Federal, state, and municipal governments, public safety agencies, utilities, service providers, and other organizations require High Availability routing (HA) in their transport networks. Loss of network services can equate to a severe impact on an organization, from loss of productivity and efficiency to loss of revenue and – in the worst-case scenario – loss of life. High Availability Routing configurations ensure critical applications management with maximum uptime for the network.

High Availability routing is one aspect of a transport network’s system reliability engineering. High Availability routing is accomplished using two redundant routers (primary and secondary), with the goal of ensuring the continuity of traffic forwarding in the event of any hardware failure. High Availability Routing has three core principles: (1) eliminate single points of failure, (2) ensure fast and reliable crossover (or failover) from one router to the other in the event of a system failure, and (3) detect and repairs failures if and when they occur.

Traditionally, HA router configurations required two separate routers, each of which has to be managed separately. This leads to unnecessary complexity due to the duplication of the router configuration management and monitoring efforts.

Implementing Aviat High Availability Routing – Maximum Availability with Minimal Complexity

Aviat’s CTR 8740 solution consists of two stacked and interconnected units that protect the network’s Data and Control planes against a single point of hardware failure. Once the two routers are connected and HA mode is enabled, the two units are synchronized via an encrypted channel, enabling them to operate as a single router instance with dual control and data planes.

The two routers logically appear on the network as one network element, with one IP address. This facilitates failover from one router to the other, and accelerates peering with the rest of the network at startup and after a network failure.

New software is loaded to the two routers via a single interface then activated in an orderly process. A Graceful Restart mechanism enables the routers to maintain traffic flow and prevent service outages.

The routers are also managed as a single entity by Aviat’s ProVision Plus web-based network management system (NMS), enabling customers to manage all Aviat networks through one screen for faster fault analysis and identification.

Each CTR 8740 also features a redundant power supply feed and redundant power supply card option, so if one power supply fails (external or internal), the other power supply keeps the router running. This eliminates a single point of power failure within each router for added resilience.

The Advantages of Aviat High Availability Routing

CTR 8740 High Availability feature delivers several key benefits to network operators:

1. Greater scalability – Every router in a network must be aware of all other routers in the network in order to route packets properly via an optimal path within the routing domain. Because two Aviat routers in HA configuration act logically as a single element, this effectively doubles the number of routers that can be deployed on the network, enhancing network scalability and allowing more sites to be added to the routing domain.
2. Lower management overhead – Both CTR 8740 routers in an HA configuration are managed as one, so management commands and software updates automatically flow to both routers, effectively cutting management traffic overhead and operator configuration actions in half.
3. Easier software updates – Updates to the CTR 8740’s software loading system allow loading via a single interface to both units in the HA system. Separate software loading and activation phases for each of the two routers ensures hitless traffic flow is maintained to prevent service outages during software upgrades.
4. Faster fault recovery – The CTR 8740 HA enables fast recovery from hardware component failures and, with Segment Routing, the routers can recover from external network failures, such as link and router failures, within tens of milliseconds.
5. Topology flexibility – The CTR 8740 supports full network-side protection for ring, spur, dual-feed, and linear network topologies.