EMM-E6 Ethernet User's Guide

ETHERNET CHANNELS A, B, C, D, E, and F
EMM-E6 User’s Guide 1-13
1.4.2 Ethernet Channels B and C
The Cabletron Systems MultiChannel family of MIMs includes the
Repeater Interface Controller Media Interface Module (RIC MIM), an
IEEE 802.3 compliant multi-port repeater. You can configure these
modules to operate on either the Ethernet Channels B or C, or as a
standalone repeater, using hardware jumpers or management software.
RIC technology provides the option of connecting multiple RIC MIMs
over one common bus. This single bus connection allows multiple RIC
MIMs, communicating over an inter-RIC bus, to act as a single logical
repeater. For example:
• An Ethernet frame follows a path from one RIC MIM, to the
inter-RIC bus, to another RIC MIM.
• The RIC MIM retimes and regenerates the frame before transmitting
it to all ports.
Using this configuration yields a path cost equivalent to only one repeater
hop. Since the limit of serially linked repeaters in an Ethernet network is
only four, using the RIC repeater offers a significant advantage. By using
cascading RIC MIMs it is possible to construct a much larger network
than you could with stand-alone repeaters.
Channels B and C traffic travels through RIC MIMs (i.e., TPRMIMs,
FORMIMs, and CXRMIMs). These MIMs repeat packets on their own,
without the EMM-E6. Ethernet Channels B and C handle network traffic
over the RIC management bus on the FNB.
When frames have destination addresses for the same bus:
• the sending RIC MIM transmits the frames over its designated
Ethernet bus;
• the other RIC MIMs on this bus receive the frames, and repeat them;
• the EMM-E6 receives the frames and, after determining the
destination, filters the frame.
CH1Book Page 13 Wednesday, March 20, 1996 7:48 AM