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PIM Sparse-Mode (PIM-SM)
Protocol-independent multicast sparse-mode (PIM-SM) is a multicast protocol that forwards multicast traffic to a subnet only after
a request using a PIM Join message; this behavior is the opposite of PIM-Dense mode, which forwards multicast traffic to all subnets
until a request to stop.
Implementation Information
The following information is necessary for implementing PIM-SM.
•
The Dell Networking implementation of PIM-SM is based on IETF
Internet Draft draft-ietf-pim-sm-v2-new-05
.
•
The platform supports a maximum of 95 PIM interfaces and 2000 multicast entries including (*,G), and (S,G) entries. The
maximum number of PIM neighbors is the same as the maximum number of PIM-SM interfaces.
•
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 first multicast packet.
•
Dell Networking OS reduces the number of control messages sent between multicast routers by bundling Join and Prune
requests in the same message.
•
Dell Networking OS supports PIM-SM on physical, virtual local area network (VLAN), and port-channel interfaces.
NOTE: Multicast routing is supported across default and non-default VRFs.
Protocol Overview
PIM-SM initially uses unidirectional shared trees to forward multicast traffic; that is, all multicast traffic must flow only from the
rendezvous point (RP) to the receivers.
After a receiver receives traffic from the RP, PM-SM switches to SPT to forward multicast traffic. Every multicast group has an RP
and a unidirectional shared tree (group-specific shared tree).
Requesting Multicast Traffic
A host requesting multicast traffic for a particular group sends an Internet group management protocol (IGMP) Join message to its
gateway router.
The gateway router is then responsible for joining the shared tree to the RP (RPT) so that the host can receive the requested traffic.
1.
After receiving an IGMP Join message, the receiver gateway router (last-hop DR) creates a (*,G) entry in its multicast routing
table for the requested group. The interface on which the join message was received becomes the outgoing interface
associated with the (*,G) entry.
2.
The last-hop DR sends a PIM Join message to the RP. All routers along the way, including the RP, create an (*,G) entry in their
multicast routing table, and the interface on which the message was received becomes the outgoing interface associated with
the (*,G) entry. This process constructs an RPT branch to the RP.
3.
If a host on the same subnet as another multicast receiver sends an IGMP report for the same multicast group, the gateway
takes no action. If a router between the host and the RP receives a PIM Join message for which it already has a (*,G) entry, the
interface on which the message was received is added to the outgoing interface list associated with the (*,G) entry, and the
message is not (and does not need to be) forwarded towards the RP.
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PIM Sparse-Mode (PIM-SM)
Содержание S4048-ON
Страница 1: ...Dell Configuration Guide for the S4048 ON System 9 9 0 0 ...
Страница 146: ...Figure 14 BFD Three Way Handshake State Changes 146 Bidirectional Forwarding Detection BFD ...
Страница 477: ...Figure 68 Inspecting Configuration of LAG 10 on ALPHA Link Aggregation Control Protocol LACP 477 ...
Страница 480: ...Figure 70 Inspecting a LAG Port on BRAVO Using the show interface Command 480 Link Aggregation Control Protocol LACP ...
Страница 481: ...Figure 71 Inspecting LAG 10 Using the show interfaces port channel Command Link Aggregation Control Protocol LACP 481 ...
Страница 522: ...Figure 87 Configuring Interfaces for MSDP 522 Multicast Source Discovery Protocol MSDP ...
Страница 523: ...Figure 88 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 523 ...
Страница 524: ...Figure 89 Configuring PIM in Multiple Routing Domains 524 Multicast Source Discovery Protocol MSDP ...
Страница 528: ...Figure 91 MSDP Default Peer Scenario 1 528 Multicast Source Discovery Protocol MSDP ...
Страница 529: ...Figure 92 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 529 ...
Страница 530: ...Figure 93 MSDP Default Peer Scenario 3 530 Multicast Source Discovery Protocol MSDP ...
Страница 633: ...Policy based Routing PBR 633 ...
Страница 777: ...Figure 119 Single and Double Tag TPID Match Service Provider Bridging 777 ...
Страница 778: ...Figure 120 Single and Double Tag First byte TPID Match 778 Service Provider Bridging ...