This section describes the high availability (HA) routing options and features that service providers can use to reduce vulnerability at the network or service provider edge and alleviate the effect of a lengthy outage on IP networks.
HA with control plane redundancy is only supported on the 7210 SAS-R6 and 7210 SAS-R12. Control plane redundancy is not supported on the 7210 SAS-Mxp, 7210 SAS-Sx/S 1/10GE, 7210 SAS-Sx 10/100GE, and 7210 SAS-T.
HA is an important feature in service provider routing systems. The unprecedented growth of IP services and applications in service provider networks is driven by the demand from the enterprise and residential communities. Downtime can be very costly, and, in addition to lost revenue, customer information and business-critical communications can be lost. HA is the combination of continuous uptime over long periods (Mean Time Between Failures (MTBF)) and the speed at which failover or recovery occurs (Mean Time To Repair (MTTR)).
The advantage of HA routing is evident at the network or service provider edge, where thousands of connections are hosted. Rerouting options around a failed piece of equipment are often limited, or, a single access link exists to a customer because of the additional cost of redundant links. As service providers converge business-critical services, such as real-time voice (VoIP), video, and VPN applications over their IP networks, the requirements for HA become more stringent compared to the requirements for best-effort data.
Network and service availability become critical aspects in advanced IP service offerings, which dictate that the IP routers used to build the foundations of these networks must be resilient to component and software outages.