Specifications

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Catalyst 4500 Se ries S wit ch C is co IO S C om mand R efer ence —Re lease I OS XE 3 .3.0 XO(1 5.1 (1)XO)
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Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
ip multicast multipath
If the ip multicast multipath command is configured with the s-g-hash keyword and multiple
equal-cost paths exist, load splitting will occur across e qual-cost paths based on so urce and group
address or on source, grou p, and next- hop address . If you s pecify the opt ional s-g-hash ke yword for l oad
splitting IP multicast traffic, you must select the algorithm used to calculate the equal-cost paths by
specifying one of the following keywor ds:
• basic—The basic S-G-hash algorithm is predictable because no randomization is used in calculating
the hash value. The basic S-G-hash algorithm, however, is subject to polarization because for a given
source and group the same hash is always chosen irrespective of the router that the hash is being
calculated on.
• next-hop-based—T he next-hop- based S-G-ha sh algorith m is predict able becaus e no randomiz ation
is used to determine the hash value. Unlike the S-hash and basic S-G-hash algorithms, the
next-hop-based hash mechanism is not subject to polarization.
Examples The following example shows how to enable ECMP multicast lo ad splitting on a router based on sou rce
address using the S-hash algorithm:
Switch(config)# ip multicast multipath
The following example shows how to enable ECMP multicast load splitting on a router based on source
and group address using the basic S-G- hash algorithm:
Switch(config)# ip multicast multipath s-g-hash basic
The following example shows how to enable ECMP multicast load splitting on a router based on source,
group, and next-hop address using the next-hop-based S-G- hash algorithm:
Switch(config)# ip multicast multipath s-g-hash next-hop-based