Implementing BGP on Cisco IOS XR Software

Information About Implementing BGP on Cisco IOS XR Software

•Commands entered at the session group level define address family-independent commands (the same commands as in the neighbor submode).

•Commands entered at the address family group level define address family-dependent commands for a specified address family (the same commands as in the neighbor-address family configuration submode).

•Commands entered at the neighbor group level define address family-independent commands and address family-dependent commands for each address family (the same as all available neighbor commands), and define the use command for the address family group and session group commands.

Template Inheritance Rules

In Cisco IOS XR software, BGP neighbors or groups inherit configuration from other configuration groups.

For address family-independent configurations:

•Neighbors can inherit from session groups and neighbor groups.

•Neighbor groups can inherit from session groups and other neighbor groups.

•Session groups can inherit from other session groups.

•If a neighbor uses a session group and a neighbor group, the configurations in the session group are preferred over the global address family configurations in the neighbor group.

For address family-dependent configurations:

•Address family groups can inherit from other address family groups.

•Neighbor groups can inherit from address family groups and other neighbor groups.

•Neighbors can inherit from address family groups and neighbor groups. Configuration group inheritance rules are numbered in order of precedence as follows:

1.If the item is configured directly on the neighbor, that value is used. In the example that follows, the advertisement interval is configured both on the neighbor group and neighbor configuration and the advertisement interval being used is from the neighbor configuration:

RP/0/RP0/CPU0:router(config)# router bgp 140

RP/0/RP0/CPU0:router(config-bgp)# neighbor-group AS_1

RP/0/RP0/CPU0:router(config-bgp-nbrgrp)# advertisement-interval 15

RP/0/RP0/CPU0:router(config-bgp-nbrgrp)# exit

RP/0/RP0/CPU0:router(config-bgp)# neighbor 10.1.1.1

RP/0/RP0/CPU0:router(config-bgp-nbr)# remote-as 1

RP/0/RP0/CPU0:router(config-bgp-nbr)# use neighbor-group AS_1

RP/0/RP0/CPU0:router(config-bgp-nbr)# advertisement-interval 20

The following output from the show bgp neighbors command shows that the advertisement interval used is 20 seconds:

RP/0/RP0/CPU0:router# show bgp neighbors 10.1.1.1

BGP neighbor is 10.1.1.1, remote AS 1, local AS 140, external link

Remote router ID 0.0.0.0

BGP state = Idle

Last read 00:00:00, hold time is 180, keepalive interval is 60 seconds

Received 0 messages, 0 notifications, 0 in queue

Sent 0 messages, 0 notifications, 0 in queue

Minimum time between advertisement runs is 20 seconds

For Address Family: IPv4 Unicast

BGP neighbor version 0

Cisco IOS XR Routing Configuration Guide

RC-7

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Cisco Systems IOS XR manual Template Inheritance Rules, RC-7
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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.
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