Catalyst Supervisor Engine 32 PISA IOS Software Configuration Guide, 12.2ZY
Configuring IPv4 Multicast Layer 3 Switching
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Configuring IPv4 Multicast Layer 3 Switching

Table Of Contents

Configuring IPv4 Multicast Layer 3 Switching

Understanding How IPv4 Multicast Layer 3 Switching Works

IPv4 Multicast Layer 3 Switching Overview

Multicast Layer 3 Switching Cache

Layer 3-Switched Multicast Packet Rewrite

Partially and Completely Switched Flows

Partially Switched Flows

Completely Switched Flows

Non-RPF Traffic Processing

Non-RPF Traffic Overview

Filtering of RPF Failures for Stub Networks

Rate Limiting of RPF Failure Traffic

Understanding How IPv4 Bidirectional PIM Works

Default IPv4 Multicast Layer 3 Switching Configuration

IPv4 Multicast Layer 3 Switching Configuration Guidelines and Restrictions

Restrictions

Unsupported Features

Configuring IPv4 Multicast Layer 3 Switching

Source-Specific Multicast with IGMPv3, IGMP v3lite, and URD

Enabling IPv4 Multicast Routing Globally

Enabling IPv4 PIM on Layer 3 Interfaces

Enabling IP Multicast Layer 3 Switching Globally

Enabling IP Multicast Layer 3 Switching on Layer 3 Interfaces

Specifying the Maximum Number of Multicast Routes

Configuring the Layer 3 Switching Global Threshold

Enabling Installation of Directly Connected Subnets

Specifying the Flow Statistics Message Interval

Enabling Shortcut-Consistency Checking

Configuring ACL-Based Filtering of RPF Failures

Displaying RPF Failure Rate-Limiting Information

Displaying IPv4 Multicast Layer 3 Hardware Switching Summary

Displaying the IPv4 Multicast Routing Table

Displaying IPv4 Multicast Layer 3 Switching Statistics

Configuring IPv4 Bidirectional PIM

Enabling IPv4 Bidirectional PIM Globally

Configuring the Rendezvous Point for IPv4 Bidirectional PIM Groups

Setting the IPv4 Bidirectional PIM Scan Interval

Displaying IPv4 Bidirectional PIM Information

Using IPv4 Debug Commands

Clearing IPv4 Multicast Layer 3 Switching Statistics

Redundancy for Multicast Traffic


Configuring IPv4 Multicast Layer 3 Switching


This chapter describes how to configure IPv4 multicast Layer 3 switching on the Catalyst 6500 series switches.


Note For complete syntax and usage information for the commands used in this chapter, refer to these publications:

The Catalyst Supervisor Engine 32 PISA Cisco IOS Command Reference, Release 12.2ZY, at this URL:

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2ZY/command/reference/cmdref.html

The Release 12.2 publications at this URL:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_installation_and_configuration_guides_list.html


This chapter consists of these sections:

Understanding How IPv4 Multicast Layer 3 Switching Works

Understanding How IPv4 Bidirectional PIM Works

Default IPv4 Multicast Layer 3 Switching Configuration

IPv4 Multicast Layer 3 Switching Configuration Guidelines and Restrictions

Configuring IPv4 Multicast Layer 3 Switching

Configuring IPv4 Bidirectional PIM

Understanding How IPv4 Multicast Layer 3 Switching Works

These sections describe how IPv4 multicast Layer 3 switching works:

IPv4 Multicast Layer 3 Switching Overview

Multicast Layer 3 Switching Cache

Layer 3-Switched Multicast Packet Rewrite

Partially and Completely Switched Flows

Non-RPF Traffic Processing

Understanding How IPv4 Bidirectional PIM Works

IPv4 Multicast Layer 3 Switching Overview

The Policy Feature Card 3B (PFC3B) provides Layer 3 switching for IP multicast flows using the hardware replication table and hardware Cisco Express Forwarding (CEF), which uses the forwarding information base (FIB) and the adjacency table on the PFC3B.

The PFC3B supports hardware switching of (*,G) state flows. The PFC3B supports rate limiting of non-RPF traffic.

Multicast Layer 3 switching forwards IP multicast data packet flows between IP subnets using advanced application-specific integrated circuit (ASIC) switching hardware, which offloads processor-intensive multicast forwarding and replication from network routers.

Layer 3 flows that cannot be hardware switched are still forwarded in the software by routers. Protocol Independent Multicast (PIM) is used for route determination.

The PFC3B uses the Layer 2 multicast forwarding table to determine on which ports Layer 2 multicast traffic should be forwarded (if any). The multicast forwarding table entries are populated in conjunction with Internet Group Management Protocol (IGMP) snooping (see Chapter 27 "Configuring IGMP Snooping for IPv4 Multicast Traffic").

Multicast Layer 3 Switching Cache

This section describes how the PFC3B maintains Layer 3 switching information in hardware tables.

The PFC3B populates the (S,G) or (*,G) flows in the hardware FIB table with the appropriate masks; for example, (S/32, G/32) and (*/0, G/32). The RPF interface and the adjacency pointer information is also stored in each entry. The adjacency table contains the rewrite and a pointer to the replication entries. If a flow matches a FIB entry, the RPF check compares the incoming interface/VLAN with the entry. A mismatch is an RPF failure, which can be rate limited if this feature is enabled.

The PISA updates its multicast routing table and forwards the new information to the PFC3B whenever it receives traffic for a new flow. In addition, if an entry in the multicast routing table on the PISA ages out, the PISA deletes the entry and forwards the updated information to the PFC3B.

The Layer 3 switching cache contains flow information for all active Layer 3-switched flows. After the switching cache is populated, multicast packets identified as belonging to an existing flow can be Layer 3 switched based on the cache entry for that flow. For each cache entry, the PFC3B maintains a list of outgoing interfaces for the IP multicast group. From this list, the PFC3B determines onto which VLANs traffic from a given multicast flow should be replicated.

These commands affect the Layer 3 switching cache entries:

When you clear the multicast routing table using the clear ip mroute command, all multicast Layer 3 switching cache entries are cleared.

When you disable IP multicast routing on the PISA using the no ip multicast-routing command, all multicast Layer 3 switching cache entries on the PFC3B are purged.

When you disable multicast Layer 3 switching on an individual interface basis using the no mls ipmulticast command, flows that use this interface as the RPF interface are routed only by the PISA in software.

Layer 3-Switched Multicast Packet Rewrite

When a multicast packet is Layer 3 switched from a multicast source to a destination multicast group, the PFC3B performs a packet rewrite that is based on information learned from the PISA and stored in the adjacency table.

For example, Server A sends a multicast packet addressed to IP multicast group G1. If there are members of group G1 on VLANs other than the source VLAN, the PFC3B must perform a packet rewrite when it replicates the traffic to the other VLANs (the switch also bridges the packet in the source VLAN).

When the PFC3B receives the multicast packet, it is (conceptually) formatted as follows:

Layer 2 Frame Header
Layer 3 IP Header
Data
FCS

Destination

Source

Destination

Source

TTL

Checksum

   

Group G1 MAC1

Source A MAC

Group G1 IP

Source A IP

n

calculation1

1 In this example, Destination B is a member of Group G1.


The PFC3B rewrites the packet as follows:

Changes the source MAC address in the Layer 2 frame header from the MAC address of the host to the MAC address of the PISA (This is the burned-in MAC address of the system. This MAC address will be the same for all outgoing interfaces and cannot be modified. This MAC address can be displayed using the show mls multicast statistics command.)

Decrements the IP header Time to Live (TTL) by one and recalculates the IP header checksum

The result is a rewritten IP multicast packet that appears to have been routed. The PFC3B replicates the rewritten packet onto the appropriate destination VLANs, where it is forwarded to members of IP multicast group G1.

After the PFC3B performs the packet rewrite, the packet is (conceptually) formatted as follows:

Frame Header
IP Header
Data
FCS

Destination

Source

Destination

Source

TTL

Checksum

   

Group G1 MAC

PISA MAC

Group G1 IP

Source A IP

n-1

calculation2


Partially and Completely Switched Flows

When at least one outgoing Layer 3 interface for a given flow is multilayer switched and at least one outgoing interface is not multilayer switched, that flow is considered partially switched. When a partially switched flow is created, all multicast traffic belonging to that flow still reaches the PISA and is forwarded by software on those outgoing interfaces that are not multilayer switched.

These sections describe partially and completely switched flow:

Partially Switched Flows

Completely Switched Flows

Partially Switched Flows

A flow might be partially switched instead of completely switched in these situations:

If the switch is configured as a member of the IP multicast group on the RPF interface of the multicast source (using the ip igmp join-group command).

During the registering state, if the switch is the first-hop router to the source in PIM sparse mode (in this case, the switch must send PIM-register messages to the rendezvous point [RP]).

If the multicast TTL threshold is configured on an outgoing interface for the flow (using the ip multicast ttl-threshold command).

If the multicast helper is configured on the RPF interface for the flow, and multicast to broadcast translation is required.

If the outgoing interface is a generic routing encapsulation (GRE) tunnel interface.

If the outgoing interface is a Distance Vector Multicast Routing Protocol (DVMRP) tunnel interface.

If Network Address Translation (NAT) is configured on an interface and source address translation is required for the outgoing interface.

Flows are partially switched if any of the outgoing interfaces for a given flow are not Layer 3 switched.

(S,G) flows are partially switched instead of completely switched in these situations:

(S,G) flows are partially switched if the (S,G) entry has the RPT-bit (R bit) set.

(S,G) flows are partially switched if the (S,G) entry does not have the SPT bit (T flag) set and the Prune bit (P flag) set.

(*,G) flows are partially switched instead of completely switched in these situations:

(*,G) flows are partially switched on the last-hop leaf router if the shared-tree to shortest-path-tree (SPT) threshold is not equal to infinity. This allows the flow to transition from the SPT.

(*,G) flows are partially switched if at least one (S,G) entry has the same RPF as a (*,g) entry but any of these is true:

The RPT flag (R bit) is not set.

The SPT flag(T bit) is not set.

The Prune-flag (P bit) is not set.

(*,G) flows are partially switched if a DVMRP neighbor is detected on the input interface of a (*,G) entry.

(*,G) flows are partially switched if the interface and mask entry is not installed for the RPF-interface of a (*,G) entry and the RPF interface is not a point-to-point interface.

Completely Switched Flows

When all the outgoing interfaces for a given flow are Layer 3 switched, and none of the above situations apply to the flow, that flow is considered completely switched. When a completely switched flow is created, the PFC3B prevents multicast traffic bridged on the source VLAN for that flow from reaching the PISA interface in that VLAN, freeing the PISA of the forwarding and replication load for that flow.

One consequence of a completely switched flow is that multicast statistics on a per-packet basis for that flow cannot be recorded. Therefore, the PFC3B periodically sends multicast packet and byte count statistics for all completely switched flows to the PISA. The PISA updates the corresponding multicast routing table entry and resets the expiration timer for that multicast route.


Note A (*,G) state is created on the PIM-RP or for PIM-dense mode but is not used for forwarding the flows, and Layer 3 switching entries are not created for these flows.


Non-RPF Traffic Processing

These sections describe non-RPF traffic processing:

Non-RPF Traffic Overview

Filtering of RPF Failures for Stub Networks

Rate Limiting of RPF Failure Traffic

Non-RPF Traffic Overview

In a redundant configuration where multiple routers connect to the same LAN segment, only one router forwards the multicast traffic from the source to the receivers on the outgoing interfaces (see Figure 25-1). In this kind of topology, only the PIM designated router (PIM DR) forwards the data in the common VLAN, but the non-PIM DR receives the forwarded multicast traffic. The redundant router (non-PIM DR) must drop this traffic because it has arrived on the wrong interface and fails the RPF check. Traffic that fails the RPF check is called non-RPF traffic.

The Catalyst 6500 series switch processes non-RPF traffic in hardware on the PFC3B by filtering (dropping) or rate limiting the non-RPF traffic.

Figure 25-1 Redundant Multicast Router Configuration in a Stub Network

Filtering of RPF Failures for Stub Networks

The PFC3B supports ACL-based filtering of RPF failures for sparse mode stub networks. When you enable the ACL-based method of filtering RPF failures by entering the mls ip multicast stub command on the redundant router, the following ACLs automatically download to the PFC3B and are applied to the interface you specify:

access-list 100 permit ip A.B.C.0 0.0.0.255 any
access-list 100 permit ip A.B.D.0 0.0.0.255 any
access-list 100 permit ip any 224.0.0.0 0.0.0.255
access-list 100 permit ip any 224.0.1.0 0.0.0.255
access-list 100 deny ip any 224.0.0.0 15.255.255.255
 
   

The ACLs filter RPF failures and drop them in hardware so that they are not forwarded to the router.

Use the ACL-based method of filtering RPF failures only in sparse mode stub networks where there are no downstream routers. For dense mode groups, RPF failure packets have to be seen on the router for the PIM assert mechanism to function properly. Use CEF-based or NetFlow-based rate limiting to limit the rate of RPF failures in dense mode networks and sparse mode transit networks.

For information on configuring ACL-based filtering of RPF failures, see the "Configuring ACL-Based Filtering of RPF Failures" section.

Rate Limiting of RPF Failure Traffic

When you enable rate limiting of packets that fail the RPF check (non-RPF packets), most non-RPF packets are dropped in hardware. According to the multicast protocol specification, the router needs to receive the non-RPF packets for the PIM assert mechanism to function properly, so all non-RPF packets cannot be dropped in hardware.

When a non-RPF packet is received, a NetFlow entry is created for each non-RPF flow.

When the first non-RPF packet arrives, the PFC3B bridges the packet to the PISA and to any bridged ports and creates a NetFlow entry that contains source, group, and ingress interface information, after which the NetFlow entry handles all packets for that source and group, sending packets only to bridged ports and not to the PISA.

To support the PIM assert mechanism, the PFC3B periodically forwards a percentage of the non-RPF flow packets to the PISA.

The first packets for directly connected sources in PIM sparse mode are also rate-limited and are processed by the CPU.

Rate limiting of RPF failures is disabled by default.

Understanding How IPv4 Bidirectional PIM Works

The PFC3B supports hardware forwarding of IPv4 bidirectional PIM groups. To support IPv4 bidirectional PIM groups, the PFC3B implements a new mode called designated forwarder (DF) mode. The designated forwarder is the router elected to forward packets to and from a segment for a IPv4 bidirectional PIM group. In DF mode, the supervisor engine accepts packets from the RPF and from the DF interfaces.

When the supervisor engine is forwarding IPv4 bidirectional PIM groups, the RPF interface is always included in the outgoing interface list of (*,G) entry, and the DF interfaces are included depending on IGMP/PIM joins.

If the route to the RP becomes unavailable, the group is changed to dense mode. Should the RPF link to the RP become unavailable, the IPv4 bidirectional PIM flow is removed from the hardware FIB.

For information on configuring IPv4 bidirectional PIM, see the "Configuring IPv4 Bidirectional PIM" section.

Default IPv4 Multicast Layer 3 Switching Configuration

Table 25-1 shows the default IP multicast Layer 3 switching configuration.

Table 25-1 Default IP Multicast Layer 3 Switching Configuration 

Feature
Default Value

ACL for stub networks

Disabled on all interfaces

Installing of directly connected subnet entries

Enabled globally

Multicast routing

Disabled globally

PIM routing

Disabled on all interfaces

IP multicast Layer 3 switching

Enabled when multicast routing is enabled and PIM is enabled on the interface

Shortcut consistency checking

Enabled


Internet Group Management Protocol (IGMP) snooping is enabled by default on all VLAN interfaces. If you disable IGMP snooping on an interface, multicast Layer 3 flows are still switched by the hardware. Bridging of the flow on an interface with IGMP snooping disabled causes flooding to all forwarding interfaces of the VLAN. For details on configuring IGMP snooping, see Chapter 27 "Configuring IGMP Snooping for IPv4 Multicast Traffic."

IPv4 Multicast Layer 3 Switching Configuration Guidelines and Restrictions

These sections describe IP Multicast Layer 3 switching configuration restrictions:

Restrictions

Unsupported Features

Restrictions

IP multicast Layer 3 switching is not provided for an IP multicast flow in the following situations:

For IP multicast groups that fall into the range 224.0.0.* (where * is in the range 0 to 255), which is used by routing protocols. Layer 3 switching is supported for groups 224.0.2.* to 239.*.*.*.


Note Groups in the 224.0.0.* range are reserved for routing control packets and must be flooded to all forwarding ports of the VLAN. These addresses map to the multicast MAC address range 01-00-5E-00-00-xx, where xx is in the range 0-0xFF.


For PIM auto-RP multicast groups (IP multicast group addresses 224.0.1.39 and 224.0.1.40).

For packets with IP options. However, packets in the flow that do not specify IP options are hardware switched.

For source traffic received on tunnel interfaces (such as MBONE traffic).

If a (S,G) entry for sparse mode does not have the SPT-bit, RPT-bit, or Pruned flag set.

A (*,G) entry is not hardware switched if at least one (S,G) entry has an RPF different from the (*,G) entry's RPF and the (S,G) is not hardware switched.

If the ingress interface of a (S,G) or (*,G) entry is null, except if the (*,G) entry is a IPv4 bidirectional PIM entry and the switch is the RP for the group.

For IPv4 bidirectional PIM entries when a DF interface or RPF interface is a tunnel.

GRE tunnel encapsulation and de-encapsulation for multicast packets is handled in software.

Supervisor Engine 32 does not support egress multicast replication and cannot detect the multicast replication mode.

Unsupported Features

If you enable IP multicast Layer 3 switching, IP accounting for Layer 3 interfaces does not report accurate values. The show ip accounting command is not supported.

Configuring IPv4 Multicast Layer 3 Switching

These sections describe how to configure IP multicast Layer 3 switching:

Source-Specific Multicast with IGMPv3, IGMP v3lite, and URD

Enabling IPv4 Multicast Routing Globally

Enabling IPv4 PIM on Layer 3 Interfaces

Enabling IP Multicast Layer 3 Switching on Layer 3 Interfaces

Specifying the Maximum Number of Multicast Routes

Configuring the Layer 3 Switching Global Threshold

Enabling Installation of Directly Connected Subnets

Specifying the Flow Statistics Message Interval

Configuring IPv4 Bidirectional PIM

Setting the IPv4 Bidirectional PIM Scan Interval

Enabling Shortcut-Consistency Checking

Configuring ACL-Based Filtering of RPF Failures

Displaying RPF Failure Rate-Limiting Information

Displaying IPv4 Multicast Layer 3 Hardware Switching Summary

Displaying the IPv4 Multicast Routing Table

Displaying IPv4 Multicast Layer 3 Switching Statistics

Displaying IPv4 Bidirectional PIM Information

Using IPv4 Debug Commands

Clearing IPv4 Multicast Layer 3 Switching Statistics

Redundancy for Multicast Traffic


Note When you are in configuration mode you can enter EXEC mode commands by entering the do keyword before the EXEC mode command.


Source-Specific Multicast with IGMPv3, IGMP v3lite, and URD

For complete information and procedures about source-specific multicast with IGMPv3, IGMP v3lite, and URL Rendezvous Directory (URD), refer to this URL:

http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/1cfssm.html

Enabling IPv4 Multicast Routing Globally

You must enable IP multicast routing globally before you can enable IP multicast Layer 3 switching on Layer 3 interfaces.

For complete information and procedures, refer to these publications:

Cisco IOS IP and IP Routing Configuration Guide, Release 12.2, at this URL:

http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/fipr_c.html

Cisco IOS IP and IP Routing Command Reference, Release 12.1, at this URL:

http://www.cisco.com/en/US/docs/ios/12_2/ipaddr/command/reference/fipras_r.html

To enable IP multicast routing globally, perform this task:

Command
Purpose

Router(config)# ip multicast-routing

Enables IP multicast routing globally.

Router(config)# no ip multicast-routing

Disables IP multicast routing globally.


This example shows how to enable multicast routing globally:

Router(config)# ip multicast-routing
Router(config)# 

Enabling IPv4 PIM on Layer 3 Interfaces

You must enable PIM on the Layer 3 interfaces before IP multicast Layer 3 switching functions on those interfaces.

To enable IP PIM on a Layer 3 interface, perform this task:

 
Command
Purpose

Step 1 

Router(config)# interface {{vlan vlan_ID} | {type1  slot/port}}

Selects an interface to configure.

Step 2 

Router(config-if)# ip pim {dense-mode | sparse-mode | sparse-dense-mode}

Enables IP PIM on a Layer 3 interface.

Router(config-if)# no ip pim [dense-mode | sparse-mode | sparse-dense-mode]

Disables IP PIM on a Layer 3 interface.

1 type = ethernet, fastethernet, gigabitethernet, or tengigabitethernet

This example shows how to enable PIM on an interface using the default mode (sparse-dense-mode):

Router(config-if)# ip pim
Router(config-if)# 

This example shows how to enable PIM sparse mode on an interface:

Router(config-if)# ip pim sparse-mode
Router(config-if)# 

Enabling IP Multicast Layer 3 Switching Globally

To enable hardware switching of multicast routes globally on your system, perform this task:

 
Command
Purpose

Step 1 

Router(config)# mls ip multicast

Globally enables hardware switching of multicast routes.

Step 2 

Router# show mls ip multicast

Displays MLS IP multicast configuration.

This example shows how to globally enable hardware switching of multicast routes:

Router(config)# mls ip multicast 

Router(config)#

Enabling IP Multicast Layer 3 Switching on Layer 3 Interfaces

IP multicast Layer 3 switching is enabled by default on the Layer 3 interface when you enable PIM on the interface. Perform this task only if you disabled IP multicast Layer 3 switching on the interface and you want to reenable it.

PIM can be enabled on any Layer 3 interface, including VLAN interfaces.


Note You must enable PIM on all participating Layer 3 interfaces before IP multicast Layer 3 switching will function. For information on configuring PIM on Layer 3 interfaces, see the "Enabling IPv4 PIM on Layer 3 Interfaces" section.


To enable IP multicast Layer 3 switching on a Layer 3 interface, perform this task:

 
Command
Purpose

Step 1 

Router(config)# interface {{vlan vlan_ID} | {type1  slot/port}}

Selects an interface to configure.

Step 2 

Router(config-if)# mls ip multicast

Enables IP multicast Layer 3 switching on a Layer 3 interface.

Step 3 

Router(config-if)# no mls ip multicast

Disables IP multicast Layer 3 switching on a Layer 3 interface.

1 type = ethernet, fastethernet, gigabitethernet, or tengigabitethernet

This example shows how to enable IP multicast Layer 3 switching on a Layer 3 interface:

Router(config-if)# mls ip multicast
Router(config-if)# 

Specifying the Maximum Number of Multicast Routes

By default, a PFC3B supports 32,000 multicast routes in sparse mode. The following default settings apply for maximum number of multicast routes:

32,000 for PIM-SM/DM/SSM for ingress- or egress-replication mode

32,000 for IPv4 bidirectional PIM ingress-replication mode

10,700 for IPv4 bidirectional PIM egress-replication mode

By entering the mls ip multicast max-routes command, you can increase the maximum number of multicast routes to 64,000 for PIM-SM/DM/SSM with either ingress- and egress-replication mode.


Note Rate limiting of directly connected sources is not available if you increase the maximum number of multicast routes above the default values.


To change the maximum number of multicast routes supported for PIM-SM/DM/SSM, perform this task:

 
Command
Purpose

Step 1 

Router(config)# mls ip multicast max-routes

Specifies the maximum number of multicast routes.

Step 1 

Router# show mls ip multicast

Displays the multicast route configuration.

Configuring the Layer 3 Switching Global Threshold

You can configure a global multicast rate threshold (specified in packets per second) below which all multicast traffic is routed by the PISA. This configuration prevents creation of switching cache entries for low-rate Layer 3 flows.


Note This command does not affect flows that are already being routed. To apply the threshold to existing routes, clear the route and let it reestablish.


To configure the Layer 3 switching threshold, perform this task:

Command
Purpose

Router(config)# mls ip multicast threshold ppsec

Configures the IP MMLS threshold.

Router(config)# no mls ip multicast threshold

Reverts to the default IP MMLS threshold.


This example shows how to configure the Layer 3 switching threshold to 10 packets per second:

Router(config)# mls ip multicast threshold 10 
Router(config)# 

Enabling Installation of Directly Connected Subnets

In PIM sparse mode, a first-hop router that is the designated router for the interface may need to encapsulate the source traffic in a PIM register message and unicast it to the rendezvous point. To prevent new sources for the group from being learned in the routing table, the (*,G) flows should remain as completely hardware-switched flows. When (subnet/mask, 224/4) entries are installed in the hardware, the FIB allows both (*,G) flows to remain completely hardware-switched flows, and new, directly connected sources to be learned correctly. The installation of directly connected subnets is enabled globally by default. One (subnet/mask, 224/4) is installed per PIM-enabled interface.

To view FIB entries, enter the show mls ip multicast connected command.

To enable installation of directly connected subnets, perform this task:

Command
Purpose

Router(config)# mls ip multicast connected

Enables installation of directly connected subnets.

Router(config)# no mls ip multicast connected

Disables installation of directly connected subnets.


This example shows how to enable installation of directly connected subnets:

Router(config)# mls ip multicast connected 
Router(config)#

Specifying the Flow Statistics Message Interval

By default, the supervisor engine forwards flow statistics messages to the PISA every 25 seconds. The messages are forwarded in batches, and each batch of messages contains statistics for 25 percent of all flows. If you leave the interval at the default of 25 seconds, it will take 100 seconds to forward statistics for all flows to the PISA.

To specify how often flow statistics messages forwarded from the supervisor engine to the PISA, perform this task:

Command
Purpose

Router(config)# mls ip multicast flow-stat-timer num

Specifies how the supervisor engine forwards flow statistics messages to the PISA.

Router(config)# no mls ip multicast flow-stat-timer num

Restores the default.


This example shows how to configure the supervisor engine to forward flow statistics messages to the PISA every 10 seconds:

Router(config)# mls ip multicast flow-stat-timer 10 
Router(config)#

Enabling Shortcut-Consistency Checking

When you enable the shortcut-consistency checking feature, the multicast route table and the multicast-hardware entries are checked for consistency, and any inconsistencies are corrected. You can view inconsistencies by entering the show mls ip multicast consistency-check command.

If consistency checking is enabled, the multicast route table will be scanned every two seconds and a full scan is completed within 4 mintues.

To enable shortcut-consistency checking, perform this task:

Command
Purpose

Router(config)# mls ip multicast consistency-check

Enables shortcut-consistency checking.

Router(config)# no mls ip multicast consistency-check num

Restores the default.


This example shows how to enable the hardware shortcut-consistency checker:

Router (config)# mls ip multicast consistency-check
Router (config)# 

Configuring ACL-Based Filtering of RPF Failures

When you configure ACL-based filtering of RPF failures, ACLs that filter RPF failures in hardware are downloaded to the hardware-based ACL engine and applied on the interface you specify.

To enable ACL-based filtering of RPF failures on an interface, perform this task:

 
Command
Purpose

Step 1 

Router(config)# interface {{vlan vlan_ID} | {type1  slot/port} | {port-channel number}}

Selects an interface to configure.

Step 2 

Router(config-if)# mls ip multicast stub

Enables ACL-based filtering of RPF failures on an interface.

Router(config-if)# no mls ip multicast stub

Disables ACL-based filtering of RPF failures on an interface.

1 type = ethernet, fastethernet, gigabitethernet, or tengigabitethernet

Displaying RPF Failure Rate-Limiting Information

To display RPF failure rate-limiting information, perform this task:

Command
Purpose

Router# show mls ip multicast summary

Displays RPF failure rate-limiting information.


This example shows how to display RPF failure rate-limiting information:

Router# show mls ip multicast summary 
10004 MMLS entries using 1280464 bytes of memory
Number of partial hardware-switched flows:4
Number of complete hardware-switched flows:10000
Router#

Displaying IPv4 Multicast Layer 3 Hardware Switching Summary


Note The show interface statistics command does not display hardware-switched packets, only packets switched by software.


The show ip pim interface count command displays the IP multicast Layer 3 switching enable state on IP PIM interfaces and the number of packets received and sent on the interface.

To display IP multicast Layer 3 switching information for an IP PIM Layer 3 interface, perform one of these tasks:

Command
Purpose

Router# show ip pim interface [{{vlan vlan_ID} | {type1  slot/port} | {port-channel number}}] count

Displays IP multicast Layer 3 switching enable state information for all PISA IP PIM Layer 3 interfaces.

Router# show ip interface

Displays the IP multicast Layer 3 switching enable state on the Layer 3 interfaces.

1 type = ethernet, fastethernet, gigabitethernet, or tengigabitethernet


These examples show how to display the IP PIM configuration of the interfaces:

Router# show ip pim interface count 
 
   
State:* - Fast Switched, D - Distributed Fast Switched
      H - Hardware Switching Enabled
Address          Interface          FS  Mpackets In/Out
10.15.1.20       GigabitEthernet4/8 * H 952/4237130770
10.20.1.7        GigabitEthernet4/9 * H 1385673757/34
10.25.1.7        GigabitEthernet4/10* H 0/34
10.11.1.30       FastEthernet6/26   * H 0/0
10.37.1.1        FastEthernet6/37   * H 0/0
1.22.33.44       FastEthernet6/47   * H 514/68
 
   

The "*" flag indicates that this interface can be fast switched and the "H" flag indicates that this interface is hardware switched. The "In" flag indicates the number of multicast packet bytes that have been received on the interface. The "Out" flag indicates the number of multicast packet bytes that have been forwarded from this interface.

Router# show ip mroute count 
IP Multicast Statistics
56 routes using 28552 bytes of memory
13 groups, 3.30 average sources per group
Forwarding Counts:Pkt Count/Pkts per second/Avg Pkt Size/Kilobits per second
Other counts:Total/RPF failed/Other drops(OIF-null, rate-limit etc)
 
Group:224.2.136.89, Source count:1, Group pkt count:29051
  Source:132.206.72.28/32, Forwarding:29051/-278/1186/0, Other:85724/8/56665
Router#

Note The -tive counter means that the outgoing interface list of the corresponding entry is NULL, and this indicates that this flow is still active.


This example shows how to display the IP multicast Layer 3 switching configuration of interface VLAN 10:

Router# show ip interface vlan 10 
Vlan10 is up, line protocol is up
  Internet address is 10.0.0.6/8
  Broadcast address is 255.255.255.255
  Address determined by non-volatile memory
  MTU is 1500 bytes
  Helper address is not set
  Directed broadcast forwarding is disabled
  Multicast reserved groups joined: 224.0.0.1 224.0.0.2 224.0.0.13 224.0.0.10
  Outgoing access list is not set
  Inbound  access list is not set
  Proxy ARP is enabled
  Security level is default
  Split horizon is enabled
  ICMP redirects are always sent
  ICMP unreachables are never sent
  ICMP mask replies are never sent
  IP fast switching is enabled
  IP fast switching on the same interface is disabled
  IP Flow switching is disabled
  IP CEF switching is enabled
  IP Fast switching turbo vector
  IP Normal CEF switching turbo vector
  IP multicast fast switching is enabled
  IP multicast distributed fast switching is disabled
  IP route-cache flags are Fast, CEF
  Router Discovery is disabled
  IP output packet accounting is disabled
  IP access violation accounting is disabled
  TCP/IP header compression is disabled
  RTP/IP header compression is disabled
  Probe proxy name replies are disabled
  Policy routing is disabled
  Network address translation is disabled
  WCCP Redirect outbound is disabled
  WCCP Redirect exclude is disabled
  BGP Policy Mapping is disabled
IP multicast multilayer switching is enabled
IP mls switching is enabled
Router#
 
   

This example shows how to display the IP multicast Layer 3 switching configuration of Gigabit Ethernet interface 1/2:

Router# show interfaces gigabitEthernet 1/2 
GigabitEthernet1/2 is up, line protocol is up (connected)
  Hardware is C6k 1000Mb 802.3, address is 0001.c9db.2441 (bia 0001.c9db.2441)
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec, 
  Last clearing of "show interface" counters 00:05:13
  ....
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue :0/40 (size/max)
  5 minute input rate 10000 bits/sec, 1 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     284 packets input, 113104 bytes, 0 no buffer
     Received 284 broadcasts (284 multicast) 
     0 runts, 41 giants, 0 throttles 
     41 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 
     0 input packets with dribble condition detected
     198 packets output, 14732 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out
Router#

Displaying the IPv4 Multicast Routing Table

The show ip mroute command displays the IP multicast routing table.

To display the IP multicast routing table, perform this task:

Command
Purpose

Router# show ip mroute partical-sc [hostname | group_number]

Displays the IP multicast routing table and the hardware-switched interfaces.


This example shows how to display the IP multicast routing table:

Router# show ip mroute 230.13.13.1 
IP Multicast Routing Table
Flags:D - Dense, S - Sparse, s - SSM Group, C - Connected, L - Local,
       P - Pruned, R - RP-bit set, F - Register flag, T - SPT-bit set,
       J - Join SPT, M - MSDP created entry, X - Proxy Join Timer Running
       A - Advertised via MSDP, U - URD, I - Received Source Specific Host
           Report 
Outgoing interface flags:H - Hardware switched
Timers:Uptime/Expires
Interface state:Interface, Next-Hop or VCD, State/Mode
 
(*, 230.13.13.1), 00:16:41/00:00:00, RP 10.15.1.20, flags:SJC
  Incoming interface:GigabitEthernet4/8, RPF nbr 10.15.1.20
  Outgoing interface list:
 GigabitEthernet4/9, Forward/Sparse-Dense, 00:16:41/00:00:00, H
 
   
(*, 230.13.13.2), 00:16:41/00:00:00, RP 10.15.1.20, flags:SJC
 Incoming interface:GigabitEthernet4/8, RPF nbr 10.15.1.20, RPF-MFD
  Outgoing interface list:
    GigabitEthernet4/9, Forward/Sparse-Dense, 00:16:41/00:00:00, H
 
(10.20.1.15, 230.13.13.1), 00:14:31/00:01:40, flags:CJT
 Incoming interface:GigabitEthernet4/8, RPF nbr 10.15.1.20, RPF-MFD
  Outgoing interface list:
    GigabitEthernet4/9, Forward/Sparse-Dense, 00:14:31/00:00:00, H
(132.206.72.28, 224.2.136.89), 00:14:31/00:01:40, flags:CJT
  Incoming interface:GigabitEthernet4/8, RPF nbr 10.15.1.20, RPF-MFD
 Outgoing interface list:Null
Router#

Note The RPF-MFD flag indicatesthat the flow is completely switched by the hardware. The H flag indicates the flow is switched by the hardware on the outgoing interface.


Displaying IPv4 Multicast Layer 3 Switching Statistics

The show mls ip multicast command displays detailed information about IP multicast Layer 3 switching.

To display detailed IP multicast Layer 3 switching information, perform one of these tasks:

Command
Purpose

Router# show mls ip multicast group ip_address [interface type slot/port | statistics]

Displays IP multicast Layer 3 switching group information.

Router# show mls ip multicast interface {{vlan vlan_ID} | {type1  slot/port} | {port-channel number}} [statistics | summary]

Displays IP multicast Layer 3 switching details for all interfaces.

Router# show mls ip multicast source ip_address [interface {{vlan vlan_ID} | {type1 slot/port} | {port-channel number}} | statistics]

Displays IP multicast Layer 3 switching source information.

Router# show mls ip multicast summary

Displays a summary of IP multicast Layer 3 switching information.

Router# show mls ip multicast statistics

Displays IP multicast Layer 3 switching statistics.

1 type = ethernet, fastethernet, gigabitethernet, or tengigabitethernet


This example shows how to display information on a specific IP multicast Layer 3 switching entry:

Router# show mls ip multicast group 10.1.0.11 
Multicast hardware switched flows:
Total shortcut installed: 0
 
   

This example shows how to display IP multicast group information:

Router# show mls ip multicast group 230.13.13.1 source 10.20.1.15 
Multicast hardware switched flows:
(10.20.1.15, 230.13.13.1) Incoming interface:Gi4/8, Packets switched:0
Hardware switched outgoing interfaces:Gi4/9 
RPF-MFD installed
 
Total hardware switched flows :1
Router#
 
   

This example shows how to display IP multicast Layer 3 switching information for VLAN 10:

Router# show mls ip multicast interface vlan 10 
Multicast hardware switched flows:
(10.1.0.15, 224.2.2.15) Incoming interface: Vlan10, Packets switched: 0
Hardware switched outgoing interfaces:
MFD installed: Vlan10
 
(10.1.0.19, 224.2.2.19) Incoming interface: Vlan10, Packets switched: 1970
Hardware switched outgoing interfaces:
MFD installed: Vlan10
 
(10.1.0.11, 224.2.2.11) Incoming interface: Vlan10, Packets switched: 0
Hardware switched outgoing interfaces:
MFD installed: Vlan10
 
(10.1.0.10, 224.2.2.10) Incoming interface: Vlan10, Packets switched: 2744
Hardware switched outgoing interfaces:
MFD installed: Vlan10
 
(10.1.0.17, 224.2.2.17) Incoming interface: Vlan10, Packets switched: 3340
Hardware switched outgoing interfaces:
MFD installed: Vlan10
 
(10.1.0.13, 224.2.2.13) Incoming interface: Vlan10, Packets switched: 0
Hardware switched outgoing interfaces:

This example shows how to display the IP multicast Layer 3 switching statistics:

Router# show mls ip multicast statistics 
 
MLS Multicast Operation Status:
MLS Multicast configuration and state:
    Router Mac: 00e0.b0ff.7b00, Router IP: 33.0.33.24
    MLS multicast operating  state: ACTIVE
    Shortcut Request Queue size 4
    Maximum number of allowed outstanding messages: 1
    Maximum size reached from feQ: 3096
    Feature Notification sent: 1
    Feature Notification Ack received: 1
    Unsolicited Feature Notification received: 0
    MSM sent: 205170
    MSM ACK received: 205170
    Delete notifications received: 0
    Flow Statistics messages received: 35211
 
MLS Multicast statistics:
    Flow install Ack: 996508
    Flow install Nack: 1
    Flow update Ack: 1415959
    Flow update Nack: 0
    Flow delete Ack: 774953
    Complete flow install Ack: 958469
 
Router#

Configuring IPv4 Bidirectional PIM

These sections describe how to configure IPv4 bidirectional protocol independent multicast (PIM):

Enabling IPv4 Bidirectional PIM Globally

Configuring the Rendezvous Point for IPv4 Bidirectional PIM Groups

Setting the IPv4 Bidirectional PIM Scan Interval

Displaying IPv4 Bidirectional PIM Information

Enabling IPv4 Bidirectional PIM Globally

To enable IPv4 bidirectional PIM, perform this task:

Command
Purpose

Router(config)# ip pim bidir-enable

Enables IPv4 bidirectional PIM globally on the switch.

Router(config)# no ip pim bidir-enable

Disables IPv4 bidirectional PIM globally on the switch.


This example shows how to enable IPv4 bidirectional PIM on the switch:

Router(config)# ip pim bidir-enable 

Router(config)#

Configuring the Rendezvous Point for IPv4 Bidirectional PIM Groups

To statically configure the rendezvous point for an IPv4 bidirectional PIM group, perform this task:

 
Command
Purpose

Step 1 

Router(config)# ip pim rp-adress ip_address access_list [override]

Statically configures the IP address of the rendezvous point for the group. When you specify the override option, the static rendezvous point is used.

Step 2 

Router(config)# access-list access-list permit | deny ip_address

Configures an access list.

Step 3 

Router(config)# ip pim send-rp-announce type number scope ttl_value [group-list access-list] [interval seconds] [bidir]

Configures the system to use Auto-RP to configure groups for which the router will act as a rendezvous point (RP).

Step 4 

Router(config)# ip access-list standard access-list-name permit | deny ip_address

Configures a standard IP access list.

Step 5 

Router(config)# mls ip multicast

Enables MLS IP multicast.

This example shows how to configure a static rendezvous point for an IPv4 bidirectional PIM group:

Router(config)# ip pim rp-address 10.0.0.1 10 bidir override 
Router(config)# access-list 10 permit 224.1.0.0 0.0.255.255 
Router(config)# ip pim send-rp-announce Loopback0 scope 16 group-list c21-rp-list-0 bidir 
Router(config)# ip access-list standard c21-rp-list-0 permit 230.31.31.1 0.0.255.255 

Setting the IPv4 Bidirectional PIM Scan Interval

You can specify the interval between the IPv4 bidirectional PIM RP Reverse Path Forwarding (RPF) scans.

To set the IPv4 bidirectional PIM RP RPF scan interval, perform this task:

Command
Purpose

Router(config)# mls ip multicast bidir gm-scan-interval interval

Specifies the IPv4 bidirectional PIM RP RPF scan interval; valid values are from 1 to 1000 seconds. The default is 10 seconds.

Router(config)# no mls ip multicast bidir gm-scan-interval

Restores the default.


This example shows how to set the IPv4 bidirectional PIM RP RPF scan interval:

Router(config)# mls ip multicast bidir gm-scan-interval 30
Router(config)# 

Displaying IPv4 Bidirectional PIM Information

To display IPv4 bidirectional PIM information, perform one of these tasks:

Command
Purpose

Router# show ip pim rp mapping [in-use]

Displays mappings between PIM groups and rendezvous points and shows learned rendezvous points in use.

Router# show mls ip multicast rp-mapping [rp_address]

Displays PIM group to active rendezvous points mappings.

Router# show mls ip multicast rp-mapping gm-cache

Displays information based on the group/mask ranges in the RP mapping cache.

Router# show mls ip multicast rp-mapping df-cache

Displays information based on the DF list in RP mapping cache.

Router# show mls ip multicast bidir

Displays IPv4 bidirectional PIM information.

Router# show ip mroute

Displays information about the multicast routing table.


This example shows how to display information about the PIM group and rendezvous point mappings:

Router# show ip pim rp mapping 
PIM Group-to-RP Mappings
This system is an RP (Auto-RP)
This system is an RP-mapping agent
Group(s) 230.31.0.0/16
  RP 60.0.0.60 (?), v2v1, bidir
    Info source:60.0.0.60 (?), elected via Auto-RP
         Uptime:00:03:47, expires:00:02:11
  RP 50.0.0.50 (?), v2v1, bidir
    Info source:50.0.0.50 (?), via Auto-RP
         Uptime:00:03:04, expires:00:02:55
  RP 40.0.0.40 (?), v2v1, bidir
    Info source:40.0.0.40 (?), via Auto-RP
         Uptime:00:04:19, expires:00:02:38
 
   

This example shows how to display information in the IP multicast routing table that is related to IPv4 bidirectional PIM:

Router# show ip mroute bidirectional 
    (*, 225.1.3.0), 00:00:02/00:02:57, RP 3.3.3.3, flags:BC
      Bidir-Upstream:GigabitEthernet2/1, RPF nbr 10.53.1.7, RPF-MFD
      Outgoing interface list:
        GigabitEthernet2/1, Bidir-Upstream/Sparse-Dense, 00:00:02/00:00:00,H
        Vlan30, Forward/Sparse-Dense, 00:00:02/00:02:57, H
 
   
    (*, 225.1.2.0), 00:00:04/00:02:55, RP 3.3.3.3, flags:BC
      Bidir-Upstream:GigabitEthernet2/1, RPF nbr 10.53.1.7, RPF-MFD
      Outgoing interface list:
        GigabitEthernet2/1, Bidir-Upstream/Sparse-Dense, 00:00:04/00:00:00,H
        Vlan30, Forward/Sparse-Dense, 00:00:04/00:02:55, H
 
   
    (*, 225.1.4.1), 00:00:00/00:02:59, RP 3.3.3.3, flags:BC
      Bidir-Upstream:GigabitEthernet2/1, RPF nbr 10.53.1.7, RPF-MFD
      Outgoing interface list:
        GigabitEthernet2/1, Bidir-Upstream/Sparse-Dense, 00:00:00/00:00:00,H
        Vlan30, Forward/Sparse-Dense, 00:00:00/00:02:59, H
 
   

This example show how to display information related to a specific multicast route. In the output below, the arrow in the margin points to information about a partical short cut:

Router# show ip mroute 239.1.1.2 4.4.4.4 
IP Multicast Routing Table
Flags:D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report, Z - Multicast Tunnel
       Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags:H - Hardware switched
 Timers:Uptime/Expires
 Interface state:Interface, Next-Hop or VCD, State/Mode
 
   
(4.4.4.4, 239.1.1.2), 1d02h/00:03:20, flags:FTZ
 Incoming interface:Loopback0, RPF nbr 0.0.0.0, Partial-SC
  Outgoing interface list:
    Vlan10, Forward/Sparse-Dense, 1d02h/00:02:39 (ttl-threshold 5)
 
   

This example shows how to display the entries for a specific multicast group address:

Router# show mls ip multicast group 230.31.31.1 
Multicast hardware switched flows:
(*, 230.31.31.1) Incoming interface:Vlan611, Packets switched:1778
Hardware switched outgoing interfaces:Vlan131 Vlan151 Vlan415 Gi4/16 Vlan611 
RPF-MFD installed
 
   

This example shows how to display PIM group to active rendezvous points mappings:

Router# show mls ip multicast rp-mapping 
State:H - Hardware Switched, I - Install Pending, D - Delete Pending, Z - Zombie
 
   
RP Address      State       RPF            DF-count    GM-count
60.0.0.60       H           Vl611                 4           1           
 
   

This example shows how to display information based on the group/mask ranges in the RP mapping cache:

Router# show mls ip multicast rp-mapping gm-cache 
State:H - Hardware Switched, I - Install Pending, D - Delete Pending,
       Z - Zombie
 
   
RP Address     State       Group           Mask            State         Packet/Byte-count
60.0.0.60      H           230.31.0.0      255.255.0.0     H             100/6400
 
   

This example shows how to display information about specific MLS IP multicasting groups:

Router# show mls ip multicast rp-mapping df-cache 
State:H - Hardware Switched, I - Install Pending, D - Delete Pending, Z - Zombie
 
   
RP Address      State        DF             State
60.0.0.60       H           Vl131            H
60.0.0.60       H           Vl151            H
60.0.0.60       H           Vl415            H
60.0.0.60       H           Gi4/16           H

Using IPv4 Debug Commands

Table 25-2 describes IPv4 multicast Layer 3 switching debug commands that you can use to troubleshoot IP multicast Layer 3 switching problems.

Table 25-2 IP Multicast Layer 3 Switching Debug Commands  

Command
Description

[no] debug mls ip multicast events

Displays IP multicast Layer 3 switching events.

[no] debug mls ip multicast errors

Turns on debug messages for multicast MLS-related errors.

[no] debug mls ip multicast group group_id group_mask

Turns on debugging for a subset of flows.

[no] debug mls ip multicast messages

Displays IP multicast Layer 3 switching messages from and to hardware switching engine.

[no] debug mls ip multicast all

Turns on all IP multicast Layer 3 switching messages.

[no] debug mdss errors

Turns on MDSS1 error messages.

[no] debug mdss events

Displays MDSS-related events for debugging.

[no] debug mdss events mroute-bidir

Displays IPv4 bidirectional PIM MDSS events for debugging.

[no] debug mdss all

Displays all MDSS messages.

[no] debug ip pim df ip_address

Displays the DF election for a given rendezvous point for debug purposes.

1 MDSS = Multicast Distributed Switching Services


Clearing IPv4 Multicast Layer 3 Switching Statistics

To clear IP multicast Layer 3 switching statistics, perform this task:

Command
Purpose

Router# clear mls ip multicast statistics

Clears IP multicast Layer 3 switching statistics.


This example shows how to clear IP multicast Layer 3 switching statistics:

Router# clear mls ip multicast statistics 
 
   

The show mls multicast statistics command displays a variety of information about the multicast flows being handled by the PFC3B. You can display entries based on any combination of the participating PISA, the VLAN, the multicast group address, or the multicast traffic source. For an example of the show mls ip multicast statistics command, see the "Displaying IPv4 Multicast Layer 3 Switching Statistics" section.

Redundancy for Multicast Traffic

Redundancy for multicast traffic requires the following conditions:

Unicast routing protocol such as OSPF or EIGRP

PIM uses RPF checks on the unicast routing table to determine the proper paths for multicast data to traverse. If a unicast routing path changes, PIM relies upon the unicast routing protocol (OSPF) to properly converge, so that the RPF checks used by PIM continue to work and show valid unicast paths to and from the source IP address of the server sourcing the multicast stream.

PIM configured on all related Layer 3 interfaces

The unicast routing table is used to do path selection for PIM. PIM uses RPF checks to ultimately determine the shortest path tree (SPT) between the client (receiver VLAN) and the source (multicast VLAN). Therefore, the objective of PIM is to find the shortest unicast path between the receiver subnet and the source subnet. You do not need to configure anything else for multicast when the unicast routing protocol is working as expected and PIM is configured on all the Layer 3 links associated with the unicast routing protocol.