19-9
Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
78-13315-02
Chapter 19 Checking Port Status and Connectivity
Using Layer 2 Traceroute
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) min/avg/max = 1/1/1
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. The Layer 2 Traceroute utility determines the path by looking at the
forwarding engine tables of the switches in the path.
Information is displayed about all Catalyst 6000 family switches that are in the path from the source to
the destination.
These sections describe how to use Layer 2 Traceroute:
•
Layer 2 Traceroute Usage Guidelines, page 19-9
•
Identifying a Layer 2 Path, page 19-10
Layer 2 Traceroute Usage Guidelines
Follow these guidelines for using the Layer 2 Traceroute utility:
•
The Layer 2 Traceroute utility works for unicast traffic only.
•
You must enable CDP on all of the Catalyst 5000 and 6000 family switches in the network. (See
Chapter 29, “Configuring CDP”
for information about enabling CDP.) If any devices in the path 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 in the same VLAN.
•
The maximum number of hops an
l2trace
query will try is 10; this includes hops involved in source
tracing.
•
The Layer 2 Traceroute utility does not work with Token Ring VLANs, or when multiple devices are
attached to one port through hubs, or when multiple neighbors are on a port.
