Configuring Msdp; Information About Msdp - Cisco Nexus 7000 Series Configuration Manual

Configuring MSDP

This chapter describes how to configure Multicast Source Discovery Protocol (MSDP) on a Cisco NX-OS
device.
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Information About MSDP

You can use the Multicast Source Discovery Protocol (MSDP) to exchange multicast source information
between multiple BGP-enabled Protocol Independent Multicast (PIM) sparse-mode domains. In addition,
MSDP can be used to create an Anycast-RP configuration to provide RP redundancy and load sharing. For
information about PIM, see Configuring PIM and PIM6. For information about BGP, see the Cisco Nexus
7000 Series NX-OS Unicast Routing Configuration Guide.
When a receiver joins a group that is transmitted by a source in another domain, the rendezvous point (RP)
sends PIM join messages in the direction of the source to build a shortest path tree. The designated router
(DR) sends packets on the source-tree within the source domain, which may travel through the RP in the
source domain and along the branches of the source-tree to other domains. In domains where there are receivers,
RPs in those domains can be on the source-tree. The peering relationship is conducted over a TCP connection.
The following figure shows four PIM domains. The connected RPs (routers) are called MSDP peers because
they are exchanging active source information with each other. Each MSDP peer advertises its own set of
multicast source information to the other peers. Source Host 2 sends the multicast data to group 224.1.1.1.
On RP 6, the MSDP process learns about the source through PIM register messages and generates Source-Active
(SA) messages to its MSDP peers that contain information about the sources in its domain. When RP 3 and
RP 5 receive the SA messages, they forward them to their MSDP peers. When RP 5 receives the request from
Host 1 for the multicast data on group 224.1.1.1, it builds a shortest path tree to the source by sending a PIM
join message in the direction of Host 2 at 192.1.1.1.
Information About MSDP, on page 157
Licensing Requirements for MSDP, on page 160
Prerequisites for MSDP, on page 160
Default Settings for MSDP, on page 160
Configuring MSDP, on page 161
Verifying the MSDP Configuration, on page 169
Monitoring MSDP, on page 169
Configuration Examples for MSDP, on page 170
Related Documents, on page 171
Standards, on page 172
C H A P T E R
Cisco Nexus 7000 Series NX-OS Multicast Routing Configuration Guide
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