Chapter 9 - Bridging | 151 |
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ϖNote: Nodes on segments connected through routers which are not doing bridging do not need to be counted. This is because a router hides the phys- ical addresses of the nodes behind it.
Aging Time
This is the number of seconds since a node’s last transmission before its address will be removed from the bridge table. Values may range from 10 to 100,000. The default is 300.
Priority (Spanning Tree)
The spanning tree algorithm uses this value to help determine the Root Bridge for a network. The priority is combined with the bridge’s node address to create an eight byte bridge ID. The bridge which has the numerically lowest bridge ID on a network will become the Root Bridge for that network. There will only be one Root Bridge per network.
Values may range from 0 to 65,535. The default value is 32,768.
ϖNote: Setting a bridge’s priority to 0 should make it the Root Bridge on the network.
Max Age (Spanning Tree)
This parameter determines the maximum amount of time before the informa- tion from the last BPDU packet received is considered stale and the spanning tree is recalculated. Values may range from 6 to 40. The default value is 20 seconds.
ϖNote: All bridges on a network use the Max Age value configured into the Root Bridge.
Hello Time (Spanning Tree)
This parameter determines the amount of time between spanning tree BPDU packets sent by the bridge. Values may range from 1 to 10. The default is 2 seconds.
ϖNote: All bridges on a network use the Hello Time value configured into the Root Bridge.
Fwd Delay (Spanning Tree)
This parameter determines the amount of time between interface state transi- tions in the bridge. After startup the bridge spends this amount of time deter- mining whether an interface should participate in the network’s spanning tree or be blocked. Once that decision has been made, the same amount of time is also spent learning addresses on the interface before forwarding is enabled.
Values may range from 4 to 30. The default value is 15 seconds.
ϖNote: All bridges on a network use the Fwd Delay value configured into the Root Bridge.
