H3C Technologies H3C SR8800 - Manual (Page 401)

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Configuring IPv6 policy-based routing
Introduction to IPv6 policy-based routing
IPv6 policy-based routing is used to route IPv6 unicasts based on a policy.
Policy-based routing
Policy-based routing (PBR) is a routing mechanism based on the user-defined policies. Different from the
traditional destination-based routing mechanism, PBR enables you to implement policies (based on the
source address, address length, and other criteria) that make packets flexibly take different routes. You
can specify the packet priority and next hop to guide forwarding of the packets matching an ACL.
According to the objects to which the PBR applies, PBR involves local PBR and interface PBR:
• Local PBR applies to locally generated packets only, such as the ICMP packets generated by using
the ping command.
• Interface PBR applies to packets forwarded through an interface only.
In most cases, interface PBR is implemented to meet the forwarding and security requirements.
In general, PBR takes precedence over destination-based routing. PBR is applied when packets match the
specified criteria. Otherwise, destination-based routing is applied.
IPv6 PBR
An IPv6 policy is used to route IPv6 packets.
An IPv6 policy can consist of one or multiple nodes.
Node
A node is identified by a node number. The node with the smallest node number has the highest priority.
A policy consists of if-match and apply clauses. An if-match clause defines specifies a match criterion on
a node, and an apply clause specifies action to be taken on packets.
The action to be taken on matched packets depends on the match mode, which can be permit or deny
Table 8 Relationship between the match mode and the clauses
If a packet…
Then…
In permit mode
In deny mode
Matches all the if-match clauses on
the policy node
The apply clause is executed, and
the packet will not go to the next
policy node for a match.
The apply clause is not executed,
the packets will not go to the next
policy node for a match, and will
be forwarded according to the
routing table.
Fails to match an if-match clause
on the policy node
The apply clause is not executed,
and the packet will go to the next
policy node for a match. The apply clause is not executed,
and the packet will go to the next
policy node for a match.