Using Layer 2 Traceroute; Usage Guidelines - Cisco WS-C4003 - Catalyst 4000 Chassis Switch Software Configuration Manual

Using Layer 2 Traceroute

808 bytes from 12.20.2.3: icmp_seq=5. time=2 ms
808 bytes from 12.20.2.3: icmp_seq=6. time=2 ms
808 bytes from 12.20.2.3: icmp_seq=7. time=2 ms
808 bytes from 12.20.2.3: icmp_seq=8. time=2 ms
808 bytes from 12.20.2.3: icmp_seq=9. time=3 ms
----17.20.2.3 PING Statistics----
10 packets transmitted, 10 packets received, 0% packet loss
round-trip (ms)
Console>
This example shows how to enter a ping command in privileged mode specifying the number of packets,
the packet size, and the timeout period:
Console> (enable) ping
Target IP Address []: 12.20.5.19
Number of Packets [5]: 10
Datagram Size [56]: 100
Timeout in seconds [2]: 10
Source IP Address [12.20.2.18]: 12.20.2.18
!!!!!!!!!!
----12.20.2.19 PING Statistics----
10 packets transmitted, 10 packets received, 0% packet loss
round-trip (ms)
Console> (enable)
Using Layer 2 Traceroute
The Layer 2 Traceroute utility allows you to identify the physical path that a packet will take when going
from a source to a destination. This utility determines the path by looking at the forwarding engine tables
of the switches in the path.
Information is displayed about all Catalyst 4000, 5000, and 6000 family switches that are in the path
from the source to the destination.

Usage Guidelines

Follow these guidelines for using the Layer 2 Traceroute utility:
•
•
•
•
•
•
Software Configuration Guide—Catalyst 4000 Family, Catalyst 2948G, Catalyst 2980G, Releases 6.3 and 6.4
19-10
min/avg/max = 2/2/3
min/avg/max = 1/1/1
The Layer 2 Traceroute utility works for unicast traffic only.
You must enable CDP on all of the Catalyst 4000, 5000 and 6000 family switches in the network.
(See Chapter 20, "Configuring CDP,"
are transparent to CDP, l2trace will not be able to trace the Layer 2 path through those devices.
You can use this utility from a switch that is not in the Layer 2 path between the source and the
destination; however, all of the switches in the path, including the source and destination, must be
reachable from the switch.
All switches in the path must be reachable from each other.
You can trace a Layer 2 path by specifying the source and destination IP addresses (or IP aliases) or
the MAC addresses. If the source and destination belong to multiple VLANs and you specify MAC
addresses, you can also specify a VLAN.
The source and destination switches must belong to the same VLAN.
Chapter 19
for information about enabling CDP.) If any devices in the path
Checking Port Status and Connectivity
78-12647-02