3Com Router Module Guide
Chapter 4
4-44
4.12
ROUTER 4-PORT E1 IMA FIC
4.12.1
Introduction
ROUTER 4-PORT E1 IMA FIC, the 4port E1 ATM inverse multiplexing interface card
provides four or eight E1 interfaces that support inverse multiplexing for ATM (IMA)
technology.
IMA technology distributes an ATM cell stream over multiple low-speed links on a cell
by cell basis and reassembles the cells into the original stream at the far end. It is a
cost-effective way for you to transmit high-speed ATM cell streams over low-speed
links while allowing for great flexibility.
This technology is common on a PDH network over which ATM cells are transmitted.
4.12.2
Interface Attributes
The following table describes the interface attributes:
Table 4-27
Interface attributes of the ROUTER 4-PORT E1 IMA FIC
Description
Attribute
ROUTER
4-PORT E1 IMA
FIC (75-ohm)
(75-ohm)
ROUTER
4-PORT E1 IMA
FIC (120-ohm)
(120-ohm)
Connector DB-68
Number of
connectors
1
Interface standard
ITU-G.703, ITU-G.704
Interface rate
2.048 Mbps
Cable type
75-ohm 8E1 conversion cable
120-ohm 8E1 conversion cable
Cable characteristic
impedance
75-ohm 120-ohm
Max transmission
distance
500 m (1640.4 feet)
150 m (492.1 feet)
Operating mode
ATM E1 independent link /IMA bundle mode
Supported service
AAL5
Protocol
PPPoA, PPPoEoA, IPoA, IPoEoA
Transmission rate
CBR/VBR-rt/VBR-nrt/UBR