Reference Guide

Policy-based Routing (PBR)

Policy-based routing (PBR) allows a switch to make routing decisions based on policies applied to an

interface.

Overview

When a router receives a packet, the router decides where to forward the packet based on the

destination address in the packet, which is used to look up an entry in a routing table. However, in some

cases, there may be a need to forward the packet based on other criteria: size, source, protocol type,

destination, and so on. For example, a network administrator might want to forward a packet that uses

transmission control protocol (TCP) across a different next-hop than packets using Internet control

message protocol (ICMP). In these situations, you can a configure switch route packet according to a

policy applied to interfaces.

In another scenario, when the packet comes from one source and wants to go to another destination,

then route it to this next-hop or onto that specific interface. This permits routing over different links or

towards different networks even while the destination is the same but depending on where the packet

originates.

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Policy-based Routing (PBR)