Introduction To Ip Multicast Policy Routing; Overview Of Ip Multicast Policy Routing; Concepts Related To Ip Multicast Policy Routing - 3Com 3C13636 Configuration Manual

3Com Router 3000 Ethernet Family
Configuration Guide
Chapter 13 IP Multicast Policy Routing

13.1 Introduction to IP Multicast Policy Routing

13.1.1 Overview of IP Multicast Policy Routing

IP multicast policy routing is subsidiary and enhancement to the function that multicast
forwards packets according to the routing table. It forwards multicast packets according
to the policy the user specifies.
IP multicast policy routing is implemented by configuring the route-policy. The
route-policy is an extension of unicast policy routing, described by a group of if-match
and apply statements the user defines. The if-match clause defines the match rule, i.e.,
the filter conditions to be met to pass the current route-policy. It specifies when a
multicast packet meets the match conditions the user defines, the multicast packet is
not forwarded according to the usual process, but forwarded according to the action the
user sets (described by the apply statement).

13.1.2 Concepts Related to IP Multicast Policy Routing

route-policy
IP multicast policy routing is implemented through route-policies. Multiple route-policies
can be configured on a router.
Policy node
A policy node is a complete policy, which sets the conditions packets should match with
the if-match command and sets the forwarding actions that should be executed to
packets meeting the match conditions with the apply command. Each node contains at
most one ACL used for defining the match conditions of packets, one ACL used for
specifying the outgoing interface and one ACL used for specifying the next hop.
Multiple nodes with different conditions and actions can be configured in a route-policy.
Different policy-nodes in each route-policy can be identified through an integer
sequence-number.
Match rule
Match conditions of multicast packets are described by the if-match clause and are set
by configuring the standard or extended ACL (ranging from 2000 to 3999).
Forwarding actions of multicast packets
Forwarding actions of multicast packets are described by the APPLY clause including
setting the outgoing interface and the next hop IP address. The output interface list is
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