Cisco Catalyst 2000 Configuration Handbook page 142

4
Catalyst C1
32768: 00-d0-00-74-60-00
4
Catalyst C1
32768:
00-d0-00-74-60-00
Bridge
Figure 7-2 Network Diagram Demonstrating Poor STP Root Placement
As it might be expected, the links between the core and other switches are Gigabit
Ethernet. The uplinks from Catalyst A into the core, however, are Fast Ethernet.
When the root bridge is elected, Catalyst A wins based on its lower MAC address. (All
switches have their default bridge priorities of 32768.) Both of the uplink ports on switch
A become designated ports because it is now the root. The downlinks from C1 and C2 to
4
4
GigE
4
19
100FX
Catalyst A
32768: 00-01-42-3a-89-00
GigE
4
4
DP
RP
100FX
19
DP
Root
Catalyst A
32768: 00-01-42-3a-89-00
Chapter 7: Spanning Tree Protocol (STP) 121
4
4
4
Catalyst C2
32768: 00-d0-04-57-38-aa
19
100FX
GigE
4
4 4
X
Catalyst C2
RP
32768:
00-d0-04-57-38-aa
100FX
19
DP