Page 1 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 First Published: August 08, 2013 Americas Headquarters Cisco Systems, Inc. 170 West Tasman Drive San Jose, CA 95134-1706 http://www.cisco.com Tel: 408 526-4000 800 553-NETS (6387) Fax: 408 527-0883 Text Part Number: OL-29424-01...
Page 2 Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company.
Page 3: Table Of Contents
Accessing the CLI through a Console Connection or through Telnet Configuring Spanning Tree Protocol C H A P T E R 2 Finding Feature Information Restrictions for STP Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 4 Configuring the Device Priority of a VLAN Configuring the Hello Time Configuring the Forwarding-Delay Time for a VLAN Configuring the Maximum-Aging Time for a VLAN Configuring the Transmit Hold-Count Monitoring Spanning-Tree Status Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 5 Rapid Convergence Synchronization of Port Roles Bridge Protocol Data Unit Format and Processing Processing Superior BPDU Information Processing Inferior BPDU Information Topology Changes Protocol Migration Process Default MSTP Configuration Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 6 BPDU Filtering UplinkFast Cross-Stack UplinkFast How Cross-Stack UplinkFast Works Events That Cause Fast Convergence BackboneFast EtherChannel Guard Root Guard Loop Guard How to Configure Optional Spanning-Tree Features Enabling PortFast Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 7 PAgP Interaction with Other Features Link Aggregation Control Protocol LACP Modes LACP Interaction with Other Features EtherChannel On Mode Load-Balancing and Forwarding Methods MAC Address Forwarding IP Address Forwarding Load-Balancing Advantages Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 8 Restrictions for Configuring Link-State Tracking Understanding Link-State Tracking How to Configure Link-State Tracking Monitoring Link-State Tracking Configuring Link-State Tracking: Example Additional References for Link-State Tracking Feature Information for Link-State Tracking Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 viii OL-29424-01...
Page 9 Feature Information for Flex Links and MAC Address-Table Move Update Configuring UniDirectional Link Detection C H A P T E R 8 Finding Feature Information Restrictions for Configuring UDLD Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 10 UDLD Reset Options Default UDLD Configuration How to Configure UDLD Enabling UDLD Globally Enabling UDLD on an Interface Monitoring and Maintaining UDLD Additional References for UDLD Feature Information for UDLD Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 11: Preface
A vertical line, called a pipe, indicates a choice within a set of keywords or arguments. [x | y] Optional alternative keywords are grouped in brackets and separated by vertical bars. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 12 Means the described action saves time. You can save time by performing the action described in the Timesaver paragraph. Means reader be warned. In this situation, you might perform an action that could result in bodily Warning injury. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 13: Related Documentation
Obtaining Documentation and Submitting a Service Request For information on obtaining documentation, submitting a service request, and gathering additional information, see the monthly What's New in Cisco Product Documentation, which also lists all new and revised Cisco technical documentation, at: http://www.cisco.com/en/US/docs/general/whatsnew/whatsnew.html...
Page 14 Preface Obtaining Documentation and Submitting a Service Request Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 15: Using The Command-Line Interface
Command Modes The Cisco IOS user interface is divided into many different modes. The commands available to you depend on which mode you are currently in. Enter a question mark (?) at the system prompt to obtain a list of commands available for each command mode.
Page 16 (with a Ethernet ports. To return to specific interface). privileged EXEC mode, press Ctrl-Z or enter end. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 17: Using The Help System
Obtains a list of commands that begin with a particular character string. Example: Switch# di? dir disable disconnect Step 3 abbreviated-command-entry <Tab> Completes a partial command name. Example: Switch# sh conf<tab> Switch# show configuration Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 18: Understanding Abbreviated Commands
CLI Error Messages This table lists some error messages that you might encounter while using the CLI to configure your switch. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 19: Configuration Logging
The software provides a history or record of commands that you have entered. The command history feature is particularly useful for recalling long or complex commands or entries, including access lists. You can customize this feature to suit your needs. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 20: Changing The Command History Buffer Size
Returns to more recent commands in the history buffer after recalling commands with Ctrl-P or the up arrow key. Repeat the key sequence to recall successively more recent commands. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 21: Disabling The Command History Feature
DETAILED STEPS Command or Action Purpose Step 1 terminal editing Reenables the enhanced editing mode for the current terminal session in privileged EXEC mode. Example: Switch# terminal editing Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 22: Editing Commands Through Keystrokes
Ctrl-U or Ctrl-X Deletes all characters from the cursor to the beginning of the command line. Ctrl-W Deletes the word to the left of the cursor. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 23: Editing Command Lines That Wrap
The following example shows how to wrap a command line that extend beyond a single line on the screen. SUMMARY STEPS 1. access-list 2. Ctrl-A 3. Return key Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 24: Searching And Filtering Output Of Show And More Commands
1. {show | more} command | {begin | include | exclude} regular-expression DETAILED STEPS Command or Action Purpose Step 1 {show | more} command | {begin | include | exclude} Searches and filters the output. regular-expression Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 25: Accessing The Cli Through A Console Connection Or Through Telnet
After you connect through the console port, through the Ethernet management port, through a Telnet session or through an SSH session, the user EXEC prompt appears on the management station. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 26 Using the Command-Line Interface Accessing the CLI through a Console Connection or through Telnet Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 27: Configuring Spanning Tree Protocol
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Page 28: Information About Spanning Tree Protocol
The spanning-tree port priority value represents the location of a port in the network topology and how well it is located to pass traffic. The path cost value represents the media speed. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 29: Spanning-Tree Topology And Bpdus
• A root port is selected for each switch (except the root switch). This port provides the best path (lowest cost) when the switch forwards packets to the root switch. When selecting the root port on a switch stack, spanning tree follows this sequence: Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 30 All paths that are not needed to reach the root switch from anywhere in the switched network are placed in the spanning-tree blocking mode. Related Topics Configuring the Root Switch, on page 29 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 31: Bridge Id, Device Priority, And Extended System Id
Restrictions for STP, on page 13 Configuring the Root Switch, on page 62 Root Switch, on page 44 Specifying the MST Region Configuration and Enabling MSTP, on page 59 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 32: Port Priority Versus Path Cost
• From blocking to listening or to disabled • From listening to learning or to disabled • From learning to forwarding or to disabled • From forwarding to disabled Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 33: Blocking State
An interface in the blocking state performs these functions: • Discards frames received on the interface • Discards frames switched from another interface for forwarding • Does not learn addresses • Receives BPDUs Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 34: Listening State
A disabled interface performs these functions: • Discards frames received on the interface • Discards frames switched from another interface for forwarding • Does not learn addresses Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 35: How A Switch Or Port Becomes The Root Switch Or Root Port
Spanning tree automatically disables one interface but enables it if the other one fails. If one link is high-speed and the other is low-speed, the low-speed link is always disabled. If the speeds Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 36: Spanning-Tree Address Management
Dynamic addresses on other VLANs can be unaffected and remain subject to the aging interval entered for the switch. Related Topics Configuring the Root Switch, on page 29 Restrictions for STP, on page 13 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 37: Spanning-Tree Modes And Protocols
The switch supports these spanning-tree modes and protocols: • PVST+—This spanning-tree mode is based on the IEEE 802.1D standard and Cisco proprietary extensions. It is the default spanning-tree mode used on all Ethernet port-based VLANs. The PVST+ runs on each VLAN on the switch up to the maximum supported, ensuring that each has a loop-free path through the network.
Page 38: Spanning-Tree Interoperability And Backward Compatibility
VLAN allowed on the trunks. When you connect a Cisco switch to a non-Cisco device through an IEEE 802.1Q trunk, the Cisco switch uses PVST+ to provide spanning-tree interoperability. If Rapid PVST+ is enabled, the switch uses it instead of PVST+.
Page 39: Spanning Tree And Switch Stacks
Default Setting Enable state Enabled on VLAN 1. Spanning-tree mode PVST+. (Rapid PVST+ and MSTP are disabled.) Switch priority 32768 Spanning-tree port priority (configurable on a per-interface basis) Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 40: How To Configure Spanning-Tree Features
Beginning in privileged EXEC mode, follow these steps to change the spanning-tree mode: SUMMARY STEPS 1. configure terminal 2. spanning-tree mode {pvst | mst | rapid-pvst} 3. interface interface-id 4. spanning-tree link-type point-to-point 5. end 6. clear spanning-tree detected-protocols Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 41 This step is optional if the designated switch detects that this switch is Switch# clear spanning-tree running rapid PVST+. detected-protocols Related Topics Spanning-Tree Modes and Protocols, on page 23 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 42: Disabling Spanning Tree
Switch(config)# no spanning-tree vlan 300 Step 3 Returns to privileged EXEC mode. Example: Switch(config)# end Related Topics Supported Spanning-Tree Instances, on page 23 Default Spanning-Tree Configuration, on page 25 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 43: Configuring The Root Switch
4 number of switches between any two end stations. The range is 2 to 7. Step 3 Returns to privileged EXEC mode. Example: Switch(config)# end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 44: Configuring A Secondary Root Device
Enters the global configuration mode. Example: Switch# configure terminal Step 2 spanning-tree vlan vlan-id root secondary Configures a switch to become the secondary root for the specified [diameter net-diameter] VLAN. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 45: Configuring Port Priority
Beginning in privileged EXEC mode, follow these steps to configure port priority: SUMMARY STEPS 1. configure terminal 2. interface interface-id 3. spanning-tree port-priority priority 4. spanning-tree vlan vlan-id port-priority priority 5. end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 46: Configuring Path Cost
How a Switch or Port Becomes the Root Switch or Root Port, on page 21 Configuring Path Cost This procedure is optional. Beginning in privileged EXEC mode, follow these steps to configure path cost: Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 47 • For cost, the range is 1 to 200000000; the default value is derived from the media speed of the interface. Step 5 Returns to privileged EXEC mode. Example: Switch(config-if)# end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 48: Configuring The Device Priority Of A Vlan
• For priority, the range is 0 to 61440 in increments of 4096; the default 20 priority 8192 is 32768. The lower the number, the more likely the switch will be chosen as the root switch. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 49: Configuring The Hello Time
VLANs separated by a comma. The range is 1 to 4094. 20-24 hello-time 3 • For seconds, the range is 1 to 10; the default is 2. Step 2 Returns to privileged EXEC mode. Example: Switch(config-if)# end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 50: Configuring The Forwarding-Delay Time For A Vlan
Switch(config)# end Configuring the Maximum-Aging Time for a VLAN This procedure is optional. Beginning in privileged EXEC mode, follow these steps to configure the maximum-aging time for a VLAN: Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 51: Configuring The Transmit Hold-Count
Rapid PVST+ mode. Lowering this value can slow down convergence in certain scenarios. We recommend that you maintain the default setting. This procedure is optional. Beginning in privileged EXEC mode, follow these steps to configure transmit hold-count: Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 52: Monitoring Spanning-Tree Status
Displays spanning-tree information for the specified VLAN. Displays spanning-tree information for the specified interface. show spanning-tree interface interface-id show spanning-tree interface Displays spanning-tree portfast information for the specified interface-id portfast interface. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 53: Additional References For Spanning-Tree Protocol
All supported MIBs for this release. To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: http://www.cisco.com/go/mibs Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 54: Feature Information For Stp
Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. Feature Information for STP Release Modification Cisco IOS 15.0(2)EX1 This feature was introduced. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 55: Configuring Multiple Spanning-Tree Protocol
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Page 56: Restrictions For Mstp
PVST+ switch. The PVST+ switches should be at the edge of the network. All stack members run the same version of spanning tree (all PVST+, all Rapid PVST+, or all MSTP). Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 57: Information About Mstp
Both MSTP and RSTP improve the spanning-tree operation and maintain backward compatibility with equipment that is based on the (original) IEEE 802.1D spanning tree, with existing Cisco-proprietary Multiple Instance STP (MISTP), and with existing Cisco PVST+ and rapid per-VLAN spanning-tree plus (Rapid PVST+).
Page 58: Mstp Configuration Guidelines
ID support, the switch sets its own priority for the specified instance to 24576 if this value will cause this switches to become the root for the specified spanning-tree instance. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 59: Multiple Spanning-Tree Regions
Prerequisites for MSTP, on page 41 Restrictions for MSTP, on page 42 Spanning-Tree Interoperability and Backward Compatibility, on page 24 Optional Spanning-Tree Configuration Guidelines BackboneFast, on page 86 UplinkFast, on page 82 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 60: Ist, Cist, And Cst
For correct operation, all switches in the MST region must agree on the same CIST regional root. Therefore, any two switches in the region only synchronize their port roles for an MST instance if they converge to a common CIST regional root. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 61: Operations Between Mst Regions
Illustration of MST Regions, on page 48 IEEE 802.1s Terminology Some MST naming conventions used in Cisco’s prestandard implementation have been changed to identify some internal or regional parameters. These parameters are significant only within an MST region, as opposed to external parameters that are relevant to the whole network.
Page 62: Illustration Of Mst Regions
3 (C) are the roots for their respective subtrees within the CIST. The RSTP runs in all regions. Figure 5: MST Regions, CIST Masters, and CST Root Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 63: Hop Count
The primary change from the Cisco prestandard implementation is that a designated port is not defined as boundary, unless it is running in an STP-compatible mode.
Page 64: Ieee 802.1S Implementation
Port Role Naming Change The boundary role is no longer in the final MST standard, but this boundary concept is maintained in Cisco’s implementation. However, an MST instance port at a boundary of the region might not follow the state of the corresponding CIST port.
Page 65: Detecting Unidirectional Link Failure
Detecting Unidirectional Link Failure This feature is not yet present in the IEEE MST standard, but it is included in this Cisco IOS release. The software checks the consistency of the port role and state in the received BPDUs to detect unidirectional link failures that could cause bridging loops.
Page 66: Mstp And Switch Stacks
The RSTP takes advantage of point-to-point wiring and provides rapid convergence of the spanning tree. Reconfiguration of the spanning tree can occur in less than 1 second (in contrast to 50 seconds with the default settings in the IEEE 802.1D spanning tree). Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 67: Port Roles And The Active Topology
Disabled Disabled Discarding To be consistent with Cisco STP implementations, this guide defines the port state as blocking instead of discarding. Designated ports start in the listening state. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 68: Rapid Convergence
You can override the default setting that is controlled by the duplex setting by using the spanning-tree link-type interface configuration command. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 69: Synchronization Of Port Roles
RSTP forces it to synchronize with new root information. In general, when the RSTP forces a port to synchronize with root information and the port does not satisfy any of the above conditions, its port state is set to blocking. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 70: Bridge Protocol Data Unit Format And Processing
2. A new 1-byte Version 1 Length field is set to zero, which means that no version 1 protocol information is present. Table 11: RSTP BPDU Flags Function Topology change (TC) Proposal Port role: 2–3: Unknown Alternate port Root port Designated port Learning Forwarding Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 71: Processing Superior Bpdu Information
When an RSTP switch detects a topology change, it deletes the learned information on all of its nonedge ports except on those from which it received the TC notification. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 72: Protocol Migration Process
Related Topics Restarting the Protocol Migration Process, on page 75 Default MSTP Configuration Table 12: Default MSTP Configuration Feature Default Setting Spanning-tree mode MSTP Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 73: How To Configure Mstp Features
1. configure terminal 2. spanning-tree mst configuration 3. instance instance-id vlan vlan-range 4. name name 5. revision version 6. show pending 7. exit 8. spanning-tree mode mst 9. end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 74 Verifies your configuration by displaying the pending configuration. Example: Switch(config-mst)# show pending Step 7 exit Applies all changes, and returns to global configuration mode. Example: Switch(config-mst)# exit Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 75 Configuring the Maximum-Hop Count, on page 71 Specifying the Link Type to Ensure Rapid Transitions, on page 72 Designating the Neighbor Type, on page 73 Restarting the Protocol Migration Process, on page 75 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 76: Configuring The Root Switch
Specifying the MST Region Configuration and Enabling MSTP, on page 59 Restrictions for MSTP, on page 42 Bridge ID, Device Priority, and Extended System ID, on page 17 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 77: Configuring A Secondary Root Switch
The range is 0 to 4094. Switch(config)# spanning-tree mst 0 root secondary Step 3 Returns to privileged EXEC mode. Example: Switch(config)# end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 78: Configuring Port Priority
ID and GigabitEthernet1/0/1 as the interface because that was the instance ID and interface set up by the instructions listed under Related Topics. SUMMARY STEPS 1. configure terminal 2. interface interface-id 3. spanning-tree mst instance-id port-priority priority 4. end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 79: Configuring Path Cost
If all interfaces have the same cost value, the MSTP puts the interface with the lowest interface number in the forwarding state and blocks the other interfaces. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 80 The range is 0 to 4094. • For cost, the range is 1 to 200000000; the default value is derived from the media speed of the interface. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 81: Configuring The Switch Priority
You must also know the specified MST instance ID used. This example uses 0 as the instance ID because that was the instance ID set up by the instructions listed under Related Topics. SUMMARY STEPS 1. configure terminal 2. spanning-tree mst instance-id priority priority 3. end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 82: Configuring The Hello Time
Beginning in privileged EXEC mode, follow these steps to configure the hello time for all MST instances. Before You Begin A multiple spanning tree (MST) must be specified and enabled on the switch. For instructions, see Related Topics. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 83: Configuring The Forwarding-Delay Time
A multiple spanning tree (MST) must be specified and enabled on the switch. For instructions, see Related Topics. SUMMARY STEPS 1. configure terminal 2. spanning-tree mst forward-time seconds 3. end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 84: Configuring The Maximum-Aging Time
A multiple spanning tree (MST) must be specified and enabled on the switch. For instructions, see Related Topics. SUMMARY STEPS 1. configure terminal 2. spanning-tree mst max-age seconds 3. end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 85: Configuring The Maximum-Hop Count
A multiple spanning tree (MST) must be specified and enabled on the switch. For instructions, see Related Topics. SUMMARY STEPS 1. configure terminal 2. spanning-tree mst max-hops hop-count 3. end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 86: Specifying The Link Type To Ensure Rapid Transitions
You must also know the specified MST instance ID and the interface used. This example uses 0 as the instance ID and GigabitEthernet1/0/1 as the interface because that was the instance ID and interface set up by the instructions listed under Related Topics. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 87: Designating The Neighbor Type
You can choose to set a port to send only prestandard BPDUs. The prestandard flag appears in all the show commands, even if the port is in STP compatibility mode. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 88 Example: Switch(config-if)# spanning-tree mst pre-standard Step 4 Returns to privileged EXEC mode. Example: Switch(config-if)# end Related Topics Specifying the MST Region Configuration and Enabling MSTP, on page 59 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 89: Restarting The Protocol Migration Process
This procedure may need to be repeated if the switch receives more legacy IEEE 802.1D configuration BPDUs (BPDUs with the protocol version set to 0). Related Topics Specifying the MST Region Configuration and Enabling MSTP, on page 59 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 90: Monitoring Mst Configuration And Status
Additional References for MSTP Related Documents Related Topic Document Title Layer 2 commands Catalyst 2960-XR Switch Layer 2 Command Reference Standards and RFCs Standard/RFC Title None — Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 91: Feature Information For Mstp
Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. Feature Information for MSTP Release Modification Cisco IOS 15.0(2)EX1 This feature was introduced. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 92 Configuring Multiple Spanning-Tree Protocol Feature Information for MSTP Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 93: Configuring Optional Spanning-Tree Features
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Page 94: Information About Optional Spanning-Tree Features
BPDU guard feature puts the port in the error-disabled state. When this happens, the switch shuts down the entire port on which the violation occurred. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 95: Bpdu Filtering
Enabling BPDU filtering on an interface is the same as disabling spanning tree on it and can result in Caution spanning-tree loops. You can enable the BPDU filtering feature for the entire switch or for an interface. Related Topics Enabling BPDU Filtering, on page 93 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 96: Uplinkfast
Specifically, an uplink group consists of the root port (which is forwarding) and a set of blocked ports, except for self-looping ports. The uplink group provides an alternate path in case the currently forwarding link fails. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 97: Cross-Stack Uplinkfast
During the fast transition, an alternate redundant link on the switch stack is placed in the forwarding state without causing temporary spanning-tree loops or loss Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 98: How Cross-Stack Uplinkfast Works
If Switch 1 fails, if its stack-root port fails, or if Link 1 fails, CSUF selects either the alternate stack-root port on Switch 2 or Switch 3 and puts it into the forwarding state in less than 1 second. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 99 The Fast Uplink Transition Protocol is implemented on a per-VLAN basis and affects only one spanning-tree instance at a time. Related Topics Enabling UplinkFast for Use with Redundant Links, on page 95 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 100: Events That Cause Fast Convergence
An inferior BPDU identifies a switch that declares itself as both the root bridge and the designated switch. When a switch receives an inferior BPDU, it means that a link to which the switch is not Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 101 Switch B is directly connected to the root switch over L1, it detects the failure, elects itself the root, and begins sending BPDUs to Switch C, identifying itself as the root. When Switch C receives the inferior Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 102 Specifying the MST Region Configuration and Enabling MSTP, on page 59 MSTP Configuration Guidelines, on page 44 Multiple Spanning-Tree Regions, on page 45 Enabling BackboneFast, on page 97 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 103: Etherchannel Guard
If the switch is operating in multiple spanning-tree (MST) mode, root guard forces the interface to be a designated port. If a boundary port is blocked in an internal spanning-tree (IST) instance because of root Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 104: Loop Guard
This procedure is optional. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 105 Returns to privileged EXEC mode. Example: Switch(config-if)# end What to Do Next You can use the spanning-tree portfast default global configuration command to globally enable the PortFast feature on all nontrunking ports. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 106: Enabling Bpdu Guard
By default, BPDU guard is disabled. Example: Switch(config)# spanning-tree portfast bpduguard default Step 3 interface interface-id Specifies the interface connected to an end station, and enters interface configuration mode. Example: Switch(config)# interface gigabitethernet1/0/2 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 107: Enabling Bpdu Filtering
This procedure is optional. Beginning in privileged EXEC mode, follow these steps to enable BPDU filtering on the switch. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 108 Enables the PortFast feature on the specified interface. Example: Switch(config-if)# spanning-tree portfast Step 5 Returns to privileged EXEC mode. Example: Switch(config-if)# end Related Topics BPDU Filtering, on page 81 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 109: Enabling Uplinkfast For Use With Redundant Links
200 of connectivity. When you enter this command, CSUF also is enabled on all nonstack port interfaces. Step 3 Returns to privileged EXEC mode. Example: Switch(config)# end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 110: Disabling Uplinkfast
1. configure terminal 2. no spanning-tree uplinkfast 3. end DETAILED STEPS Command or Action Purpose Step 1 configure terminal Enters the global configuration mode. Example: Switch# configure terminal Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 111: Enabling Backbonefast
If you use BackboneFast, you must enable it on all switches in the network. BackboneFast is not supported on Token Ring VLANs. This feature is supported for use with third-party switches. SUMMARY STEPS 1. configure terminal 2. spanning-tree backbonefast 3. end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 112: Enabling Etherchannel Guard
This procedure is optional. Beginning in privileged EXEC mode, follow these steps to enable EtherChannel Guard on the switch. SUMMARY STEPS 1. configure terminal 2. spanning-tree etherchannel guard misconfig 3. end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 113: Enabling Root Guard
You cannot enable both root guard and loop guard at the same time. You can enable this feature if your switch is running PVST+, Rapid PVST+, or MSTP. This procedure is optional. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 114: Enabling Loop Guard
This feature is most effective when it is configured on the entire switched network. Loop guard operates only on interfaces that are considered point-to-point by the spanning tree. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 115 Enters global configuration mode. Example: Switch# configure terminal Step 3 spanning-tree loopguard default Enables loop guard. By default, loop guard is disabled. Example: Switch(config)# spanning-tree loopguard default Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 116: Monitoring The Spanning-Tree Status
Additional References for Optional Spanning Tree Features Related Documents Related Topic Document Title Layer 2 commands Catalyst 2960-XR Switch Layer 2 Command Reference Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 117: Feature Information For Optional Spanning-Tree Features
Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. Feature Information for Optional Spanning-Tree Features Release Modification Cisco IOS 15.0(2)EX1 This feature was introduced. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 118 Configuring Optional Spanning-Tree Features Feature Information for Optional Spanning-Tree Features Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 119: Configuring Etherchannels
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Page 120: Information About Etherchannels
Related Topics Configuring Layer 2 EtherChannels, on page 123 EtherChannel Configuration Guidelines, on page 120 Default EtherChannel Configuration, on page 119 Layer 2 EtherChannel Configuration Guidelines, on page 122 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 121: Etherchannel Modes
Related Topics Configuring Layer 2 EtherChannels, on page 123 EtherChannel Configuration Guidelines, on page 120 Default EtherChannel Configuration, on page 119 Layer 2 EtherChannel Configuration Guidelines, on page 122 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 122: Etherchannel On Switches
You can create an EtherChannel on a switch, on a single switch in the stack, or on multiple switches in the stack (known as cross-stack EtherChannel). Figure 20: Single-Switch EtherChannel Figure 21: Cross-Stack EtherChannel Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 123: Etherchannel Link Failover
An EtherChannel comprises a channel group and a port-channel interface. The channel group binds physical ports to the port-channel interface. Configuration changes applied to the port-channel interface apply to all the physical ports bound together in the channel group. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 124 Layer 2 EtherChannel Configuration Guidelines, on page 122 Configuring the Physical Interfaces, on page 127 EtherChannel Configuration Guidelines, on page 120 Default EtherChannel Configuration, on page 119 Layer 2 EtherChannel Configuration Guidelines, on page 122 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 125: Port Aggregation Protocol
Port Aggregation Protocol Port Aggregation Protocol The Port Aggregation Protocol (PAgP) is a Cisco-proprietary protocol that can be run only on Cisco switches and on those switches licensed by vendors to support PAgP. PAgP facilitates the automatic creation of EtherChannels by exchanging PAgP packets between Ethernet ports. PAgP can be enabled on cross-stack EtherChannels.
Page 126: Silent Mode
Network devices are classified as PAgP physical learners or aggregate-port learners. A device is a physical learner if it learns addresses by physical ports and directs transmissions based on that knowledge. A device Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 127: Pagp Interaction With Virtual Switches And Dual-Active Detection
The PAgP PDUs identify the active switch, and the remote switches forward the PDUs to core switches so that the core switches are in sync. If the active switch fails or resets, the standby switch Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 128: Pagp Interaction With Other Features
Link Aggregation Control Protocol The LACP is defined in IEEE 802.3ad and enables Cisco switches to manage Ethernet channels between switches that conform to the IEEE 802.3ad protocol. LACP facilitates the automatic creation of EtherChannels by exchanging LACP packets between Ethernet ports.
Page 129: Lacp Interaction With Other Features
MAC addresses, IP addresses, source addresses, destination addresses, or both source and destination addresses. The selected mode applies to all EtherChannels configured on the switch. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 130: Mac Address Forwarding
But packets sent from different source IP addresses to the same destination IP address are always sent on the same port in the channel. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 131: Load-Balancing Advantages
In the following figure, an EtherChannel of four workstations communicates with a router. Because the router is a single MAC-address device, source-based forwarding on the switch EtherChannel ensures that the switch Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 132: Etherchannel And Switch Stacks
EtherChannel-related stack configuration. The stack member also receives the operational information (the list of ports that are up and are members of a channel). Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 133: Switch Stacks And Pagp
Aggregate-port learning on all ports. LACP port priority 32768 on all ports. LACP system priority 32768. LACP system ID LACP system priority and the switch or stack MAC address. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 134: Etherchannel Configuration Guidelines
• In a mixed switch stack that contains one or more Catalyst 2960-S switches, do not configure more than six EtherChannels on the switch stack. • Configure a PAgP EtherChannel with up to eight Ethernet ports of the same type. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 135 EtherChannel on Switches, on page 108 EtherChannel Link Failover, on page 109 LACP Modes, on page 114 PAgP Modes , on page 111 Silent Mode, on page 112 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 136: Layer 2 Etherchannel Configuration Guidelines
LACP Modes, on page 114 PAgP Modes , on page 111 Silent Mode, on page 112 Creating Port-Channel Logical Interfaces, on page 126 Channel Groups and Port-Channel Interfaces, on page 109 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 137: Layer 3 Etherchannel Configuration Guidelines
If you enabled PAgP on a port in the auto or desirable mode, you must reconfigure it for either the on mode or the LACP mode before adding this port to a cross-stack EtherChannel. PAgP does not support cross-stack EtherChannels. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 138 • auto —Enables PAgP only if a PAgP device is detected. It places the port into Example: a passive negotiating state, in which the port responds to PAgP packets it receives but does not start PAgP packet negotiation. This keyword is not Switch(config-if)# Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 139 PAgP Modes , on page 111 Silent Mode, on page 112 EtherChannel Configuration Guidelines, on page 120 Default EtherChannel Configuration, on page 119 Layer 2 EtherChannel Configuration Guidelines, on page 122 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 140: Configuring Layer 3 Etherchannels
Example: For port-channel-number, the range is 1 to 48. Switch(config)# interface port-channel 5 Step 3 Puts the interface into Layer 3 mode. no switchport Example: Switch(config-if)# no switchport Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 141: Configuring The Physical Interfaces
4. no switchport 5. channel-group channel-group-number mode { auto [ non-silent ] | desirable [ non-silent ] | on } | { active | passive } 6. end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 142 • non-silent—(Optional) If your switch is connected to a partner that is PAgP capable, configures the switch port for nonsilent operation when the port is in Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 143: Configuring Etherchannel Load-Balancing
This task is optional. SUMMARY STEPS 1. configure terminal 2. port-channel load-balance { dst-ip | dst-mac | src-dst-ip | src-dst-mac | src-ip | src-mac } 3. end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 144: Configuring The Pagp Learn Method And Priority
Configuring the PAgP Learn Method and Priority This task is optional. SUMMARY STEPS 1. configure terminal 2. interface interface-id 3. pagp learn-method physical-port 4. pagp port-priority priority 5. end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 145 PAgP Learn Method and Priority, on page 112 EtherChannel Configuration Guidelines, on page 120 Default EtherChannel Configuration, on page 119 Monitoring EtherChannel, PAgP, and LACP Status, on page 135 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 146: Configuring Lacp Hot-Standby Ports
Beginning in privileged EXEC mode, follow these steps to configure the LACP system priority. This procedure is optional. SUMMARY STEPS 1. configure terminal 2. lacp system-priority priority 3. end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 147: Configuring The Lacp Port Priority
Beginning in privileged EXEC mode, follow these steps to configure the LACP port priority. This procedure is optional. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 148 EtherChannel Configuration Guidelines, on page 120 Default EtherChannel Configuration, on page 119 Layer 2 EtherChannel Configuration Guidelines, on page 122 Monitoring EtherChannel, PAgP, and LACP Status, on page 135 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 149: Monitoring Etherchannel, Pagp, And Lacp Status
Configuring the PAgP Learn Method and Priority, on page 130 PAgP Learn Method and Priority, on page 112 Configuring the LACP System Priority, on page 132 Configuring the LACP Port Priority, on page 133 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 150: Configuration Examples For Configuring Etherchannels
This example shows how to create the logical port channel 5 and assign 172.10.20.10 as its IP address: Switch# configure terminal Switch(config)# interface port-channel 5 Switch(config-if)# no switchport Switch(config-if)# ip address 172.10.20.10 255.255.255.0 Switch(config-if)# end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 151: Configuring Etherchannel Physical Interfaces: Examples
Additional References for EtherChannels Related Documents Related Topic Document Title Layer 2 command reference Catalyst 2960-XR Switch Layer 2 Command Reference Standards and RFCs Standard/RFC Title None — Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 152: Feature Information For Etherchannels
Cisco.com user ID and password. Feature Information for EtherChannels Release Modification Cisco IOS 15.0(2)EX1 This feature was introduced. Support for the LACP max-bundle feature and the port channel min-links features was added. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 153: Configuring Link-State Tracking
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Page 154: Understanding Link-State Tracking
An interface can be an aggregation of ports (an EtherChannel) or a single physical port in either access Note or trunk mode. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 155 ◦ Switch A provides primary links to server 1 and server 2 through link-state group 1. Port 1 is connected to server 1, and port 2 is connected to server 2. Port 1 and port 2 are the downstream interfaces in link-state group 1. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 156 You can recover a downstream interface link-down condition by removing the failed downstream port from the link-state group. To recover multiple downstream interfaces, disable the link-state group. Related Topics How to Configure Link-State Tracking, on page 143 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 157: How To Configure Link-State Tracking
[ number ]{upstream | Specifies a link-state group and configures the interface as either an downstream} upstream or downstream interface in the group. Example: Switch(config-if)# link state group 2 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 158: Monitoring Link-State Tracking
Switch(config-if)# link state group 1 downstream Switch(config-if)# end Related Topics Understanding Link-State Tracking, on page 140 How to Configure Link-State Tracking, on page 143 Monitoring Link-State Tracking Status Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 159: Additional References For Link-State Tracking
Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 160: Feature Information For Link-State Tracking
Configuring Link-State Tracking Feature Information for Link-State Tracking Feature Information for Link-State Tracking Releases Feature Information Cisco IOS Release 15.0(2)EX1 This feature was introduced. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 161: Configuring Flex Links And The Mac Address-Table Move Update Feature
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Page 162: Information About Flex Links And Mac Address-Table Move Update
When the active link comes back up, it goes into standby mode and does not forward traffic. STP is disabled on Flex Links interfaces. Related Topics Configuring a Preemption Scheme for a Pair of Flex Links, on page 155 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 163: Flex Links Configuration
VLANs. In addition to providing the redundancy, this Flex Links pair can be used for load balancing. Flex Links VLAN load balancing does not impose any restrictions on uplink switches. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 164: Multicast Fast Convergence With Flex Links Failover
The reports are sent by hosts when a general query is received, and a general query is sent within 60 seconds in normal scenarios. When the backup link starts forwarding, to achieve faster convergence of multicast data, Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 165: Leaking Igmp Reports
In the following figure, switch A is an access switch, and ports 1 and 2 on switch A are connected to uplink switches B and D through a Flex Links pair. Port 1 is forwarding traffic, and port 2 is in the backup state. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 166 Switch A does not need to wait for the MAC address-table update. The switch detects a failure on port 1 and immediately starts forwarding server traffic from port 2, the new forwarding port. This change occurs in 100 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 167: Flex Links Vlan Load Balancing Configuration Guidelines
Related Topics Configuring a Preemption Scheme for a Pair of Flex Links, on page 155 Configuring Flex Links, on page 154 Configuring Flex Links: Examples, on page 161 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 168: How To Configure Flex Links And The Mac Address-Table Move Update Feature
Flex Links pair with the interface. When one link is forwarding traffic, the other interface is in standby mode. Example: Switch(conf-if)# switchport backup interface gigabitethernet1/0/2 Step 4 Returns to privileged EXEC mode. Example: Switch(conf-if)# end Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 169: Configuring A Preemption Scheme For A Pair Of Flex Links
Flex Links pair with the interface. When one link is forwarding traffic, the other interface is in standby mode. Example: Switch(conf-if)# switchport backup interface gigabitethernet1/0/2 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 170 Restrictions for Configuring Flex Links and MAC Address-Table Move Update, on page 147 Configuring Flex Links: Examples, on page 161 Flex Links Configuration, on page 149 Monitoring Flex Links and the MAC Address-Table Move Update, on page 160 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 171: Configuring Vlan Load Balancing On Flex Links
Switch (config-if)# end Related Topics Flex Links VLAN Load Balancing Configuration Guidelines, on page 153 Restrictions for Configuring Flex Links and MAC Address-Table Move Update, on page 147 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 172: Configuring Mac Address-Table Move Update
VLAN ID on the interface, which is used for sending the MAC address-table move update. When one link is forwarding traffic, the other interface is in standby Example: mode. Switch(config-if)# switchport backup interface gigabitethernet0/2 mmu primary vlan 2 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 173: Configuring A Switch To Obtain And Process Mac Address-Table Move Update Messages
Configuring a Switch to Obtain and Process MAC Address-Table Move Update Messages SUMMARY STEPS 1. configure terminal 2. mac address-table move update receive 3. end DETAILED STEPS Command or Action Purpose Step 1 configure terminal Enters global configuration mode Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 174: Monitoring Flex Links And The Mac Address-Table Move Update
Displays the MAC address-table move update information on the switch Related Topics Configuring a Preemption Scheme for a Pair of Flex Links, on page 155 Configuring Flex Links, on page 154 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 175: Configuration Examples For Flex Links
When both interfaces are up, Gi2/0/8 forwards traffic for VLANs 60 and 100 to 120 and Gi2/0/6 forwards traffic for VLANs 1 to 50. Switch# show interfaces switchport backup Switch Backup Interface Pairs: Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 176 Flex Links VLAN Load Balancing Configuration Guidelines, on page 153 Restrictions for Configuring Flex Links and MAC Address-Table Move Update, on page 147 Configuring VLAN Load Balancing on Flex Links, on page 157 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 177: Configuring The Mac Address-Table Move Update: Examples
Switch(config-if)# switchport mode trunk Switch(config-if)# end Switch# show interfaces switchport backup detail Switch Backup Interface Pairs: Active Interface Backup Interface State GigabitEthernet1/0/11 GigabitEthernet1/0/12 Active Up/Backup Standby Preemption Mode : off Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 178 GigabitEthernet1/0/12 Active Up/Backup Standby Preemption Mode : off Multicast Fast Convergence : On Bandwidth : 100000 Kbit (Gi1/0/11), 100000 Kbit (Gi1/0/12) Mac Address Move Update Vlan : auto Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 179: Additional References For Flex Links And Mac Address-Table Move Update
Related Topic Document Title Layer 2 command reference Catalyst 2960-XR Switch Layer 2 Command Reference switchport backup interface command Catalyst 2960-XR Switch Interface and Hardware Component Command Reference Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 180: Feature Information For Flex Links And Mac Address-Table Move Update
Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. Feature Information for Flex Links and MAC Address-Table Move Update Release Modification Cisco IOS 15.0(2)EX1 This feature was introduced. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 181: Chapter 8 Configuring Unidirectional Link Detection
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Page 182: Information About Udld
• On fiber-optic or twisted-pair links, one of the ports cannot send or receive traffic. • On fiber-optic or twisted-pair links, one of the ports is down while the other is up. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 183: Methods To Detect Unidirectional Links
Because this behavior is the same on all UDLD neighbors, the sender of the echoes expects to receive an echo in reply. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 184: Udld Reset Options
UDLD per-port enable state for twisted-pair (copper) Disabled on all Ethernet 10/100 and 1000BASE-TX media ports UDLD aggressive mode Disabled Related Topics Enabling UDLD Globally, on page 171 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 185: How To Configure Udld
The range is from 1 to 90 seconds; the default value is 15. Note This command affects fiber-optic ports only. Use the udld interface configuration command to enable UDLD on other port types. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 186: Enabling Udld On An Interface
Enters global configuration mode. configure terminal Example: Switch# configure terminal Step 2 interface interface-id Specifies the port to be enabled for UDLD, and enters interface configuration mode. Example: Switch(config)# interface Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 187: Monitoring And Maintaining Udld
Default UDLD Configuration, on page 170 Monitoring and Maintaining UDLD Command Purpose show udld [interface-id | neighbors] Displays the UDLD status for the specified port or for all ports. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 188: Additional References For Udld
Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds. Access to most tools on the Cisco Support website requires a Cisco.com user ID and password. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 189: Feature Information For Udld
Configuring UniDirectional Link Detection Feature Information for UDLD Feature Information for UDLD Release Modification Cisco IOS 15.0(2)EX1 This feature was introduced. Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 190 Configuring UniDirectional Link Detection Feature Information for UDLD Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01...
Page 191 Fast Uplink Transition Protocol BPDU 14, 15, 56, 81 normal-convergence events contents cross-stack UplinkFast,STP 83, 86 filtering described RSTP format fast-convergence events bridge identifier (bridge ID) bridge protocol data units Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01 IN-1...
Page 192 VLAN load balancing examples LACP 114, 115, 132, 133 Flex Links failover hot-standby ports forward-delay time 36, 69 interaction with other features MSTP modes port priority system priority Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 IN-2 OL-29424-01...
Page 193 Leaking IGMP Reports MST region learn method and priority configuration path cost Link Failure, detecting unidirectional port priority link redundancy root device See Flex Links Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01 IN-3...
Page 194 Rapid Spanning Tree Protocol shutdown Port Fast-enabled port See RSTP stack changes, effects of redundancy 21, 83, 106 status, displaying EtherChannel Multicast Fast Convergence 150, 163 Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 IN-4 OL-29424-01...
Page 195 ID 13, 17, 29, 30 source-and-destination-IP address based forwarding, effects on root device EtherChannel effects on the secondary root device source-IP address based forwarding, EtherChannel overview Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 OL-29424-01 IN-5...
Page 196 STP and IEEE 802.1Q trunks VLAN-bridge switchport backup interface VLAN-bridge STP system priority with dual-action detection trunk failover with STP twisted-pair, detecting unidirectional links Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1 IN-6 OL-29424-01...

Cisco Catalyst 2960-XR Configuration Manual

Table of Contents

CHAPTER 1 Using the Command-Line Interface

CHAPTER 2 Configuring Spanning Tree Protocol

CHAPTER 3 Configuring Multiple Spanning-Tree Protocol

Step 1/Step 9 End

CHAPTER 4 Configuring Optional Spanning-Tree Features

CHAPTER 5 Configuring Etherchannels

Configuring Link-State Tracking

CHAPTER 6 Configuring Link-State Tracking

Configuring Flex Links and the Mac Address-Table Move Update Feature

CHAPTER 7 Configuring Flex Links and the MAC Address-Table Move Update Feature

Chapter 8 Configuring Unidirectional Link Detection

Quick Links

Chapters

Related Manuals for Cisco Catalyst 2960-XR

Summary of Contents for Cisco Catalyst 2960-XR