Abstract: A method is implemented by a network device functioning as a Border Gateway Protocol (BGP) speaker to adaptively control a flow of link-state information to a peer BGP speaker. The network device stores, in a database, link-state information pertaining to a network in which it operates. The method includes determining that a pending change to the link-state information in the link-state database exists, determining whether a length of a change list queue meets/exceeds a threshold value, holding off on enqueuing link-state information into the change list queue while the length of the change list queue meets or exceeds the threshold value, determining aggregated link-state information to transmit to the peer BGP speaker in response to a determination that the length of the change list queue falls below the threshold value, and enqueuing the aggregated link-state information into the change list queue for eventual transmission to the peer BGP speaker.

Abstract: A method is implemented by a network device functioning as a Border Gateway Protocol (BGP) speaker to adaptively control a flow of link-state information to a peer BGP speaker. The network device stores, in a database, link-state information pertaining to a network in which it operates. The method includes determining that a pending change to the link-state information in the link-state database exists, determining whether a length of a change list queue meets/exceeds a threshold value, holding off on enqueuing link-state information into the change list queue while the length of the change list queue meets or exceeds the threshold value, determining aggregated link-state information to transmit to the peer BGP speaker in response to a determination that the length of the change list queue falls below the threshold value, and enqueuing the aggregated link-state information into the change list queue for eventual transmission to the peer BGP speaker.

Abstract: A method is implemented by a network device functioning as a Border Gateway Protocol (BGP) speaker to transmit aggregated link-state information pertaining to a network in which the network device operates to a peer BGP speaker. The method includes storing, in a link-state database, node entries representing nodes in the network, fragment entries representing fragments received from nodes in the network, and link/prefix entries representing links/prefixes in the network. Each link/prefix entry is assigned a state from a possible set of states, where the possible set of states include a new entry state, a modified entry state, a deleted entry state, and an unmodified entry state. The method further includes determining link-state information to transmit to the peer BGP speaker based on a state assigned to a link/prefix entry, and transmitting the determined link-state information to the peer BGP speaker.

Abstract: A method is implemented by a network device functioning as a Border Gateway Protocol (BGP) speaker to transmit aggregated link-state information pertaining to a network in which the network device operates to a peer BGP speaker. The method includes storing, in a link-state database, node entries representing nodes in the network, fragment entries representing fragments received from nodes in the network, and link/prefix entries representing links/prefixes in the network. Each link/prefix entry is assigned a state from a possible set of states, where the possible set of states include a new entry state, a modified entry state, a deleted entry state, and an unmodified entry state. The method further includes determining link-state information to transmit to the peer BGP speaker based on a state assigned to a link/prefix entry, and transmitting the determined link-state information to the peer BGP speaker.

Abstract: A method of a network device identifies multi-homed prefixes in an intermediate system-intermediate system (IS-IS) area or IS-IS domain during shortest path first (SPF) computation for use in a loop free alternate (LFA) computation. The method and network device select a next node in a shortest path tree (SPT) and determine a set of prefixes associated with the selected node in the SPT. A next prefix from the set of prefixes of the selected node is selected and a check is made whether the selected prefix exists in the local RIB associated with another node of a same level, then the selected prefix is marked as a multi-homed prefix in the local RIB. A check is made whether all prefixes associated with the selected node are processed and whether all nodes in the SPT have been processed, before downloading the local RIB to a global RIB.

Abstract: A method is executed by a network device to a calculate loop free alternative (LFA) for each node in an intermediate system-intermediate system (IS-IS) area or IS-IS domain where the network device is connected with other nodes via multiple parallel links. The method includes a shortest path first (SPF) computation of the primary paths for the network device that tracks directly connected links from each node in the IS-IS area or IS-IS domain to the network device which is a source node for the SPF. These tracked links can then be utilized in subsequent LFA computations to avoid unnecessary calculations.

Abstract: A method is executed by a network device to determine a loop free alternate (LFA) for a multi-homed prefix in an IS-IS area or IS-IS domain. The method includes selecting a next node from the IS-IS area or the IS-IS domain and selecting a next prefix for the selected node. A check is made whether the selected prefix is a multi-homed prefix (MHP). A check is made whether a shortest path first (SPF) cost of the selected node and cost to the selected prefix is equal to an SPF cost of the selected prefix, whether a next hop of selected prefix is same as next hop of selected node, and whether a LFA next hop of the selected node is better protection than a current next hop protection of the selected prefix and the LFA next hop of the selected node is then inherited for the selected prefix.

Abstract: A method is implemented by a network device to determine loop free alternatives (LFA) for each next hop in a default route to border nodes of a level 1 intermediate system-intermediate system (IS-IS) area of the network device. The method selects a next next-hop for the default route and looks up a corresponding border node for the selected next-hop in a local routing information base (RIB). A next next-hop of the corresponding border node is selected. A check is made whether the selected next-hop of the corresponding border node is the same as selected next-hop of default route. Then an LFA of the selected next-hop of the corresponding border node is assigned as LFA of the selected next-hop of the default route.

Abstract: A method is executed by a network device to determine a loop free alternate (LFA) for a multi-homed prefix in an IS-IS area or IS-IS domain. The method includes selecting a next node from the IS-IS area or the IS-IS domain and selecting a next prefix for the selected node. A check is made whether the selected prefix is a multi-homed prefix (MHP). A check is made whether a shortest path first (SPF) cost of the selected node and cost to the selected prefix is equal to an SPF cost of the selected prefix, whether a next hop of selected prefix is same as next hop of selected node, and whether a LFA next hop of the selected node is better protection than a current next hop protection of the selected prefix and the LFA next hop of the selected node is then inherited for the selected prefix.

Abstract: A method is implemented by a network device to determine loop free alternatives (LFA) for each next hop in a default route to border nodes of a level 1 intermediate system—intermediate system (IS-IS) area of the network device. The method selects a next next-hop for the default route and looks up a corresponding border node for the selected next-hop in a local routing information base (RIB). A next next-hop of the corresponding border node is selected. A check is made whether the selected next-hop of the corresponding border node is the same as selected next-hop of default route. Then an LFA of the selected next-hop of the corresponding border node is assigned as LFA of the selected next-hop of the default route.

Abstract: A method is executed by a network device to a calculate loop free alternative (LFA) for each node in an intermediate system-intermediate system (IS-IS) area or IS-IS domain where the network device is connected with other nodes via multiple parallel links. The method includes a shortest path first (SPF) computation of the primary paths for the network device that tracks directly connected links from each node in the IS-IS area or IS-IS domain to the network device which is a source node for the SPF. These tracked links can then be utilized in subsequent LFA computations to avoid unnecessary calculations.

Abstract: A method of a network device identifies multi-homed prefixes in an intermediate system-intermediate system (IS-IS) area or IS-IS domain during shortest path first (SPF) computation for use in a loop free alternate (LFA) computation. The method and network device select a next node in a shortest path tree (SPT) and determine a set of prefixes associated with the selected node in the SPT. A next prefix from the set of prefixes of the selected node is selected and a check is made whether the selected prefix exists in the local RIB associated with another node of a same level, then the selected prefix is marked as a multi-homed prefix in the local RIB. A check is made whether all prefixes associated with the selected node are processed and whether all nodes in the SPT have been processed, before downloading the local RIB to a global RIB.