GateD Versions 4.2/5.x/6.x

6.3.4 Other Multicast Support

6.3.4.2 Multicast Statement

The multicast statement is used to set interface-specific options such as rate limits, TTL thresholds, and admin scope boundaries (admin scope boundaries are not yet implemented).

GateD-5.0 also supports static group memberships on interfaces. These can be used to manually configure tree branches, and can be used regardless of whether a multicast routing protocol is configured on the relevant interface.

Syntax

Static joins and scoped boundaries are configured by commands inside the "multicast {}" block. The new syntax for the multicast block is:

   multicast {
      interface interface_list [threshold number] [ratelimit number];
      join network [(mask mask) | (masklen number)] interface_list;
      boundary network [(mask mask) | (masklen number)] interface_list;
   }

The multicast statement need not exist for multicast routing to work; it is only used for overriding default options.

interface interface_list [threshold number] [ratelimit number]

This is used to specify TTL thresholds (defaults to 1) and rate limits (defaults to none) on multicast-capable interfaces.

join network [(mask mask) | (masklen number)] interface_list

This is used to manually configure tree branches on the indicated interface(s). Since this prevents pruning, static joins should be used only in exceptional circumstances. Note that this does not cause GateD to join the indicated group(s); it only causes GateD to act as if downstream members are present and have joined the group.

Example:

      multicast {
         interface le1 threshold 16 ratelimit 500;
         join 239.1.2.3 le1;
      };

The example above configures interface le1 with a TTL threshold of 16, a rate limit on multicast traffic of 500 Kbps, and forces GateD to believe that downstream members of group 239.1.2.3 exist on that interface.

boundary network [(mask mask) | (masklen number)] interface_list

This is used (in versions of GateD after the 11/11 snapshot) to configure administratively scoped group boundaries on the indicated interface(s).

Example:

 
      multicast {
         interface le1 threshold 16 ratelimit 500;
         boundary 239.255.0.0 masklen 16 le1;
      };

The example above configures interface le1 with a TTL threshold of 16, a rate limit on multicast traffic of 500 Kbps, and sets a boundary for 239.255/16 on it.

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