Cisco Catalyst 4500 Series Software Configuration Guide

26-13
Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 26 Configuring Optional STP Features
Configuring Bridge Assurance
Observe these guidelines when configuring Bridge Assurance:
• It can be enabled or disabled globally.
• It applies to all operational network ports, including alternate and backup ports.
• Only Rapid PVST+ and MST spanning tree protocols support Bridge Assurance. PVST+ does not
support Bridge Assurance.
• For Bridge Assurance to work properly, it must be supported and configured on both ends of a
point-to-point link. If the device on one side of the link has Bridge Assurance enabled and the device
on the other side does not, then the connecting port is blocked (a Bridge Assurance inconsistent
state). We recommend that you enable Bridge Assurance throughout your network.
• To enable Bridge Assurance on a port, BPDU filtering and BPDU Guard must be disabled.
• You can enable Bridge Assurance in conjunction with Loop Guard.
• You can enable Bridge Assurance in conjunction with Root Guard. The latter is designed to provide
a way to enforce the root bridge placement in the network.
Configuring Bridge Assurance
This example show how to display spanning tree information and verify if Bridge Assurance is enabled.
Look for these details in the output:
• Portfast Default—Network
• Bridge Assurance—Enabled
Switch# show spanning-tree summary
Switch is in rapid-pvst mode
Root bridge for: VLAN0199-VLAN0200, VLAN0128
EtherChannel misconfig guard is enabled
Extended system ID is enabled
Portfast Default is network
Portfast Edge BPDU Guard Default is disabled
Portfast Edge BPDU Filter Default is disabled
Loopguard Default is enabled
PVST Simulation Default is enabled but inactive in rapid-pvst mode
Bridge Assurance is enabled
UplinkFast is disabled
BackboneFast is disabled
Command Purpose
Step 1
Switch # configure terminal
Enters the global configuration mode.
Step 2
Switch(config)# spanning-tree bridge assurance
Enables Bridge Assurance on all network ports on the
switch.
Bridge Assurance is enabled by default.
Use the no version of the command to disable the feature.
Disabling Bridge Assurance causes all configured
network ports to behave as normal spanning tree ports.
Step 3
Switch(config-if)# end
Exits configuration mode.
Step 4
Switch# show spanning-tree summary
Displays spanning tree information and shows if Bridge
Assurance is enabled

Cisco Catalyst 4500 Series Specifications

General

Series	Catalyst 4500 Series
Category	Switch
Layer Support	Layer 2, Layer 3
Form Factor	Modular chassis
Stackable	No
Chassis Slots	3, 6, 7, 10
Power Supply Options	AC, DC
Redundancy	Power supply, Supervisor engine
Network Management	Cisco IOS Software CLI, SNMP, Cisco Prime Infrastructure
Features	Security, QoS
Port Density	Up to 384 ports per chassis
Security Features	802.1X, ACLs, DHCP Snooping, Dynamic ARP Inspection, IP Source Guard
Supervisor Engine	8-E