Configuring policy-based routing (PBR) on a Cisco Layer 3 switch involves setting up rules to forward traffic based on specific criteria, such as source IP address, protocol, or application. Here’s a general guide on how to configure PBR on a Cisco Layer 3 switch:

1. Access the Configuration Mode:
   Log in to the Cisco Layer 3 switch and access privileged EXEC mode:

   enable

2. Enter Global Configuration Mode:

   configure terminal

3. Create an Access Control List (ACL):
   Define the criteria for policy-based routing using an ACL. For example, to match traffic from a specific source IP address:

   access-list <acl_number> permit ip <source_ip> <wildcard_mask>

Replace <acl_number> with a numerical value to identify the ACL, <source_ip> with the specific source IP address, and <wildcard_mask> with the corresponding wildcard mask.

4. Configure Route Map:
   Create a route map that references the previously created ACL and specifies the next hop IP address for matched traffic:

   route-map <route_map_name> permit <sequence_number>
    match ip address <acl_number>
    set ip next-hop <next_hop_ip>

Replace <route_map_name> with a name to identify the route map, <sequence_number> with a numerical value to specify the order of precedence, <acl_number> with the ACL number created in step 3, and <next_hop_ip> with the IP address of the next hop router.

5. Apply Route Map to Interface:
   Apply the route map to the interface where traffic should be subjected to PBR:

   interface <interface_type> <interface_number>
    ip policy route-map <route_map_name>

Replace <interface_type> and <interface_number> with the corresponding interface type and number (e.g., GigabitEthernet, FastEthernet, etc.), and <route_map_name> with the name of the route map created in step 4.

6. Verify Configuration:
   Verify the PBR configuration using the show route-map and show ip policy commands:

   show route-map <route_map_name>
   show ip policy

Ensure that the ACL, route map, and interface configuration are correctly applied.

7. Save Configuration:
   Save the configuration changes:

   end
   write memory

This ensures that the configuration persists across device reboots.

Remember to replace placeholder values with your specific network requirements. Additionally, always test the PBR configuration in a controlled environment to ensure that it behaves as expected before deploying it in a production network.