Administrator 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 dierent next-hop than packets using Internet control message protocol (ICMP). In these
situations, you can a congure 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 specic interface. This permits routing over dierent links or towards dierent networks even while the destination is the same but
depending on where the packet originates.
To enable PBR, create a redirect list. Redirect lists are dened by rules or routing policies. You can dene following parameters in routing
policies or rules:
• IP address of the forwarding router (next-hop IP address)
• Protocol as dened in the header
• Source IP address and mask
• Destination IP address and mask
• Source port
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