Administrator Guide

the RPF neighbor. When a Dell EMC Networking system is the last hop to the destination, Dell EMC Networking OS sends a response
to the query.
To print the network path, use the following command.
• Print the network path that a multicast packet takes from a multicast source to receiver, for a particular group.
EXEC Privilege mode
mtrace multicast-source-address multicast-receiver-address multicast-group-address
From source (?) to destination (?)
----------------------------------------------------------------------------------------
|Hop| OIF IP |Proto| Forwarding Code |Source Network/Mask|
----------------------------------------------------------------------------------------
0 “destination ip(to)” --> Destination
-1 “Outgoing intf addr” “Proto” “Err/fwd code if present” “Src Mask”
-2 “Outgoing intf addr” “Proto” “Err/fwd code if present” “Src Mask”
.
.
-“n” “source ip(from)” --> Source
-----------------------------------------------------------------------------------------
The mtrace command traverses the path of the response data block in the reverse direction of the multicast data traffic. As a result,
the tabular output of the mtrace command displays the destination details in the first row, followed by the RPF router details along the
path in the consequent rows, and finally the source details in the last row. The tabular output contains the following columns:
• Hop — a hop number(counted negatively to indicate reverse-path)
• OIF IP — outgoing interface address
• Proto — multicast routing protocol
• Forwarding code — error code as present in the response blocks
• Source Network/Mask — source mask
The following is an example of tracing a multicast route.
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
-4 103.103.103.3 --> Source
------------------------------------------------------------------
The following table explains the output of the mtrace command:
Table 49. mtrace Command Output — Explained
Command Output Description
Querying reverse path for source
103.103.103.3 to destination 1.1.1.1 via
group 226.0.0.3
mtrace traverses the reverse path from the given destination to the given
source for the given group
From source (?) to destination (?)
In case the provided source or destination IP can be resolved to a hostname
the corresponding name will be displayed. In cases where the IP cannot be
resolved, it is displayed as (?)
0 1.1.1.1 --> Destination
The first row in the table corresponds to the destination provided by the
user.
-1 1.1.1.1 PIM Reached RP/Core
103.103.103.0/24
The information in each of the response blocks is displayed as follows:
• o (-1) Hop count is always a negative number to indicate reverse path
Multicast Features 493