HP 37717C
Communications
Performance Analyzer
SDH Concept
Guide
Copyright HewlettPackard Ltd.1998
All rights reserved.
Reproduction, adaption,
or translation without prior
written permission is
prohibited, except as
allowed under the
copyright laws.
Information in this
document may apply to
modules which use the
VxWORKS TM software.
The VxWORKS TM
software was developed by
Wind River Systems, Inc.,
which has copyright to it.
HP Part No. 37717-90417
First Edition, Feb 98
Printed in U.K.
Warranty
The information contained
in this document is subject
to change without notice.
Hewlett-Packard mak es no
warranty of any kind with
regard to this material,
including, but not limited
to, the implied warranties
or merchanability and
fitness for a particular
purpose.
Hewlett-Packard shall not
be liable for errors
contained herein or for
incidental or
consequential damages in
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furnishing, performance,
or use of this material.
WARNING
Warning Symbols Used
on the Product
!
The product is marked
with this symbol when the
user should refer to the
instruction manual in order
to protect the apparatus
against damage.
The product is marked
with this symbol to
indicate that hazardous
voltages are present
The product is marked
with this symbol to
indicate that a laser is
fitted. The user should
refer to the laser safety
information in the
Calibration Manual.
Hewlett-Packard Limited
Telecomms Networks Test Division
South Queensferry
West Lothian, Scotland EH30 9TG
SDH Concept Guide
HP 37717C Communications
Performance Analyzer
About This Book
The information on SDH testing in this book covers the following subjects:
• An Introduction to SDH, the SDH modules and their features.
• Measurement examples.
• Measurement result definitions
• Logging messages
• Self test error codes
For some operations and measurements, information from one of the associated
books listed at the rear of this guide may be required.
iv
Contents
1 Introduction to SDH Testing
Introduction to SDH 2
Option A3R [A3S] SDH Generation and Analysis 4
2 SDH Testing
Add/Drop Multiplexer Testing 6
Alarm Stimulus/Response 11
DCC Testing 15
Desynchroniser Stress 18
Frame Synchronization 21
SDH Jitter Transfer 27
MSP Stimulus/Response 30
Optical Clock Recovery Stress 34
Payload Mapping/Demapping 36
Performance Monitor Stimulus / Response 42
Selective Jitter Transfer Measurement 46
Automatic Alarm and BIP Error Monitoring 50
Automatic Verification of ADM Installation 53
Verification of Protection Switching 57
3 Result Definitions
Trouble Scan 62
Error Summary 62
Short Term Results 63
Cumulative Results 64
SDH Error Analysis 65
v
Contents
G.826 Analysis B1 BIP 65
G.826 Analysis B2 BIP 66
G.826 Analysis MS-REI 67
G.826 B3 BIP Analysis 68
G.826 HP-REI Analysis 69
G.826 HP-IEC Analysis 70
G.826 TU BIP Analysis - 34 Mb/s Payload 71
G.826 TU BIP Analysis - 2 Mb/s Payload 72
G.826 LP-REI Analysis - 34 Mb/s Payload 73
G.826 LP-REI Analysis - 2 Mb/s Payload 74
SDH Pointer Value Results 75
SDH Alarm Seconds 76
Frequency Measurement 77
Optical Power 77
4 SDH Logging Messages
Logging Devices 80
Results Logging 81
81
During the Measurement Period 81
At the End of the Measurement Period 86
Bar Graph Logging 87
Graphics Text Results Logging 88
Results Snapshot Logging 89
Overhead Capture Logging 91
Overhead Snapshot Logging 92
SDH Tributary Scan Logging 93
Pointer Graph Logging 94
vi
Contents
5 SDH Self Test Error Codes
6 Terminology
ETSI / ANSI Equivalent Terms 116
Current / Previous Terminology 118
vii
Contents
viii
1
Introduction to SDH page 2
37717C SDH Options page 3
1 Introduction to SDH Testing
Information on SDH in general and the SDH test
features of the HP 37717C.
Introduction to SDH Testing
Introduction to SDH
Introduction to SDH
Synchronous Digital Heirarchy (SDH) is an international standard (ETSI)
for high speed synchronous optical telecommunications networks.
The concept of a synchronous transport system, based on SDH standards, goes
beyond the basic needs of a point to point transmission system. It includes the
requirements of telecommunications networking - switching, transmission and
network control. These capabilities allow SDH to be used in all three traditional
network application areas - Local Network, Inter-exchange Netw ork and Long Haul
Network - thus providing a unified telecommunication network structure.
The SDH standards are based on the principle of direct synchronous multiplexing.
This means that individual tributary signals (Payload) may be multiplexed directly
into a higher rate SDH signal without intermediate stages of multiplexing. SDH
network elements, even those supplied by different manufacturers, can be
interconnected directly giving cost and equipment savings.
SDH is capable of transporting all the common tributary signals
E1 (2.048 Mb/s), E3 (34.368 Mb/s), E4 (139.264 Mb/s), DS1 (1.544 Mb/s) and
DS3 (44.736 Mb/s) currently in use. In addition SDH has the flexibility to readily
accommodate any new types of service which are being introduced for example
(ATM) or which may be required in the future. Approximately 5% of the SDH
signal structure (Overhead) is reserved for network management and maintenance.
This means that SDH can be deployed as an overlay to the existing network thus
providing enhanced network flexibility.
The HP 37717C provides comprehensive testing of both payload and overhead at
electrical and optical SDHinterfaces.
2
Introduction to SDH Testing
37717C SDH Options
37717C SDH Options
Option A3R [A3S] SDH Generation and Analysis page 4
SDH generation and analysis with STM-0 and STM-1 electrical interfaces,
Option A3R.
Additional SDH interface capability is provided by the following Options::
STM-1 Optical Interface, Option UH1.
STM-0, STM-1 and STM-4 optical interfaces at 1310nm, Option 131.
STM-0, STM-1 and STM-4 optical interfaces at 1310nm and 1550nm, Option 130.
STM-0, STM-1, and STM4 binary interfaces, Option 0YH
3
SDH
STM-0/STM-1
2M REF IN
120
Introduction to SDH Testing
Option A3R [A3S] SDH Generation and Analysis
Option A3R [A3S] SDH Generation and Analysis
Option A3R [A3S] provides STM-0 and STM-1 Electrical interfaces.
When Option UH1 is fitted STM-1 Optical interfaces are provided.
When Option 130 or 131 is fitted STM-1 and STM-4 optical interfaces are
provided.
RS449
Ω
When STM1-1 Optical is selected, the STM-1 electrical output is also active.
The THRU mode capability allows you to overwrite the TU-2, TU-3, AU-3,
TU12 and AU-4 payloads and the section overhead of the incoming STM-0/
STM-1/STM-4 signal.
Frequency offset of the SDH signal of 999 ppm is available.
Bulk Filled and Mixed payloads are available. If Option UKJ, Structured
PDH, is fitted, DS1 and DS3 payloads are available and a 2 Mb/s, 34 Mb/s
and 140 Mb/s Insert Port is provided. Bit errors can be added to the
payload.Errors & Alarms can be added to the SDH signal.
ERROR
OUT
OUT IN
Option A3R
AU and TU Pointer Movements can be added to the SDH signal and a
Graphical display of Pointer activity is available.
Section and path Overhead bytes are user programmable and can be
monitored and displayed in Hexadecimal or as 8 bit bytes. Selected overhead
bytes can be transmitted with a programmed sequence of data.
Ω
75
Receive sequences can be captured and displayed. K4 and V5 ov erhead bytes
can be accessed.
Allows BER testing of section and path overhead bytes.
Ω
75
Allows testing of MSP Linear and Ring architectures.
Ω
75
DCC Drop and Insert capability is included.
Allows Protection Switch time testing if Option UKJ, Structured PDH, is
fitted.
Optical Power measurement is available.
Optical Clock stress capability at STM-1 and STM-4 is included.
Provides SDH Alarm Scan and Tributary Scan.
4
2
Add/Drop Multiplexer Testing page 6
Alarm Stimulus/Response page 11
DCC Testing page 15
Desynchroniser Stress page 18
Frame Synchronization page 21
SDH Jitter Transfer page 27
MSP Stimulus/Response page 30
Optical Clock Recovery Stress page 34
Payload Mapping/Demapping page 36
Performance Monitor Stimulus / Response page 42
Selective Jitter Transfer Measurement page 46
Automatic Alarm and BIP Error Monitoring page 50
Automatic Verification of ADM Installation page 53
Verification of Protection Switching page 57
2 SDH Testing
This Chapter gives examples of the instrument
operation in typical SDH test applications.
SDH Testing
Add/Drop Multiplexer Testing
Add/Drop Multiplexer Testing
Application
The insertion of tributary signals into the Add/Drop multiplexer, which are then
mapped into the SDH signal, should take place without introducing errors. The
insertion and mapping process is tested by adding a test pattern to the tributary
inserted at the tributary insert port. At the SDH side of the Add/Drop multiplexer the
tributary is demapped by the HP 37717C Communications Performance Analyzer.
By using the Optical Splitter, at the optical side of the Add/Drop multiplexer, the
Add/Drop multiplexer need not be taken out of service. A Bit error rate (BER) test is
performed on the recovered tributary test pattern to determine whether errors have
been introduced by the Add/Drop multiplexer.
Default (Known State) Settings
It is advisable to set the HP 37717C to a known state before setting up a
measurement. This clears all previous settings and provides a clearly defined
instrument state. The default settings are set by selecting
SETTINGS RECALL
STORED SETTING NUMBER 0 and pressing .
OTHER
STORED
Add/Drop Multiplexer Testing Test Setup Procedure
The following Options must be fitted to the HP 37717C to perform this test :
• UKJ [USA]or UKK [USB] - PDH Module
• A3R [A3S] - SDH Module
• 130 or 131 - STM-0/1/4 Optical Interface
In this setup a 2 Mb/s payload, containing a test pattern, is inserted at the tributary
insert port of the Add/Drop multiplexer multiplexer. A portion of the STM4 Optical
signal is tapped off by the Optical Splitter (approx 10%) and the 2 Mb/s tributary is
demapped by the HP 37717C Communications Performance Analyzer.
An Error measurement is performed on the demapped 2 Mb/s tributary test pattern.
A SINGLE test period of 24 HOURS is used and the internal printer is enabled to
record results and alarms.
The HP 37717C Communications Performance Analyzer GRAPHICS function is
enabled. The graphical results can be viewed on the display
6
GRAPH
SDH Testing
Add/Drop Multiplexer Testing
1. Connect the HP 37717C to the network equipment and set the
SETTINGS CONTROL
Changes made on the display will not affect the display
and changes made on the display will not affect the
TRANSMITTER AND RECEIVER to INDEPENDENT.
TRANSMIT
RECEIVE
OTHER
RECEIVE
TRANSMIT
display.
2. Set up the display as shown
TRANSMIT
opposite.
The PAYLOAD TYPE determines the
Framing. .
7
SDH Testing
Add/Drop Multiplexer Testing
3. Set up the display as shown
RECEIVE
opposite.
Continuity Check
Before running the test carry out a continuity test to verify the measurement path.
1. Set up the display as shown
RESULTS
opposite.
2. Press to start a
RUN/STOP
measurement.
3. Press error add three times and
SINGLE
check that the errors are recorded on the
RESULTS
display.
3. Check that the errors are recorded on the
RESULTS
4. Press to stop the measurement.
display.
RUN/STOP
Select the required logging DEVICE and
set up the display,
OTHER
LOGGING
function, as shown opposite.
8
SDH Testing
Add/Drop Multiplexer Testing
Start the Add/Drop Multiplexer Test
1. Set up the display as shown
RESULTS
opposite.If you do not require stored
graphics results select STORAGE [OFF].
Graphics results can be stored to the
instrument store - INTERNAL or to DISK.
SHORT TERM PERIOD need only be set
if it is intended to view Short Term results.
2. Press to start the
RUN/STOP
measurement.
The measurement results and alarms are
available on the display during
RESULTS
the test period.
The graphical measurement results and
alarms are stored in non volatile memory
for viewing later on the GRAPH display.
The test can be halted at any time by
pressing
RUN/STOP
9
SDH Testing
Add/Drop Multiplexer Testing
At the End of the Test (Add/Drop Multiplexer Testing)
• The Date and Time the test started and the instrument setup are logged To the
selected logging device.
• Results are logged To the selected logging device at 1 hour intervals if the error
count is greater than 0.
• Any alarms which occur during the test period will be logged To the selected
logging device.
• At the end of the test period a complete set of cumulative results are logged To
the selected logging device.
• A graphical record of the results during the test period can be viewed on the
GRAPH
display. If a printer option is fitted the graph results can be logged to a
printer, at a later date.
• Results and Alarm summaries can be viewed on the display.
GRAPH
The total graphics store capacity is normally 20,000 events. An event is the
occurrence of an error or an alarm.
The resolution, determined by the selection made under STORAGE on the
RESULTS
display, affects the ZOOM capability when viewing the bar graphs. If 1
SECOND is selected all resolutions are available under ZOOM. If 1 MIN is selected
only 1 MIN/BAR, 15 MINS/BAR and 60 MINS/BAR are available. If 15 MINS is
selected only 15 MINS/BAR and 60 MINS/BAR are available. If 1 HOUR is
selected only 60 MINS/BAR is available.
Up to 10 sets of graphical results can be stored. If an attempt is made to store more
than 10 sets of results, then a first in first out policy is operated and the oldest set of
results will be lost. If graphics are enabled and a test is run which exceeds the
remaining storage capacity, then some previously stored graphical results will be
lost.
To prevent accidental overwriting of previously stored results the graphics
capability should be disabled, when graphical results are not required, by selecting
STORAGE [OFF] on the display.
RESULTS
10
SDH Testing
Alarm Stimulus/Response
Alarm Stimulus/Response
Application
SDH Network elements transmit alarms in response to certain error/alarm
conditions to advise upstream and downstream equipment that these conditions
exist. If these alarms are not transmitted in the proper manner, at the proper time,
degradations in service will occur.
Alarm testing entails transmitting an alarm signal from the Communications
Performance Analyzer and monitoring the network equipment alarm indicators and
the upstream or downstream signal for the correct response.
Default (Known State) Settings
It is advisable to set the HP 37717C to a known state before setting up a
measurement. This clears all previous settings and provides a clearly defined
instrument state. The default settings are set by selecting
SETTINGS RECALL
STORED SETTING NUMBER 0 and pressing .
OTHER
STORED
Alarm Stimulus/Response Test Setup Procedure
The following options must be fitted to the HP 37717C to perform this test:
• A3R [A3S] - SDH module
• UH1, - STM-1 Optical interface or 130 or 131 STM-0/1/4 Optical interface
In this setup the Communications Performance Analyzer transmits MS-AIS Alarm
(Line AIS) into the network. The network equipment alarm indicators are monitored
for the appropriate alarms. The upstream signal is monitored for occurrences of MSRDI . The downstream signal can be monitored for occurrences of AU-AIS.
A similar procedure can be used for testing all other SDH alarms. See the following
tables.
11
SDH Testing
Alarm Stimulus/Response
SDH Alarms
Alarm RSTE MSTE PTE
Down Up Down Up Down Up
Loss Of Signal MS-AIS N/A AU-AIS MS-RDI TU-AIS LP-RDI
Loss Of Frame MS-AIS N/A AU-AIS MS-RDI TU-AIS LP-RDI
Loss Of Pointer N/A N/A AU-AIS MS-RDI TU-AIS LP-RDI
MS-AIS N/A N/A AU-AIS MS-RDI TU-AIS LP-RDI
MS-RDI N/A N/A N/A N/A N/A N/A
12
SDH Testing
Alarm Stimulus/Response
1. Set up the ;
CONTROL
Any changes made on the or
RECEIVE
2. Set up the ; display
OTHER
SETTINGS
display as shown opposite.
TRANSMIT
display will affect the other.
TRANSMIT
SDH
as shown opposite.
3. Set up the ; TEST
TRANSMIT
FUNCTION display as shown opposite.
The ERROR ADD TYPE selected does not
matter as long as RATE [OFF] is selected.
13
SDH Testing
Alarm Stimulus/Response
4. Set up the display as
RESULTS
shown opposite
SHORT TERM PERIOD need only be
set if it is intended to view Short Term
results
Start the Alarm Stimulus/Response Test
1. Connect the Communications Performance Analyzer to the upstream port of the
network equipment and press on the HP 37717C.
RUN/STOP
2. Check that the network equipment
registers MS-AIS and that MS-RDI alarm
seconds are recorded on the
RESULTS
display .
ALARM SECONDS are displayed but any
of the other results can be selected from the
softkey menu without affecting the
measurement
The MS-RDI indicator on the front panel in
conjunction with will
SHOW HISTORY
also give an indication that the MS-RDI alarm has occurred.
14
SDH Testing
DCC Testing
DCC Testing
Application
The section overhead contains two Data Communication Channels (DCC),
Regenerator Section DCC at 192 kb/s (overhead bytes D1- D3) and Multiplexer
Section DCC at 576 kb/s (overhead bytes D4 - D12). The DCC communicates
network management messages between network elements and the network
controller via the operations support computer system.
If the DCC is not operating correctly these network management messages will be
lost and degradations in network performance will pass unnoticed. This may result
in a failure condition.
Full testing of the line and section DCC’s can be carried out using a protocol
analyzer connected via the HP 37717C Communications Performance Analyzer to
the appropriate overhead bytes. At the far end the HP 37717C Communications
Performance Analyzer can drop the selected DCC to the protocol analyzer allowing
the DCC integrity to be analyzed.
If you do not have access to a protocol analyzer capable of handling SDH DCC
protocol, the DCC integrity can be verified by a BER test using an HP 37732A,
Digital Telecomm/Datacomm Analyzer.
Default (Known State) Settings
It is advisable to set the HP 37717C to a known state prior to setting up a
measurement. This clears all previous settings and provides a clearly defined
instrument state. The default settings are set by selecting
SETTINGS RECALL
DCC Test Setup Procedure
Alarm Stimulus/Response Test Setup Procedure
The following options must be fitted to the HP 37717C to perform this test:
• A3R [A3S]- SDH module
• UH1, - STM-1 Optical interface or 130 or 131 STM-0/1/4 Optical interface
IIn this procedure the HP 37717C Communications Performance Analyzer accepts a
576 kb/s test pattern via the protocol analyzer port, inserting the test pattern in bytes
D4 - D12 of the Multiplexer Section overhead and transmitting an STM-1 optical
STORED SETTING NUMBER 0 and pressing
OTHER
STORED
15
SDH Testing
DCC Testing
signal. The HP 37717C Communications Performance Analyzer receives the STM1 optical signal and drops the Multiplexer Section DCC, via the protocol analyzer
port, to the HP 37732A which performs the BER measurement.
1. Connect the HP 37732A and the HP
37717C to the network element, as shown
and set up the ;
CONTROL
OTHER
SETTINGS
display as shown opposite.
2. Set up the SDH display as
TRANSMIT
shown opposite.
The CLOCK SYNC selection determines
the synchronization source for the
TRANSMIT
clock. If
EXTERNAL MTS
is selected a 2 Mb/s reference must be
connected to the front panel 2M REF IN
port. The format can be CLOCK or DATA.
16
SDH Testing
DCC Testing
3. Set up the ; TEST
TRANSMIT
FUNCTION display as shown opposite.
4. Set up the ; TEST
RECEIVE
FUNCTION display as shown opposite.
Start the DCC Test
1. Select TEST SELECT DATACOM on the HP 37732A.
2. Set TX Clock Source and RX Clock Source to [INTERF ACE] on the HP 37732A
(Clock from HP 37717C protocol port).
3. Select the required pattern and monitor logic errors and frequency to verify the
integrity of the DCC.
17
SDH Testing
Desynchroniser Stress
Desynchroniser Stress
Application
At the boundary of the SDH network the 2 Mb/s or 140 Mb/s payload is demapped
from the SDH signal. Pointer adjustments in the signal may cause high levels of
tributary jitter in the output payload. Excessive amounts of trib utary jitter will result
in errors.
The desynchronizing phase lock loop of the network element should minimize the
level of tributary jitter in the payload but correct operation under stress conditions
must be verified. The desynchronizing phase lock loop can be stressed by adding
pointer movement sequences (defined in CCITT standard G.783) to the SDH signal
such that the test virtual container moves with respect to the SDH frame.
A jitter measurement is made to verify that the desynchroniser output jitter is within
the required specification.
Default (Known State) Settings
It is advisable to set the HP 37717C to a known state before setting up a
measurement. This clears all previous settings and provides a clearly defined
instrument state. The default settings are set by selecting
SETTINGS RECALL
STORED SETTING NUMBER 0 and pressing .
OTHER
STORED
Desynchroniser Stress Test Setup Procedure
The following options must be fitted to the HP 37717C to perform this test:
• UKK [USB] or UKJ [USA]- PDH module
• A3L, A3V or A3N - Jitter measurement module
• A3R [A3S]- SDH module
• 130 or 131 STM-0/1/4 Optical interface
The HP 37717C Communications Performance Analyzer transmits an STM-4
optical signal carrying 2 Mb/s payload. Pointer movement sequences are added in a
controlled manner. The desynchroniser output is returned to the HP 37717C and a
jitter measurement is performed on the demapped 2 Mb/s signal.
18
SDH Testing
Desynchroniser Stress
1. Connect the HP 37717C to the network
equipment and set up the ;
display as shown opposite.
SDH
TRANSMIT
The CLOCK SYNC selection determines
the synchronization source for the
TRANSMIT
clock. If
EXTERNAL MTS
is selected a 2 Mb/s reference must be
connected to the 2M REF IN port. The
format can be CLOCK or DATA.
2. Set up the ; TEST
TRANSMIT
FUNCTION display as shown opposite.
Pointer adjustments are made every 10 ms
with an extra ADDED adjustment as
defined in CCITT standard G.783.
Pointer sequences are started by selecting
STARTED
.
19
SDH Testing
Desynchroniser Stress
3. Set up the ; JITTER
RECEIVE
PDH
display as shown opposite.
SHORT TERM PERIOD need only be set
if it is intended to view Short Term results
4. Set up the display as
RESULTS
shown opposite. .
Start the Desynchroniser Stress Test
1. Press to start the Jitter
RUN/STOP
measurement.
Jitter Hits or any other result can also be
viewed without affecting the measurement
20
SDH Testing
Frame Synchronization
Frame Synchronization
Application
A network element should maintain synchronization even in the presence of some
frame errors. If the number of frame errors exceeds the specified threshold for 3 ms,
the network element will lose frame synchronization causing a new search for frame
alignment to begin.
The frame synchronization process of the network element can be stressed by
injecting frame errors, into the A1 and A2 framing bytes of the Regenerator Section
overhead. As the frame error injection rate is increased to the frame synchronization
threshold, the network element should indicate Out Of Frame (OOF) and Loss Of
Frame (LOF) conditions. As the frame error injection rate is decreased again, the
network element should regain frame synchronization.
Default (Known State) Settings
It is advisable to set the HP 37717C to a known state before setting up a
measurement. This clears all previous settings and provides a clearly defined
instrument state. The default settings are set by selecting
SETTINGS RECALL
STORED SETTING NUMBER 0 and pressing .
OTHER
STORED
Frame Synchronization Test Setup Procedure
Frame Error Add Test Function In this setup the HP 37717C Communications
Performance Analyzer is used to insert frame errors in the A1 and A2, framing bytes
of the Regenerator section overhead of an STM-1 optical signal. The STM-1 optical
signal is transmitted to the network equipment. The network equipment OOF and
LOF alarms are monitored as the frame error add rate is increased and decreased.
Sequence Generation Test Function
In this setup procedure the HP 37717C Communications Performance Analyzer
generates a sequence of errored framing bytes to test the OOF and LOF alarm
threshold criteria. The upstream STM-1 optical signal is monitored for occurrences
of Multiplexer Section FERF. The downstream STM-1 optical signal can be
monitored for AIS.
21
SDH Testing
Frame Synchronization
1. Connect the HP 37717C to the network
equipment and set up the ;
SETTINGS CONTROL
OTHER
display as shown
opposite.
2. Set up the ; display
TRANSMIT
SDH
as shown opposite.
The CLOCK SYNC selection determines
the synchronization source for the
TRANSMIT
clock. If
EXTERNAL MTS
is selected a 2 Mb/s reference must be
connected to the front panel 2M REF IN
port. The format can be CLOCK or DATA.
22
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