Using Layer 2 Traceroute; Understanding Layer 2 Traceroute - Cisco 2950 - Catalyst Switch Configuration Manual

Diagnosing Connectivity Problems
Note Though other protocol keywords are available with the ping command, they are not supported in this
release.
This example shows how to ping an IP host:
Switch# ping 172.20.52.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echoes to 172.20.52.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
Switch#
Table 32-1
Table 32-1 Ping Output Display Characters
Character
!
.
U
C
I
?
&
To terminate a ping session, enter the escape sequence (Ctrl-^ X by default). You enter the default by
simultaneously pressing and releasing the Ctrl, Shift, and 6 keys, and then pressing the X key.

Using Layer 2 Traceroute

This section describes this information:
•
•
•

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 determines 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.
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
32-16
describes the possible ping character output.
Description
Each exclamation point means receipt of a reply.
Each period means the network server timed out while waiting for a reply.
A destination unreachable error PDU was received.
A congestion experienced packet was received.
User interrupted test.
Unknown packet type.
Packet lifetime exceeded.
Understanding Layer 2 Traceroute, page 32-16
Usage Guidelines, page 32-17
Displaying the Physical Path, page 32-18
Chapter 32 Troubleshooting
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