Concept Guide

The response data block lled in by the last-hop router contains a Forwarding code eld. Forwarding code can be added at any node and is
not restricted to the last hop router. This eld is used to record error codes before forwarding the response to the next neighbor in the path
towards the source. In a response data packet, the following error codes are supported:
Table 68. Supported Error Codes
Error Code Error Name Description
0x00 NO_ERROR No error
0x01 WRONG_IF Traceroute request arrived on the wrong
interface. The router does not use this
interface to forward packets to the source,
group, and destination.
0x05 NO_ROUTE The router has no route for the source or
group and cannot determine a potential
route.
0x06 WRONG_LAST_HOP The router is not the proper last-hop router.
0x08 REACHED_RP Reached Rendezvous Point or Core.
0x09 RPF_IF Traceroute request arrived on the expected
RPF interface for this source and group.
0x0A NO_MULTICAST Traceroute request arrived on an interface
which is not enabled for multicast.
0x81 NO_SPACE There is not enough room to insert another
response data block in the packet.
mtrace Scenarios
This section describes various scenarios that may result when an mtrace command is issued.
The following table describes various scenarios when the mtrace command is issued:
Table 69. Mtrace Scenarios
Scenario Output
When you want to trace a route with the
multicast tree for a source, group, and
destination, you can specify all the
parameters in the command. Mtrace will
trace the complete path from source to
destination by using the multicast tables for
that group.
R1>mtrace 103.103.103.3 1.1.1.1 226.0.0.3
Type Ctrl-C to abort.
Querying reverse path for source 103.103.103.3 to destination
1.1.1.1 via group 226.0.0.3
From source (?) to destination (?)
--------------------------------------------------------------
---
|Hop| OIF IP |Proto| Forwarding Code |Source Network/
Mask|
--------------------------------------------------------------
---
0 1.1.1.1 --> Destination
-1 1.1.1.1 PIM Reached RP/Core
103.103.103.0/24
-2 101.101.101.102 PIM -
103.103.103.0/24
-3 2.2.2.1 PIM -
103.103.103.0/24
614 Multicast Features