Cisco Systems OL-4580-01 manual Configuring Spanning-Tree Bridge Priority

Chapter 2 Configuring Spanning-Tree Bridging for the CSS

Configuring Spanning-Tree Bridge Priority

To set the bridge maximum age to 21, enter:

(config)# bridge max-age 21

To restore the default maximum age of 6, enter:

(config)# no bridge max-age

Configuring Spanning-Tree Bridge Priority

In spanning tree, the 2-octet field is prepended to the 6-octet MAC address to form an 8-octet bridge identifier. The device with the lowest bridge identifier is considered the highest priority bridge and becomes the root bridge. By default, the bridge priority is set to 32768. Use the bridge priority command to set the priority that the bridge spanning tree uses to choose the root bridge in the network. The range for bridge priority is 0 to 65535.

For example:

(config)# bridge priority 1700

To restore the bridge priority to the default of 32768, enter:

(config)# no bridge priority

Disabling Bridge Spanning-Tree

Spanning-tree bridging is enabled by default. When you disable spanning-tree bridging, the CSS forwards all multicast traffic, including bridge protocol data units (BPDUs) for the bridge multicast group and for trunked VLANs. The CSS can still operate in an 802.1Q spanning-tree environment as long as you do not require that the CSS put any of its ports into a blocking state.

Caution Disabling spanning-tree bridging may make your network susceptible to packet storms.

	Cisco Content Services Switch Routing and Bridging Configuration Guide
OL-4580-01		2-5