Cisco catalyst 3750 Command Reference Manual page 905

Chapter 2 Catalyst 3750 Switch Cisco IOS Commands
The Layer 2 traceroute feature 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 an error message appears.
This feature is not supported in Token Ring VLANs.
Examples
This example shows how to display the Layer 2 path by specifying the source and destination IP
addresses and by using the detail keyword:
Switch# traceroute mac ip 2.2.66.66 2.2.22.22 detail
Translating IP to mac .....
2.2.66.66 => 0000.0201.0601
2.2.22.22 => 0000.0201.0201
Source 0000.0201.0601 found on con6[WS-C2950G-24-EI] (2.2.6.6)
con6 / WS-C3750-12T / 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.
This example shows how to display the Layer 2 path by specifying the source and destination hostnames:
Switch# traceroute mac ip con6 con2
Translating IP to mac .....
2.2.66.66 => 0000.0201.0601
2.2.22.22 => 0000.0201.0201
Source 0000.0201.0601 found on con6
con6 (2.2.6.6) :Gi0/0/1 => Gi0/0/3
con5
con1
con2
Destination 0000.0201.0201 found on con2
Layer 2 trace completed
This example shows the Layer 2 path when ARP cannot associate the source IP address with the
corresponding MAC address:
Switch# traceroute mac ip 2.2.66.66 2.2.77.77
Arp failed for destination 2.2.77.77.
Layer2 trace aborted.
Related Commands Command
traceroute mac
OL-8552-07
Gi0/0/1 [auto, auto] => Gi0/0/3 [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]
(2.2.5.5
(2.2.1.1
(2.2.2.2
Description
Displays the Layer 2 path taken by the packets from the specified source MAC
address to the specified destination MAC address.
) : Gi0/0/3 => Gi0/1
) : Gi0/0/1 => Gi0/2
) : Gi0/0/2 => Fa0/1
Catalyst 3750 Switch Command Reference
traceroute mac ip
2-875