Configuring Pbr; Introduction To Pbr; Policy - HP 6125XLG Configuration Manual

Configuring PBR

Introduction to PBR

Policy-based routing (PBR) uses user-defined policies to route packets. A policy can specify the next hop
and other parameters for packets that match specific criteria, such as ACLs.
A device uses PBR to forward matching packets and uses the routing table to forward other packets. If
PBR is not configured, the device uses the routing table to forward packets.
The device supports only interface PBR, which guides the forwarding of packets received on an interface
only.

Policy

A policy comprises match criteria and actions to be taken on the matching packets. A policy can have
one or multiple nodes as follows:
Each node is identified by a node number. A smaller node number has a higher priority.
•
• A node comprises if-match and apply clauses. An if-match clause specifies a match criterion, and
an apply clause specifies an action.
A node has a match mode of permit or deny.
•
A policy matches nodes in priority order against packets. If a packet satisfies the match criteria on a node,
it is processed by the action on the node. Otherwise, it goes to the next node for a match. If the packet
does not match the criteria on any node, it is forwarded according to the routing table.
if-match clause
PBR supports only the if-match acl clause, which sets an ACL match criterion.
You can specify only one if-match clause of each type for a node.
apply clause
PBR supports only the apply next-hop clause, which sets the next hop for packets.
Relationship between the match mode and clauses on the node
Does a packet match all
the if-match clauses on
the node?
Yes.
No.
permit
•
If the node is configured with an
apply clause, PBR executes the apply
clause on the node.
•
If the node is configured with no
apply clause, the packet is forwarded
according to the routing table.
PBR matches the packet against the next
node.
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Match mode
Deny
The packet is forwarded according
to the routing table.
PBR matches the packet against the
next node.