EMM-E6 Ethernet User's Guide

SAMPLE NETWORK CONFIGURATIONS
EMM-E6 User’s Guide 2-13
The Star Hub, which is an MMAC-FNB that uses a configuration similar
to the closet hubs, is the central repeater interconnect for the closets, but
does not constitute a single point of failure.
The EMM-E6 in each MMAC-FNB utilizes the 802.1d Spanning Tree
Algorithm. By configuring the Root Path Cost and the Bridge Priority on
the EMM-E6, you can bridge primary paths from each segment to
Network D from each EMM-E6 (indicated by the solid line between
Ethernet channel A and the bridge in closet 1, Ethernet channel B and the
bridge in closet 2, and Ethernet channel C and the bridge in closet 3). The
dotted lines between the other Ethernet channels and the bridge show the
backup paths in a standby condition. If any repeater link fails, or if an
active bridge path fails, one or many backup bridge paths may become
active, replacing the failed repeater link or bridge path.
An additional level of redundancy is achieved by using the cable
redundancy algorithm built into Cabletron’s EMM-E6. This feature
enables you to configure redundant bridge paths, with one path remaining
in backup, standby mode until the primary path fails.
In the example, Segment D provides a manageable backbone, using a
MiniMMAC. Segment D provides intercommunication for channels A, B,
and C, as well as serving as the network management segment for the
hierarchy. The individual protocol segments are filtered by the EMM-E6
bridge component, so that the only traffic on segment D is minimal inter-
channel communication (i.e., mail). Otherwise, only network
management data is on segment D, out-of-band of the traffic on channels
A, B, and C.
CH1Book Page 13 Wednesday, March 20, 1996 7:48 AM