CHAPTER 1: INTRODUCTION
1.4ETHERNET 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.
1.4.1Ethernet 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.
