HP Routing Services -UX 11i v2 manual How to Configure mrouted

Models: Routing Services -UX 11i v2

1 113
Download 113 pages 40.09 Kb
Page 34
Image 34

Configuring mrouted

How to Configure mrouted

The TTL value of forwarded packets is only compared with the threshold value; it is not decremented by the threshold. An application that initiates the IP multicast datagram sets the TTL, and typically represents the number of subnets, or hops, the datagram has to traverse to reach its destination. Every time a multicast datagram passes through a multicast router, the TTL value is decremented by 1. HP recommends that you use the default threshold value unless you have a specific reason to set it otherwise.

In general, all interfaces connected to a particular subnet or tunnel should use the same metric and threshold values for that subnet or tunnel.

You can use the rate_limit option to specify a certain bandwidth in Kbits/second which is allocated to multicast traffic. The default value is 500Kbps on tunnels and 0 (unlimited) on physical interfaces.

You can use the boundary option to configure an interface as an administrative boundary for the specified boundary-nameor scoped-addr(scoped address). You can specify more than one boundary option in the phyint and tunnel commands. Packets belonging to the scoped address, which is an IP multicast group address, are not forwarded on this interface. mask-lenindicates the number of leading 1s in the mask applied (by means of a bitwise logically AND operation) to the scoped address. For example, the statement boundary 239.2.3.3/16 would result in the mask 255.255.0.0 being calculated by means of an AND operation with 239.2.3.3 to isolate the first two octets, 239.2, of the scoped address. Therefore, all IP multicast addresses beginning with 239.2 will not be forwarded on the specified interface.

The primary use of the boundary option is to allow concurrent use of the same IP multicast addresses on downstream subnets, without interfering with multicast broadcasts using the same IP multicast addresses on subnets that are upstream from the mrouted gateway.

The cache_lifetime value determines the amount of time that a cached multicast route remains in the kernel before timing out. This value is specified in seconds and must be between 300 (5 minutes) and 86400 (24 hours). The default value is 300.

You can use the pruning off command to explicitly configure mrouted as a nonpruning router. When pruning is off, IP multicast datagrams are forwarded to leaf subnets of the broadcast routing tree even when

34

Chapter 2

Page 34
Image 34
HP Routing Services -UX 11i v2 manual How to Configure mrouted