Peak Cell Rate
• Cell Jitter
“Peak Cell Rate” specifies the nominal time spacing between test cells, ∆t.
The “Cell Jitter” parameter is used to alter the nominal time spacing (---> ∆t’) and thus cause a
variation in the nominal cell arrival times. The profile used for this corresponds to an increasing
ramp function.
The ramp rises until the cell arrival is advanced by the entered value. A gap then occurs in the
cell arrival times to ensure that the correct mean cell rate is reached. The period of the ramp is
based on the “Peak Cell Rate” setting and is calculated by the instrument automatically.
without Jitter
. . .
∆t
with superimposed
Jitter
. . .
∆t’
Cell Jitter
Fig. TB-2Principles of “Constant Bit Rate” source model.
Filling cells
The specified jitter is superimposed on the source before multiplexing. Due to the unavoidable
effects of multiplexing, the traffic profile actually transmitted may be modified again.
This source model is particularly suitable for testing CBR, DBR and UBR traffic contracts. The
profile of the superimposed cell jitter makes it easy to test a traffic contract in respect of its Cell
Delay Variation Tolerance (CDVT
PCR
).
t
t
Technical BackgroundTB-3
Broadband Analyzer/GeneratorANT-20/ANT-20E
1.3.2“On-Off” source model
The “On-Off” source model generates test cells in bursts. Fill cells are inserted in the gaps
(see Fig.TB-3). The desired traffic profile can be influenced using the following parameters:
• Peak Cell Rate
• Mean Cell Rate
• Burst Size
• Cell Jitter
“Peak Cell Rate” specifies the nominal time spacing between test cells within a burst, ∆t.
“Mean Cell Rate” specifies the mean cell rate.
“Burst Size” determines the length of a burst. The burst period to be used is calculated by the
instrument automatically. It is largely based on the ratio of “Peak Cell Rate” to “Mean Cell Rate”.
The “Cell Jitter” parameter is used to cause a variation in the nominal cell arrival times. The
profile used for this corresponds to an increasing ramp function. where the length of the ramp
corresponds to the “Burst Size”.
The ramp rises until the cell arrival is advanced by the entered value. The gap between bursts
is increased correspondingly to ensure that the correct mean cell rate is reached.
Burst Size
without Jitter
∆t
with superimposed
Jitter
∆t’
Cell Jitter
Fig. TB-3Principles of “On-Off” source model
. . .
Filling cells
t
t
The specified jitter is superimposed on the source before multiplexing. Due to the unavoidable
effects of multiplexing, the traffic profile actually transmitted may be modified again.
This source model is particularly suitable for testing VBR and SBR traffic contracts. The profile
of the superimposed cell jitter makes it easy to test a traffic contract in respect of its Cell Delay
Variation Tolerance (CDVT
PCR
).
TB-4Technical Background
ANT-20/ANT-20EBroadband Analyzer/Generator
1.4Traffic Control and Multiplexing Method
As well as being able to set the source parameters “off-line”, i.e. before starting the
measurement, the “ATM Test Control” VI also allows you to change all the relevant source
parameters “on-line”, i.e. during a measurement. The parameters are defined off-line using the
“Test Setup” dialog (b) (see Fig.TB-4). In contrast, the “Test Online Control” dialog (c) is used
to alter parameters on-line. Please note that each change in a source parameter results in a
complete re-calculation of the entire multiplex.
Users should be aware that ATM multiplex formation makes it unavoidable that a changed
setting in one channel (e.g Channel A, see index card (a)) may also affect the other channels
(i.e. Channels B, C and D). This is particularly the case where the physical link is loaded to a
high percentage.
The channel priorities for the multiplex procedure are fixed by two rules, whereby rule 1 has
precedence over rule 2.
Rule 1
Channels with a bit rate above 2.5 Mbit/s have priority over channels with a bit rate below 2.5
Mbit/s. This rule takes account of the fact that lower bit rate channels usually allow a higher
CDVT than that of higher bit rate channels.
Rule 2
The priority of the channels decreases from left to right, i.e. channel A has the highest priority,
channel B the next highest, and so on.
Technical BackgroundTB-5
Broadband Analyzer/GeneratorANT-20/ANT-20E
a
d
b
a
c
Fig. TB-4“Test Setup” and “Test Online Control” dialog windows
with index cards and “Multiplexer” section
e
f
To make it easier to see the complex procedures during multiplex formation, an overview of the
status of each channel is given in the “Multiplexer” field.
In the “Test Setup” dialog, this information (d) has the character of a traffic prediction, as the
generator is not yet active. THis makes it possible to set the generator precisely, before starting
the measurement.
In the “Online Control” dialog, in contrast, this information (f) reflects the actual status of the
channel. The following information is provided:
TB-6Technical Background
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