Configuring the MAC Address-Table Move Update Feature

Configuring the MAC Address-Table Move

Update Feature

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Finding Feature Information, page 1

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Information About MAC Address-Table Move Update, page 1

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How to Configure MAC Address-Table Move Update, page 3

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Monitoring the MAC Address-Table Move Update, page 6

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Configuration Examples for Flex Links, page 6

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and

feature information, see Bug Search Tool and the release notes for your platform and software release. To

find information about the features documented in this module, and to see a list of the releases in which each

feature is supported, see the feature information table at the end of this module.

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.

Information About MAC Address-Table Move Update

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MAC Address-Table Move Update

The MAC address-table move update feature allows the switch to provide rapid bidirectional convergence

when a primary (forwarding) link goes down and the standby link begins forwarding traffic.

Software Configuration Guide, Cisco IOS Release 15.2(5)E (Catalyst 2960-L Switches)

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.

Traffic from the PC to the server is forwarded from port 1 to port 3. The MAC address of the PC has been

learned on port 3 of switch C. Traffic from the server to the PC is forwarded from port 3 to port 1.

Figure 1: MAC Address-Table Move Update Example

If the MAC address-table move update feature is not configured and port 1 goes down, port 2 starts forwarding

traffic. However, for a short time, switch C keeps forwarding traffic from the server to the PC through port

3, and the PC does not get the traffic because port 1 is down. If switch C removes the MAC address of the

PC on port 3 and relearns it on port 4, traffic can then be forwarded from the server to the PC through port 2.

If the MAC address-table move update feature is configured and enabled on the switches, and port 1 goes

down, port 2 starts forwarding traffic from the PC to the server. The switch sends a MAC address-table move

update packet from port 2. Switch C gets this packet on port 4 and immediately learns the MAC address of

the PC on port 4, which reduces the reconvergence time.

You can configure the access switch, switch A, to send MAC address-table move update messages. You can

also configure the uplink switches B, C, and D to get and process the MAC address-table move update

messages. When switch C gets a MAC address-table move update message from switch A, switch C learns

the MAC address of the PC on port 4. Switch C updates the MAC address table, including the forwarding

table entry for the PC.

Software Configuration Guide, Cisco IOS Release 15.2(5)E (Catalyst 2960-L Switches)

Configuring the MAC Address-Table Move Update Feature

MAC Address-Table Move Update

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 less

than 100 milliseconds (ms). The PC is directly connected to switch A, and the connection status does not

change. Switch A does not need to update the PC entry in the MAC address table.

Related Topics

Configuring a Switch to Obtain and Process MAC Address-Table Move Update Messages , on page 5

Configuring MAC Address-Table Move Update , on page 3

Configuring the MAC Address-Table Move Update: Examples, on page 6

MAC Address-Table Move Update Configuration Guidelines

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You can enable and configure this feature on the access switch to send the MAC address-table move

updates.

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You can enable and configure this feature on the uplink switches to get the MAC address-table move

updates.

How to Configure MAC Address-Table Move Update

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Configuring MAC Address-Table Move Update

SUMMARY STEPS

configure terminal

interface interface-id

Use one of the following:

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switchport backup interface interface-id

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switchport backup interface interface-id mmu primary vlan vlan-id

end

mac address-table move update transmit

end

Software Configuration Guide, Cisco IOS Release 15.2(5)E (Catalyst 2960-L Switches)

Configuring the MAC Address-Table Move Update Feature

MAC Address-Table Move Update Configuration Guidelines

DETAILED STEPS

PurposeCommand or Action

Enters global configuration mode.configure terminal

Example:

Switch# configure terminal

Step 1

Specifies the interface, and enters interface configuration mode.

The interface can be a physical Layer 2 interface or a port channel

(logical interface). The port-channel range is 1 to 24.

interface interface-id

Example:

Switch#interface gigabitethernet1/0/1

Step 2

Configures a physical Layer 2 interface (or port channel), as part

of a Flex Links pair with the interface. The MAC address-table

move update VLAN is the lowest VLAN ID on the interface.

Use one of the following:

Step 3

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switchport backup interface interface-id

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switchport backup interface interface-id

mmu primary vlan vlan-id

Configure a physical Layer 2 interface (or port channel) and specifies

the VLAN ID on the interface, which is used for sending the MAC

address-table move update.

Example:

Switch(config-if)# switchport backup

When one link is forwarding traffic, the other interface is in standby

mode.

interface

gigabitethernet0/2 mmu primary vlan 2

Returns to global configuration mode.end

Example:

Switch(config-if)# end

Step 4

Enables the access switch to send MAC address-table move updates

to other switches in the network if the primary link goes down and

the switch starts forwarding traffic through the standby link.

mac address-table move update transmit

Example:

Switch(config)#

Step 5

mac address-table move update

transmit

Returns to privileged EXEC mode.end

Example:

Switch(config)# end

Step 6

Software Configuration Guide, Cisco IOS Release 15.2(5)E (Catalyst 2960-L Switches)

Configuring the MAC Address-Table Move Update Feature

Configuring MAC Address-Table Move Update

Related Topics

Configuring the MAC Address-Table Move Update: Examples, on page 6

MAC Address-Table Move Update, on page 1

Configuring the MAC Address-Table Move Update: Examples, on page 6

Configuring a Switch to Obtain and Process MAC Address-Table Move Update Messages

SUMMARY STEPS

configure terminal

mac address-table move update receive

end

DETAILED STEPS

PurposeCommand or Action

Enters global configuration modeconfigure terminal

Step 1

Example:

Switch# configure terminal

Enables the switch to obtain and processes the MAC

address-table move updates.

mac address-table move update receive

Example:

Switch (config)# mac address-table move update

Step 2

receive

Returns to privileged EXEC mode.end

Example:

Switch (config)# end

Step 3

Related Topics

Configuring the MAC Address-Table Move Update: Examples, on page 6

MAC Address-Table Move Update, on page 1

Configuring the MAC Address-Table Move Update: Examples, on page 6

Software Configuration Guide, Cisco IOS Release 15.2(5)E (Catalyst 2960-L Switches)

Configuring the MAC Address-Table Move Update Feature

Configuring MAC Address-Table Move Update

Monitoring the MAC Address-Table Move Update

PurposeCommand

Displays the MAC address-table move update information on the

switch.

show mac address-table move update

Configuration Examples for Flex Links

Configuring the MAC Address-Table Move Update: Examples

This example shows how to verify the configuration after you configure an access switch to send MAC

address-table move updates:

Switch# show mac address-table move update

Switch-ID : 010b.4630.1780

Dst mac-address : 0180.c200.0010

Vlans/Macs supported : 1023/8320

Default/Current settings: Rcv Off/On, Xmt Off/On

Max packets per min : Rcv 40, Xmt 60

Rcv packet count : 5

Rcv conforming packet count : 5

Rcv invalid packet count : 0

Rcv packet count this min : 0

Rcv threshold exceed count : 0

Rcv last sequence# this min : 0

Rcv last interface : Po2

Rcv last src-mac-address : 000b.462d.c502

Rcv last switch-ID : 0403.fd6a.8700

Xmt packet count : 0

Xmt packet count this min : 0

Xmt threshold exceed count : 0

Xmt pak buf unavail cnt : 0

Xmt last interface : None

Related Topics

Configuring MAC Address-Table Move Update , on page 3

Configuring a Switch to Obtain and Process MAC Address-Table Move Update Messages , on page 5

Configuring MAC Address-Table Move Update , on page 3

MAC Address-Table Move Update, on page 1

Software Configuration Guide, Cisco IOS Release 15.2(5)E (Catalyst 2960-L Switches)

Configuring the MAC Address-Table Move Update Feature

Monitoring the MAC Address-Table Move Update