Abstract: A method of providing token security implemented by a network device in a network. The method includes encoding, into a signature mask, an identity of one or more token cells that have been signed; encoding, into the signature mask, an indication of which of the one or more token cells have been partially signed; and encoding, into the signature mask, an indication of which portion of the one or more partially signed token cells have been signed. A method of utilizing a scratchpad and a method of decomposing a contract clause are also disclosed.

Abstract: A computer-implemented method for processing a data packet in a network node includes determining a level of deterioration of a primary path between the network node and the destination node. The determined level of deterioration is based at least on a non-congestion-related loss for a primary link associated with one or more subsequent hops of the data packet from the network node toward the destination node along the primary path. Based on the determined level of deterioration of the primary path being above a threshold, the primary path is changed to an alternate path from the network node to the destination node. The data packet is forwarded to a next network node on the alternate path.

Abstract: A method for using metadata in an Internet Protocol (IP) packet is provided. A first processor at a first node sets a dedicated field of the IP packet to a predetermined value to indicate that metadata is present in the IP packet, and adds metadata to the IP packet by inserting the metadata between an original transport header of the IP packet and an original packet payload of the IP packet. A second processor at a second node receives the IP packet from the first node, reads the dedicated field to identify the predetermined value indicating that metadata is present in the IP packet, and identifies the metadata in the IP packet based on the predetermined value.

Abstract: A method for using metadata in an Internet Protocol (IP) packet is provided. A first processor at a first node sets a dedicated field of the IP packet to a predetermined value to indicate that metadata is present in the IP packet, and adds metadata to the IP packet by inserting the metadata between an original transport header of the IP packet and an original packet payload of the IP packet. A second processor at a second node receives the IP packet from the first node, reads the dedicated field to identify the predetermined value indicating that metadata is present in the IP packet, and identifies the metadata in the IP packet based on the predetermined value.

Abstract: A technique protects against failure of a network element using Multi-Topology Repair Routing (MTRR) in a computer network. According to the novel technique, a protecting node (e.g., a router) maintains Multi-Topology Routing (MTR) databases for a first topology and at least a second topology. The protecting node determines whether any acceptable repair paths are available in the first topology for a protected network element (e.g., node, link, etc.) of the first topology. If not, the protecting node may establish a repair path (e.g., for Fast ReRoute, FRR) in the second topology for the protected network element.

Abstract: In one embodiment, a connection verification (CV) message is initiated from an initiating maintenance end point (MEP) for an MPLS LSP, the CV message carried in a packet having a time-to-live (TTL) value of 1. Each maintenance intermediate point (MIP) along the MPLS LSP receives the packet and decrements the TTL, and in response to determining that the TTL equals 0, examines a payload of the packet to determine that the packet carries the CV message. The MIP may then append its MIP ID to a route record field of the payload having any previous MIP IDs of upstream MIPs, and forwards the CV message downstream along the MPLS LSP in a packet having a TTL value of 1. The end MEP receives the CV message, and sends a CV reply having the route record field with MIP IDs and an end MEP ID to the initiating MEP.

Abstract: In one embodiment, a method includes sending an adjacency discovery message 1 from a local router over a direct link to a first neighbor router. An adjacency discovery message is not forwarded and includes a repair address. The repair address indicates the local router but is not advertised as reachable over the direct link. An outbound routing update message is sent to a different second neighbor router. The outbound routing update message is forwarded and includes reachability data that indicates the repair address is reachable. A payload of an inbound tunneled packet received at the local router and directed to the repair address is forwarded based on a destination indicated in the payload.

Abstract: A method of constructing a backup path in an autonomous system (AS) for failure of an inter-AS link is described. The method comprises identifying an alternate inter-AS path and constructing a tunnel to an end point on the alternate path.

Abstract: A method of implementing a backup path in an autonomous system (AS) for failure of an inter-AS link is described. The method comprises forwarding data elements destined for the failed link via a backup path and including a loop prevention attribute in the packet.

Abstract: In one embodiment, a connection verification (CV) message is initiated from an initiating maintenance end point (MEP) for an MPLS LSP, the CV message carried in a packet having a time-to-live (TTL) value of 1. Each maintenance intermediate point (MIP) along the MPLS LSP receives the packet and decrements the TTL, and in response to determining that the TTL equals 0, examines a payload of the packet to determine that the packet carries the CV message. The MIP may then append its MIP ID to a route record field of the payload having any previous MIP IDs of upstream MIPs, and forwards the CV message downstream along the MPLS LSP in a packet having a TTL value of 1. The end MEP receives the CV message, and sends a CV reply having the route record field with MIP IDs and an end MEP ID to the initiating MEP.

Abstract: In one embodiment, a method includes sending an adjacency discovery message 1 from a local router over a direct link to a first neighbor router. An adjacency discovery message is not forwarded and includes a repair address. The repair address indicates the local router but is not advertised as reachable over the direct link. An outbound routing update message is sent to a different second neighbor router. The outbound routing update message is forwarded and includes reachability data that indicates the repair address is reachable. A payload of an inbound tunneled packet received at the local router and directed to the repair address is forwarded based on a destination indicated in the payload.

Abstract: A method is described of constructing a transition route in a data communication network having as components nodes and links. Upon receipt of a transition notification identifying a first component a non-neighboring node constructs a transition route around the first component. In an embodiment, a node performs detecting the first component transition; issuing a transition notification identifying the first component and recognizable by nodes configured to construct a transition route around the first component; and upon expiry of a notification transition period, issuing a transition advertisement recognizable by all nodes on the network.

Abstract: A technique protects against failure of a network element using Multi-Topology Repair Routing (MTRR) in a computer network. According to the novel technique, a protecting node (e.g., a router) maintains Multi-Topology Routing (MTR) databases for a first topology and at least a second topology. The protecting node determines whether any acceptable repair paths are available in the first topology for a protected network element (e.g., node, link, etc.) of the first topology. If not, the protecting node may establish a repair path (e.g., for Fast ReRoute, FRR) in the second topology for the protected network element.

Abstract: A method of constructing a backup path in an autonomous system (AS) for failure of an inter-AS link is described. The method comprises identifying an alternate inter-AS path and constructing a tunnel to an end point on the alternate path.

Abstract: A method of implementing a backup path in an autonomous system (AS) for failure of an inter-AS link is described. The method comprises forwarding data elements destined for the failed link via a backup path and including a loop prevention attribute in the packet.

Abstract: A method of constructing a backup path in an autonomous system (AS) for failure of a first inter-AS link serving a first set of prefixes is described. The method comprises identifying an alternate inter-AS link serving said plurality of prefixes and constructing a tunnel thereto.

Abstract: A method of advertising repair capability in a network repair scheme using network repair addresses for repairing around a repairable network component in a data communications network having, as components, nodes and links therebetween, comprises establishing whether an alternate repair path is available around a repairable component. If such a repair path is available, the method further comprises issuing a corresponding notification to nodes in the network.

Abstract: A method is disclosed for constructing a backup route from a source node around an adjacent component. The source node derives a first set of nodes reachable from it without traversing the adjacent component and a second set of nodes from which a neighbor node of adjacent components is reachable without traversing the adjacent component. The source node then constructs a backup route via an intermediate node in the intersection of the first and second sets.

Abstract: A method of updating a label-switched path for forwarding data in a data communications network in response to a change in a network comprises the step, performed at an updating node of receiving notification of a network change, of constructing a post-change label-switched path in the changed network. The method further comprises, after termination of a first period, forwarding data using the post-change label-switched path.

Abstract: A method is disclosed for constructing a repair path for multicast data around a non-available component in a data communications network having as components nodes and links therebetween. The method comprises the step performed at a repairing node, of receiving from a notifying node in a network, a notification identifying the notifying node and components through which the notifying node can be reached. The method further comprises the steps of deriving, from the notification, a network repair address for use in the event of non-availability of a component identified in the notification; and constructing a repair path for multicast data for the repair address.