trace-l2

Displays the Layer 2 path that a packet takes from a source device to a destination device and displays all paths in the specified VLAN.
Syntax
trace-l2 vlan vlan-id {mac adress|ip address|hostname}
trace-l2 show
Command Default

The results of this command are stored for no more than 10 minutes on a device or are replaced when a subsequent trace-l2 command is issued.

Parameters
vlan vlan-id
Specifies the VLAN.
mac address
Specifies the destination MAC address. Only Unicast destination MAC addresses are supported.
ip address
Specifies the destination IP address.
hostname
Specifies the destination hostname.
show
To show the hop number, input and output ports, IP/Mac address, microsec, comment, and hostname fields of each hop.
Modes

User EXEC mode

Usage Guidelines

This command traces the traffic path through a specified device in a VLAN. It can also be used to probe all reachable paths to all devices in the VLAN.

The Layer 2 trace route utility detects the IP as the IP of the virtual Ethernet (VE) interface, if available; else it will try to detect the IP of the Loopback interface. To use the the Layer 2 trace route utility with a hostname, a DNS mapping with the hostname must be present in the DNS server.

On a topology where loops are avoided by a loop avoidance protocol, the traced path will honor the loop-free network path.

Devices and interfaces that do not support the Layer 2 trace route utility will act as transparent bridges and will be invisible to the trace-l2 result. The Layer 2 trace route utility is not supported on breakout ports.

The destination for trace-l2 operation must be a another ICX device and not an end host.

At any point in time only one trace-l2 operation can be running in a network.

The Layer 2 trace route utility results can discover up to 8 hops in a single path.

Examples

The following example shows how to run a trace and then show the path information.

device# trace-l2 vlan 1
device# trace-l2 show

*** Warning! The following 4 hops form a loop in vlan 1

hop   input  output IP and/or MAC address       microsec comment    hostname

  1                    d4c1.9e18.7ca8

  2   e2/1/35          609c.9f52.19b2

  3   e1/1/23          d4c1.9e18.8b19

  4   e1/1/11          0000.0000.00bb

Vlan 1 L2 topology was probed 6 sec ago, # of paths: 2

path 1 from e1/1/27, 3 hops:

  hop   input  output IP and/or MAC address       microsec comment    hostname

  1   e2/1/35 e2/1/23  10.0.0.6  609c.9f52.19b2     65611

  2   e1/1/23 e1/1/36  10.0.0.7  d4c1.9e18.8b19     64415

  3   e1/1/11          10.0.0.8  0000.0000.00bb     62042

path 2 from e1/1/1, 3 hops:

  hop   input  output IP and/or MAC address       microsec comment    hostname

  1   e1/1/10 e1/1/11  10.0.0.8  0000.0000.00bb     67943

  2   e1/1/36 e1/1/23  10.0.0.7  d4c1.9e18.8b19     6044

  3   e2/1/23          10.0.0.6  609c.9f52.19b2     1262

device#
History
Release version Command history
10.0.10f and 10.0.20 This command was reintroduced.
Parent topic: Commands Si - Z