Olicom CrossFire 8730, Reference Manual

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CrossFire 8730 Switch Reference Guide, DOC-7047 v. 1.1 Switch Overview
Figure 7. Source Route Bridging (SRB) Mode
Redundant Connections to Fast Ethernet Network
A connection to the Ethernet cloud can be made using several Fast Ethernet ports
from multiple switches. Fast Ethernet ports connected from one switch to the same
Ethernet cloud should be grouped into one common CRF with an assigned LAN
segment number. From each switch, one CRF can be connected to the same
Ethernet cloud.
Redundant connections between source-routed and transparent networks may
cause ARE frame duplication and infinite ARE frame loops as a result of discarding
source routing information during translation from Token-Ring to Ethernet format.
There are, however, solutions to both problems:
•
Infinite frame loops are eliminated by using a common LAN segment number
for the entire Ethernet cloud or by proper Spanning Tree configuration. The
recommended CRF number is 4095.
•
Frame duplication is eliminated by a proper STP configuration allowing only
one link between the Token-Ring cloud and the Ethernet to be forwarding.
See the next section “Network Scenarios—Preventing Frame Duplication and
Looping” on page 26 for details.
3 2 5 4 8 7 6 10 9 15 12 11 14 13 17 16 19 18 20
STACK-LINK
ATTACH RX TX
DIAG PWR RST ERR MANAGEMENT
21 FAST ETHERNET 21-22 25-26 22 26 25
1
Fast Ethernet Translation Switch
CrossFire 8730
FAULT
STATUS
FAULT
STATUS
LINK
100
ACT
LINK
100
ACT
LINK
100
ACT
LINK
100
ACT
Ethernet cloud
Token-Ring
cloud
Token-Ring
cloud
SR Bridge
All translational links grouped
into one CRF (SRB mode). If
more than one link is used, IEEE
STP must be enabled.
BRF with IEEE STP enabled
CRF with
Token-Ring
ports in SRT or SRB mode
CRF with
Token-Ring
ports in SRT or SRB mode