Brocade Multi-Service IronWare Multicast Configuration Guide (Supporting R05.6.00) - Manual (Page 146)

134 Multi-Service IronWare Multicast Configuration Guide
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IP multicast traffic reduction
1
IP Multicast CPU Protection
When IGMP snooping is enabled, IP Multicast CPU Protection protects the MP CPU from high CPU
usage by the multicast tasks in scenarios where there is a large number of streams for specific
groups with large number of OIFs thereby resulting in numerous pending FID updates.
IP Multicast CPU Protection introduces (*,G) based forwarding for snooping to relieve the MP CPU
of numerous pending FID updates, and aging out OIFs, especially in cases when there are multiple
sources and receivers for a specific group G. The ACL modification and deletion events are
reflected in the cpu-protection entries.
IP Multicast CPU protection also handles the addition of new VLANs. They inherit the global CPU
protection configuration if any.
ACL traffic filtering
An extended ACL needs to be provided as the parameter. It should have the group(s) for which
cpu-protection is intended. As such, the ACL must contain statement(s) equivalent to the form
permit ip|ipv6 any any G/32 where G is the multicast group for which cpu-protection is intended.
The ACL provided as parameter may be already defined or defined later after the initial
configuration. Whenever there is a change in that ACL, previous cpu-protection groups will be
deleted and reprogrammed with the cpu-protection group(s) for relevant VLANs. An undefined ACL
or ACLs without having clauses equivalent to the form permit ip|ipv6 any any G/32 will not be
programming any cpu-protection entries.
Configuration Considerations
• The ip multicast cpu-protection command also supports IPv6 traffic. The ipv6 multicast
cpu-protection acl-name command must be configured under the IPv6 router configuration to
support IPv6. Only ACL names are supported when using this command with IPv6.
• CPU protection can be configured both at the global level as well as vlan-specific level.
• Global CPU protection configuration is inherited by all current and new VLAN.
• An extended ACL needs to be provided as the parameter. It should have the group(s) for which
cpu-protection is intended. As such, the ACL must contain statement(s) equivalent to the form
permit ip|ipv6 any any G/32 where G is the multicast group for which cpu-protection is
intended.
• The ACL provided as parameter may be already defined or defined later after configuration.
Whenever there is a change in that ACL, previous cpu-protection groups will be deleted and
reprogrammed with the cpu-protection group(s) for relevant VLANs. An undefined ACL or ACLs
without having clauses equivalent to the form permit ip|ipv6 any any G/32 will not be
programming any cpu-protection entries.
Enabling IP multicast CPU Protection
To globally enable IP Multicast CPU Protection, enter the following command.
Brocade(config)# ip multicast cpu-protection 101
Syntax: [no] ip multicast cpu-protection acl-id or acl-name
The acl-id or acl-name parameter specifies the ACL ID or name used to configure CPU protection.