EMM-E6 Ethernet User's Guide

CHAPTER 1: INTRODUCTION
1-12 EMM-E6 User’s Guide
1.4 ETHERNET CHANNELS A, B, C, D, E, and F
The EMM-E6 manages all Ethernet bridging traffic within its resident
hub. This means that the EMM-E6 controls up to six of the Ethernet
bridging channels - A, B, C, D, E, and, in the future, F. These channels
access the same EMM-E6 shared memory, so bridging between channels
is concurrent.
1.4.1 Ethernet Channel A
Channel A operates over the MMAC Power and Management Bus,
Cabletron’s original Ethernet channel. Only Cabletron Systems
non-repeater MIMs (i.e., TPMIMs, FOMIMs, and THN-MIMs) access
the EMM-E6 through Ethernet Channel A. Additionally, the TPXMIM
Ethernet Port Assignment modules are able to communicate through
Ethernet Channel A, as well as the additional backplane channels. When
the EMM-E6 receives a frame on Channel A, it goes through the same
bridging functions as any of the other channels. In addition, the EMM-E6
incorporates IEEE 802.3 repeater logic to repeat Channel A frames. In
other words:
• the EMM-E6 bridges for all attached devices, and provides Ethernet
repeating functions for Channel A modules
• even if the EMM-E6 does not bridge the Channel A traffic it
receives, it still repeats the information back out onto the Ethernet A
Channel.
CH1Book Page 12 Wednesday, March 20, 1996 7:48 AM