Using Layer 2 Traceroute; Understanding Layer 2 Traceroute; Usage Guidelines - Cisco IE 3000 Software Configuration Manual

Using Layer 2 Traceroute

Table 34-1
Character
?
&
To end a ping session, enter the escape sequence (Ctrl-^ X by default). Simultaneously press and release
the Ctrl, Shift, and 6 keys and then press the X key.
Using Layer 2 Traceroute
These sections contain this information:
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Understanding Layer 2 Traceroute

The Layer 2 traceroute feature allows the switch to identify the physical path that a packet takes from a
source device to a destination device. Layer 2 traceroute supports only unicast source and destination
MAC addresses. It finds the path by using the MAC address tables of the switches in the path. When the
switch detects a device in the path that does not support Layer 2 traceroute, the switch continues to send
Layer 2 trace queries and lets them time out.
The switch can only identify the path from the source device to the destination device. It cannot identify
the path that a packet takes from source host to the source device or from the destination device to the
destination host.

Usage Guidelines

These are the Layer 2 traceroute usage guidelines:
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Cisco IE 3000 Switch Software Configuration Guide
34-10
Ping Output Display Characters (continued)
Description
Unknown packet type.
Packet lifetime exceeded.
Understanding Layer 2 Traceroute, page 34-10
Usage Guidelines, page 34-10
Displaying the Physical Path, page 34-11
Cisco Discovery Protocol (CDP) must be enabled on all the devices in the network. For Layer 2
traceroute to function properly, do not disable CDP.
For a list of switches that support Layer 2 traceroute, see the
page 34-10. If any devices in the physical path are transparent to CDP, the switch cannot identify
the path through these devices. For more information about enabling CDP, see
"Configuring CDP."
A switch is reachable from another switch when you can test connectivity by using the ping
privileged EXEC command. All switches in the physical path must be reachable from each other.
The maximum number of hops identified in the path is ten.
You can enter the traceroute mac or the traceroute mac ip privileged EXEC command on a switch
that is not in the physical path from the source device to the destination device. All switches in the
path must be reachable from this switch.
Chapter 34 Troubleshooting
"Usage Guidelines" section on
Chapter 24,
OL-13018-01