This manual contains information that is proprietary to RAD Data Communications. No part of this
publication may be reproduced in any form whatsoever without prior written approval by RAD Data
Communications.
No representation or warranties for fitness for any purpose other than what is specifically mentioned in
this manual is made either by RAD Data Communications or its agents.
For further information contact RAD Data Communications at the address below or contact your local
distributor.
International Headquarters
RAD Data Communications Ltd.
24 Raoul Wallenberg St.
Tel Aviv 69719 Israel
Tel: 972-3-6458181
Fax: 972-3-6498250
E-mail: rad@rad.co.il
This RAD product is warranted against defects in material and workmanship for a period of one year
from date of shipment. During the warranty period, RAD will, at its option, either repair or replace
products which prove to be defective. For warranty service or repair, this product must be returned to
a service facility designated by RAD. Buyer shall prepay shipping charges to RAD and RAD shall pay
shipping charges to return the product to Buyer. However, Buyer shall pay all shipping charges, duties
and taxes for products returned to RAD from another country.
Limitation of Warranty
The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance
by Buyer, Buyer-supplied firmware or interfacing, unauthorized modification or misuse, operation
outside of the environmental specifications for the product, or improper site preparation or
maintenance.
Exclusive Remedies
The remedies provided herein are the Buyer’s sole and exclusive remedies. RAD shall not be liable for
any direct, indirect special, incidental, or consequential damages, whether based on contract, tort, or
any legal theory.
Regulatory Information
FCC-15 User Information
This equipment has been tested and found to comply with the limits of the Class B digital device,
pursuant to Part 15 of the FCC rules. These limits are designed to provide reasonable protection
against harmful interference when the equipment is operated in a commercial environment. This
equipment generates, uses and can radiate radio frequency energy and, if not installed and used in
accordance with the instruction manual, may cause harmful interference to the radio communications.
Operation of this equipment in a residential area is likely to cause harmful interference in which case
the user will be required to correct the interference at his own expense.
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Safety Warnings
The exclamation point within a triangle is intended to warn the operator
or service personnel of operation and maintenance factors relating to the
product and its operating environment which could pose a safety hazard.
Always observe standard safety precautions during installation, operation and maintenance of this
product. Only a qualified and authorized service personnel should carry out adjustment, maintenance
or repairs to this instrument. No adjustment, maintenance or repairs should be performed by either the
operator or the user.
Telecommunication Safety
The safety status of each of the ports on IPmux-1/1E is declared according to EN 41003 and is detailed
in the table below:
Safety Status Ports
SELV LAN, Unbalanced E1, E&M, ISDN-S
TNV-1 Balanced E1, T1
TNV-2 FXS
TNV-3 FXO
SELV = Safety Extra-Low Voltage
TNV-1 = Telecommunications Network Voltage within the limits of SELV and subject to overvoltages
TNV-2 = Telecommunications Network Voltage not subject to overvoltages
TNV-3 = Telecommunications Network Voltage subject to overvoltages
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Declaration of Conformity
Manufacturer’s Name: RAD Data Communications Ltd.
Manufacturer’s Address: 24 Raoul Wallenberg St.
Tel Aviv 69719
Israel
declares that the product:
Product Name: IPmux-1
conforms to the following standard(s) or other normative document(s):
EMC:EN 55022 (1998) Information technology equipment – Radio disturbance
characteristics – Limits and methods of measurement.
EN 50024 (1998) Information technology equipment –Immunity
characteristics – Limits and methods of measurement.
Safety:EN 60950/A4 (1996) Safety of information technology equipment, including electrical
business equipment.
Supplementary Information:
The product herewith complies with the requirements of the EMC Directive 89/336/EEC and the
Low Voltage Directive 73/23/EEC. The product was tested in a typical configuration.
Tel Aviv, March 18
th
, 2001
Haim Karshen
VP Quality
European Contact: RAD Data Communications GmbH, Berner Strasse 77, 60437 Frankfurt am Main, Germany
IPmux-1/1E offers a solution for extending traditional E1/T1, ISDN, or POTS TDM
services transparently over the widely deployed IP networks. The device converts
the data stream coming from its user ports into configurable sized IP packets that
are extended over the Fast Ethernet port and vice versa. IPmux-1/1E offers
end-to-end synchronization for voice applications. IPmux-1/1E also offers large
buffers to compensate for the delay variation inserted by the network. The device
can be used to extend E1/T1 or ISDN/POTS circuits over IP networks for
Metropolitan Area Network applications. IPmux-1/1E also features a Fast Ethernet
user port for data (Ethernet) connectivity to the IP/Ethernet network. Management
is performed locally by a terminal, or remotely via Telnet or SNMP.
Versions
IPmux-1 has a single E1/T1 port.
IPmux-1E offers one of the following options:
• 4 BRI – a card with 4 ISDN standard S-interfaces
• 4 FXS – a card with 4 FXS ports
• Optional user Ethernet port.
The IPmux family implements TDMoIP technology to carry TDM transport over IP.
IPmux-1E BRI channels are transported as TDM timeslots, while the Analog FXS
channels are digitized and carried as fractional E1/T1 with CAS.
• IPmux-1 with E1 interface
− Balanced line with an RJ-45 connector
− Unbalanced line with a mini-coaxial connector (TBNC)
• IPmux-1 with T1 interface – Balanced with an RJ-45 connector
• IPmux-1E with FXS interface – 4 Analog ‘FXS’ RJ-11 connectors
Overview1-1
An external clock port is optional for IPmux-1.
A user Ethernet interface is optional for IPmux-1/1E (Ordering options).
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Applications
Typical IPmux-1/1E applications are shown with E1/T1, ISDN, and FXS interfaces.
Figure 1-1 illustrates Multiplexing Voice and Data over an Ethernet Trunk.
Figure 1-2 shows an E1/T1 circuit extension over an IP based Network.
Figure 1-3 illustratesmixed BRI and POTS support application of V5.1 concentration of BRI remote terminals.
Figure 1-4 shows mixed BRI and POTS support application of S/U interface concentration.
Figure 1-5 illustrates extending BRI ports and LAN of a Small Office.
Figure 1-6 shows Ethernet-based multi-tenant with voice and data integrated
access.
SITE A
E1/T1E1/T1
PBXPBX
10/100
Mbps
IPmux-1IPmux-1
Ethernet
Switch
Ethernet
Ethernet
Switch
10/100
Mbps
SITE B
Figure 1-1. Multiplexing Voice and Data over an Ethernet Trunk
1-2Overview
IPmux-1/1E Installation and Operation Manual Chapter 1 Introduction
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Fractional
E1/T1
10/100 Mbps
Ethernet
Switch
100 Mbps
IPmux-16
IPmux-4
Ethernet
Switch
IP Network
Public Internet
or
n E1/T1
×
100 Mbps
Fiber
PBX
IPmux-1
PSTN
Fractional
E1/T1
PBX
PBX
IPmux-1
Figure 1-2. E1/T1 Circuit Extension over an IP Based Network
Overview 1-3
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Megaplex
For BRI
Grooming
ISDN Telephone
ISDN Telephone
POTS
IPmux-1
IPmux-1
Telephone
Switch
Fast Ethernet
Switch
E1 CAS
For FXS
Grooming
Fast Ethernet
Switch
E1 Link
Network
V5.1
POTS
POTS
POTS
Computer
Worksta tion
ISDN Telephone
ISDN Telephone
Computer
Workstation
Fast Ethernet
Switch
Computer
Workstation
IPmux-1
ISDN Telephone
ISDN Telephone
Figure 1-3. Mixed BRI and POTS Support Application (V5.1 Concentration of BRI Remote Terminals)
1-4Overview
IPmux-1/1E Installation and Operation Manual Chapter 1 Introduction
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Megaplex
For BRI
Grooming
POTS
ISDN Telephone
ISDN Telephone
IPmux-1
IPmux-1
Telephone
Switch
Fast Ethernet
Switch
E1 CAS
For FXS
Grooming
Fast Ethernet
Switch
E1 Link
Network
TE U Ports
ISDN Telephone
ISDN Telephone
Computer
Workstation
PBX
Computer
Workstation
Fast Ethernet
Switch
Computer
Workstation
Figure 1-4. U Interface Concentration
TE
S
Network
IPmux-1E
NT
IPmux-1E
Figure 1-5. Extending BRI Ports of a Small Office
IPmux-1
ISDN Telephone
ISDN Telephone
ISDN Telephone
ISDN Telephone
Computer
Workstation
Overview 1-5
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E1/T1
IPmux-1
ISDN
FXS
Phones
IPmux-1E
BRI
Internet
IPmux-1E
Telephony Switch
Features
Ethernet
Switch
IPmux-16
Switch
IP Network
Figure 1-6. Ethernet-based Multi-tenant Application with Voice and Data Integrated Access
IPmux-1/1E is a 1U high, easy-to-install standalone unit. A rack mount installation
option is available.
IPmux-1 can be ordered with AC or DC power supply. IPmux-1E is only available
with AC power supply.
Management
IPmux-1/1E can be managed locally by connecting an ASCII terminal to the
RS-232 port on the front panel or remotely via Telnet or SNMP. The SNMP
management capability enables fully graphical, user-friendly management using
the RADview network management stations offered by RAD, as well as
management by other SNMP-based management systems.
1-6Overview
T1
The T1 port and framers comply with ANSI T1.403 standards. T1 jitter
performance is according to G.704, G.824, TR-62411. The T1 framers support
pass-through, SF, ESF and CAS framing. The T1 port supports long haul and short
haul input signals and can be monitored for alarms and error statistics. FDL and
transmit PRM for T1/ESF are also supported.
E1
The E1 port complies with G.703, G.704, and G.823 standards. E1 framers comply
with G.704. The E1 framers support pass-through, framed, CRC4 MF and CAS MF
framing. The E1 port supports long haul and short haul input signals and can be
monitored for alarms and error statistics.
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ISDN BRI
IPmux-1E has 4-ports, S-interface only. Each port can be configured as either NT
or TE (Network/User) by jumper and software; NT or TE is configured per device.
IPmux-1E can be configured to 1, 2, 3 or 4 active ports.
IPmux-1E works in transparent mode (no termination/compression of D channels).
It operates opposite IPmux with E1/T1 and a Megaplex unit as a concentrator in
transparent mode or opposite another IPmux-1E with ISDN BRI ports.
FXS
IPmux-1E has 4 FXS interface ports for POTS connection. A central IPmux unit
with an E1/T1 CAS interface can groom FXS channels from the remote site.
IP
The data stream coming from the E1 or T1 port is converted into IP packets that
are transported over the Fast Ethernet port, and vice versa.
TDM bytes are encapsulated in a UDP frame that runs over IP and over Ethernet.
The number of TDM bytes in an IP frame is configurable for throughput/delay
tradeoff.
Each device has a single IP address (Host IP). A configurable destination IP address
is assigned to the IP packets. IP ToS field support can be configured for IP Level
Priority.
Ethernet User Port
IPmux-1E has an optional user port for user LAN connectivity/access as well as
TDM services connectivity. A transparent bridging mode is supported
(user/network Ethernet port) and a second mode which enables user port rate
limiting.
Ethernet Physical Port
IPmux-1/1E is available with Ethernet ports (user or network port). The Ethernet
network port can be either UTP or fiber. The Ethernet user port is UTP only.
• UTP option – A standard 10/100BaseT half/full duplex port with
auto-negotiation support. If auto-negotiation is disabled, IPmux-1 capabilities
can be configured to 100BaseT – full duplex, 100BaseT – half duplex,
10BaseT – full duplex, or 10BaseT – half-duplex. Half-duplex operation in
IPmux-1 network port is not recommended, because collisions and backoffs
cause large delay variation and may exceed the delay variation buffer
tolerance at the receiving end, causing buffer underflows and errors to occur.
Overview1-7
• Fiber option – standard 100BaseF full duplex port (see Table 1-1).
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Table 1-1. Fiber Options
Interface Type Wavelength
(nm)
SC Multimode 1300 –20 –14 –31 8* 1 4
SC Single mode 1300 –20 –14 –31 8* 0.5 0.8
LC Multimode 1300 –19 –14 –32 10* 1 4
LC Single mode 1300 –15 –8 –32 14* 0.5 0.8
Optical Power
(dBm)
Min Max
Receive
Sensitivity
(dBm)
Optical
Budget
(dB)*
Loss
(dB/km)
Min Max
• Permitted fiber optic cable length differs according to fiber characteristics,
splices, and connectors.
Note
When a user port option (only UTP) is chosen, the network fiber option is LC. If
there is no user port, the network fiber option is SC.
• Fractional E1/T1 with CAS over UDP over IP over Ethernet.
IPmux-1E with BRI can operate in two modes:
• NT mode
• TE mode.
IPmux-1E with FXS can operate in three modes:
• E1 mode
• T1 mode D4 mode
• T1 ESF mode.
1-8Overview
IPmux-1/1E Installation and Operation Manual Chapter 1 Introduction
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Note
IPmux E1/T1 working opposite IPmux-1E with BRI ports should work in Fractional
E1/T1 mode (no CAS). When working opposite IPmux-1E with FXS, use E1/T1 CAS
mode.
QoS
QoS support:
• Labeling IP level priority (ToS) for TDMoIP packets
• VLAN tagging and priority labeling according to IEEE 802.1p&q for TDMoIP
packets.
The user can configure the ToS (Type of Service) of the outgoing TDMoIP packets.
This allows an en-route Layer 3 router or switch, which supports ToS, to give
higher priority to IPmux-1/1E TDMoIP traffic for delay-sensitive and secure
applications. IPmux-1 allows you to configure the WHOLE ToS byte field, since
different vendors may use different bits to tag packets for traffic prioritization.
This also enables you to work according to various RFC definitions (for example
RFC 2474, RFC 791). The user can also configure VLAN priority bits for
Level 2 Priority.
Note
Timing
IPmux-1 maintains synchronization between TDM devices by deploying advanced
clock distribution mechanisms.
Available timing modes are:
• Loopback
• Adaptive
• Internal Clock
• External Clock.
For more details see Timing Modes in Section 1.3.
Standards
G.703, G.704, G.706, G.823, ANSI T1.403, AT&T TR-62411, G.824, IEEE 802.3,
I.430, IEEE 802.3D, IEEE 802.1p&q, EMC Class B compliance – EN55022 Class B
Overview 1-9
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1.2 Physical Description
IPmux-1 is a 1U high 19-in (IPmux-1E is a 1U high ½ 19-in), easy-to-install
standalone unit. A rack mounting kit option is available (ordered separately).
Figure 1-7 shows a 3-dimensional view of IPmux-1; Figure 1-8 shows a
3-dimensional view of IPmux-1E.
Figure 1-7. IPmux-1 3-D View
Figure 1-8. IPmux-1E 3-D View
1-10Physical Description
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Front Panel
The control interface and indicator LEDs are located on the front panel of
IPmux-1/1E. For further details see Chapter 2.
Rear Panel
User and network ports and power supply are located on the rear panel of
IPmux-1/1E. For further details see Chapter 2.
1.3 Functional Description
IPmux-1 supports a single E1 or T1 TDM interface; it provides TDM connectivity
across the IP network. A single bundle (group of timeslots) can be transmitted to a
predefined far-end bundle. IPmux-1 supports ICMP (ping), and generates ARP in
case of unknown next hop MAC addresses, answers ARP requests, and supports
802.3 Ethernet format.
IPmux-1E supports 4 BRI or 4 FXS ports for transparent connectivity over the IP
network.
Both IPmux-1 and IPmux-1E support Ethernet user port for user LAN connectivity.
Configuration and management are provided via the IPmux-1/1E local terminal,
Telnet or RADview management tool (SNMP).
Figure 1-9 shows a typical application for IPmux-1.
E1/T1 Port
IPmux-1
10/100BaseT
100BaseF100BaseF
IP
10/100BaseT
E1/T1 Port
IPmux-1
Figure 1-9. IPmux-1 Functional Diagram
IPmux-1/1E works in conjunction with the rest of the IPmux product line (see
Figure 1-10). The combination of IPmux products provides up to 31 per E1 or
24 per T1 remote bundles, attached to one central IPmux-4/16 (see Figure 1-10).
Functional Description 1-11
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Sub E1/T1
IPmux-1
E1/T1 Line 1
E1/T1 Line 2
E1/T1 Line 3
E1/T1 Line 4
Other BRI/FXS applications are shown in Figure 1-3, Figure 1-4, and Figure 1-5.
Operation Modes
IPmux-1 E1/T1
IPmux-1 E1/T1 operation modes are:
• Unframed
IPmux-1
IP over
Ethernet
IPmux-4/16
IPmux-1
IPmux-1
Sub E1/T1
Figure 1-10. Grooming of Timeslots from Remote Sites into a
Single E1/T1 Port at Central Site
Sub E1/T1
Sub E1/T1
Note
• Fractional
• Fractional with CAS.
Unframed
In the transparent mode, the incoming bit stream from each channel (regardless of
framing) is converted into IP over Ethernet frames. This option provides clear
channel end-to-end service (unframed).
Fractional
In the fractional mode, the incoming bit stream is regarded as a sequence of
n x 64 kbps channel groups (according to framing). Each predefined group of
channels is converted into a structure block. The structure block is packetized into
IP frames and transmitted.
This mode allows transmission of several selected timeslots without the whole E1
or T1 frame, as in transparent mode.
Use Fractional mode when grooming ISDN BRI channels from a remote IPmux-1E
unit.
1-12Functional Description
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Fractional with CAS
In the fractional-with-CAS mode, the structure block (as described under
Fractional Operation Modes, above) also includes Channel Associated Signaling
(CAS). The relevant portion of the signaling channel is packetized and sent to the
destination.
Note
Use Fractional with CAS mode when grooming FXS channels from a remote
IPmux-1E unit.
IPmux-1E ISDN BRI
The IPmux-1E ISDN BRI S interface operation modes are:
• TE mode
• NT mode.
The selected mode applies to all 4 channels. The NT or TE mode is determined by
phantom feeding and software setting, which is enabled/disabled by jumpers
located on the BRI card (see Chapter 2).
Note
TE Mode
All four channels are configured in TE (Terminal Equipment) as defined in I.430.
NT Mode
All four channels are configured in NT (Network Termination) as defined in I.430.
TE Deactivation is not used in NT mode, and Layer 1 is in active mode all the
time.
If phantom feeding is enabled by the jumpers, the TE mode cannot be selected as
the IPmux-1E operation mode. If phantom feeding is disabled, both NT and TE are
valid options.
IPmux-1E FXS
IPmux-1E FXS operates in:
• E1 mode
• T1-D4 mode
• T1 ESF mode.
Functional Description 1-13
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The IPmux-1E FXS operation modes allow IPmux to work opposite E1, T1-D4, or
T1-ESF. Two parameters are set internally when choosing one of the options:
• A-Law/µ-Law
− A-Law when E1 mode is selected
− µ-Law is used in PCM CODEC when T1 (D4 or ESF) is selected.
• E1, T1-D4, and T1-ESF with CAS are structured differently in the TDM ↔IP
interworking function. A different structure must be used when working
opposite each one.
BRI/FXS TS Assignment in a Bundle
BRI
The TS assignment in a Bundle for IPmux-1E with BRI (when working opposite
IPmux with E1/T1 or Megaplex) is assigned as follows:
First ChannelSecond Channel
Testing
B1
B2D
MSB Bits 7, 6 contain
D channel informat ion
B1
B2D
MSB Bits 7, 6 contain
D channel informat ion
…
Figure 1-11. TS Assignment in a Bundle for IPmux-1E/BRI
As shown in Figure 1-11, the 4 BRI channels consume 12 timeslots in the Bundle.
The E1/T1 IPmux should work in framed mode (no CAS).
The three TS groups in the bundle are assigned according to BRI channel numbers;
the first group is assigned to the lowest BRI channel that is enabled, etc.
FXS
The TS assignment in a Bundle for IPmux-1E with FXS is straightforward. Each
timeslot in a Bundle is assigned to a specific FXS channel. Time slots in the bundle
are assigned according to FXS channel numbers; the first timeslot is assigned to the
lowest FXS channel that is configured, etc. As shown in Figure 1-11, the 4 FXS
channels consume 4 timeslots in the Bundle.
The E1/T1 IPmux that works opposite the FXS channels should work in Framed
with CAS mode.
1-14 Functional Description
Diagnostic capabilities include E1/T1 or BRI S local and remote loopback tests for
rapid localization of faults. The E1/T1 or BRI S channel can be looped locally,
toward the line, or toward the remote end (see Chapter 4 for more information).
Remote Loopback and Tone Injection are available for the FXS port.
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Timing Modes
The E1/T1 Tx clock, or ISDN/FXS PCM clock, can operate in several timing modes
to provide maximum flexibility for connecting the IPmux-1 E1, T1, ISDN or FXS
channels.
Each of the clocks must be configured correctly on both the Receive and Transmit
ends to ensure proper operation and prevent pattern slips (see Figure 1-12,
Figure 1-14, and Figure 1-15).
E1/T1
The E1/T1 available Tx modes are:
• Loopback Timing – the E1/T1 Tx clock is derived from the E1/T1 receive (Rx)
clock.
• Adaptive Timing – in this mode, the E1 or T1 Tx clock is regenerated using the
Adaptive method. In this method, the fill level of the buffer receiving packets is
monitored. If the buffer begins to overfill, the regenerated Tx clock frequency
increases to avoid overflow. If the buffer begins to empty, the Tx clock (toward
the TDM device) decreases to avoid underflow.
Note
Warning
• Internal Clock Timing – in this mode, the Tx clock is received from an internal
oscillator.
• External Clock Timing – in this mode the Tx clock is taken from the external
clock input (Ordering option). The External Clock port also outputs the input
clock signal to allow connection to other units, if needed.
In Adaptive Timing mode the regenerated clock is subject to network Packet Delay
Variation and may not comply with jitter and wander specifications.
FXS/BRI
The available timing modes for the PCM clock are:
• Loopback Timing – available only when IPmux-1E BRI is configured as TE (not
available in BRI NT mode or for FXS interface). In this mode the PCM clock is
derived from Channel 1.
It is recommended not to deactivate Channel 1 while it is in loopback clock so
that data will not be damaged. If Channel 1 is disconnected or deactivated (by
the NT side), the PCM clock will change to Internal clock and a momentary
disruption will occur to the other channels (2,3,4), if they are active.
Functional Description1-15
• Adaptive Mode – the clock is regenerated using the Adaptive method, where
the rate of arriving packets is used to regenerate the clock (see E1/T1).
• Internal Mode – the clock is received from an internal oscillator.
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Network Timing Schemes
The following paragraphs describe typical timing schemes and the correct timing
mode settings for achieving end-to-end synchronization.
External Network Timing
When the edges of the network are synchronized according to an external
network clock source, all the IPmux-1 units should be configured to work in
loopback timing mode (see Figure 1-12). This topology enables any-to-any
connectivity.
Clock from External Distribution Network
E1/T1 Device
E1/T1 Device
E1/T1
E1/T1
LBT Mode
LBT Mode
IPmux-1
IPmux-1
IP over
Ethernet
IPmux-1
IPmux-1
E1/T1
E1/T1
LBT Mode
E1/T1
E1/T1
LBT Mode
Figure 1-12. IPmux-1 in Loopback Timing Mode
External timing from the network can also be issued to IPmux-1 by External Clock
input; in this case, the E1/T1 device will use the LBT mode.
Clock from External Distribution Network
E1/T1 Device
LBT Mode
External
Clock Mode
IPmux-1
IP over
Ethernet
IPmux-1
E1/T1 Device
E1/T1
E1/T1
Figure 1-13. IPmux-1 in External Clock Mode
E1/T1 Device
E1/T1 Device
LBT Mode
1-16Functional Description
Single Source Clock Network
When a common clock is not available on all the ends of the network one of the
IPmux-1 devices is configured to work in Loopback timing mode, while the other
IPmux-1 device is configured to work in Adaptive timing mode (see Figure 1-14).
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Master Clock
Source Devi ce
E1/T1 DeviceE1/T1 Device
Loopback Timing Mode
E1/T1
E1/T1
IPmux-1
IP over
Ethernet
Adaptive Mode
E1/T1
E1/T1
IPmux-1
Remote Loopback
Timing Device
Figure 1-14. IPmux-1 in Adaptive Timing Mode
Adaptive
ISDN
ISDN
ISDN
POTS
Adaptive
LBT
IP over
Ethernet
IPmux-4/16
Adaptive
Grooming
of BRI
E1
Megaplex
Grooming of FXS
in E1 CAS
LBT
V5.1
Telephone
Switch
Figure 1-15. IPmux-1E in Adaptive Timing Mode
Frame Format
The Ethernet frame sent by the IPmux-1 is a UDP datagram that transfers E1/T1
payload bytes over IP over Ethernet (UDP payload + UDP header + IP header +
Ethernet header).
The UDP payload size is equal to TDM bytes per frame (TDM bytes/frame
configuration).
Table 1-2 specifies the structure of the different headers, special fields, and the
payload in the Ethernet packet.
MACIPUDP
Payload
Figure 1-16. TDMoIP Frame Structure
Functional Description 1-17
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Table 1-2. Ethernet Frame Structure
Field length (bytes) Field
7 Preamble
MAC
Layer
LLC
Layer
IP Layer
UDP
Layer
Data
Layer
1 SFD
6 Destination MAC Address
6 Source MAC Address
2 Type
1 Vers/HLEN
1 Service Type
2 Total Length
2 Identification
1 Flags/Fragment Offset (most)
1 Fragment Offset (least)
1 Time to Live
1 Protocol
2 Header Checksum
4 Source IP Address
4 Destination IP Address
2 UDP Source Port
2 UDP Destination Port
2 UDP Message Length
2 UDP Checksum
... Payload
Note: IEEE 802.1p&q VLAN
Tagging (additional 4 bytes if
enabled)
Note: The UDP source port
field is used to transfer the
destination bundle number.
MAC
Layer
1-18Functional Description
4 CRC
VLAN Support
VLAN, according to IEEE 802.1p&q, adds four bytes to the MAC layer of the
Ethernet frame. The contents of these bytes, MAC layer priority and VLAN ID, can
be set by the user. In this mode, only VLAN format frames are sent and received
by IPmux-1. Figure 1-17 describes the VLAN tag format.
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8100
802.1D Tag Protocol Type
UDP Support
Field Length (Bits) Field Description Value Function
2 bytes UDP Source Port 2–497d* Destination timeslots bundle
2 bytes UDP Destination Port 2142d Standard TDMoIP UDP port
* The MSB of this field can be either 1 or 0 for inband end-to-end proprietary signaling.
Note
The UDP Source Port field is used for destination timeslots bundle indication.
For example, if the destination is:
Bundle 1 – 02, Bundle 2 – 03, Bundle 3 – 04, Bundle 4 – 05, etc.
user_priority
CFI = 0
8654181
Priority
Figure 1-17. VLAN Tag Format (802.1p&q)
Table 1-3. UDP Ports Definition
VID
VLAN ID
For more information about VLAN tagging, refer to IEEE Std 802.1p&q.
Packet Delay Variation
Packets are transmitted at set intervals. Packet Delay Variation is the maximum
deviation from the nominal time the packets are expected to arrive at the far end
device. IPmux-1 has a buffer that compensates for the deviation from the expected
packet arrival time to prevent IPmux-1 buffers from emptying out or overflowing.
Packet Delay Variation is an important network parameter. Large PDV (exceeding
the jitter buffer configuration) will cause receive buffer underflows and errors at
the E1/T1 level (see Figure 1-18).
To compensate for large PDV, configure the PDVT (jitter) buffer to a higher value.
Functional Description 1-19
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Packets Leaving IPmux-1
Packets Arriving
PDVT (Jitter) Buffer
IPmux-1 is equipped with a Packet DVT (Delay Variation Tolerance) buffer. The
PDVT buffer or jitter buffer is filled by the incoming IP packets and emptied out to
fill the E1/T1 stream. The buffer begins to empty out only after it is half full in order
to compensate for packet starvation from the Ethernet side. The time it takes for
half of the buffer to empty out is the maximum DVT time. Delay Variation
Tolerance is configurable. The PDVT (jitter) buffer is designed to compensate for
packet delay variation caused by the network + intrinsic PDV.
It supports a delay variation of up to 300 ms for E1 or T1.
PDV
Figure 1-18. Packet Delay Variation
t
t
➤
Note
To configure jitter buffer depth:
Estimated or Measured PDV introduced by the network + intrinsic PDV
(if it exists) introduced by the module as a result of configuring the
TDM bytes / frame > 48 (see explanation of calculating intrinsic PDV, below).
Intrinsic PDV
If TDM bytes/frame is greater than 48, there is an intrinsic delay variation (intrinsic
PDV). The intrinsic PDV introduced by the module is a function of n>1 in
TDM bytes/frame configuration as follows:
I.PDV (ms) = [(n-1) x 1000) / (frames per second × n]
where n =
tes/fram TDM Configured
48
eb
(n = 1 to 8).
For a bundle that contains a few timeslots (i.e. 1–3) the minimal jitter buffer should
be 6 ms.
PDVT Buffer Effect on Delay
The PDVT buffer is on the TDM path; it adds to the total end-to-end delay (see
delay calculation, below).
Ethernet Throughput
1-20Functional Description
Configuring the TDM bytes per frame (TDM bytes/frame) parameter can reduce
Ethernet throughput (bandwidth or traffic travelling through the Ethernet). This
parameter controls the number of TDM bytes encapsulated in one frame. The
TDM bytes/frame parameter can be configured to n x 48 bytes where n is an
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integer between 1 and 8. Configuring TDM bytes/frame to a higher value reduces
the IP/Ethernet overhead segment of the total packet and thus can significantly
reduce the total Ethernet throughput.
On the other hand, packetization delay and intrinsic packet delay variation (PDVT)
are increased; this contributes to a higher end-to-end delay. This effect can be
small and negligible when a full E1 (or many timeslots) are transferred but can be
very significant when few timeslots are transferred. In this case, the packetization
delay and the intrinsic PDV when configuring a large value of
TDM bytes/frame can be very large and may exceed the maximum PDVT (jitter)
buffer on the receiving end. Table 1-4 and Table 1-5 show throughput as a
function of the TDM bytes/frame configuration for full E1 and full T1.
Table 1-4. Ethernet Throughput – Unframed E1
TDM
bytes/frame
48 94 46 96 5447 4.1
96 142 46 48 2724 3.1
144 190 46 32 1816 2.76
192 238 46 24 1362 2.6
240 286 46 19 1089 2.5
288 334 46 16 908 2.43
336 382 46 14 778 2.38
384 430 46 12 681 2.34
Frame
Length
(bytes)
Overhead
(bytes)
Overhead
(%)
Packets
per
Second
Throughput
(Mbps)
Table 1-5. Ethernet Throughput – Unframed T1
TDM
bytes/frame
48 94 46 96 4107 3.08
Frame
length
(bytes)
Over head
(bytes)
Over head
(%)
Packets
per
Second
Throughput
(Mbps)
Functional Description1-21
96 142 46 48 2054 2.32
144 190 46 32 1369 2.07
192 238 46 24 1027 1.95
240 286 46 19 821 1.87
288 334 46 16 685 1.82
336 382 46 14 587 1.78
384 430 46 12 513 1.76
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To calculate Ethernet throughput and intrinsic PDV as a function of
➤
TDM bytes/frame:
Ethernet load (bps) =
[(frame overhead (bytes) + TDM bytes/frame) x 8] x frames/second