Cisco Catalyst 4500 Series Configuration Manual page 1186

traceroute mac
Layer 2 traceroute supports only unicast traffic. If you specify a multicast source or destination MAC
address, the physical path is not identified, and a message appears.
The traceroute mac command output shows the Layer 2 path when the specified source and destination
addresses belong to the same VLAN. If you specify source and destination addresses that belong to
different VLANs, the Layer 2 path is not identified, and a message appears.
If the source or destination MAC address belongs to multiple VLANs, you must specify the VLAN to
which both the source and destination MAC addresses belong. If the VLAN is not specified, the path is
not identified, and a message appears.
Layer 2 traceroute is not supported when multiple devices are attached to one port through hubs (for
example, multiple CDP neighbors are detected on a port). When more than one CDP neighbor is detected
on a port, the Layer 2 path is not identified, and a message appears.
This feature is not supported in Token Ring VLANs.
Examples The following example shows how to display the Layer 2 path by specifying the source and destination
MAC addresses:
Switch# traceroute mac 0000.0201.0601 0000.0201.0201
Source 0000.0201.0601 found on con6[WS-C2950G-24-EI] (2.2.6.6)
con6 (2.2.6.6) :Fa0/1 =>Fa0/3
con5
con1
con2
Destination 0000.0201.0201 found on con2[WS-C3550-24] (2.2.2.2)
Layer 2 trace completed
Switch#
The following example shows how to display the detailed Layer 2 path:
Switch# traceroute mac 0000.0201.0601 0000.0201.0201 detail
Source 0000.0201.0601 found on con6[WS-C2950G-24-EI] (2.2.6.6)
con6 / WS-C2950G-24-EI / 2.2.6.6 :
con5 / WS-C2950G-24-EI / 2.2.5.5 :
con1 / WS-C3550-12G / 2.2.1.1 :
con2 / WS-C3550-24 / 2.2.2.2 :
Destination 0000.0201.0201 found on con2[WS-C3550-24] (2.2.2.2)
Layer 2 trace completed.
Switch#
The following example shows the Layer 2 path when the switch is not connected to the source switch:
Switch# traceroute mac 0000.0201.0501 0000.0201.0201 detail
Source not directly connected, tracing source .....
Source 0000.0201.0501 found on con5[WS-C2950G-24-EI] (2.2.5.5)
con5 / WS-C2950G-24-EI / 2.2.5.5 :
con1 / WS-C3550-12G / 2.2.1.1 :
con2 / WS-C3550-24 / 2.2.2.2 :
Destination 0000.0201.0201 found on con2[WS-C3550-24] (2.2.2.2)
Layer 2 trace completed.
Switch#
Catalyst 4500 Series Switch Cisco IOS Command Reference—Release XE 3.9.xE and 15.2(5)Ex
2-1136
(2.2.5.5
(2.2.1.1
(2.2.2.2
Fa0/1 [auto, auto] =>Fa0/3 [auto, auto]
Fa0/3 [auto, auto] =>Gi0/1 [auto, auto]
Gi0/1 [auto, auto] =>Gi0/2 [auto, auto]
Gi0/2 [auto, auto] =>Fa0/1 [auto, auto]
Fa0/1 [auto, auto] =>Gi0/1 [auto, auto]
Gi0/1 [auto, auto] =>Gi0/2 [auto, auto]
Gi0/2 [auto, auto] =>Fa0/1 [auto, auto]
) : Fa0/3 =>Gi0/1
) : Gi0/1 =>Gi0/2
) : Gi0/2 =>Fa0/1
Chapter 2