Viewing the port and VLAN MAC addresses

The MAC address assigned to each switch port is used internally by such features as Flow Control and the spanning-tree protocol. Using the walkmib command to determine the MAC address assignments for individual ports can sometimes be useful when diagnosing switch operation.

Switch series' and their MAC address allocations

Switch series

MAC address allocation

8212zl

The switch allots 24 MAC addresses per slot. For a given slot, if a four-port module is installed, the switch uses the first four MAC addresses in the allotment for that slot, and the remaining 18 MAC addresses are unused.If a 24-port module is installed, the switch uses the first 24 MAC addresses in the allotment, and so on.

All Models

The switch's base MAC address is assigned to VLAN (VID) 1 and appears in the walkmib listing after the MAC addresses for the ports. (All VLANs in the switch have the same MAC address.)

NOTE:

This procedure displays the MAC addresses for all ports and existing VLANs in the switch, regardless of which VLAN you select.

Example

A 8212zl switch with the following module configuration shows MAC address assignments similar to those shown in Example of Port MAC address assignments on a switch:

  • A 4-port module in slot A, a 24-port module in slot C, and no modules in slots B and D

  • Two non-default VLANs configured

Example of Port MAC address assignments on a switch
NOTE:

When configuring an "out" monitor on a VLAN or an interface to a remote mirror, the mirrored packet will always be untagged when the original packet arrives on a zlV2 module.

When configuring a "both" monitor on an interface to a remote mirror, tags will not be present in the mirrored packet in these specific situations:

  • For an interface monitor, packets transmitted by the monitored port that originally arrived on a zlV2 module.

  • For a VLAN monitor, packets routed onto the monitored VLAN that originally arrived on a zlV2 module.

  1. If the switch is at the CLI Operator level, use the enable command to enter the Manager level of the CLI.

  2. Enter the following command to display the MAC address for each port on the switch: 
    Switch# walkmib ifPhysAddress
    NOTE:

    The above command is not case-sensitive.