Segmentation
5-21
Ethernet
Multichannel Ethernet
Multichannel Ethernet is an inventive means of segmenting a network without
requiring more than one hub. The Flexible Network Bus of the MMAC-FNB
models provides three separate Ethernet buses, or “channels”: Ethernet Channel
A, Ethernet Channel B, and Ethernet Channel C. The basic MIMs that we have
discussed so far all operate on Ethernet Channel A. By connecting to that channel,
the modules pass signals that come in through their ports to the management
unit, which repeats it back across the bus to the other modules on that bus. By
using MIMs that can operate on Ethernet Channels B or C, we provide space for
up to three separate bridged Ethernet networks in one hub.
Normally, in order to do that, we would need a separate management module for
each network segment. That is certainly not a cost-effective solution. Instead,
Cabletron Systems produces a management module that can perform repeating
functions for Ethernet Channel A, as well as bridge to an external Channel D
through a front panel AUI port and to Channels B and C of the hub. This
management module is called an EMME, or Ethernet Management Module with
Ethernet bridging.
The EMME and EMM-E6 (a related module) provide repeating for the Ethernet
Channel A bus, supply extensive management functions for all Ethernet modules
in the chassis, and interconnect Channels A, B, and C of the backplane using the
customer’s choice of bridging or routing. Also, these Multichannel Ethernet
management modules provide bridged or routed connections to external
networks. The EMME supports one front panel segmented connection to an
external Ethernet network, while the EMM-E6 can support the four connections
the EMME is capable of, as well as one connection to an external network of
several diffent types through the use of Bridge/Router Interface Modules.
That still leaves us with a shortfall, though. Every hub module needs to be
repeated. While the EMME does handle repeating for the Ethernet Channel A
MIMs, modules on Channels B and C still need to be repeated. In order to do this,
we place the repeating functions on the individual MIM boards, not in a separate
management module. This important feature allows each module to do all of its
own repeating; they need no management module in order to operate. In the
event of the failure or removal of the EMME, the network users connected to
these self-repeating MIMs can still communicate with the other stations
connected to the channel populated by that MIM.
Summary of Contents for MMAC-5FNB
Page 1: ...Cabletron Systems Networking Guide MMAC FNB Solutions ...
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Page 188: ...Expansion Ethernet 8 12 Port Assignment and Virtual LANs ...
Page 194: ...Expansion Token Ring 9 6 Port Assignment ...