Multicast Source Discovery Protocol Commands

Syntax Description

ip-address | name

IP address or name of the MSDP peer to which the TCP connection is cleared.

Command Modes

EXEC

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

This command closes the TCP connection to the peer, resets all the MSDP peer statistics, and clears the input and output queues to and from the MSDP peer.

Examples

The following example clears the TCP connection to the MSDP peer at 120.15.9.8:

clear ip msdp peer 120.15.9.8

Related Commands

Command	Description
ip msdp peer	Configures an MSDP peer.

Syntax Description

group-address | name

(Optional) Multicast group address or name for which Source-Active entries are cleared from the Source-Active cache.

Command Modes

EXEC

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

Syntax Description

peer-address | name

(Optional) Address or name of the MSDP peers whose statistics counters, reset count, and input/output count are cleared.

Command Modes

EXEC

Command History

Release	Modification
12.0(7)T	This command was introduced.

Examples

The following example clears the counters for the peer named sanjose:

clear ip msdp statistics sanjose

Syntax Description

sa-address	Active source IP address.
type number	Interface type and number from which the IP address is derived and used as the RP address in Source-Active messages. Thus, MSDP peers can forward Source-Active messages away from this border. The IP address of the interface is used as the Originator-ID, which is the RP field in the MSDP Source-Active message.

Defaults

The active sources in the dense-mode region will not participate in MSDP.

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

Note This command is not recommended. It is better to configure the border router in the sparse mode domain to proxy-register sources in the dense-mode domain, and have the sparse mode domain use standard MSDP procedures to advertise these sources.

Use this command if you want the router to send Source-Active messages for sources active in the PIM dense-mode region to MSDP peers.

Note If you use this command, you MUST constrain the sources advertised by using the ip msdp redistribute command. Configure the ip msdp redistribute command to apply to only local sources. Be aware that this can result in (S,G) state remaining long after a source in the dense-mode domain has stopped sending.

Syntax Description

list access-list-number

(Optional) Extended IP access list number in the range from 100 to 199 that defines which source/group pairs to cache.

Defaults

The router does not create SA state.

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

Use this command if you prefer to sacrifice some memory in order to overcome the latency problem for a member who joins a group right after the Source-Active message arrives, and misses the message. If you configure this command, the router can supply Source-Active information to the late joiner from cache, instead of making the member wait until the next Source-Active message is received.

This command is not required in every MSDP speaker.

An alternative to this command is using the ip msdp sa-request command to have the router send Source-Active Request messages to the MSDP peer when a new joiner from the group becomes active.

Examples

The following example caches state for all sources in 171.69.0.0/16 sending to groups 224.2.0.0/16:

ip msdp cache-sa-state 100
access-list 100 permit ip 171.69.0.0 0.0.255.255 224.2.0.0 0.0.255.255

Related Commands

Command	Description
clear ip msdp sa-cache	Clears MSDP Source-Active cache entries.
ip msdp sa-request	Configures the router to send Source-Active Request messages to the MSDP peer when a new joiner from the group becomes active.
show ip msdp sa-cache	Displays (S,G) state learned from MSDP peers.

Syntax Description

ip-address | name	IP address or Domain Name System (DNS) name of the MSDP default peer.
prefix-list list	(Optional) Border Gateway Protocol (BGP) prefix-list that specifies the peer will be a default peer only for the prefixes listed in the list specified by the list argument. Of course, there must be a BGP prefix-list configured for this prefix-list list keyword and argument to have any effect.

Defaults

No default MSDP peer exists.

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

Use the ip msdp default-peer command if you do not want to configure your MSDP peer to be a BGP peer also.

If only one MSDP peer is configured (with the ip msdp peer command), that will be used as a default peer, no matter what. Therefore, you don't need to configure a default peer with this command.

If the prefix-list list keyword and argument are not specified, all SA messages received from the configured default peer are accepted.

Remember to configure a BGP prefix list if you intend to configure the prefix-list list keyword and argument with the ip msdp default-peer command.

If the prefix-list list keyword and argument are specified, SA messages originated from RPs covered by the prefix-list list keyword and argument will be accepted from the configured default peer. If the prefix-list list keyword and argument are specified but no prefix list is configured, the default peer will be used for all prefixes.

The following two bullets explain how you can enter multiple ip msdp default-peer commands, with or without the prefix-list keyword. However, all commands must either have the keyword or all must not have the keyword.

• When you use multiple ip msdp default-peer commands with the prefix-list keyword, you use all the default peers at the same time for different RP prefixes. This syntax is typically used in a Service Provider cloud that connects stub site clouds.

• When you use multiple ip msdp default-peer commands without the prefix-list keyword, you use a single active peer to accept all SA messages. If that peer goes down, then you move to the next configured default peer to accept all SA messages. This syntax is typically used at a stub site.

Examples

The following example configures the router named router.cisco.com as the default peer to the local router:

ip msdp peer 131.12.2.3
ip msdp peer 131.13.4.5
ip msdp default-peer router.cisco.com    !At a stub site
 

The following example configures two default peers:

ip msdp peer 131.12.2.3
ip msdp peer 131.13.4.5
ip msdp default-peer 131.12.2.3 prefix-list site-c
ip prefix-list site-a permit 131.12.0.0/16
ip msdp default-peer 131.13.4.5 prefix-list site-a
ip prefix-list site-a permit 131.13.0.0/16

Related Commands

Command	Description
ip msdp peer	Configures an MSDP peer.
ip prefix-list	Creates a prefix list.

Syntax Description

peer-name | peer-address	Peer name or address to which this description applies.
text	Description of the MSDP peer.

Defaults

No description is associated with an MSDP peer.

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

Configure a description to make the MSDP peer easier to identify. This description is visible in the output of the show ip msdp peer command.

Examples

The following example configures the router at the IP address 131.107.5.4 with a description indicating it is a router at customer A:

ip msdp description 131.107.5.4 router at customer a

Syntax Description

ip-address | name	IP address or name of the MSDP peer from which the local router requests Source-Active messages when a new joiner for the group becomes active.
list access-list-number	(Optional) Standard IP access list number that describes a multicast group address. The access list number is in the range 1 to 99. If no access list is specified, all Source-Active Request messages are ignored.

Defaults

If this command is not configured, all Source-Active Request messages are honored. If this command is configured but no access list is specified, all SA Request messages are ignored.

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

By default, the router honors all Source-Active Request messages from peers. Use this command if you want to control exactly which SA Request messages the router will honor.

If no access list is specified, all SA Request messages are ignored. If an access list is specified, only SA Request messages from those groups permitted will be honored, and all others will be ignored.

Examples

The following example configures the router to filter Source-Active Request messages from the MSDP peer at 171.69.2.2. Source-Active Request messages from sources on the network 192.4.22.0 pass access list 1 and will be honored; all others will be ignored.

ip msdp filter sa-request 171.69.2.2 list 1
access-list 1 permit 192.4.22.0 0.0.0.255

Related Commands

Command	Description
ip msdp peer	Configures an MSDP peer.

Syntax Description

name	Name of the mesh group.
ip-address | name	IP address or name of the MSDP peer to be a member of the mesh group.

Defaults

The MSDP peers do not belong to a mesh group.

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

A mesh group is a group of MSDP speakers that have fully meshed MSDP connectivity among themselves. Any SA messages received from a peer in a mesh group are not forwarded to other peers in the same mesh group.

Mesh groups can be used to achieve two goals:

• To reduce SA message flooding

• To simplify peer-RPF flooding (no need to run BGP or MBGP among MSDP peers)

Examples

The following example configures the MSDP peer at address 1.1.1.1 to be a member of the mesh group named internal:

ip msdp mesh-group internal 1.1.1.1

Syntax Description

type number

Interface type and number on the local router, whose IP address is used as the RP address in Source-Active messages.

Defaults

The RP address is used as the Originator ID.

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

Syntax Description

peer-name | peer-address	DNS name or IP address of the router that is to be the MSDP peer.
connect-source type number	(Optional) Interface type and number whose primary address becomes the source IP address for the TCP connection. This interface is on the router being configured.
remote-as as-number	(Optional) Autonomous system number of the MSDP peer. This is used for display purposes only. There are cases where a peer might appear to be in another autonomous system (other than the one it really resides in) when you MSDP-peer but do not BGP-peer with that peer. In this case, if the prefix of the peer is injected by another autonomous system (AS), it is displayed as the AS number of the peer (and is misleading).

Defaults

No MSDP peer is configured.

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

The router specified should also be configured as a BGP neighbor.

If you are also BGP peering with this MSDP peer, you should use the same IP address for MSDP as you do for BGP. However, you are not required to run BGP or MBGP with the MSDP peer, as long as there is a BGP or MBGP path between the MSDP peers. If there is not, you must configure the ip msdp default-peer command.

Examples

The following example configures the router at the IP address 131.108.1.2 as an MSDP peer to the local router. The neighbor belongs to autonomous system 109.

ip msdp peer 131.108.1.2 connect-source ethernet 0
router bgp 110
 network 131.108.0.0
 neighbor 131.108.1.2 remote-as 109
 neighbor 131.108.1.2 update-source ethernet 0
 

The following example configures the router named router.cisco.com as an MSDP peer to the local router:

ip msdp peer router.cisco.com
 

The following example configures that the router named router.cisco.com is an MSDP peer in AS 109. The primary address of Ethernet interface 0 is used as the source address for the TCP connection.

ip msdp peer router.cisco.com connect-source ethernet0 remote-as 109

Related Commands

Command	Description
neighbor remote-as	Adds an entry to the BGP neighbor table.

Syntax Description

list access-list-name	(Optional) Name or number of a standard or extended IP access list that controls which local sources are advertised and to which groups they send.
asn aspath-access-list-number	(Optional) Standard or extended IP access list number in the range 1 to 199. This access list number must also be configured in the ip as-path command.
route-map map	(Optional) Standard or extended IP access list number in the range 1 to 199. This access list number must also be configured in the ip as-path command.

Defaults

• If no portion of this command is configured, only local sources are advertised, provided they send to groups for which this router is a rendezvous point (RP).

• If no portion of this command is configured and if the ip msdp border sa-address command is configured, all local sources are advertised.

• If the ip msdp redistribute command is configured with no keywords, no multicast sources are advertised.

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

This command affects SA message origination, not SA message forwarding. If you want to filter which SA messages are forwarded to MSDP peers, use the ip msdp sa-filter in or ip msdp sa-filter out command.

The ip msdp redistribute command controls which (S,G) pairs the router advertises from the multicast routing table. By default, only sources within the local domain are advertised. Use the following guidelines for the ip msdp redistribute command:

• If you specify the list access-list-name kyeword and argument only, you filter which local sources are advertised and to what groups they send. The access list specifies a source address, source mask, group address, and group mask.

• If you specify the asn aspath-access-list-number keyword and argument only, you advertise all sources sending to any group, which sources pass the autonomous system path access list. The autonomous system path access list number refers to the ip as-path command, which specifies an access list. If the asn 0 keyword is specified, sources from all autonomous systems are advertised. The asn 0 keyword is useful when connecting dense-mode domains to a sparse mode domain running MSDP, or when using MSDP in a router that is not configured with BGP (and, therefore you do not know if a source is local or not).

• If you specify the route-map map keyword and argument only, you advertise all sources that satisfy the match criteria in the route map map.

• If you specify all three keywords (list, asn, and route-map), all conditions must be true before any multicast source is advertised in an SA message.

• If you specify the ip multicast redistribute command with no other keywords or arguments, no multicast sources are advertised.

Examples

The following example configures which (S,G) entries from the multicast routing table are advertised in SA messages originated to MSDP peers:

ip msdp redistribute route-map customer-sources
 
route-map customer-sources permit
match as-path customer-as
 
ip as-path access-list ^109$

Related Commands

Command	Description
ip as-path	Defines a BGP-related access list.
ip msdp border	Configures a router that borders a PIM sparse mode region and dense-mode region to use MSDP.

Syntax Description

ip-address | name	IP address or name of the MSDP peer from which the Source-Active messages are filtered.
list access-list-name	(Optional) IP access list name. If no access list is specified, all source/group pairs from the peer are filtered.
route-map map-tag	(Optional) Route map name. From the specified MSDP peer, passes only those SA messages that meet the match criteria in the route map map-tag. If all match criteria are true, a permit keyword from the route-map will pass routes through the filter. A deny keyword will filter routes. If both the list and the route-map keywords are used, all conditions must be true to pass any (S,G) pair in incoming SA messages.

Defaults

• If this command is not configured, no incoming messages are filtered; all SA messages are accepted from the peer.

• If the command is configured, but no access list or route map is specified, all source/group pairs from the peer are filtered.

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Examples

The following example configures that all Source-Active messages from the peer named router.cisco.com are filtered:

ip msdp peer router.cisco.com connect-source ethernet 0
ip msdp sa-filter in router.cisco.com
 

Related Commands

Command	Description
ip msdp peer	Configures an MSDP peer.
ip msdp sa-filter out	Configures an outgoing filter list for Source-Active messages sent to the specified MSDP peer.

Syntax Description

ip-address | name	IP address or DNS name of the MSDP peer to which the Source-Active messages are filtered.
list access-list-name	(Optional) Extended IP access list number or name. If no access list is specified, all source/group pairs are filtered. To the specified MSDP peer, passes only those Source-Active messages that pass the extended access list. If both the list and the route-map keywords are used, all conditions must be true to pass any (S,G) pairs in outgoing SA messages.
route-map map-tag	(Optional) Route map name. To the specified MSDP peer, passes only those Source-Active messages that meet the match criteria in the route map map-tag. If all match criteria are true, a permit from the route-map will pass routes through the filter. A deny will filter routes. If both the list and the route-map keywords are used, all conditions must be true to pass any (S,G) pairs in outgoing SA messages.

Defaults

• If this command is not configured, no outgoing messages are filtered; all SA messages received are forwarded to the peer.

• If the command is configured, but no access list or route map is specified, all source/group pairs are filtered.

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Examples

The following example allows only (S,G) pairs that pass access list 100 to be forwarded in a Source-Active message to the peer named router.cisco.com:

ip msdp peer router.cisco.com connect-source ethernet 0
ip msdp sa-filter out router.cisco.com list 100
access-list 100 permit ip 171.69.0.0 0.0.255.255 224.2.0.0 0.0.255.255

Related Commands

Command	Description
ip msdp peer	Configures an MSDP peer.
ip msdp sa-filter in	Configures an incoming filter list for Source-Active messages received from the specified MSDP peer.

Syntax Description

ip-address | name

IP address or name of the MSDP peer from which the local router requests Source-Active messages when a new joiner for the group becomes active.

Defaults

The router does not send Source-Active Request messages to the MSDP peer.

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

By default, the router does not send any Source-Active Request messages to its MSDP peers when a new member joins a group and wants to receive multicast traffic. The new member just waits to receive any Source-Active messages that eventually arrive.

Use this command if you want a new member of a group to learn the current, active multicast sources in a connected PIM sparse mode domain that are sending to a group. The router will send Source-Active Request messages to the specified MSDP peer when a new member joins a group. The peer replies with the information it is SA cache. If the peer does not have a cache configured, this command provides nothing.

An alternative to this command is using the ip msdp cache-sa-state command to have the router cache messages.

Examples

The following example configures the router to send Source-Active Request messages to the MSDP peer at 171.69.1.1:

ip msdp sa-request 171.69.1.1
 

Related Commands

Command	Description
ip msdp cache-sa-state	Causes the router to create Source-Active (SA) state, so when a multicast group member joins a group right after a Source-Active message arrives, the router can supply Source-Active information to the late joiner from cache.
ip msdp peer	Configures an MSDP peer.

Syntax Description

peer-address | peer-name

IP address or name of the MSDP peer to shut down.

Defaults

No action is taken to shut down an MSDP peer.

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Examples

The following example shuts down the MSDP peer at IP address 136.5.7.20:

ip msdp shutdown 136.5.7.20

Related Commands

Command	Description
ip msdp peer	Configures an MSDP peer.

Syntax Description

ip-address | name	IP address or name of the MSDP peer to which the ttl limitation applies. The default value of the ttl argument is 0, meaning all multicast data packets are forwarded to the peer until the TTL is exhausted.
ttl	Time-to-live (TTL) value.

Defaults

ttl = 0

Command Modes

Global configuration

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

This command limits which multicast data packets are sent in data-encapsulated SA messages. Only multicast packets with an IP-header TTL greater than or equal to the ttl argument are sent to the MSDP peer specified by the IP address or name.

Use this command if you want to use TTL to scope your multicast data traffic. For example, you could limit internal traffic to a TTL of 8. If you want other groups to go to external locations, you would need to send those packets with a TTL greater than 8.

Examples

The following example configures a TTL threshold of 8 hops:

ip msdp ttl-threshold 8

Related Commands

Command	Description
ip msdp peer	Configures an MSDP peer.

Syntax Description

autonomous-system-number

(Optional) Displays the number of sources and group originated in SA messages from the specified autonomous system.

Command Modes

EXEC

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

The ip msdp cache-sa-state command must be configured for this command to have any output.

Examples

The following is sample output of the show ip msdp count command:

Router# show ip msdp count
 
SA State per ASN Counters, <asn>: <# sources>/<# groups>
    Total entries: 2398
    267: 1/1, 704: 1479/143, 3582: 236/28, 6461: 50/0
    10876: 5/1, 10888: 627/88
 

Related Commands

Command	Description
ip msdp cache-sa-state	Causes the router to create Source-Active (SA) state, so when a multicast group member joins a group right after a Source-Active message arrives, the router can supply Source-Active information to the late joiner from cache.

Syntax Description

peer-address | name

Address or name of the MSDP peer for which information is displayed.

Command Modes

EXEC

Command History

Release	Modification
12.0(7)T	This command was introduced.

Examples

The following is sample output of the show ip msdp peer command:

Router# show ip msdp peer 198.9.200.65
 
MSDP Peer Status Summary
Peer Address        AS         State        Uptime/     Msgs Sent/      Peer Name
                                            Downtime    Received
198.9.200.65        10888      Up           2d10h       50584/48022     ?
 
TCP connection source: Loopback 0
SA input filter: None
SA output filter: None
SA-Request filter: None
Sending SA-Requests to peer: Disabled
 

Related Commands

Command	Description
ip msdp peer	Configures an MSDP peer.

Syntax Description

group-address | source-address | group-name | source-name	(Optional) Group address, source address, group name, or source name of the group or source about which (source, group) information is displayed. If two address or names are specified, an (S, G) entry corresponding to those addresses is displayed. If only one group address is specified, all sources for that group are displayed. If no options are specified, the entire SA cache is displayed.
autonomous-system-number	(Optional) Only state originated by the autonomous system specified is displayed.

Command Modes

EXEC

Command History

Release	Modification
12.0(7)T	This command was introduced.

Usage Guidelines

Related Commands

Command	Description
clear ip msdp sa-cache	Clears MSDP Source-Active cache entries.
ip msdp cache-sa-state	Causes the router to create Source-Active state, so when a multicast group member joins a group right after a Source-Active message arrives, the router can supply Source-Active information to the late joiner from cache.

Syntax Description

This command has no arguments or keywords.

Command Modes

EXEC

Command History

Release	Modification
12.0(7)T	This command was introduced.

Examples

The following is sample output of the show ip msdp summary command:

Router# show ip msdp summary
 
MSDP Peer Status Summary
Peer Address     AS    State     Uptime/   Msgs Sent/  Peer Name
                                 Downtime  Received
198.9.200.65     10888 Up        2d10h     50569/48007 ?
198.9.201.122    6461  Up        3d13h     145892/11218?
198.9.200.34     704   Up        06:34:44  6118/6508   ?
198.9.201.113    3967  Listen    4d11h     0/0         ?
198.9.201.2      24    Up        02:27:03  4880/160    ?