Using layer 2 traceroute, Understanding layer 2 traceroute, Usage guidelines – Dell POWEREDGE M1000E User Manual
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47-12
Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
OL-13270-03
Chapter 47 Troubleshooting
Using Layer 2 Traceroute
describes the possible ping character output.
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:
•
Understanding Layer 2 Traceroute, page 47-12
•
•
Displaying the Physical Path, page 47-13
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:
•
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
. 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
Table 47-1
Ping Output Display Characters
Character
Description
!
Each exclamation point means receipt of a reply.
.
Each period means the network server timed out while waiting for a reply.
U
A destination unreachable error PDU was received.
C
A congestion experienced packet was received.
I
User interrupted test.
?
Unknown packet type.
&
Packet lifetime exceeded.