Motorola T1/E1 User Manual download pdf (Page 25)

Canopy T1/E1MultiplexerSeptember2004

 T1/E1MultiplexerFPGAVersion3.4

Page25 of 73

In a scenario where T1/E1 devices are configured with an external master clock source,

each Canopy T1/E1 Multiplexer should be configured in Loopback Timing Mode. Each

Canopy T1/E1 Multiplexer will take the timing signal from the incoming T1/E1, derive the

clock and then return the clock to the T1/E1 device. The external clock source may be

obtained from any number of sources including Carrier services, GPS, or other high-

quality clock source.

For example, each of the two PBXs might have a SONET connection from the local

telephone company operator. This connection would be used as the master clock source

for both PBXs. Alternatively, each PBX could have a Stratum 3 clock source from the

same Central Office, or could be connected to GPS receivers.

1.5.5 EthernetThroughput

The Ethernet port to the Canopy BH module is a 100-Mbps full duplex port, transmitting

at a throughput rate that does not cause buffer overload in the Canopy modules. The

LAN side Ethernet port, connected to the customer LAN, also transmits at 100 Mbps full

duplex. The Canopy T1/E1 Multiplexer will insert T1/E1 traffic into the Ethernet bit

stream and therefore the Ethernet throughput will be reduced by approximately 2 Mbps

for each T1/E1 that is programmed.

The rates for Ethernet throughput for each programmed T1/E1 connection are displayed

in Table 11.

Table 11: Canopy BH20 Ethernet throughput for programmed T1/E1 connections

Active

T1/E1

Channels

Ethernet Half-duplex

Throughput on LAN

Port in T1 mode.

Ethernet Half-duplex

Throughput on LAN

Port in E1 mode.

1 5.4 Mbps 5.4 Mbps

2 4.1 Mbps 2.66 Mbps

3 2.34 Mbps 24 Kbps

4 240 Kbps N/A*

* Due to the bandwidth limitations of the Canopy BH, only 3 E1 channels can be

used.



NOTE:

The maximum packet rate in T1 mode is 666 packets/sec. The

maximum packet rate in E1 mode is 442 packets/sec. Maximum

Ethernet rate occurs when using 1518-byte packet streams.

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