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Cisco IOS Software Releases 12.0 T

Multicast Source Discovery Protocol

Table Of Contents

Multicast Source Discovery Protocol

Feature Overview

How MSDP Works

Benefits

Supported Platforms

Prerequisites

Supported Standards, MIBs, and RFCs

Configuration Tasks

Configuring an MSDP Peer

Caching Source-Active State

Requesting Source Information from an MSDP Peer

Controlling Source Information Your Router Originates

Redistributing Sources

Filtering Source-Active Request Messages

Controlling Source Information Your Router Forwards

Using a Filter

Using TTL to Limit the Multicast Data Sent in SA Messages

Controlling Source Information Your Router Receives

Configuring a Default MSDP Peer

Configuring an MSDP Mesh Group

Shutting Down an MSDP Peer

Including a Bordering PIM Dense-Mode Region in MSDP

Configuring an Originating Address Other Than the RP Address

Monitoring and Maintaining MSDP

Configuration Examples

Default MSDP Peer

Logical RP

Command Reference

clear ip msdp peer

Syntax Description

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

clear ip msdp sa-cache

Syntax Description

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

clear ip msdp statistics

Syntax Description

Command Modes

Command History

Examples

ip msdp border

Syntax Description

Defaults

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

ip msdp cache-sa-state

Syntax Description

Default

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

ip msdp default-peer

Syntax Description

Default

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

ip msdp description

Syntax Description

Default

Command Modes

Command History

Usage Guidelines

Examples

ip msdp filter-sa-request

Syntax Description

Default

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

ip msdp mesh-group

Syntax Description

Default

Command Modes

Command History

Usage Guidelines

Examples

ip msdp originator-id

Syntax Description

Default

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

ip msdp peer

Syntax Description

Default

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

ip msdp redistribute

Syntax Description

Defaults

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

ip msdp sa-filter in

Syntax Description

Default

Command Modes

Command History

Examples

Related Commands

ip msdp sa-filter out

Syntax Description

Default

Command Modes

Command History

Examples

Related Commands

ip msdp sa-request

Syntax Description

Default

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

ip msdp shutdown

Syntax Description

Default

Command Modes

Command History

Examples

Related Commands

ip msdp ttl-threshold

Syntax Description

Default

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

show ip msdp count

Syntax Description

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

show ip msdp peer

Syntax Description

Command Modes

Command History

Examples

Related Commands

show ip msdp sa-cache

Syntax Description

Command Modes

Command History

Usage Guidelines

Examples

Related Commands

show ip msdp summary

Syntax Description

Command Modes

Command History

Examples

Debug Commands

debug ip msdp

Syntax Description

Command History

Examples

debug ip msdp resets

Syntax Description

Command Modes

Command History


Multicast Source Discovery Protocol


This feature module describes the Multicast Source Discovery Protocol feature. It includes information on the benefits of the new feature, supported platforms, related documents, and so forth.

This document includes the following sections:

Feature Overview

Supported Platforms

Prerequisites

Supported Standards, MIBs, and RFCs

Configuration Tasks

Monitoring and Maintaining MSDP

Configuration Examples

Command Reference

Debug Commands

Feature Overview

Multicast Source Discovery Protocol (MSDP) is a mechanism to connect multiple PIM sparse-mode (SM) domains. MSDP allows multicast sources for a group to be known to all rendezvous point(s) (RPs) in different domains. Each PIM-SM domain uses its own RPs and need not depend on RPs in other domains. An RP runs MSDP over TCP to discover multicast sources in other domains.

An RP in a PIM-SM domain has an MSDP peering relationship with MSDP-enabled routers in another domain. The peering relationship occurs over a TCP connection, where primarily a list of sources sending to multicast groups is exchanged. The TCP connections between RPs are achieved by the underlying routing system. The receiving RP uses the source lists to establish a source path.

The purpose of this topology is to have domains discover multicast sources in other domains. If the multicast sources are of interest to a domain that has receivers, multicast data is delivered over the normal, source-tree building mechanism in PIM-SM.

MSDP is also used to announce sources sending to a group. These announcements must originate at the domain's RP.

MSDP depends heavily on (M)BGP for interdomain operation. It is recommended that you run MSDP in RPs in your domain that are RPs for sources sending to global groups to be announced to the internet.

How MSDP Works

illustrates MSDP operating between two MSDP peers. PIM uses MSDP as the standard mechanism to register a source with the RP of a domain.

When MSDP is configured, the following sequence occurs. When a source's first data packet is registered by the first-hop router, that same data packet is decapsulated by the RP and forwarded down the shared tree. That packet is also re-encapsulated in a Source-Active (SA) message that is immediately forwarded to all MSDP peers. The SA message identifies the source, the group the source is sending to, and the RP's own address or the originator ID, if configured. If the peer is an RP and has a member of that multicast group, the data packet is decapsulated and forwarded down the shared-tree in the remote domain.

The PIM designated router (DR) directly connected to the source sends the data encapsulated in a PIM Register message to the RP in the domain.


Note   Note that this happens only once per source, when the source goes active. If the source times out, this process happens again when it goes active again. This is different from the periodic SA message that contains all sources that are registered to the originating RP. These messages have no data.


Each MSDP peer receives and forwards the SA message away from the originating RP to achieve "peer-RPF flooding." The concept of peer-RPF flooding is with respect to forwarding SA messages. The router examines the BGP or MBGP routing table to determine which peer is the next hop toward the originating RP of the SA message. Such a peer is called an "RPF peer" (Reverse-Path Forwarding peer). The router forwards the message to all MSDP peers other than the RPF peer.

If the MSDP peer receives the same SA message from a non-RPF peer toward the originating RP, it drops the message. Otherwise, it forwards the message on to all its MSDP peers.

When an RP for a domain receives an SA message from an MSDP peer, it determines if it has any group members interested in the group the SA message describes. If the (*,G) entry exists with a nonempty outgoing interface list, the domain is interested in the group, and the RP triggers an (S,G) join toward the source.

Figure 1 MSDP Running Between RP Peers

Benefits

MSDP has the following benefits:

It breaks up the shared multicast distribution tree. You can make the shared tree local to your domain. Your local members join the local tree, and Join messages for the shared tree never have to leave your domain.

PIM sparse-mode domains can rely on their own RPs only, thus decreasing reliance on RPs in another domain. This increases security because you can prevent your sources from being known outside your domain.

Domains with only receivers can receive data without globally advertising group membership.

Global source multicast routing table state is not required, thus saving on memory.

Supported Platforms

MSDP operates on all Cisco IOS platforms that run Cisco IOS Release 11.1 CC, 12.0(5)S, or 12.0(7)T.

Prerequisites

Before configuring MSDP, the addresses of all MSDP peers must be known in BGP or MBGP. If that does not occur, you must configure MSDP default peering when you configure MSDP.

Supported Standards, MIBs, and RFCs

MIBs

No new or modified MIBs are supported by this feature.

For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.

RFCs

None

Standards

This feature supports Internet Engineering Task Force draft Multicast Source Discovery Protocol (MSDP).

Configuration Tasks

To configure an MSDP peer and various MSDP options, perform the following tasks. The first task is required; the remaining are optional.

Configuring an MSDP Peer (Required)

Caching Source-Active State (Optional)

Requesting Source Information from an MSDP Peer (Optional)

Controlling Source Information Your Router Originates (Optional)

Controlling Source Information Your Router Forwards (Optional)

Controlling Source Information Your Router Receives (Optional)

Configuring a Default MSDP Peer (Optional)

Configuring an MSDP Mesh Group (Optional)

Shutting Down an MSDP Peer (Optional)

Including a Bordering PIM Dense-Mode Region in MSDP (Optional)

Configuring an Originating Address Other Than the RP Address (Optional)

Configuring an MSDP Peer

You enable MSDP by configuring an MSDP peer to the local router.


Note   The router you specify by Domain Naming System (DNS) name or IP address as an MSDP peer is probably a BGP neighbor. If it is not, see the section "Configuring a Default MSDP Peer" later in this document.


To configure an MSDP peer, use the following commands in global configuration mode. The second command is optional.

Command
Purpose

ip msdp peer {peer-name | peer-address} [connect-source type number] [remote-as as-number]

Enables MSDP and configures an MSDP peer as specified by the DNS name or IP address.

If you specify the connect-source keyword, the primary address of the specified local interface type and number is used as the source IP address for the TCP connection. The connect-source keyword is recommended, especially for MSDP peers on a border that peer with a router inside the remote domain.

ip msdp description {peer-name | peer-address} text

Configures a description for a specified peer to make it easier to identify in a configuration or in show command output.


Caching Source-Active State

By default, the router does not cache source/group pairs from received SA messages. Once the router forwards the MSDP Source-Active information, it does not store it in memory. Therefore, if a member joins a group soon after a Source-Active message is received by the local RP, that member will have to wait until the next SA message to hear about the source. This delay is known as join latency.

If you want to sacrifice some memory in exchange for reducing the latency of the source information, you can configure the router to cache Source-Active messages. To have the router cache source/group pairs, use the following command in global configuration mode

Command
Purpose

ip msdp cache-sa-state [list access-list-number]

Creates SA state (cache source/group pairs). Those pairs that pass the access list are cached.


:

An alternative to caching the source-active state is to request source information from a peer, which is described in the section "Requesting Source Information from an MSDP Peer." If you cache the information, you don't need to trigger a request for it.

Requesting Source Information from an MSDP Peer

Local RPs can send Source-Active Requests and get immediate response for all active sources for a given group. 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 the next periodic Source-Active message.

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, configure the router to send Source-Active Request messages to the specified MSDP peer when a new member joins a group. Doing so reduces join latency, but requires some memory.

Note that information can be requested only from caching peers.

To configure this feature, use the following command in global configuration mode

Command
Purpose

ip msdp sa-request {ip-address | name}

Configures the router to send Source-Active Request messages to the specified MSDP peer when a receiver becomes active, so the receiver can learn about multicast sources in 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.


:

Repeat the preceding command for each MSDP peer that you want to supply you with Source-Active messages.

An alternative to requesting source information is to cache the source-active state, which is described in the earlier section "Caching Source-Active State." If you cache the information, you don't need to trigger a request for it.

Controlling Source Information Your Router Originates

There are two ways to control the multicast source information that originates with your router. You can control the following:

Which sources you will advertise (based on your sources)

Whom you will provide source information to (based on knowing who is asking you for information)

To control which sources you will advertise, see the section "Redistributing Sources" later in this document. To control whom you will provide source information to, see the section "Controlling Source Information Your Router Forwards."

Redistributing Sources

Source-Active messages are originated on RPs to which sources have registered. By default, any source that registers with an RP will be advertised. The "A flag" is set in the RP when a source is registered. This means the source will be advertised in an SA unless it is filtered with the command below.

To further restrict which registered sources are advertised, use the following command in global configuration mode. The access list or autonomous system path access list determines which (S,G) pairs are advertised

Command
Purpose

ip msdp redistribute [list access-list-name] [asn aspath-access-list-number] [route-map map]

Advertises (S,G) pairs that pass the access list or route map to other domains.


.


Note   The ip msdp redistribute command could also be used to advertise sources that are known to the RP but not registered. However, it is strongly recommended you NOT originate advertisements for sources that have not registered with the RP.


Filtering Source-Active Request Messages

By default, only routers that are caching Source-Active information can respond to Source-Active Reuqests. By default, such a router honors all Source-Active Request messages from its MSDP peers. That is, it will supply the IP addresses of the sources that are active.

However, you can configure the router to ignore all Source-Active Requests from an MSDP peer. Or, you can honor only those Source-Active Request messages from a peer for groups described by a standard access list. If the access list passes, Source-Active Request messages will be accepted. All other such messages from the peer for other groups will be ignored.

To configure one of these options, use the appropriate command in global configuration mode

Command
Purpose

ip msdp filter-sa-request ip-address | name

Filters all Source-Active Request messages from the specified MSDP peer.

ip msdp filter-sa-request ip-address | name list access-list-number

Filters Source-Active Request messages from the specified MSDP peer for groups that pass the standard access list. The access list describes a multicast group address.


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Controlling Source Information Your Router Forwards

By default, the router forwards all Source-Active messages it receives to all of its MSDP peers. However, you can prevent outgoing messages from being forwarded to a peer by using a filter or by setting a time to live (TTL). These methods are described in the following sections.

Using a Filter

By creating a filter, you can do one of the following:

Filter all source/group pairs

Specify an extended access list to pass only certain source/group pairs

Filter based on match criteria in a route map

To apply a filter, use one of the following commands in global configuration mode

Command
Purpose

ip msdp sa-filter out {ip-address | name}

Filters all Source-Active messages to the specified MSDP peer.

ip msdp sa-filter out {ip-address | name} list access-list-name

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) pair in outgoing SA messages.

ip msdp sa-filter out {ip-address | name} route-map map-tag

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) in outgoing SA messages.


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Using TTL to Limit the Multicast Data Sent in SA Messages

You can use TTL to control what data will be encapsulated in the first SA message for every source. For example, you could limit internal traffic to a TTL of 8. If you want other groups to go to external locations, you would have to send those packets with a TTL greater than 8.

To establish a TTL threshold, use the following command in global configuration mode:

Command
Purpose

ip msdp ttl-threshold {ip-address | name} ttl

Limits which multicast data will be encapsulated in the first Source-Active message to the specified MSDP peer.


Controlling Source Information Your Router Receives

By default, the router receives all Source-Active messages its MSDP Reverse-Path Forwarding peers send to it. However, you can control the source information you receive from MSDP peers by filtering incoming Source-Active messages. In other words, you can configure the router not to accept them.

You can do one of the following:

Filter all incoming Source-Active messages from an MSDP peer

Specify an extended access list to pass certain source/group pairs

Filter based on match criteria in a route map

To apply a filter, use one of the following commands in global configuration mode

Command
Purpose

ip msdp sa-filter in ip-address | name

From the specified MSDP peer, filters all Source-Active messages received.

ip msdp sa-filter in ip-address | name list access-list-name

From the specified MSDP peer, passes incoming 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) pair in incoming SA messages.

ip msdp sa-filter in ip-address | name route-map map-tag

From 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) in incoming SA messages.


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Configuring a Default MSDP Peer

An MSDP peer of the local router is probably a BGP peer also. However, if you do not want to have or cannot have a BGP peer, you could define a default MSDP peer from which to accept all SA messages. The default MSDP peer must be a previously configured MSDP peer. Perform this task when you are not BGP- or MBGP-peering with an MSDP peer. If a single MSDP peer is configured, a router will always accept all SA messages sent to it from that peer.

illustrates a scenario where default MSDP peers might be used. In the figure, a customer who owns Router B is connected to the internet via two Internet Service Providers (ISPs), one who owns Router A and the other who owns Router C. They are not running BGP or MBGP between them. In order for the customer to learn about sources in the ISP's domain or in other domains, Router B identifies Router A as its default MSDP peer. Router B advertises SA messages to both Router A and Router C, but accepts SA messages either from Router A only or Router C only. If Router A is first in the configuration file, it will be used if it is up and running. If Router A isn't running, then and only then will Router B accept SA messages from Router C.

The ISP will also likely use a prefix list to define which prefixes it will accept from the customer's router. The customer will define multiple default peers, each having one or more prefixes associated with it.

The customer has two ISPs to use. He defines both ISPs as default peers. As long as the first default peer identified in the configuration is up and running, it will be the default peer and the customer will accept all SA messages it receives from that peer.

Figure 2 Default MSDP Peer Scenario

Router B advertises SAs to Router A and Router C, but uses only Router A or Router C to accept SA messages. If Router A is first in the configuration file, it will be used if it is up and running. If Router A isn't running, then, and only then, will Router B accept SAs from Router C. This is the behavior without a prefix list.

If you specify a prefix list, the peer will be a default peer only for the prefixes in the list. You can have multiple active default peers when you have a prefix list associated with each. When you do not have any prefix lists, you can configure multiple default peers, but only the first one is the active default peer as long as the router has connectivity to this peer and the peer is alive. If the first configured peer goes down or the connectivity to this peer goes down, the second configured peer becomes the active default, and so on.

To specify a default MSDP peer, use the following command in global configuration mode

Command
Purpose

ip msdp default-peer ip-address | name [prefix-list list]

Defines a default MSDP peer.


:

See the section "Default MSDP Peer" for a sample configuration.

Configuring an MSDP Mesh Group

An MSDP mesh group is a group of MSDP speakers that have fully meshed MSDP connectivity between one another. Any SA messages received from a peer in a mesh group are not forwarded to other peers in the same mesh group. Thus, you reduce SA message flooding and simplify peer-RPF flooding. The command below is used when there are multiple RPs within a domain. It is especially used to transit SA messages across a domain.

You can configure multiple mesh groups (with different names) in a single router.

To create a mesh group, use the following command in global configuration mode for each MSDP peer in the group:

Command
Purpose

ip msdp mesh-group name {ip-address | name}

Configures an MSDP mesh group and indicates that an MSDP peer belongs to that mesh group.


Shutting Down an MSDP Peer

If you want to configure many MSDP commands for the same peer and you do not want the peer to go active, you can shut down the peer, configure it, and later bring it up.

You might also want to shut down an MSDP session without losing configuration information for the peer.

When in shutdown mode, the TCP connection is terminated and not restarted.

To shut down a peer, use the following command in global configuration mode:

Command
Purpose

ip msdp shutdown {peer-name | peer address}

Administratively shuts down the specified MSDP peer.


Including a Bordering PIM Dense-Mode Region in MSDP

You might have a router that borders a PIM sparse-mode region with a dense-mode region. By default, sources in the dense-mode region are not included in MSDP. You could configure this border router to send SA messages for sources active in the dense-mode region. If you do so, it is very important to also configure the ip msdp redistribute command to apply to only local sources. This can result in (S, G) state remaining long after a source in the dense-mode domain has stopped sending.


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 to the RP of the sparse-mode domain and have the sparse-mode domain use standard MSDP procedures to advertise these sources.


To configure the border router to send SA messages for sources active in the dense-mode region, use the following command in global configuration mode

Command
Purpose

ip msdp border sa-address type number

Configures the router on the border between a dense-mode and sparse-mode region to send SA messages about active sources in the dense-mode region. The IP address of the interface is used as the Originator-ID, which is the RP field in the SA message.


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Configuring an Originating Address Other Than the RP Address

If you want to change the Originator ID for any reason, use the ip msdp originator-id command in this section. For example, you might change the Originator ID in one of these cases:

If you configure a logical RP on multiple routers in an MSDP mesh-group. For an example of a logical RP, see the section "Logical RP" later in this document.

If you have a router that borders a PIM sparse-mode domain and a dense-mode domain. If a router borders a dense-mode domain for a site, and sparse-mode is being used externally, you might want dense-mode sources to be known to the outside world. Because this router is not an RP, it would not have an RP address to use in an SA message. Therefore, this command provides the RP address by specifying the address of the interface.

To allow an MSDP speaker that originates a Source-Active message to use its interface's IP address as the RP address in the SA message, use the following command in global configuration mode

Command
Purpose

ip msdp originator-id type number

Configures the RP address in SA messages to be the address of the originating router's interface.


:

Monitoring and Maintaining MSDP

To monitor MSDP Source-Active messages, peers, state, or peer status, use the following commands in EXEC mode:

Command
Purpose

debug ip msdp [peer-address | name] [detail] [routes]

Debugs an MSDP activity.

debug ip msdp resets

Debugs MSDP peer reset reasons.

show ip msdp count [autonomous-system-number]

Displays the number of sources and groups originated in SA messages from each autonomous system. The ip msdp cache-sa-state command must be configured for this command to produce any output.

show ip msdp peer [peer-address | name]

Displays detailed information about an MSDP peer.

show ip msdp sa-cache [group-address | source-address] [group-name | source-name] [autonomous-system-number]

Displays (S,G) state learned from MSDP peers.

show ip msdp summary

Displays MSDP peer status and SA message counts.


To clear MSDP connections, statistics, or SA cache entries, use the following commands in EXEC mode:

Command
Purpose

clear ip msdp peer [peer-address | name]

Clears the TCP connection to the specified MSDP peer, resetting all MSDP message counters.

clear ip msdp statistics [peer-address | name]

Clears the TCP connection to the specified MSDP peer, reset all MSDP message counters.

clear ip msdp sa-cache [group-address | name]

Clears the Source-Active cache entries for all entries, all sources for a specific group, or all entries for a specific source/group pair.


Configuration Examples

This section contains the following MSDP configurations examples:

Default MSDP Peer

Logical RP

Default MSDP Peer

The following example is a partial configuration of Router A and Router C in . Each of these ISPs may have more than one customer like the customer in the figure who use default peering (no BGP or MBGP). In that case, they may have similar configurations. That is, they will only accept SAs from a default peer if the SA is permited by the corresponding prefix list.

Router A

ip msdp default-peer 10.1.1.1
ip msdp default-peer 10.1.1.1 prefix-list site-a ge 32
ip prefix-list site-b permit 10.0.0.0/8

Router C

ip msdp default-peer 10.1.1.1 prefix-list site-a ge 32
ip prefix-list site-b permit 10.0.0.0/8

Logical RP

The following example configures a logical RP using an MSDP mesh-group. The four routers that are logical RPs are RouterA, RouterB, RouterC, and RouterD. RouterE is an MSDP border router that is not an RP. illustrates the logical RP environment in this example; the configurations for routers A, B and E follow the figure.

It is important to note the use of the loopback interface and how those host routes are advertised in OSPF. It is also important to carefully choose the OSPF router ID loopback so the ID does not use the logical RP address.

In this example, all the logical RPs are on the same LAN, but this is not typical. The host-route for the RP address is advertised throughout the domain and each PIM DR in the domain joins to the closest RP. The RPs each share (S,G) information with each other by sending SA messages. Each logical RP must use a separate Originator-ID.

Note there are two MSDP mesh-groups on RouterA. The routes for the loopback interfaces are in OSPF. Loopback 0 is the Router ID and is used as the connect-source/update-source for MBGP/MSDP. Loopback 10 is the same on all routers in the example.

All networks are 171.69.0.0. The RP address is 10.10.10.10 on Loopback 10 on all RPs. BGP connections are 192.168.1.x on Loopback 0. Loopback 0 is put into BGP with network 192.168.1.3 mask 255.255.255.255 nlri unicast multicast.

Figure 3 Logical RP using MSDP

RouterA

!
hostname RouterA
!
ip routing
!
ip subnet-zero
ip multicast-routing
!
!
interface Loopback0
 ip address 192.168.1.2 255.255.255.255
 no shutdown
!
interface Loopback10
 ip address 10.10.10.10 255.255.255.255
 no ip directed-broadcast
 ip pim sparse-dense-mode
 no shutdown
!
interface Ethernet1/2
 description LANethernet2
 ip address 171.69.2.2 255.255.255.0
ip pim sparse-dense-mode
no  shutdown
!
interface Ethernet4/0/0
 description LANethernet3
 ip address 171.69.3.2 255.255.255.0
ip pim sparse-dense-mode
no shutdown
!
router ospf 10
 network 171.69.0.0 0.0.255.255 area 0
 network 10.10.10.10 0.0.0.0 area 0
 network 192.168.1.2 0.0.0.0 area 0
!
router bgp 1
 no synchronization
 network 171.69.0.0 nlri unicast multicast
 network 192.168.1.2 mask 255.255.255.255 nlri unicast multicast 
 neighbor 192.168.1.3 remote-as 1 nlri unicast multicast
neighbor description routerB
 neighbor 192.168.1.3 next-hop-self
neighbor 192.168.1.3 update-source loopback0
neighbor 192.168.1.4 remote-as 1 nlri unicast multicast
neighbor  description routerC 
neighbor 192.168.1.4 update-source loopback0
neighbor 192.168.1.5 remote-as 1 nlri unicast multicast
neighbor  description routerD 
 neighbor 192.168.1.5 next-hop-self
neighbor 192.168.1.5 update-source loopback0
neighbor 192.168.1.6 remote-as 1 nlri unicast multicast
neighbor description routerE
 neighbor 192.168.1.6 update-source Loopback0
 neighbor 192.168.1.6 next-hop-self
!
!
ip msdp peer 192.168.1.3 connect-source loopback 0
ip msdp peer 192.168.1.5 connect-source loopback 0
ip msdp peer 192.168.1.4 connect-source loopback 0
ip msdp peer 192.168.1.6 connect-source Loopback0
ip msdp mesh-group inside-test 192.168.1.3
ip msdp mesh-group inside-test 192.168.1.4
ip msdp mesh-group inside-test 192.168.1.5
ip msdp mesh-group outside-test 192.168.1.6
ip msdp originator-id loopback0
!
ip classless
ip pim send-rp-disc scope 10
ip pim send-rp-anno loopback 10 scope 10
!

RouterB

!
hostname RouterB
!
ip routing
!
ip multicast-routing
ip dvmrp route-limit 20000
!
interface Loopback0
 ip address 192.168.1.3 255.255.255.255
 no shutdown
!
interface Loopback10
 ip address 10.10.10.10 255.255.255.255
ip pim sparse-dense-mode
 no shutdown
!
interface Ethernet2
 description LANethernet 0
 ip address 171.69.0.3 255.255.255.0
ip pim sparse-dense-mode
no shutdown
!
interface Ethernet3
 description LANethernet 2
 ip address 171.69.2.3 255.255.255.0
ip pim sparse-dense
!
router ospf 10
 network 171.69.0.0 0.0.255.255 area 0
 network 10.10.10.10 0.0.0.0 area 0
 network 192.168.1.3 0.0.0.0 area 0
!
router bgp 1
 no synchronization
 network 171.69.0.0 nlri unicast multicast
 network 192.168.1.3 mask 255.255.255.255 nlri unicast multicast
 neighbor 192.168.1.2 remote-as 1 nlri unicast multicast
neighbor  description routerA 
neighbor 192.168.1.2 update-source loopback0
neighbor 192.168.1.4 remote-as 1 nlri unicast multicast
neighbor  description routerC
neighbor 192.168.1.4 update-source loopback0
neighbor 192.168.1.5 remote-as 1 nlri unicast multicast
neighbor  description routerD 
neighbor 192.168.1.5 update-source loopback0
neighbor 192.168.1.5 soft-recon in
!
ip msdp peer 192.168.1.2 connect-source loopback 0
ip msdp peer 192.168.1.5 connect-source loopback 0
ip msdp peer 192.168.1.4 connect-source loopback 0
ip msdp mesh-group inside-test 192.168.1.2
ip msdp mesh-group inside-test 192.168.1.4
ip msdp mesh-group inside-test 192.168.1.5
ip msdp originator-id loopback0
!
ip classless
ip pim send-rp-disc scope 10
ip pim send-rp-anno loopback 10 scope 10
!

RouterE

!
hostname RouterE
!
ip routing
!
ip subnet-zero
ip routing
ip multicast-routing
ip dvmrp route-limit 20000
!
interface Loopback0
 ip address 192.168.1.6 255.255.255.255
no shutdown
!
interface Ethernet2
 description LANethernet 3
 ip address 171.69.3.6 255.255.255.0
ip pim sparse-dense-mode
no shutdown
!
interface Ethernet5
 description LANethernet 6
 ip address 192.169.1.6 255.255.255.0
ip pim sparse-dense-mode
 ip multicast boundary 20
no shutdown
!
router ospf 10
 network 171.69.0.0 0.0.255.255 area 0
 network 192.168.1.6 0.0.0.0 area 0
 default-information originate metric-type 1
!
router bgp 1
 no synchronization
 network 171.69.0.0 nlri unicast multicast
 network 192.168.1.6 mask 255.255.255.255 nlri unicast multicast
 network 192.168.1.0
 neighbor 192.168.1.2 remote-as 1 nlri unicast multicast
 neighbor 192.168.1.2 update-source Loopback0
 neighbor 192.168.1.2 next-hop-self
neighbor 192.168.1.2 route-map 2-intern out
neighbor 192.169.1.7 remote-as 2 nlri unicast multicast
neighbor 192.169.1.7 route-map 2-extern out
 neighbor 192.169.1.7 default-originate
!
ip classless
ip msdp peer 192.168.1.2 connect-source Loopback0
ip msdp peer 192.169.1.7
ip msdp mesh-group outside-test 192.168.1.2
ip msdp originator-id Loopback0
!
access-list 1 permit 192.168.1.0
access-list 1 deny 192.168.1.0 0.0.0.255
access-list 1 permit any
!
route-map 2-extern permit 10
 match ip address 1
!
route-map 2-intern deny 10
 match ip address 1
!

Command Reference

This section documents the following new commands that configure MSDP. All other commands used in this document can be found in the Cisco IOS 12.0 command reference publications.

clear ip msdp peer

clear ip msdp sa-cache

clear ip msdp statistics

ip msdp border

ip msdp cache-sa-state

ip msdp default-peer

ip msdp description

ip msdp filter-sa-request

ip msdp mesh-group

ip msdp originator-id

ip msdp peer

ip msdp redistribute

ip msdp sa-filter in

ip msdp sa-filter out

ip msdp sa-request

ip msdp shutdown

ip msdp ttl-threshold

show ip msdp count

show ip msdp peer

show ip msdp sa-cache

show ip msdp summary


Note   For show and more commands: Required information. When show or more commands are documented for a feature, you must include the following standard text about the search and filter functionality (introduced in Release 12.0(1)T) immediately after the bulleted list of commands.


In Cisco IOS Release 12.0(1)T or later, you can search and filter the output for show and more commands. This functionality is useful when you need to sort through large amounts of output, or if you want to exclude output that you do not need to see.

To use this functionality, enter a show or more command followed by the "pipe" character (|), one of the keywords begin, include, or exclude, and an expression that you want to search or filter on:

command | {begin | include | exclude} regular-expression

Following is an example of the show atm vc command in which you want the command output to begin with the first line where the expression "PeakRate" appears:

show atm vc | begin PeakRate

For more information on the search and filter functionality, refer to the Cisco IOS Release 12.0(1)T feature module titled CLI String Search.

clear ip msdp peer

To clear the TCP connection to the specified MSDP peer, use the clear ip msdp peer EXEC command.

clear ip msdp peer {ip-address | name}

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.


clear ip msdp sa-cache

To clear MSDP Source-Active cache entries, use the clear ip msdp sa-cache EXEC command.

clear ip msdp sa-cache [group-address | name]

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

In order to have any SA entries in the cache to clear, Source-Active caching must have been enabled with the ip msdp cache-sa-state command

If no multicast group is identified by group address or name, all SA cache entries are cleared.

Examples

The following example clears the Source-Active entries for the multicast group 224.5.6.7 from the cache:

clear ip msdp sa-cache 224.5.6.7

Related Commands

Command
Description

ip msdp cache-sa-state

Configures the router to create Source-Active state.

show ip msdp sa-cache

Displays (S,G) state learned by MSDP peers.


clear ip msdp statistics

To clear statistics counters for one or all of the MSDP peers without resetting the sessions, use the clear ip msdp statistics EXEC command.

clear ip msdp statistics [peer-address | name]

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

ip msdp border

To configure a router that borders a PIM sparse-mode region and dense-mode region to use MSDP, use the ip msdp border global configuration command. To prevent this action, use the no form of this command.

ip msdp border sa-address type number

no ip msdp border sa-address type number

Syntax Description

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.


Note that the ip msdp originator-id co