Motorola T1/E1 - Manual (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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