Implementing Routing Policy on Cisco IOS XR Software

Information About Implementing Routing Policy

IS-IS Policy Attach Points

This section describes each of the IS-IS policy attach points and provides a summary of the BGP attributes and operators.

Redistribute

The redistribute attach point within IS-IS allows routes from other protocols to be readvertised by IS-IS. The policy is a set of control structures for selecting the types of routes that a user wants to redistribute into IS-IS. The policy can also control which IS-IS level the routes are injected into and at what metric values.

The following example shows how to redistribute routes from IS-IS instance 1 into IS-IS instance instance_10 using the policy ISIS-redist. This policy sets the level to level-1-2 for all redistributed routes. OSPF routes with a tag of 10 have their metric set to 100, and IS-IS routes with a tag of 20 have their IS-IS metric set to 200. Any IS-IS routes not carrying a tag of either 10 or 20 are not be redistributed into the IS-IS database.

route-policy ISIS-redist set level level-1-2 if tag eq 10 then

set metric 100 elseif tag eq 20 then set metric 200

else drop

endif

end-policy

router isis instance_10

address-family ipv4 unicast redistribute ospf 1 policy ISIS-redist

.

.

.

IS-IS Attributes and Operators

Table 7 summarizes the IS-IS attributes and operators.

Table 7

IS-IS Attributes and Operators

 

 

 

 

 

Attribute

 

Match

Set

 

 

 

 

Destination

 

in

n/a

 

 

 

 

Level

 

n/a

set

 

 

 

 

metric

 

n/a

set

 

 

 

 

metric-type

 

n/a

set

 

 

 

rib-has-route

in

n/a

 

 

 

 

route-type

 

is

n/a

 

 

 

 

tag

 

eq, ge, le

n/a

 

 

 

 

Cisco IOS XR Routing Configuration Guide

RC-234

Page 250
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Cisco Systems IOS XR manual IS-IS Policy Attach Points, IS-IS Attributes and Operators, RC-234

IOS XR specifications

Cisco Systems IOS XR is an advanced operating system designed specifically for high-performance routers and service provider networks. It serves as the backbone for many of Cisco's high-end routing platforms, enabling service providers to manage their networks with increased efficiency, flexibility, and scalability.

One of the main features of IOS XR is its modular architecture. This allows for the independent operation of various components within the OS, facilitating the deployment of new features and updates without affecting the overall stability of the system. This modularity ensures that service providers can implement rapid changes and enhancements while maintaining service continuity.

Another characteristic of IOS XR is its support for 64-bit architecture, which provides enhanced performance and the ability to manage larger amounts of data. This is particularly beneficial for service providers that deal with high traffic volumes and require robust data processing capabilities. The utilization of 64-bit technology also enables the operating system to utilize memory more efficiently, allowing for greater scalability.

IOS XR incorporates advanced technologies such as Distributed System Architecture (DSA) and Multiple Routing Instances (Merging Routes). DSA allows for the distribution of routing processes across multiple hardware resources, maximizing performance and redundancy. Multiple Routing Instances enable operators to create separate logical routing tables for different services, improving isolation and efficiency in managing network traffic.

The operating system also focuses heavily on security, featuring extensive encryption methods and access controls to safeguard network resources. IOS XR supports various authentication protocols, ensuring secure access to routers and switches. In addition, the OS includes comprehensive logging and monitoring capabilities, allowing network administrators to track activities and respond quickly to potential threats.

Another critical aspect of IOS XR is its adherence to the principles of service-oriented architecture (SOA). This approach permits the development of applications and services that can operate independently, fostering innovation and enabling service providers to tailor their offerings based on customer demands.

Ultimately, Cisco IOS XR is a powerful, reliable operating system that meets the complex needs of modern telecommunications networks. With its focus on modularity, performance, security, and scalability, it enables service providers to deliver high-quality, resilient services to their customers while efficiently managing network resources. As the industry continues to evolve, IOS XR remains a vital tool for those aiming to stay competitive in the ever-changing landscape of networking.