Deployment Guide

PIM Sparse-Mode (PIM-SM)

Dell Networking OS supports protocol-independent multicast sparse-mode (PIM-SM).

PIM-SM is a multicast protocol that forwards multicast trac to a subnet only after a request using a PIM Join message; this behavior is

the opposite of PIM-Dense mode, which forwards multicast trac to all subnets until a request to stop.

Topics:

• Implementation Information

• Protocol Overview

• Conguring PIM-SM

• Enable PIM-SM

• Conguring S,G Expiry Timers

• Conguring a Static Rendezvous Point

• Conguring a Designated Router

• Creating Multicast Boundaries and Domains

• Enabling PIM-SM Graceful Restart

Implementation Information

Be aware of the following PIM-SM implementation information.

• The Dell Networking implementation of PIM-SM is based on IETF Internet Draft draft-ietf-pim-sm-v2-new-05.

• FN IOM supports a maximum of 31 PIM interfaces and 2K multicast entries including (*,G), and (S,G) entries. There is no limit on the

number of PIM neighbors FN IOM can have.

• The SPT-Threshold is zero, which means that the last-hop designated router (DR) joins the shortest path tree (SPT) to the source after

receiving the rst multicast packet.

• The Dell Networking operating system (OS) reduces the number of control messages sent between multicast routers by bundling Join

and Prune requests in the same message.

• The Dell Networking OS supports PIM-SM on physical, virtual local area network (VLAN), and port-channel interfaces.

• The Dell Networking OS supports 2000 IPv6 multicast forwarding entries, with up to 128 PIM-source-specic multicast (SSM)

neighbors/interfaces.

• IPv6 Multicast is not supported on synchronous optical network technologies (SONET) interfaces.

Protocol Overview

PIM-SM initially uses unidirectional shared trees to forward multicast trac; that is, all multicast trac must ow only from the rendezvous

point (RP) to the receivers.

After a receiver receives trac from the RP, PM-SM switches to SPT to forward multicast trac. Every multicast group has an RP and a

unidirectional shared tree (group-specic shared tree).

PIM Sparse-Mode (PIM-SM) 599