Default Ip Multicast Layer 3 Switching Configuration - Cisco 6500 Series Software Configuration Manual

Chapter 18 Configuring IP Multicast Layer 3 Switching
NetFlow-Based Rate Limiting of RPF Failures
With NetFlow-based rate limiting of RPF failures, a NetFlow entry is created for each non-RPF flow.
When a non-RPF packet arrives, the MSFC communicates information about the group, the source, and
the interface on which the packet arrived to the PFC. The PFC then installs a NetFlow entry and bridges
the packet to all ports in the VLAN, excluding the internal router port.
The PFC checks for non-RPF traffic every 2 seconds. An entry is kept for a maximum of 20 seconds if
non-RPF traffic exists.
To configure NetFlow-based rate limiting of RPF failures, see the
Limiting of RPF Failures" section on page
CEF-Based Rate Limiting of RPF Failures
PFC2 and the DFCs support both CEF-based rate limiting of RPF failures and NetFlow-based rate
limiting of RPF failures. In the CEF-based mode, the PFC2 or the DFC drops non-RPF packets instead
of bridging them to the MSFC2. To support the PIM assert mechanism, CEF-based rate limiting works
in 10-second intervals. For a short duration in each 10-second interval, packets are leaked to the MSFC.
During the remainder of each 10-second interval, the non-RPF packets are dropped in hardware.
CEF-based rate limiting of RPF failures is enabled by default on systems with PFC2 and on the DFCs
and does not require any user configuration.
For information on configuring CEF-based rate limiting of RPF failures, see the
Rate Limiting of RPF Failures" section on page

Default IP Multicast Layer 3 Switching Configuration

Table 18-1
Table 18-1 Default IP Multicast Layer 3 Switching Configuration
Feature
ACL for stub networks
Installing of directly connected subnet entries
CEF-based rate limiting
Netflow-based rate limiting
Multicast routing
PIM routing
IP multicast Layer 3 switching
Shortcut consistency checking
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 hardware switched.
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
Snooping."
78-14099-04
shows the default IP multicast Layer 3 switching configuration.
Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
Default IP Multicast Layer 3 Switching Configuration
"Enabling NetFlow-Based Rate
18-12.
18-13.
Default Value
Disabled on all interfaces
Enabled globally
Enabled globally (PFC2 only)
Disabled globally
Disabled globally
Disabled on all interfaces
Enabled when multicast routing is enabled and PIM
is enabled on the interface
Enabled
"Enabling CEF-Based
Chapter 21, "Configuring IGMP
18-7