Introduction To Ipv6 Unicast Policy Routing; Configuring Ipv6 Unicast Policy Routing; Defining An Ipv6 Policy - 3Com MSR 50 Series Configuration Manual

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Introduction to IPv6
Unicast Policy Routing
Configuring IPv6
Unicast Policy Routing

Defining an IPv6 Policy

IP 6 U
V NICAST
C
ONFIGURATION
When configuring IPv6 unicast policy routing, go to these sections for information
you are interested in:
"Introduction to IPv6 Unicast Policy Routing" on page 731
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"Configuring IPv6 Unicast Policy Routing" on page 731
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"Displaying and Maintaining IPv6 Unicast Policy Routing Configuration" on
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page 734
"IPv6 Unicast Policy Routing Configuration Examples" on page 734
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Policy routing (also known as policy based routing) is a routing mechanism based
on the user-defined policies. Different from the traditional destination-based
routing mechanism, policy routing enables you to implement policies (based on
the source address, address length, and other criteria) that make packets flexibly
take different routes.
Policy routing involves system policy routing and interface policy routing:
System policy routing applies to locally generated packets only, instead of
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forwarded packets. In most cases, interface policy routing applies;
Interface policy routing applies to incoming packets on an interface, instead of
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locally generated packets (for example, ping packets).
In general, policy routing takes precedence over destination-based routing. That is,
policy routing is applied when packets match the policy, and otherwise,
destination-based routing is applied. However, if a default outgoing interface (next
hop) is configured, the destination-based routing takes precedence over policy
routing.
An IPv6 policy can consist of multiple nodes identified by node number. The
smaller a node number is, the higher the priority the node has. A policy, which
consists of if-match clauses and apply clauses, is used to route IPv6 packets.
An if-match clause defines what kind of packets can pass, and an apply clause
defines the action for forwarding permitted packets.
Currently, two types of if-match clause are available: if-match packet-length
and if-match acl6. In each policy, you can specify only one if-match clause for
each type.
P R
OLICY OUTING