Cisco Catalyst 2960-XR Configuration Guide

Information About Spanning Tree Protocol 14
Spanning Tree Protocol 14
Spanning-Tree Topology and BPDUs 15
Bridge ID, Device Priority, and Extended System ID 17
Port Priority Versus Path Cost 18
Spanning-Tree Interface States 18
Blocking State 19
Listening State 20
Learning State 20
Forwarding State 20
Disabled State 20
How a Switch or Port Becomes the Root Switch or Root Port 21
Spanning Tree and Redundant Connectivity 21
Spanning-Tree Address Management 22
Accelerated Aging to Retain Connectivity 22
Spanning-Tree Modes and Protocols 23
Supported Spanning-Tree Instances 23
Spanning-Tree Interoperability and Backward Compatibility 24
STP and IEEE 802.1Q Trunks 24
VLAN-Bridge Spanning Tree 24
Spanning Tree and Switch Stacks 25
Default Spanning-Tree Configuration 25
How to Configure Spanning-Tree Features 26
Changing the Spanning-Tree Mode 26
Disabling Spanning Tree 28
Configuring the Root Switch 29
Configuring a Secondary Root Device 30
Configuring Port Priority 31
Configuring Path Cost 32
Configuring the Device Priority of a VLAN 34
Configuring the Hello Time 35
Configuring the Forwarding-Delay Time for a VLAN 36
Configuring the Maximum-Aging Time for a VLAN 36
Configuring the Transmit Hold-Count 37
Monitoring Spanning-Tree Status 38
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
iv OL-29424-01
Contents

Cisco Catalyst 2960-XR Specifications

General

Stacking Bandwidth	80 Gbps
Layer Support	Layer 2 and Layer 3
Jumbo Frame Support	9198 bytes
RAM	512 MB
Input Voltage	100-240V AC
Model	Catalyst 2960-XR
Uplink Interfaces	4 x 1G SFP or 2 x 10G SFP+
Downlink Interfaces	24 or 48 x Gigabit Ethernet ports
Power Supply	Internal
MAC Address Table Size	16, 000 entries
PoE	Available on PoE models
Weight	4.5 kg
Features	energy efficiency
Stacking	Up to 8 switches
Operating Temperature	0 to 45°C