32Policy-based Routing (PBR)Policy-based Routing (PBR) allows a switch to make routing decisions based on policies applied to aninterface.This chapter covers the following topics:• Overview• Implementing Policy-based Routing with Dell Networking OS• Configuration Task List for Policy-based Routing• Sample ConfigurationOverviewWhen a router receives a packet it normally decides where to forward it based on the destination addressin the packet, which is used to look up an entry in a routing table. However, in some cases, there may bea need to forward the packet based on other criteria: size, source, protocol type, destination, etc. Forexample, a network administrator might want to forward a packet that uses TCP across a different next-hop than packets using ICMP. In these situations, you can configure a switch route packets according toa policy applied to interfaces.Rules for PBR can also be a combination of things:When the packet comes from this source and wants to go to that destination then route it to this next-hop or onto that specific interface. This permits routing over different links or towards different networkseven while the destination is the same but depending on where the packet originates.592 Policy-based Routing (PBR)
