Abstract: High availability BGP4 is based on redundant hardware as well as redundant software that replicates the RUN state of BGP4. There are two copies, respectively active and backup, of BGP4 running on two separate redundant hardware platforms. All BGP4 internal implementations apply various methods to replicate the running state of BGP4 independently of peer network routers. When this hardware or software fails on one redundant hardware platform, peer routers are unaware of the failure. Internally, based on duplicative states, the local router recovers from the failure and keeps the protocol running. During the recovery period, the local router can bring up a backup again. In the HA architecture, these activities are not detected by peer routers, such that there is no instability to the Internet backbone caused by BGP4 failure.

Abstract: High availability BGP4 is based on redundant hardware as well as redundant software that replicates the RUN state of BGP4. There are two copies, respectively active and backup, of BGP4 running on two separate redundant hardware platforms. All BGP4 internal implementations apply various methods to replicate the running state of BGP4 independently of peer network routers. When this hardware or software fails on one redundant hardware platform, peer routers are unaware of the failure. Internally, based on duplicative states, the local router recovers from the failure and keeps the protocol running. During the recovery period, the local router can bring up a backup again. In the HA architecture, these activities are not detected by peer routers, such that there is no instability to the Internet backbone caused by BGP4 failure.

Abstract: High availability BGP4 is based on redundant hardware as well as redundant software that replicates the RUN state of BGP4. There are two copies, respectively active and backup, of BGP4 running on two separate redundant hardware platforms. All BGP4 internal implementations apply various methods to replicate the running state of BGP4 independently of peer network routers. When this hardware or software fails on one redundant hardware platform, peer routers are unaware of the failure. Internally, based on duplicative states, the local router recovers from the failure and keeps the protocol running. During the recovery period, the local router can bring up a backup again. In the HA architecture, these activities are not detected by peer routers, such that there is no instability to the Internet backbone caused by BGP4 failure.

Abstract: A router rolls back a current running configuration to a selected prior running configuration without requiring interruption or reinitialization of the router or of its network connections. The router retrieves command line interface control settings associated with the selected prior running configuration and those associated with the current running configuration. The router then generates and executes a rollback script based on the difference between the prior control settings and the current control settings.

Abstract: In highly-available Open Shortest Path First (OSPF) routing in a network, the dynamic state of a backup OSPF instance in a router is synchronized with the dynamic state of an active OSPF instance using explicit message transmission from the active instance to the backup instance. After this, the dynamic state synchronization of the backup OSPF instance is maintained using a combination of explicit message updates from the active OSPF instance together with a message flow-through mechanism. In the event of fail-over of the active OSPF instance, then the router recovers seamlessly without reconfiguring or interrupting traffic among peer routers in the network, by functionally substituting the synchronized backup OSPF instance for the active OSPF instance, such that the backup OSPF instance establishes itself as the new active OSPF instance.

Abstract: High availability BGP4 is based on redundant hardware as well as redundant software that replicates the RUN state of BGP4. There are two copies, respectively active and backup, of BGP4 running on two separate redundant hardware platforms. All BGP4 internal implementations apply various methods to replicate the running state of BGP4 independently of peer network routers. When this hardware or software fails on one redundant hardware platform, peer routers are unaware of the failure. Internally, based on duplicative states, the local router recovers from the failure and keeps the protocol running. During the recovery period, the local router can bring up a backup again. In the HA architecture, these activities are not detected by peer routers, such that there is no instability to the Internet backbone caused by BGP4 failure.

Abstract: The HA IS-IS system provides a redundant backup IS-IS protocol instance that can seamlessly assume the function of the active IS-IS instance in the event of active MCP failure. Once the backup is online, the active synchronizes its global, interface, adjacency, neighbor, and LSP system state information. In the ongoing synchronization phase, the active and the backup maintain synchronization using a combination of explicit message updates from active to backup together with message flow-through. In the recovery phase, the operating system detects the failure of the active and notifies the backup, which assumes the active function as a standalone system without reconfiguring or interrupting traffic among peer network routers, and starts computing forwarding tables and updating routing tables.

Abstract: High availability BGP4 is based on redundant hardware as well as redundant software that replicates the RUN state of BGP4. There are two copies, respectively active and backup, of BGP4 running on two separate redundant hardware platforms. All BGP4 internal implementations apply various methods to replicate the running state of BGP4 independently of peer network routers. When this hardware or software fails on one redundant hardware platform, peer routers are unaware of the failure. Internally, based on duplicative states, the local router recovers from the failure and keeps the protocol running. During the recovery period, the local router can bring up a backup again. In the HA architecture, these activities are not detected by peer routers, such that there is no instability to the Internet backbone caused by BGP4 failure.

Abstract: Virtual routers within a single physical router share a centralized data plane containing a centralized switch fabric and a plurality of physical network interfaces, each assigned to only one virtual router. Using a logical cut-through device between a pair of virtual routers designated respectively client and server, packet forwarding information from the server is imported into the client, which creates, allocates, and maintains a data structure for the imported information, which then resides on the client interfaces. This imported forwarding information is then integrated into a single forwarding table that is used to recognize an incoming packet at the client and forward it appropriately out through a server interface with a single packet forwarding decision in a single transit through the switch fabric. Within a physical router, a client virtual router can communicate with multiple servers and can concurrently function as a server to multiple clients.

Abstract: Virtual routers within a single physical router share a centralized data plane containing a centralized switch fabric and a plurality of physical network interfaces, each assigned to only one virtual router. Using a logical cut-through device between a pair of virtual routers designated respectively client and server, packet forwarding information from the server is imported into the client, which creates, allocates, and maintains a data structure for the imported information, which then resides on the client interfaces. This imported forwarding information is then integrated into a single forwarding table that is used to recognize an incoming packet at the client and forward it appropriately out through a server interface with a single packet forwarding decision in a single transit through the switch fabric. Within a physical router, a client virtual router can communicate with multiple servers and can concurrently function as a server to multiple clients.

Abstract: The HA IS-IS system provides a redundant backup IS-IS protocol instance that can seamlessly assume the function of the active IS-IS instance in the event of active MCP failure. Once the backup is online, the active synchronizes its global, interface, adjacency, neighbor, and LSP system state information. In the ongoing synchronization phase, the active and the backup maintain synchronization using a combination of explicit message updates from active to backup together with message flow-through. In the recovery phase, the operating system detects the failure of the active and notifies the backup, which assumes the active function as a standalone system without reconfiguring or interrupting traffic among peer network routers, and starts computing forwarding tables and updating routing tables.

Abstract: A router rolls back a current running configuration to a selected prior running configuration without requiring interruption or reinitialization of the router or of its network connections. The router retrieves command line interface control settings associated with the selected prior running configuration and those associated with the current running configuration. The router then generates and executes a rollback script based on the difference between the prior control settings and the current control settings.

Abstract: High availability BGP4 is based on redundant hardware as well as redundant software that replicates the RUN state of BGP4. There are two copies, respectively active and backup, of BGP4 running on two separate redundant hardware platforms. All BGP4 internal implementations apply various methods to replicate the running state of BGP4 independently of peer network routers. When this hardware or software fails on one redundant hardware platform, peer routers are unaware of the failure. Internally, based on duplicative states, the local router recovers from the failure and keeps the protocol running. During the recovery period, the local router can bring up a backup again. In the HA architecture, these activities are not detected by peer routers, such that there is no instability to the Internet backbone caused by BGP4 failure.

Abstract: In highly-available Open Shortest Path First (OSPF) routing in a network, the dynamic state of a backup OSPF instance in a router is synchronized with the dynamic state of an active OSPF instance using explicit message transmission from the active instance to the backup instance. After this, the dynamic state synchronization of the backup OSPF instance is maintained using a combination of explicit message updates from the active OSPF instance together with a message flow-through mechanism. In the event of fail-over of the active OSPF instance, then the router recovers seamlessly without reconfiguring or interrupting traffic among peer routers in the network, by functionally substituting the synchronized backup OSPF instance for the active OSPF instance, such that the backup OSPF instance establishes itself as the new active OSPF instance.