Policy-Based Routing Guidelines and Limitations

BCD.

Policy-based routing has the following configuration guidelines and limitations: " A policy-based routing route mapcan have only one match or set statement per route-map statement.

" A match command cannot refer to more than one ACL in a single route-map statement/clause.

" Policy-based routing is not supported with inbound traffic on FEX ports.

" An ACL used in a policy-based routing route map cannot include a deny statement.

" The same route map can be shared among different interfaces for policy-based routing as long as the interfaces belong to the same virtual routing and forwarding (VRF) instance.

" Setting atunnel interface or an IP address via a tunnel interface as a next hop in a policy-based routing policy is not supported.

References:

Policy-based routing (PBR) is a technique used to selectively modify the path that packets take through a network based on specific criteria defined in a route map. However, there are certain guidelines and limitations to keep in mind while implementing PBR. Let's discuss the three true guidelines and limitations mentioned in the question.

A. A match command can refer to more than one ACL in a route map for policy-based routing. This statement is true. In a PBR route map, multiple ACLs can be referenced in a match statement to provide a more granular selection of traffic to be matched. For example, you could match traffic from a specific source IP address and a specific destination port number.

B. Setting a tunnel interface or an IP address via a tunnel interface as a next hop in a police-based routing policy is not supported. This statement is true. PBR does not support setting a tunnel interface or an IP address via a tunnel interface as a next hop in a route map. This is because the tunnel interface does not have a direct interface associated with it, which is required for PBR to function correctly.

C. The same route map can be shared among different interfaces for policy-based routing as long as interfaces belong to the same VRF instance. This statement is true. PBR route maps can be applied to different interfaces as long as the interfaces belong to the same VRF (Virtual Routing and Forwarding) instance. This allows for greater flexibility in implementing PBR in a multi-interface, multi-VRF environment.

D. An ACL used in a policy-based routing route map cannot include a deny statement. This statement is false. ACLs used in a PBR route map can include deny statements to match and route traffic in a particular manner. For example, you could deny traffic from a specific source IP address and route all other traffic via a different path.

E. A policy-based routing route map can have multiple match or set statements per route-map statement. This statement is true. PBR route maps can include multiple match and set statements in a single route-map statement, allowing for more complex routing decisions to be made based on multiple criteria.

F. Policy-based routing and WCCPv2 are not supported on the same interface if bank chaining is disabled. This statement is true. If WCCPv2 (Web Cache Communication Protocol version 2) and PBR are used on the same interface and bank chaining is disabled, there can be conflicts in how packets are routed. In this case, it is recommended to either enable bank chaining or use separate interfaces for PBR and WCCPv2.

In conclusion, PBR is a powerful tool for selectively routing traffic through a network based on specific criteria. However, there are certain guidelines and limitations that need to be kept in mind while implementing it.