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T
UTORIAL
2-16
7.
When bridge 2 receives the BPDU from the Root Bridge (bridge 1)
on LAN A, it adds 100 (the Path Cost of LAN A from bridge 2 back
to the root) to the Path Cost value in the received BPDU, then sends
this value in a BPDU to bridge 4. Bridge 4 receives the BPDU and
adds 15,625 (the Path Cost of the link between bridge 4 and bridge 2
back to the root) to the received Path Cost, making a total of 15,725.
8.
When bridge 3 receives the BPDU from the Root Bridge (bridge 1)
on LAN B, it adds 100 (the Path Cost of LAN B from bridge 3 back
to the root) to the Path Cost value in the received BPDU, then sends
this value in a BPDU to bridge 4. Bridge 4 receives the BPDU and
adds 100 (the Path Cost of LAN C between bridge 4 and bridge 3
back to the root) to the received Path Cost, making a total of 200.
9.
Since the cost of the path via bridge 3 is lower, bridge 4 chooses this
path as the primary, and the link via bridge 2 as the secondary. The
port connected to LAN C becomes the Designated Port for bridge 4.
Bridges 2 and 3 perform similar processes to choose their least cost
paths back to the Root Bridge.
Bridge 1
Bridge 2
LAN A
LAN B
Bridge 4
LAN C
Bridge 3
Host X
Workstation A
64 Kbps
Figure 2-7 Network Loop Eliminated
The above process for this relatively trivial network would be followed in
any network with multiple physical paths. These physical paths may have
been planned to provide failure tolerance in the network, or they may have
been created by accident, which is quite possible in large global networks.
Summary of Contents for Marlin
Page 1: ...ISSUE 3 0 MAN ML BRIDGE REF MARLIN BRIDGE REFERENCE MANUAL Issue 3 0 ...
Page 3: ...ISSUE 3 0 MAN ML BRIDGE REF 1996 Scorpion Logic Ltd A Bay Networks company ...
Page 13: ...CONTENTS Issue 3 0 ...
Page 21: ...OVERVIEW 1 8 ...
Page 30: ...TUTORIAL 2 9 Figure 2 4 Multiple Remote Bridges ...
Page 46: ...TUTORIAL 2 25 ...
Page 74: ...NETWORKING EXAMPLES 3 28 ...