Motorola T1/E1 - Manual (Page 26)

Canopy T1/E1 Multiplexer September 2004
T1/E1 Multiplexer FPGA Version 3.4
Page 26 of 73
1.5.6 VLAN Support
The Canopy T1/E1 Multiplexer fully supports customer VLAN traffic. The Canopy T1/E1
Multiplexer has an increased maximum Ethernet packet size of 1600 bytes. Typically,
the maximum packet size is 1518 bytes for Ethernet traffic, however VLAN traffic adds an
extra 4 bytes for the VLAN tag as in the 802.1Q protocol. In addition, some
manufacturers, such as Cisco, have proprietary VLAN applications that result in extra
long Ethernet packets.
1.5.7 Round‐Trip Packet Delay
The one-directional delay between the two T1/E1 endpoints would be approximately 20
milliseconds. This delay does not include any delay added by Canopy Backhaul Modules.
The Ethernet throughput delay is the time required for one Ethernet packet to pass
through the LAN port of the Canopy T1/E1 Multiplexer. The maximum one-directional
delay for an Ethernet packet of size 1518 Bytes is approximately 240 microseconds,
excluding the delay that Canopy BH modules introduce.
1.5.8 Alarms
The Canopy T1/E1 Multiplexer supports the Alarm Indication Signal (AIS). It is sent
under 2 conditions: a loss of incoming T1/E1 signal (in which case AIS is sent out to the
far end and the same for the other end losing T1/E1 signal) and a loss of BH link (in
which case the AIS is sent in both directions).
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