Ip Multicast Multipath - Cisco Catalyst 4500 Series Command Reference Manual

ip multicast multipath

ip multicast multipath
To enable load splitting of IP multicast traffic over Equal Cost Multipath (ECMP), use the
ip multicast multipath command in global configuration mode. To disable this functionality, use the no
form of this command.
Syntax Description vrf vrf-name
s-g-hash basic |
next-hop-based
Command Default If multiple equal-cost paths exist, multicast traffic will not be load-split across those paths.
Command Modes Global configuration (config)
Command History Release
12.2(53)SG
Usage Guidelines The ip multicast multipath command does not work with bidirectional Protocol Independent Multicast
(PIM).
Use the ip multicast multipath command to enable load splitting of IP multicast traffic across multiple
equal-cost paths.
If two or more equal-cost paths from a source are available, unicast traffic will be load-split across those
paths. However, by default, multicast traffic is not load-split across multiple equal-cost paths. In general,
multicast traffic flows down from the reverse path forwarding (RPF) neighbor. According to the PIM
specifications, this neighbor must have the highest IP address if more than one neighbor has the same
metric.
When you configue load splitting with the ip multicast multipath command, the system splits multicast
traffic across multiple equal-cost paths based on source address using the S-hash algorithm. When the
ip multicast multipath command is configured and multiple equal-cost paths exist, the path in which
Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.4.0SG and IOS 15.1(2)SG)
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ip multicast [vrf vrf-name] multipath [s-g-hash {basic | next-hop-based}]
no ip multicast [vrf vrf-name] multipath [s-g-hash {basic | next-hop-based}]
(Optional) Enables ECMP multicast load splitting for IP multicast traffic
associated with the Multicast Virtual Private Network (MVPN) routing and
forwarding (MVRF) instance specified for the vrf-name argument.
(Optional) Enables ECMP multicast load splitting based on source and group
address or on source, group, and next-hop address.
The basic keyword enables a simple hash based on source and group address.
This algorithm is referred to as the basic S-G-hash algorithm.
The next-hop-based keyword enables a more complex hash based on source,
group, and next-hop address. This algorithm is referred to as the
next-hop-based S-G-hash algorithm.
Modification
The s-g-hash keyword was introduced on the Catalyst 4500 switch.
Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
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