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Command Modes EXEC Privilege
Command
History
Version Description
9.11.0.0 Re-introduced the mtrace command on the Dell EMC Networking OS.
7.5.1.0 Expanded to support originator.
7.4.1.0 Expanded to support the intermediate (transit) router.
Usage
Information
Mtrace is an IGMP based protocol that provides a multicast trace route facility and is implemented
according to the IETF draft “A trace route facility for IP Multicast” (draft-fenner-traceroute-ipm-01.txt).
Dell EMC Networking OS supports the Mtrace client and transit functionality.
As an Mtrace client, Dell EMC Networking OS transmits Mtrace queries, receives, parses, and prints out
the details in the response packet received.
A transit or intermediate router, forwards mtrace requests to the RPF neighbor after appending its
response block to the packet. In case it is the first hop router, it sends a response.
As an Mtrace transit or intermediate router, Dell EMC Networking OS returns the response to Mtrace
queries. After receiving the Mtrace request, Dell EMC Networking OS computes the RPF neighbor for the
source, fills in the request and the forwards the request to the RPF neighbor.
Example
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 mtrace command traverses the path of the response data block in the reverse direction of
the multicast data traffic. The mtrace command traverses the reverse path to the source from the
destination. 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
show ip mroute
View the multicast routing table.
Syntax
show ip mroute [static | group-address [source-address] | count | snooping
[vlan vlan-id] [group-address [source-address]] | summary | vlt [group-
address [source-address] | count]
Parameters
static (OPTIONAL) Enter the keyword static to view static multicast routes.
group-address
[ source-address ]
(OPTIONAL) Enter the multicast group-address to view only routes associated with
that group.
790 Multicast