Carrier Grade Linux


Carrier Grade Linux is a set of specifications which detail standards of availability, scalability, manageability, and service response characteristics which must be met in order for Linux kernel-based operating system to be considered "carrier grade". The term is particularly applicable as telecom converges technically with data networks and commercial off-the-shelf commoditized components such as blade servers.
Carrier-grade is a term for public network telecommunications products that require up to 5 nines or 6 nines availability, which translates to downtime per year of 30 seconds to 5 minutes. The term "5 nines" is usually associated with carrier-class servers, while "6 nines" is usually associated with carrier-class switches.

CGL project and goals

The primary motivation behind the CGL effort is to present an open architecture alternative to the closed, proprietary software on proprietary hardware systems that are currently used in telecommunication systems. These proprietary systems are monolithic and operate well as a unit. However, they are hard to maintain and scale as telecommunications companies have to utilize the services of the vendor for even relatively minor enhancements to the system.
CGL seeks to progressively reduce or to eliminate this dependence on proprietary systems and provide a path for easy deployment and scalability by utilizing cheap COTS systems to assemble a telecommunications system.
The CGL effort was started by the Open Source Development Lab. The specification is now in the combined Linux Foundation. The latest specification release is CGL 5.0. Several CGL-registered Linux distributions exist, including MontaVista, Wind River Systems and Red Flag Linux.

Applications and services

The OSDL CGLWG defines three main types of applications that carrier-grade Linux will support — gateways, signaling servers, and management.