Abstract: Methods and apparatus for allowing a traffic level switch associated with an automatic protection switching (APS) topology to occur transparently and without reconverging routing are described. According to one aspect of the present invention, a method for providing protection switching configuration information associated with a router arrangement to includes identifying a first interface and a second interface of the router arrangement as an APS group. The method also includes providing information regarding the APS group to a process that implements a routing protocol. Providing the information regarding the group includes identifying the first interface as a primary interface and identifying the second interface as a backup interface that is arranged to protect the primary interface.

Abstract: Techniques are disclosed for synchronizing a database related to a first node in a network with multiple nodes. Each node includes a database different from a database on a different node. An inquiry control message is sent to each node in a candidate set of one or more nodes on the network, which are different from the first node. In response to the inquiry control message, the first node receives a first set of one or more messages from a particular node different from the first node. The first set indicates a portion from the database of the particular node. The portion is relevant for the first node. A particular portion of a first database for the first node is derived from the first set of messages. The particular portion is less than all of the first database. These techniques allow the first node to derive its full database from multiple adjacent nodes.

Abstract: A router identifies transit links and non-transit links. Only the non-transit links are advertised as routes to adjacent routers, thereby protecting the transit links from edge traffic which terminates on a network on one of the transit links. In another aspect of the invention, an administrative whitelist supplements the routes which identify the transit link network routes. In another aspect of the invention, a method for advertising routes identifies entries in a router table as broadcast or point-to-point. Only the router table entries for point-to-point links which are not transit or broadcast links that are not for a neighboring router are advertised, whereas the point-to-point transit links or broadcast transit links are advertised as transit links if an administrative whitelist is enabled.

Abstract: A method and system for determining route redistribution are disclosed. The method generally comprises receiving an information packet from a neighbor source. The information packet identifies the source as a stub router and specifies route types that the source will advertise. Upon receiving notice of a failed link within the network, query packets are sent only to neighboring devices that have not been identified as stub routers to request route information.

Abstract: Techniques are disclosed for synchronizing a database related to a first node in a network with multiple nodes. Each node includes a database different from a database on a different node. An inquiry control message is sent to each node in a candidate set of one or more nodes on the network, which are different from the first node. In response to the inquiry control message, the first node receives a first set of one or more messages from a particular node different from the first node. The first set indicates a portion from the database of the particular node. The portion is relevant for the first node. A particular portion of a first database for the first node is derived from the first set of messages. The particular portion is less than all of the first database. These techniques allow the first node to derive its full database from multiple adjacent nodes.

Abstract: Techniques are disclosed for synchronizing a database related to a first node in a network with multiple nodes. Each node includes a database different from a database on a different node. An inquiry control message is sent to each node in a candidate set of one or more nodes on the network, which are different from the first node. In response to the inquiry control message, the first node receives a first set of one or more messages from a particular node different from the first node. The first set indicates a portion from the database of the particular node. The portion is relevant for the first node. A particular portion of a first database for the first node is derived from the first set of messages. The particular portion is less than all of the first database. These techniques allow the first node to derive its full database from multiple adjacent nodes.

Abstract: A router identifies transit links and non-transit links. Only the non-transit links are advertised as routes to adjacent routers, thereby protecting the transit links from edge traffic which terminates on a network on one of the transit links. In another aspect of the invention, an administrative whitelist supplements the routes which identify the transit link network routes. In another aspect of the invention, a method for advertising routes identifies entries in a router table as broadcast or point-to-point. Only the router table entries for point-to-point links which are not transit or broadcast links that are not for a neighboring router are advertised, whereas the point-to-point transit links or broadcast transit links are advertised as transit links if an administrative whitelist is enabled.

Abstract: A technique efficiently notifies EIGRP neighbors when destroying adjacencies in a computer network. A goodbye notification packet is provided that enables an EIGRP router to inform one or more of its neighbors of its intention to destroy their existing adjacencies. The goodbye notification packet comprises an EIGRP packet header with variable-length fields embodied as an appended goodbye attribute. The appended goodbye attribute is illustratively tagged according to a TLV encoding format that defines a new type (T) field called “a goodbye” having a predetermined type that distinguishes it from a conventional EIGRP Hello packet. A value (V) field of information conveyed within the goodbye attribute contains a list of neighbor (peer) identifiers (IDs). The peer IDs on this list instruct those neighbor routers to “go away” so that their adjacencies can be destroyed.

Abstract: The present invention describes a method and apparatus to ensure bi-directional connectivity between neighbor network elements in distance-vector protocol (e.g., EIGRP). The method further defines the dampening of neighbors that cannot establish a bi-directional connectivity. When a router receives an unreliable packet from a neighbor, the router adds the neighbor in neighbor table by gradually developing the reliability of the neighbor. First, the router adds neighbor's address into a dampening table and a ‘neighbor pending’ table. The router establishes a reliable communication with the neighbor. If the router cannot establish the reliable communication with the neighbor, the router dampens the neighbor and removes neighbor's address from ‘neighbor pending’ table. When the router establishes a reliable communication with the neighbor, the router ‘promotes’ the neighbor to the neighbor table.

Abstract: Methods and apparatus for allowing a traffic level switch associated with an automatic protection switching (APS) topology to occur transparently and without reconverging routing are described. According to one aspect of the present invention, a method for providing protection switching configuration information associated with a router arrangement to includes identifying a first interface and a second interface of the router arrangement as an APS group. The method also includes providing information regarding the APS group to a process that implements a routing protocol. Providing the information regarding the group includes identifying the first interface as a primary interface and identifying the second interface as a backup interface that is arranged to protect the primary interface.

Abstract: A method and system for determining route redistribution are disclosed. The method generally comprises receiving an information packet from a neighbor source. The information packet identifies the source as a stub router and specifies route types that the source will advertise. Upon receiving notice of a failed link within the network, query packets are sent only to neighboring devices that have not been identified as stub routers to request route information.

Abstract: A technique efficiently notifies EIGRP neighbors when destroying adjacencies in a computer network. A goodbye notification packet is provided that enables an EIGRP router to inform one or more of its neighbors of its intention to destroy their existing adjacencies. The goodbye notification packet comprises an EIGRP packet header with variable-length fields embodied as an appended goodbye attribute. The appended goodbye attribute is illustratively tagged according to a TLV encoding format that defines a new type (T) field called “a goodbye” having a predetermined type that distinguishes it from a conventional EIGRP Hello packet. A value (V) field of information conveyed within the goodbye attribute contains a list of neighbor (peer) identifiers (IDs). The peer IDs on this list instruct those neighbor routers to “go away” so that their adjacencies can be destroyed.