Abstract: The present invention elects an area border router from a plurality of potential area border routers by determining a full set of all areas attached to a router. A determination is made as to a full set of area pairs from the determined full set of areas. Routers are identified in a first area of the determined full set of areas that are reachable through an intra-area route in the first area, and routers are identified in a second area of the determined full set of areas that are reachable through an intra-area route in the second area. If there is a router that is unreachable through either an intra-area route in the first area or an intra-area route in the second area, then declare the first router to be an area border router, else new first and second areas are selected.

Abstract: Techniques for detecting loops in routes that cross route information boundaries include receiving a control message at a first edge node on one side of the boundary that is connected to a different second edge node on another side of the boundary. The control message indicates a particular network address of a particular node that is reachable from the first edge node. Distinguisher data is determined that indicates if a node in the first collection can reach the first edge node without leaving the first collection. An advertising message is sent from the first edge node to the second edge node that includes route data that indicates the particular network address and the distinguisher data. Based on the distinguisher data, a testing edge node in the first collection can determine whether there is a loop comprising both an internal path and an external path to the first edge node.

Abstract: The present invention provides automatic classification of an IPv6 packet to a given topology. A topology identifier is carried as an embedded field in the interface ID portion of an IPv6 address. Automatic classification of an IPv6 packet for a given topology prevents manual configuration in intermediate nodes. Further, it remedies the value limit problem of differentiated services code points (DSCPs) and re-use of DSCP values within each topology.

Abstract: The present invention provides a method of determining whether database located on a first router is synchronized with the database located on a second router by performing a hash function on the values contained in a link state database to derive a SHA-1 digest value. In an embodiment, the digest value is based on LSA type. The digest value is exchanged initially during a database description packet swap between the first router and second router. If the digest values are the same, the databases are already synchronized. The routers thus skip the database description packet exchange of LSAs in the database and go directly to FULL state, indicating full synchronization between databases on the first and second router and announcing adjacency to each other. If the digest differs, normal database description packet exchange is performed as specified in OSPF.

Abstract: The present invention supports the operation of IS-IS over UDLs without the need for encapsulation of IS-IS PDUs in IP and without the need for a large-scale upgrade of the protocol in the network. The present invention also supports adjacency establishment when the return path from a router at the receive end of a to the router at the transmit end of the unidirectional link is via another unidirectional link.

Abstract: A method of supporting a unidirectional link from a first router to a second router, the first and second routers existing in an area of a communication network, the method comprising: the second router receiving a hello packet from the first router; the second router determining that its topology information for the communication network is incomplete; the second router encapsulating an open shortest path first (OSPF) packet into an Opaque link state advertisement (LSA); and the second router flooding the Opaque LSA over the area.

Abstract: A method and apparatus for managing network communication that operate on the idea that if a new neighboring node is already reachable as represented in a shortest path data structure that the local node consults, there is no urgency in doing a full database synchronization between the local node and the neighboring node. The present invention delays database synchronization as long as possible to reduce unnecessary OSPF packets traversing communication links between nodes of the network. Since unsynchronized neighbors remain in 2-way state, OSPF updates are not flooded over the corresponding interfaces.

Abstract: A method and apparatus are presented supporting shortest path first (SPF) routing of data packets over a network by establishing link-state data at an router. Link-state data indicates direct links between the router and a different router and establishes an adjacency relationship with the different node. Initial link-state data is stored at a first router. After the initial link-state data is stored, a hello message is received at the first router. The hello message indicates a direct connection with a different second router on one network segment. Based on the initial link-state data, it is determined whether establishing an adjacency relationship with the second router is sufficiently valuable. If not, then an adjacency relationship is not established with the second router in response to the hello message. A shortest path first routing for a data packet traversing the network is determined based on one or more adjacency relationships indicated in link-state data stored at the first router.