IOS XR

"IOX" redirects here. For the remote sensing satellite package, see Ionospheric Occultation Experiment.

This article relies on references to primary sources. Please add references to secondary or tertiary sources. (December 2012)

Line card running IOS XR.

IOS XR is a train of Cisco Systems' widely deployed Internetworking Operating System (IOS), used on their high-end carrier-grade routers such as the CRS-1, 12000, and ASR9000 series.

1 Architecture
2 History
3 References
4 External links

Architecture [edit]

According to Cisco's product literature, IOS XR shares very little infrastructure with the other IOS trains, and is instead built upon a "preemptive, memory protected, multitasking, microkernel-based operating system".^[1] The microkernel is provided by QNX.^[2]

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

Improved high availability (largely through support for hardware redundancy and fault containment methods such as protected memory spaces for individual processes and process restartability)
Better scalability for large hardware configurations (through a distributed software infrastructure and a two-stage forwarding architecture)
A package based software distribution model (allowing optional features such as multicast routing and MPLS to be installed and removed while the router is in service)
The ability to install package upgrades and patches (potentially while the router remains in service)
A web-based GUI for system management (making use of a generic, XML management interface)

History [edit]

IOS XR was announced along with the CRS-1 in May 2004.^[3] 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 series. The most recent release is 4.2 which was released on December 23rd, 2011. ^[4]