Multicast Tool and Utility Commands on Cisco IOS XR Software
This chapter describes the commands used to troubleshoot multicast routing sessions on .
For detailed information about multicast routing concepts, configuration tasks, and examples, refer to
Implementing Multicast Routing on Cisco IOS XR Software
in
Cisco IOS XR Multicast Configuration Guide for the Cisco XR 12000 Series Router.
To query neighboring multicast routers peering with the local router, use the
mrinfo command in EXEC mode.
mrinfo [ipv4] host-address [source-address]
Syntax Description
ipv4
(Optional) Specifies IPv4 address prefixes.
host-address
Can be either the Domain Name System (DNS) name or IP address of a multicast
router entered in A.B.C.D format.
Note
If omitted, the router queries itself.
source-address
(Optional) Source address used on multicast routing information (mrinfo)
requests. If omitted, the source is based on the outbound interface for the
destination.
Command Default
IPv4 addressing is the default.
Command Modes
EXEC
Command History
Release
Modification
Release 3.2
This command was introduced.
Release 3.5.0
The host-address argument was changed from optional to required.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The mrinfo command determines which neighboring multicast
routers are peering with a multicast router.
You can query a multicast router with this command. The output format is identical to
the multicast routed version of Distance Vector Multicast Routing Protocol (DVMRP). (The
mrouted software is the UNIX software that implements DVMRP.)
Task ID
Task ID
Operations
multicast
execute
Examples
The following is sample output from the mrinfo command. The
first line shows the multicast configuration with version number and flags Parent
Multicast Agent (PMA). The flags mean that the configuration is prune capable, mtrace
capable, and SNMP capable. For each neighbor of the queried multicast router, the IP
address of the queried router is displayed, followed by the IP address of the neighbor.
The metric (cost of connect) and the threshold (multicast time to live) are displayed.
Other information is available, such as whether this router is
(Optional) Domain Name System (DNS) name or the IP address of the
multicast-capable source. This is a unicast address of the beginning of the
path to be traced.
destination
(Optional) DNS name or address of the unicast destination. If omitted, the
mtrace starts from the system where the command originated.
group
(Optional) DNS name or multicast address of the group to be traced. Default
address is 224.2.0.1 (the group used for MBONE Audio). When address 0.0.0.0
is used, the software invokes a weak mtrace. A weak mtrace is one
that follows the Reverse Path Forwarding (RPF) path to the source,
regardless of whether any router along the path has multicast routing table
state.
ttl
(Optional) Time-to-live (TTL) threshold for a multicast trace request.
Range is 1 to 255 router hops.
Command Default
By default, this feature is disabled.
IPv4 addressing is the default.
Command Modes
EXEC
Command History
Release
Modification
Release 3.2
This command was introduced.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The trace request generated by the mtrace command is multicast
to the multicast group to find the last-hop router to the specified destination. The
trace follows the multicast path from destination to source by passing the mtrace
request packet using unicast to each hop. Responses are unicast to the querying router
by the first-hop router to the source. This command allows you to isolate multicast
routing failures.
If no arguments are entered, the router interactively prompts you for them.
This command is identical in function to the UNIX version of mtrace.
Task ID
Task ID
Operations
multicast
execute
Examples
The following is sample output from the mtrace command:
RP/0/0/CPU0:router# mtrace 172.16.1.0 172.16.1.10 239.254.254.254
Type escape sequence to abort.
Mtrace from 172.16.1.0 to 172.16.1.10 via group 239.254.254.254
From source (?) to destination (?)
Querying full reverse path...
Switching to hop-by-hop:
0 172.16.1.10
-1 172.17.20.101 PIM Reached RP/Core [172.16.1.0/24]
-2 172.18.10.1 PIM [172.16.1.0/32]
-3 172.16.1.0 PIM [172.16.1.0/32]
sap cache-timeout
To limit how long a Session Announcement Protocol (SAP) cache entry stays active in the
cache, use the sap cache-timeout command in global
configuration mode. To return to the default behavior, use the
no form of this command.
sapcache-timeoutminutes
nosapcache-timeout
Syntax Description
minutes
Time that a SAP cache entry is active in the cache. Range is 1 to 1440.
Command Default
minutes: 1440 (24 hours)
Command Modes
Global configuration
Command History
Release
Modification
Release 3.2
This command was introduced.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The sap cache-timeout command defines how long session
announcements are cached by the router. Active session announcements are periodically
re-sent by the originating site, refreshing the cached state in the router. The minimum
interval between announcements for a single group is 5 minutes. Setting the cache
timeout to a value less than 30 minutes is not recommended. Set the cache timeout to 0
to keep entries in the cache indefinitely.
Task ID
Task ID
Operations
multicast
read, write
Examples
The following example shows the SAP cache entry timeout being configured at 10
minutes:
RP/0/0/CPU0:router(config)# sap cache-timeout 10
sap listen
To configure the Session Announcement Protocol (SAP) designated router (SDR) listener on
a group address, use the sap listen command in global
configuration mode. To return to the default behavior, use the
no form of this command.
saplisten
[
ip-address | name
]
nosaplisten
Syntax Description
ip-address
(Optional) Group IP address for an address range.
name
(Optional) Name of a prefix for an address range.
Command Default
When no group address is configured, the SDR listener is configured on the global SAP
announcement group (224.2.127.254).
Command Modes
Global configuration
Command History
Release
Modification
Release 3.2
This command was introduced.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The sap listen command configures an SDR listener that listens
to SAP announcements on the configured group address. The group IP address can be any
group in the range from 224.2.128.0 to 224.2.255.255.
Task ID
Task ID
Operations
multicast
read, write
Examples
The following example configures an SDR listener for group on IP address
224.2.127.254:
RP/0/0/CPU0:router(config)# sap listen 224.2.127.254
(Optional) Group IP address or name of the session that is learned.
session-name
(Optional) Session name.
detail
(Optional) Provides more SAP information.
Command Default
IPv4 addressing is the default.
Command Modes
EXEC
Command History
Release
Modification
Release 3.2
This command was introduced.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.
The show sap command displays the sessions learned on the
configured multicast groups. The detail keyword displays
verbose session information.
Use the sap listen command to configure the SDR listener on a
group IP address.
Task ID
Task ID
Operations
multicast
read
Examples
The following is sample output from the show sap command.
Information is summarized and shows one entry.
RP/0/0/CPU0:router# show sap
Sap Session Table Summary
Cisco Systems, Inc
Src: 192.168.30.101, Dst: 224.2.127.254, Last Heard: 00:00:23
Total Entries : 1
Table 1 describes the significant
fields shown in the display.
Table 1 show sap Field Descriptions
Field
Description
Src
IP address of the host from which this session announcement was
received.
Dst
Destination IP multicast group address where the announcement was
sent.
Last Heard
Time (in hours, minutes, and seconds) when SAP announcements were last
heard from the source.
Total Entries
Total number of entries displayed.
The following is sample output from the show sap command with
the detail keyword specified for the SAP session, Cisco
Systems, Inc.
RP/0/0/CPU0:router# show sap detail
Sap Session Table
Session Name: Cisco Systems, Inc
Description: IPTV Streaming Video
Group: 225.225.225.1 TTL: 2
Announcement source: 192.30.30.101, Destination: 224.2.127.254
Created by: - 0050c200aabb 9 IN IP4 10.10.176.50
Session Permanent Attribute: packetsize:4416
Attribute: packetformat:RAW
Attribute: mux:m1s
Attribute: keywds:
Attribute: author:Cisco Systems, Inc
Attribute: copyright:Cisco Systems, Inc
Media : video, Transport Protocol : udp, Port : 444
Total Entries : 1
Table 2 describes the
significant fields shown in the display.
Table 2 show sap detail Field Descriptions
Field
Description
Session Name
Descriptive name of the SAP session.
Description
An expanded description of the session.
Group
IP multicast group addresses used for this session.
Announcement source
IP address of the host from which this session announcement was
received.
Destination
Destination IP multicast group address that the announcement was sent
to.
Created by
Information for identifying and tracking the session announcement.
Attribute
Indicates attributes specific to the session.
Media
Indicates the media type (audio, video, or data), transport port that the
media stream is sent to, transport protocol used for these media (common
values are User Datagram Protocol [UDP] and Real-Time Transport Protocol
[RTP]/AVP), and list of media formats that each media instance can use.
The first media format is the default format. Format identifiers are
specific to the transport protocol used.