Users Guide
37
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 dierent next-hop than packets using Internet control message
protocol (ICMP). In these situations, you can a congure 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 specic interface. This permits routing over dierent links or towards dierent 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 dened by rules or routing policies. You can dene following parameters in
routing policies or rules:
• IP address of the forwarding router (next-hop IP address)
• Protocol as dened in the header
• Source IP address and mask
• Destination IP address and mask
• Source port
Policy-based Routing (PBR)
611