Spanning-Tree Timers; Creating The Spanning-Tree Topology; Spanning-Tree Interface States - Cisco M10-RM Software Manual

Chapter 8 Configuring Spanning Tree Protocol

Spanning-Tree Timers

Table 8-1
Table 8-1 Spanning-Tree Timers
Variable Description
Hello timer Determines how often the access point broadcasts hello messages to other access points.
Forward-delay timer Determines how long each of the listening and learning states last before the interface begins
forwarding.
Maximum-age timer Determines the amount of time the access point stores protocol information received on an interface.

Creating the Spanning-Tree Topology

In Figure
is set to the default (32768) and bridge 4 has the lowest MAC address. However, because of traffic
patterns, number of forwarding interfaces, or link types, bridge 4 might not be the ideal spanning-tree
root. By increasing the priority (lowering the numerical value) of the ideal bridge so that it becomes the
spanning-tree root, you force a spanning-tree recalculation to form a new topology with the ideal bridge
as the spanning-tree root.
Figure 8-1
LAN segment A
LAN segment B

Spanning-Tree Interface States

Propagation delays can occur when protocol information passes through a wireless LAN. As a result,
topology changes can take place at different times and at different places in the network. When an
interface transitions directly from nonparticipation in the spanning-tree topology to the forwarding state,
OL-14209-01
describes the timers that affect the entire spanning-tree performance.
8-1, bridge 4 is elected as the spanning-tree root because the priority of all the access points
Spanning-Tree Topology
Bridge 1
Bridge 3
Cisco IOS Software Configuration Guide for Cisco Aironet Access Points
Understanding Spanning Tree Protocol
Bridge 2
Bridge 4
8-5