Multicast Boundary; Understanding How Ipv4 Bidirectional Pim Works; Default Ipv4 Multicast Layer 3 Switching Configuration - Cisco 7604 Configuration Manual

Chapter 28 Configuring IPv4 Multicast Layer 3 Switching
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.

Multicast Boundary

The multicast boundary feature allows you to configure an administrative boundary for multicast group
addresses. By restricting the flow of multicast data packets, you can reuse the same multicast group
address in different administrative domains.
You configure the multicast boundary on an interface. A multicast data packet is blocked from flowing
across the interface if the packet's multicast group address matches the access control list (ACL)
associated with the multicast boundary feature.
Multicast boundary ACLs can be processed in hardware by the Policy Feature Card (PFC), a Distributed
Forwarding Card (DFC), or in software by the Multilayer Switch Feature Card (MSFC). The multicast
boundary ACLs are programmed to match the destination address of the packet. These ACLs are applied
to traffic on the interface in both directions (input and output).
To support multicast boundary ACLs in hardware, the switch creates new ACL TCAM entries or
modifies existing ACL TCAM entries (if other ACL-based features are active on the interface). To verify
TCAM resource utilization, enter the show tcam counts ip command.
If you configure the filter-autorp keyword, the administrative boundary also examines auto-RP
discovery and announcement messages and removes any auto-RP group range announcements from the
auto-RP packets that are denied by the boundary ACL.

Understanding How IPv4 Bidirectional PIM Works

The PFC3 supports hardware forwarding of IPv4 bidirectional PIM groups. To support IPv4
bidirectional PIM groups, the PFC3 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
section on page

Default IPv4 Multicast Layer 3 Switching Configuration

Table 28-1
OL-4266-08
28-23.
shows the default IP multicast Layer 3 switching configuration.
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
Understanding How IPv4 Bidirectional PIM Works
"Configuring IPv4 Bidirectional PIM"
28-7