Overview of PBR

Policy-Based Routing (PBR) is a networking technique used to change the next hop IP address for traffic matching certain predefined policies or rule, rather than relying solely on traditional routing protocols and routing table entries. With PBR, administrators can direct traffic along specific paths according to various factors such as source/destination IP address, source/destination port.

After the device configures PBR, if the received messages match the rules of the PBR, they are forwarded according to the PBR route; if they fail to match, they are forwarded according to the destination address according to the traditional forwarding process.

The implementation and deployment of Policy-Based Routing consists of the following aspects:

1. Policy Definition: Administrators define policies that specify conditions under which certain types of traffic should be routed differently from the default routing behavior. A complete policy should be configured including Match Rule, Action and Applying Interface.

2. Match Rule: Policies in PBR include match rule, which are conditions that incoming packets must meet in order to be subjected to the policy. Match rule includes attributes such as source/destination IP address, source/destination port.

and is the logical operator between the matching fields with the same sequence number, that is, to be considered to match a PBR rule, the packets must match all the matching fields with the same sequence number.

3. Action: Once a packet matches the specified rule in a policy, an action is taken based on the policy configuration. This action involves routing the packet through a specific next-hop router or changing Quality of Service (QoS) policies such as DSCP value.

4. Applying Interface: Applying this policy to the VLAN interface where the traffic is coming in.

PBR provides flexibility and granular control over network traffic routing, allowing administrators to tailor routing decisions based on specific requirements or business needs, enhancing network performance, security, and flexibility.