ACLs are a common matching tool in routing policies. An ACL can be configured on a router to match routes.

The statement is correct. In network devices, particularly those running advanced operating systems like Huawei's VRP, Access Control Lists (ACLs) serve a dual purpose. While their primary and most well-known function is for packet filtering (a data-plane operation), they are also commonly used as a matching tool within routing policies (a control-plane operation). A route-policy uses if-match clauses to identify routes based on their attributes. One such clause is if-match acl, which uses an ACL to match routes based on their network prefix (destination address) and mask length.

The alternative, "False," is incorrect because it would imply that ACLs are exclusively used for packet filtering. This is a common misconception. Advanced routing policies leverage ACLs as a convenient method to define a list of network prefixes for matching and subsequent manipulation, a fundamental capability in route control.

1. Official Vendor Documentation: Huawei HCIP-Datacom-Core Technology V1.0 Training Material.

Reference: In the chapter "Routing Policy and Route Control"

Section "Matching Tools in a Route-Policy".

Content: The material explicitly lists ACLs as one of the primary tools for matching routes. It states

"An ACL can be used to match routes. When an ACL is used to filter routes

the source IP address field in the ACL specifies the network address of the route

and the wildcard mask in the ACL specifies the mask of the route." This confirms that ACLs are a standard and sanctioned tool for this purpose.

2. Official Vendor Documentation: Huawei VRP V800R021C00 Command Reference.

Reference: Section "Route-Policy Commands"

Command if-match acl.

Content: The documentation for the route-policy configuration details the if-match acl command. The description specifies its function: "This command configures a filtering condition based on a basic or advanced ACL in a Route-Policy. The device will match the destination address and mask of routes against the rules defined in the specified ACL." This provides direct

command-level evidence of the feature.

3. University Courseware: Computer Networking: A Top-Down Approach by J. Kurose

K. Ross.

Reference: While not specific to Huawei

this foundational textbook

used in numerous university courses

explains the concept of route policies (often called route maps) in the context of BGP.

Content: In Chapter 5

"The Network Layer: Control Plane

" the text discusses BGP policy. It explains that policies are based on matching route attributes

and lists of IP prefixes are a common attribute to match. While it may not name "ACL" directly in this context

it establishes the principle that lists of prefixes are a fundamental matching criterion

and an ACL is a primary mechanism for defining such a list on a router. This supports the general networking principle behind the statement.