CHAPTER 5
Implementing Routing Policy
A routing policy instructs the router to inspect routes, filter them, and potentially modify their attributes as
they are accepted from a peer, advertised to a peer, or redistributed from one routing protocol to another.
This module describes how routing protocols make decisions to advertise, aggregate, discard, distribute,
export, hold, import, redistribute and modify the routes based on configured routing policy.
The routing policy language (RPL) provides a single, straightforward language in which all routing policy
needs can be expressed. RPL was designed to support large-scale routing configurations. It greatly reduces
the redundancy inherent in previous routing policy configuration methods. RPL streamlines the routing policy
configuration, reduces system resources required to store and process these configurations, and simplifies
troubleshooting.
• Currently, only default VRF is supported. L3VPN, VPNv4, VPNv6 and VPN routing and forwarding
(VRF) address families and Multicast will be supported in a future release.
Note
• Restrictions for Implementing Routing Policy, on page 127
• Define Route Policy, on page 128
• Attach Routing Policy to BGP Neighbor, on page 129
• Modify Routing Policy Using Text Editor, on page 130
• References for Routing Policy, on page 133
Restrictions for Implementing Routing Policy
These restrictions apply when working with Routing Policy Language implementation:
• Border Gateway Protocol (BGP), integrated Intermediate System-to-Intermediate System (IS-IS), or
Open Shortest Path First (OSPF) must be configured in your network.
• An individual policy definition of up to 1000 statements are supported. The total number of statements
within a policy can be extended to 4000 statements using hierarchical policy constructs. However, this
limit is restricted with the use of apply statements.
• When a policy that is attached directly or indirectly to an attach point needs to be modified, a single
commit operation cannot be performed when:
Routing Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 6.3.x
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