IOS XR is a train of Cisco Systems

Cisco Systems

Cisco Systems, Inc. is an American multinational corporation headquartered in San Jose, California, United States, that designs and sells consumer electronics, networking, voice, and communications technology and services. Cisco has more than 70,000 employees and annual revenue of US$...

' widely deployed Internetworking Operating System (IOS)

Cisco IOS

Cisco IOS is the software used on the vast majority of Cisco Systems routers and current Cisco network switches...

, used on their high-end carrier-grade routers such as the CRS-1, 12000

Cisco 12000

The Cisco 12000, also known as a Gigabit Switch Router or GSR, is a series of large network routers designed and manufactured by Cisco Systems. It is marketed primarily to large service providers, as well as for use in some enterprise networks...

, and ASR9000

ASR9000

The ASR9000 is a router built by Cisco Systems, and is intended for Service Provider market.The major characteristics are:* From the ground up designed for Metro Ethernet networks* Designed for Video and other High Bandwidth applications...

 series.

Architecture

According to Cisco's product literature, IOS XR shares very little infrastructure with the other IOS trains, and is instead built upon a "preemptive

Preemption (computing)

In computing, preemption is the act of temporarily interrupting a task being carried out by a computer system, without requiring its cooperation, and with the intention of resuming the task at a later time. Such a change is known as a context switch...

, memory protected

Memory protection

Memory protection is a way to control memory access rights on a computer, and is a part of most modern operating systems. The main purpose of memory protection is to prevent a process from accessing memory that has not been allocated to it. This prevents a bug within a process from affecting...

, multitasking

Computer multitasking

In computing, multitasking is a method where multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for...

, microkernel-based

Microkernel

In computer science, a microkernel is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system . These mechanisms include low-level address space management, thread management, and inter-process communication...

 operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

". The microkernel is provided by QNX

QNX

QNX is a commercial Unix-like real-time operating system, aimed primarily at the embedded systems market. The product was originally developed by Canadian company, QNX Software Systems, which was later acquired by Canadian BlackBerry-producer Research In Motion.-Description:As a microkernel-based...

.

IOS XR aims to provide the following advantages over the earlier IOS trains:

• Improved high availability
  High availability
  High availability is a system design approach and associated service implementation that ensures a prearranged level of operational performance will be met during a contractual measurement period....
  
   (largely through support for hardware redundancy
  Redundancy (engineering)
  In engineering, redundancy is the duplication of critical components or functions of a system with the intention of increasing reliability of the system, usually in the case of a backup or fail-safe....
  
   and fault containment methods such as protected memory spaces for individual processes and process restartability)
• Better scalability for large hardware configurations (through a distributed
  Distributed computing
  Distributed computing is a field of computer science that studies distributed systems. A distributed system consists of multiple autonomous computers that communicate through a computer network. The computers interact with each other in order to achieve a common goal...
  
   software infrastructure and a two-stage forwarding architecture)
• A package
  Software package (installation)
  In package management systems, which are commonly used with Linux-based operating systems, a package is a specific piece of software which the system can install and uninstall....
  
   based software distribution model (allowing optional features such as multicast routing
  IP Multicast
  IP multicast is a method of sending Internet Protocol datagrams to a group of interested receivers in a single transmission. It is often employed for streaming media applications on the Internet and private networks. The method is the IP-specific version of the general concept of multicast...
  
   and MPLS
  Mpls
  MPLS or Mpls can refer to:* Minneapolis, Minnesota, United States* Multiprotocol Label Switching, a data-carrying mechanism in computer networking...
  
   to be installed and removed while the router is in service)
• The ability to install package upgrades and patches
  Patch (computing)
  A patch is a piece of software designed to fix problems with, or update a computer program or its supporting data. This includes fixing security vulnerabilities and other bugs, and improving the usability or performance...
  
   (potentially while the router remains in service)
• A web-based GUI
  Graphical user interface
  In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...
  
   for system management (making use of a generic, XML
  XML
  Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
  
   management interface)

History

IOS XR was announced along with the CRS-1 in May 2004. The first generally available version was 2.0; the first version generally available for the 12000 router series was 3.2. Version 3.9 was the first generally available version for the ASR9000

ASR9000

The ASR9000 is a router built by Cisco Systems, and is intended for Service Provider market.The major characteristics are:* From the ground up designed for Metro Ethernet networks* Designed for Video and other High Bandwidth applications...

series. The most recent release is 4.1.1 which was released on July 29th, 2011.

External links

• Cisco multimedia documentation covering IOS XR and its supported systems
• Cisco Security Advisories - complete history
• Cisco IOS XR Software General Information
• Cisco CRS Support Page
• Cisco XR 12000 Series Router Support
• Cisco ASR 9000 Series Support
• HEAnet's New Network and Working with IOS-XR