Users Guide

Policy-based Routing (PBR)

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

Topics:

• Overview

• Implementing Policy-based Routing with Dell Networking OS

• Configuration Task List for Policy-based Routing

• Sample Configuration

Overview

When a router receives a packet it normally decides where to forward it 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 TCP across

a different next-hop than packets using ICMP. In these situations, you can a configure switch route packet according to a policy applied to

interfaces.

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 networks even while the destination is the same but depending on

where the packet originates.

To enable a PBR, create a redirect list. Redirect lists are defined by rules, or routing policies. You can define following parameters in routing

policies or rules:

• IP address of the forwarding router (next-hop IP address)

• Protocol as defined in the header

• Source IP address and mask

• Destination IP address and mask

496 Policy-based Routing (PBR)