Patent ID: 12212490

DETAILED DESCRIPTION

The following detailed description of example implementations refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements.

Intermediate system-intermediate system (IS-IS) flood reflection (FR) enables creation of flood-reflection topologies where Level 1 (also referred to as L1) areas (also referred to as FR clusters) provide transit forwarding for Level 2 (also referred to as L2) destinations within an L2 topology. This is accomplished by providing L1 and L2 (L1/L2) nodes (also referred to as L2 flood-reflection adjacencies) within each L1 area. The L1/L2 nodes are used to flood L2 link-state packet data units (PDUs) that are used in a Level 2 shortest-path-first (SPF) computation.

RSVP with traffic engineering (RSVP-TE) is a network signaling protocol used to set up and manage LSPs with traffic engineering capabilities. RSVP-TE enables nodes within a network to send signaling messages to each other to reserve resources along the path of an LSP. However, in an IS-IS FR network, L2 nodes and L1 nodes are not able to directly communicate with each other, and therefore an optimal LSP (e.g., that satisfies one or more traffic engineering requirements) cannot be established across the IS-IS FR network.

Some implementations described herein include a head L2 node of an IS-IS FR network. The head L2 node determines an end-to-end path from the head L2 node to a tail L2 node of the IS-IS FR network. The head L2 node then sends information associated with the end-to-end path to another node (e.g., a next-hop node in the end-to-end path) to cause an LSP to be established, from the head L2 node to the tail L2 node, that traverses one or more FR clusters of the IS-IS FR network (e.g., traverses one or more L1 links within each FR cluster of the one or more FR clusters). For example, the head L2 node may communicate with a path computation node to receive an end-to-end path that identifies L1 and/or L1/L2 nodes of the one or more FR clusters, and therefore the head L2 node may send information associated with the end-to-end path to cause an LSP to be established that traverses the L1 and/L1/L2 nodes. As another example, the head L2 node may determine an end-to-end path that identifies FR clusters, or L1/L2 nodes of FR clusters, and the head L2 node may send information associated with the end-to-end path to cause an ingress L1/L2 node of an FR cluster (e.g., that is identified by the end-to-end path) to determine an L1 path (e.g., comprising one or more L1 links) through the FR cluster. The ingress L1/L2 node may modify the information associated with the end-to-end path to indicate the L1 path, which facilitates establishment of an LSP that traverses the L1 path of the FR cluster.

In this way, some implementations described herein enable an LSP to be established (e.g., dynamically established) in an IS-IS FR network that traverses one or more FR clusters of the IS-IS FR network (e.g., via one or more L1 links of the one or more FR clusters), which is not currently feasible for IS-IS FR networks. Accordingly, some implementations enable establishment of an optimal LSP (e.g., that satisfies one or more traffic engineering requirements) in an IS-IS FR network that would otherwise not be able to be established.

FIGS.1A-1Eare diagrams of an example implementation100associated with RSVP-TE path computation across FR clusters of an IS-IS FR network. As shown inFIGS.1A-1E, example implementation100includes a plurality of nodes in an IS-IS FR network. These devices are described in more detail below in connection withFIGS.2-4.

The plurality of nodes may include, for example, a plurality of L1 nodes (shown with no shading), a plurality of L2 nodes (shown with shading), and a plurality of L1/L2 nodes (shown with partial shading). In some implementations, as shown inFIG.1A, the IS-IS FR network may include a plurality of FR clusters (shown as FR clusters A, B, and C), where each FR cluster includes a plurality of L1 nodes and a plurality of L1/L2 nodes connected by a plurality of L1 links (shown as solid lines). For example, the FR cluster A shown inFIG.1Amay include the L1 nodes31,32,33, and34, and the L1/L2 nodes21,22,23,24,41, and42(e.g., where each L1/L2 node may be configured to be an ingress L1/L2 node, an egress L1/L2 node, and/or an FR L1/L2 node for the FR cluster A) that are variously connected by a plurality of L1 links. Further, the plurality of L1/L2 nodes within each FR cluster may be connected by a plurality of L2 FR links (shown as dashed lines with arrow heads). For example, the L1/L2 nodes21,22,23,24,41, and42are variously connected by a plurality of L2 FR links.

Additionally, as further shown inFIG.1A, the IS-IS FR network may include a plurality of L2 nodes that are connected to L1/L2 nodes of the plurality of FR clusters via a plurality of L2 links. For example, as shown inFIG.1A, the IS-IS FR network may include the L2 nodes11,12,13,14,15,16,17, and18that are each connected to L1/L2 nodes of one or more FR clusters by L2 links.

In some implementations described herein, a first L2 node of the IS-IS FR network, referred to herein as a head L2 node, may determine information to facilitate establishment of an LSP to a second L2 node of the IS-IS FR network, referred to as a tail L2 node.FIGS.1B-1Eshow the L2 node11as the head L2 node and L2 node18as the tail L2 node, but other examples may be used.

As shown inFIG.1B, the IS-IS FR network may additionally include a path computation node (shown as a PCN node, with a dashed outline). The path computation node may include a path computation engine (PCE) and may be configured to determine a topology of the IS-IS FR network, such as by communicating (e.g., using a communication protocol, such as border gateway protocol link-state (BGP-LS)) with the plurality of nodes of the IS-IS FR network (e.g., the plurality of L1 nodes, the plurality of L2 nodes, and the plurality of L1/L2 nodes). Accordingly, the path computation node may be configured to determine respective intra-FR topologies of L1 nodes and L1/L2 nodes of individual FR clusters within the IS-IS FR network (e.g., a plurality of L1 topologies of the IS-IS FR network), an inter-FR topology of the L2 nodes and the L1/L2 nodes of the IS-IS FR network (e.g., an L2 topology of the IS-IS FR network), and/or an overall topology (e.g., an L1/L2 topology of the IS-IS FR network) of the plurality of nodes of the IS-IS FR network.

As further shown inFIG.1B, and by reference number102, the head L2 node (e.g., the L2 node11) may send a path communication request to the path computation node. The head L2 node may send the path communication request to the path computation node via a link (e.g., an L2 link) between the head L2 node and the path computation node. Accordingly, the path computation node may receive the path communication request from the head L2 node (e.g., via the link).

The path communication request may be a request for a path from the head L2 node to the tail L2 node (e.g., the L2 node18). In some implementations, the path communication request may indicate that the path is to traverse at least one FR cluster of the IS-IS FR network. That is, the path communication request may indicate that the path is to identify one or more L1 links (e.g., between L1 nodes and/or L1/L2 nodes) of at least one FR cluster that are to be traversed (e.g., from the head L2 node to the tail L2 node). Additionally, or alternatively, the path communication request may indicate that the path is to traverse at least one particular FR cluster of the IS-IS FR network and/or that the path is to not traverse at least one particular FR cluster of the IS-IS FR network. In some implementations, the path communication request may be a path computation element protocol (PCEP) message (e.g., where the PCEP is extended to support a message that requests traversal across at least one particular FR in the path, and requests inclusions and/or exclusions of at least one particular FR cluster in the path).

As shown by reference number104, the path computation node may determine (e.g., based on the path communication request, such as based on the path communication request indicating that the path is to traverse at least one FR cluster of the IS-IS FR network) an end-to-end path (e.g., from the head L2 node to the tail L2 node). For example, the path computation node may process one or more topologies of the IS-IS FR network (e.g., one or more of the plurality of intra-FR topologies, the inter-FR topology, and/or the overall topology) to determine the end-to-end path. In some implementations, the end-to-end path may traverse one or more FR clusters of the IS-IS FR network. For example, for each FR cluster of the one or more FR clusters, the end-to-end path may traverse one or more L1 links (e.g., between L1 nodes and/or L1/L2 nodes) within the FR cluster. In this way, the end-to-end path may be referred to as including one or more L1 paths (e.g., comprising one or more L1 links within the one or more FR clusters).

In some implementations, when the communication request indicates that the path is to traverse at least one particular FR cluster, the end-to-end path may traverse the at least one particular FR cluster. Additionally, or alternatively, when the communication request indicates that the path is to not traverse at least one particular FR cluster, the end-to-end path may not traverse the at least one particular FR cluster (e.g., the end-to-end path may not traverse any L1 links within the at least one particular FR cluster).

As shown by reference number106, the path computation node may send the end-to-end path (e.g., from the head L2 node to the tail L2 node) to the head L2 node (e.g., in response to the path computation request). The path computation node may send the end-to-end path to the head L2 node via the link between the head L2 node and the path computation node. Accordingly, the head L2 node may receive the end-to-end path from the path computation node (e.g., via the link).

In this way (e.g., by communicating with the path computation node), the head L2 node may determine the end-to-end path. For example, to determine the end-to-end path, the head L2 node may send the path computation request to the path computation node, and may receive (e.g., based on sending the path computation request) the end-to-end path from the path computation node.

As shown by reference number108, the head L2 node may send information associated with the end-to-end path to another node identified in the end-to-end path (e.g., a next-hop node from the head L2 node in the end-to-end path, shown as the L1/L2 node21). The head L2 node may send the information associated with the end-to-end path to the other node via a link (e.g., an L2 link) between the head L2 node and the other node. Accordingly, the other node may receive the information associated with the end-to-end path from the head L2 node (e.g., via the link).

Sending the information associated with the end-to-end path to the other node may cause an LSP to be established (e.g., from the head L2 node to the tail L2 node, such as shown inFIG.1E). For example, the head L2 node may include the information associated with the end-to-end path in an RSVP-TE message and may send the RSVP-TE message to the other node, which allows for an LSP to be established. Accordingly, because the LSP is established based on the end-to-end path, the LSP may traverse one or more FR clusters of the IS-IS FR network (e.g., the same one or more FR clusters that are traversed by the end-to-end path). For example, for each FR cluster of the one or more FR clusters, the LSP may traverse one or more L1 links (e.g., between L1 nodes and/or L1/L2 nodes) within the FR cluster (e.g., the same one or more L1 links within the FR cluster that are traversed by the end-to-end path). In this way, the LSP may be referred to as including one or more L1 paths (e.g., within the one or more FR clusters).

As an alternative to the operations shown inFIG.1B, one or more of the operations shown inFIG.1Cmay be performed by the head L2 node and/or one or more other nodes of the IS-IS FR network.

As shown inFIG.1C, and by reference number110, the head L2 node may determine an end-to-end path from the head L2 node to the tail L2 node (e.g., instead of communicating with a path computation node). In some implementations, because the head L2 node is an L2 node, the head L2 node may be configured to communicate (e.g., using a communication protocol, such as BGP-LS) with the other L2 nodes and the L1/L2 nodes of the IS-IS FR network. Accordingly, the head L2 node may determine an inter-FR topology of the L2 nodes and the L1/L2 nodes of the IS-IS FR network (e.g., an L2 topology of the IS-IS FR network), and may thereby determine the end-to-end path.

The end-to-end path may traverse L2 nodes and/or L1/L2 nodes of the IS-IS FR network. In some implementations, the end-to-end path may identify a set of two or more L1/L2 nodes that are associated with a particular FR cluster of the IS-IS FR network and that are connected by one or more L2 FR links. In a specific example, the head L2 node (e.g., the L2 node11) may determine an end-to-end path to the tail L2 node (e.g., the L2 node18), where the end-to-end path identifies (e.g., in a traversal sequence) L1/L2 node21, L1/L2 node42, L1/L2 node24, L2 node13, L1/L2 node51, L1/L2 node71, L1/L2 node54, L2 node16, L1/L2 node81, L1/L2 node2, L1/L2 node83, and L2 node18. The L1/L2 node21, the L1/L2 node42, and the L1/L2 node24are included in the FR cluster A and connected by first L2 FR links; the L1/L2 node51, the L1/L2 node71, and the L1/L2 node54are included in the FR cluster B and connected by second L2 FR links; and the L1/L2 node81, the L1/L2 node2, and the L1/L2 node83are included in the FR cluster C and connected by third L2 FR links.

As shown by reference number112, the head L2 node may send information associated with the end-to-end path to another node identified in the end-to-end path (e.g., a next-hop node from the head L2 node in the end-to-end path). The head L2 node may send the information associated with the end-to-end path to the other node via a link (e.g., an L2 link) between the head L2 node and the other node. Accordingly, the other node may receive the information associated with the end-to-end path from the head L2 node (e.g., via the link). With respect to the specific example, as shown inFIG.1C, the head L2 node (e.g., the L2 node11) may send the information associated with the end-to-end path to the L1/L2 node21(e.g., because the L1/L2 node21is the next-hop node from the head L2 node in the end-to-end path).

The information associated with the end-to-end path may indicate the nodes of the end-to-end path, and may include additional information, such as whether consecutive L1/L2 nodes are connected by an L2 FR link (e.g., which indicates that the consecutive L1/L2 nodes are in the same FR cluster). Accordingly, the information associated with the end-to-end path may indicate a set of two or more L1/L2 nodes and that the set of two more L1/L2 nodes are connected by the one or more L2 FR links (e.g., within an FR cluster). Further, the information associated with the end-to-end path may indicate that a path between consecutive L1/L2 nodes of the set of two or more L1/L2 nodes, within the end-to-end path, is to be expanded (e.g., to allow traversal via one or more L1 nodes of the FR cluster between the consecutive L1/L2 nodes). For example, the information associated with the end-to-end path may include a flag (e.g., a hop-attribute flag) to indicate a hop expansion for an L1/L2 node and/or a flag indicating that the L1/L2 node is an ingress node or an egress node of an FR cluster. The RSVP-TE protocol may be extended to provide such functionality (e.g., within explicit route objects (EROs) and record route objects (RROs)).

Sending the information associated with the end-to-end path to the other node (e.g., the L1/L2 node21) may cause an LSP to be established (e.g., from the head L2 node to the tail L2 node, such as shown inFIG.1E). For example, the head L2 node may include the information associated with the end-to-end path in an RSVP-TE message and may send the RSVP-TE message to the other node, which allows for an LSP to be established.

As shown by reference number114, sending the information associated with the end-to-end path to the other node allows an ingress L1/L2 node (e.g., of a set of two or more L1/L2 nodes that are associated with a particular FR cluster of the IS-IS FR network and that are connected by one or more L2 FR links) to determine an L1 path from the ingress L1/L2 node to an egress L1/L2 node (e.g., of the set of two or more L1/L2 nodes), via a set of one or more L1 links of the particular FR cluster. For example, because the ingress L1/L2 node of the particular FR cluster is an L1/L2 node, the ingress L1/L2 node may be configured to communicate (e.g., using a communication protocol, such as BGP-LS) with the L1 nodes and the other L1/L2 nodes of the particular FR cluster. Accordingly, the ingress L1/L2 node may determine an intra-FR topology of the L1 nodes and the L1/L2 nodes of the particular FR cluster (e.g., an L1 topology of the particular FR cluster), and may thereby determine the L1 path (e.g., that comprises one or more L1 links from the ingress L1/L2 node to the egress L1/L2 node).

As shown by reference number116, the ingress L1/L2 node may therefore modify the information associated with the end-to-end path to indicate the L1 path. For example, the ingress L1/L2 node may remove all L1/L2 nodes, from the ingress L1/L2 node to the egress L1/L2 node of the particular FR cluster, from the information associated with the end-to-end path, and may include the L1 path (e.g., in the place of the removed L1/L2 nodes).

With respect to the specific example, as shown inFIG.1C, the L1/L2 node21, which received the information associated with the end-to-end path from the head L2 node (e.g., the L2 node11), is an ingress L1/L2 node for the FR cluster A. Accordingly, the L1/L2 node21may determine an L1 path from the L1/L2 node21to the L1/L2 node24(e.g., the egress L1/L2 node of the FR cluster A, as indicated in the information associated with the end-to-end path). The L1 path may traverse, for example, L1 node32, L1/L2 node42, L1 node34, and L1/L2 node24(e.g., via L1 links). The L1/L2 node21may therefore modify the information associated with the end-to-end path to indicate the L1 path. For example, the L1/L2 node21may remove L1/L2 nodes21,42, and24from the end-to-end path (e.g., that includes a traversal sequence of L1/L2 node21, L1/L2 node42, L1/L2 node24, L2 node13, L1/L2 node51, L1/L2 node71, L1/L2 node54, L2 node16, L1/L2 node81, L1/L2 node2, L1/L2 node83, and L2 node18), and may include the L1 path (e.g., in place of the removed L1/L2 nodes). Accordingly, the information associated with the end-to-end path may indicate a traversal sequence, from the L1/L2 node21, of L1 node32, L1/L2 node42, L1 node34, L1/L2 node24, L2 node13, L1/L2 node51, L1/L2 node71, L1/L2 node54, L2 node16, L1/L2 node81, L1/L2 node2, L1/L2 node83, and L2 node18.

The ingress L1/L2 node may then send (e.g., after modifying the information associated with the end-to-end path) the information associated with the end-to-end path to another node identified in the end-to-end path (e.g., a next-hop node from ingress L1/L2 node in the end-to-end path). With respect to the specific example, as shown inFIG.1C, the L1/L2 node21may send the information associated with the end-to-end path to the L1 node32(e.g., because the L1 node32is the next-hop node from the L1/L2 node21in the end-to-end path). In this way, the ingress L1/L2 node facilitates establishment of the LSP (e.g., because the information associated with the end-to-end path may be iteratively passed to a next-hop node in the end-to-end path, where an ingress L1/L2 node of an FR cluster modifies the information associated with the end-to-end path to indicate an L1 path through the FR cluster).

Accordingly, because the LSP is established based on the end-to-end path (e.g., that is modified by ingress L1/L2 nodes of FR clusters to traverse the FR clusters), the LSP may traverse one or more FR clusters of the IS-IS FR network. For example, for each FR cluster of the one or more FR clusters, the LSP may traverse one or more L1 links (e.g., between L1 nodes and/or L1/L2 nodes) within the FR cluster (e.g., an L1 path determined by the ingress L1/L2 node of the FR cluster). In this way, the LSP may be referred to as including one or more L1 paths (e.g., within the one or more FR clusters).

As an alternative to the operations shown inFIGS.1B and1C, one or more of the operations shown inFIG.1Dmay be performed by the head L2 node and/or one or more other nodes of the IS-IS FR network.

As shown inFIG.1D, and by reference number118, the head L2 node may determine an end-to-end path from the head L2 node to the tail L2 node (e.g., instead of communicating with a path computation node). In some implementations, because the head L2 node is an L2 node, the head L2 node may be configured to communicate (e.g., using a communication protocol, such as BGP-LS) with the other L2 nodes and the L1/L2 nodes of the IS-IS FR network. Accordingly, the head L2 node may determine an inter-FR topology of the L2 nodes and the L1/L2 nodes of the IS-IS FR network (e.g., an L2 topology of the IS-IS FR network), and may thereby determine the end-to-end path.

The end-to-end path may traverse one or more L2 nodes and/or one or more FR clusters of the IS-IS FR network. That is, the end-to-end path may identify one or more particular L2 nodes and/or one or more particular FR clusters (but not L1 nodes or L1/L2 nodes of the particular clusters). In a specific example, the head L2 node (e.g., the L2 node11) may determine an end-to-end path to the tail L2 node (e.g., the L2 node18), where the end-to-end path identifies (e.g., in a traversal sequence) FR cluster A, FR cluster B, FR cluster C, and L2 node18.

As shown by reference number120, the head L2 node may send information associated with the end-to-end path to another node identified in the end-to-end path (e.g., a next-hop node from the head L2 node in the end-to-end path). The head L2 node may send the information associated with the end-to-end path to the other node via a link (e.g., an L2 link) between the head L2 node and the other node. Accordingly, the other node may receive the information associated with the end-to-end path from the head L2 node (e.g., via the link). With respect to the specific example, as shown inFIG.1D, the head L2 node (e.g., the L2 node11) may send the information associated with the end-to-end path to the L1/L2 node21(e.g., because the end-to-end path indicates that the FR cluster A is a next hop, and the L1/L2 node21is an ingress L1/L2 node of the FR cluster A).

The information associated with the end-to-end path may indicate the one or more L2 nodes and/or one or more FR clusters of the end-to-end path, and may include additional information, such as whether the end-to-end path includes FR clusters (e.g., a path-attribute flag) and whether a particular hop in the end-to-end path is an L2 node or an FR cluster (e.g., as a hop-attribute flag). The PCEP and RSVP-TE protocols may be extended to provide such functionality (e.g., within node capability signaling, and/or within EROs and RROs).

In some implementations, sending the information associated with the end-to-end path to the other node (e.g., the L1/L2 node21) may cause an LSP to be established (e.g., from the head L2 node to the tail L2 node, such as shown inFIG.1E). For example, the head L2 node may include the information associated with the end-to-end path in an RSVP-TE message and may send the RSVP-TE message to the other node, which allows for an LSP to be established.

As shown by reference number122, sending the information associated with the end-to-end path to the other node allows an ingress L1/L2 node of a particular FR cluster to determine an L1 path from the ingress L1/L2 node to an egress L1/L2 node of the particular FR cluster via a set of one or more L1 links of the particular FR cluster. For example, because the ingress L1/L2 node of the particular FR cluster is an L1/L2 node, the ingress L1/L2 node may be configured to communicate (e.g., using a communication protocol, such as BGP-LS) with the L1 nodes and the other L1/L2 nodes of the particular FR cluster. Accordingly, the ingress L1/L2 node may determine an intra-FR topology of the L1 nodes and the L1/L2 nodes of the particular FR cluster (e.g., an L1 topology of the particular FR cluster), and may thereby determine the L1 path (e.g., that comprises one or more L1 links from the ingress L1/L2 node to the egress L1/L2 node).

As shown by reference number124, the ingress L1/L2 node may therefore modify the information associated with the end-to-end path to indicate the L1 path. For example, the ingress L1/L2 node may remove the particular FR cluster from the information associated with the end-to-end path, and may include the L1 path (e.g., in the place of the particular FR cluster that has been removed).

Additionally, the ingress L1/L2 node may determine an L2 path from the egress L1/L2 node of the particular FR cluster to another FR cluster (e.g., when the next-hop in the end-to-end path, after the L1 path, is the other FR cluster) via a set of one or more L2 links between the particular FR cluster and the other FR cluster. For example, because the ingress L1/L2 node of the particular FR cluster is an L1/L2 node, the ingress L1/L2 node may be configured to communicate (e.g., using a communication protocol, such as BGP-LS) with the L2 nodes and the other L1/L2 nodes of the IS-IS FR network. Accordingly, the ingress L1/L2 node may determine an inter-FR topology of the L2 nodes and the L1/L2 nodes of the IS-IS FR network (e.g., an L2 topology of the IS-IS FR network), and may thereby determine the L2 path (e.g., that comprises one or more L2 links from the egress L1/L2 node of the particular FR cluster to an ingress L1/L2 node of the other FR cluster).

The ingress L1/L2 node may therefore modify the information associated with the end-to-end path to indicate the L2 path. For example, the ingress L1/L2 node may append the L2 path to the L1 path, such that the end-to-end path indicates, in a traversal sequence, the L1 path and then the L2 path.

With respect to the specific example, as shown inFIG.1D, the L1/L2 node21, which received the information associated with the end-to-end path from the head L2 node (e.g., the L2 node11), is an ingress L1/L2 node for the FR cluster A. Accordingly, the L1/L2 node21may determine an L1 path from the L1/L2 node21to the L1/L2 node24(e.g., the egress L1/L2 node of the FR cluster A). The L1 path may traverse, for example, L1 node32, L1/L2 node42, L1 node34, and L1/L2 node24(e.g., via L1 links). The L1/L2 node21may therefore modify the information associated with the end-to-end path to indicate the L1 path. For example, the L1/L2 node21may remove FR cluster A from the end-to-end path (e.g., that includes a traversal sequence of FR cluster A, FR cluster B, FR cluster C, and L2 node18), and may include the L1 path (e.g., in place of the removed FR cluster A). Accordingly, the information associated with the end-to-end path may indicate a traversal sequence, from the L1/L2 node21, of L1 node32, L1/L2 node42, L1 node34, L1/L2 node24, FR cluster B, FR cluster C, and L2 node18.

Additionally, the L1/L2 node21may determine an L2 path from the L1/L2 node24(e.g., the egress L1/L2 node of the FR cluster A) to the L1/L2 node51(e.g., the ingress L1/L2 node of the FR cluster B). The L2 path may traverse, for example, L2 node13and L1/L2 node51(e.g., via L2 links). The L1/L2 node21may therefore modify the information associated with the end-to-end path to indicate the L2 path. For example, the L1/L2 node21may append the L2 path to the L1 path, such that the information associated with the end-to-end path may indicate a traversal sequence, from the L1/L2 node21, of L1 node32, L1/L2 node42, L1 node34, L1/L2 node24, L2 node13, L1/L2 node51, FR cluster B, FR cluster C, and L2 node18.

The ingress L1/L2 node may then send (e.g., after modifying the information associated with the end-to-end path) the information associated with the end-to-end path to another node identified in the end-to-end path (e.g., a next-hop node from the ingress L1/L2 node in the end-to-end path). With respect to the specific example, as shown inFIG.1Dthe L1/L2 node21may send the information associated with the end-to-end path to the L1 node32(e.g., because the L1 node32is the next-hop node from the L1/L2 node21in the end-to-end path). In this way, the ingress L1/L2 facilitates establishment of the LSP (e.g., because the information associated with the end-to-end path may be iteratively passed to a next-hop node in the end-to-end path, where an ingress L1/L2 node of an FR cluster modifies the information associated with the end-to-end path to indicate an L1 path through the FR cluster and/or to indicate an L2 path from the FR cluster to another FR cluster).

Accordingly, because the LSP is established based on the end-to-end path (e.g., that is modified by ingress L1/L2 nodes of FR clusters to traverse the FR clusters), the LSP may traverse one or more FR clusters of the IS-IS FR network. For example, for each FR cluster of the one or more FR clusters, the LSP may traverse one or more L1 links (e.g., between L1 nodes and/or L1/L2 nodes) within the FR cluster (e.g., an L1 path determined by the ingress L1/L2 node of the FR cluster). In this way, the LSP may be referred to as including one or more L1 paths (e.g., within the one or more FR clusters).

FIG.1Eshows an example LSP that may be established by any of the respective operations described herein in relation toFIGS.1B,1C, and1D. As shown inFIG.1E, the LSP may extend from a head L2 node (e.g., the L2 node11) to a tail L2 node (e.g., the L2 node18), wherein the LSP traverses one or more FR clusters (e.g., traverses one or more L1 links within each of the one or more FR clusters).

As indicated above,FIGS.1A-1Eare provided as an example. Other examples may differ from what is described with regard toFIGS.1A-1E. The number and arrangement of devices shown inFIGS.1A-1Eare provided as an example. In practice, there may be additional devices, fewer devices, different devices, or differently arranged devices than those shown inFIGS.1A-1E. Furthermore, two or more devices shown inFIGS.1A-1Emay be implemented within a single device, or a single device shown inFIGS.1A-1Emay be implemented as multiple, distributed devices. Additionally, or alternatively, a set of devices (e.g., one or more devices) shown inFIGS.1A-1Emay perform one or more functions described as being performed by another set of devices shown inFIGS.1A-1E.

FIG.2is a diagram of an example environment200in which systems and/or methods, described herein, may be implemented. As shown inFIG.2, environment200may include a group of nodes210(shown as node210-1through node210-N), and a network220. Devices of environment200may interconnect via wired connections, wireless connections, or a combination of wired and wireless connections.

The node210includes one or more devices capable of receiving, processing, storing, routing, and/or providing information, such as information described herein. For example, the node210may include a router, such as a label switching router (LSR), a label edge router (LER), an ingress router, an egress router, a provider router (e.g., a provider edge router, a provider core router, etc.), a virtual router, and/or the like. Additionally, or alternatively, the node210may include a gateway, a switch, a firewall, a hub, a bridge, a reverse proxy, a server (e.g., a proxy server, a cloud server, a data center server, etc.), a load balancer, and/or a similar device. In some implementations, the node210may be a physical device implemented within a housing, such as a chassis. In some implementations, the node210may be a virtual device implemented by one or more computer devices of a cloud computing environment or a data center. In some implementations, a group of nodes210may be a group of data center nodes that are used to route traffic flow through network220. In some implementations, the node210may be an L1 node, an L2 node, or an L1/L2 node (e.g., when the network220includes an IS-IS FR network).

The network220includes one or more wired and/or wireless networks. For example, the network220may include an IS-IS FR network, a packet switched network, a cellular network (e.g., a fifth generation (5G) network, a fourth generation (4G) network, such as a long-term evolution (LTE) network, a third generation (3G) network, a code division multiple access (CDMA) network), a public land mobile network (PLMN), a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), a telephone network (e.g., the Public Switched Telephone Network (PSTN)), a private network, an ad hoc network, an intranet, the Internet, a fiber optic-based network, a cloud computing network, or the like, and/or a combination of these or other types of networks.

The number and arrangement of devices and networks shown inFIG.2are provided as an example. In practice, there may be additional devices and/or networks, fewer devices and/or networks, different devices and/or networks, or differently arranged devices and/or networks than those shown inFIG.2. Furthermore, two or more devices shown inFIG.2may be implemented within a single device, or a single device shown inFIG.2may be implemented as multiple, distributed devices. Additionally, or alternatively, a set of devices (e.g., one or more devices) of environment200may perform one or more functions described as being performed by another set of devices of environment200.

FIG.3is a diagram of example components of a device300associated with RSVP-TE path computation across FR clusters of an IS-IS FR network. The device300may correspond to node210. In some implementations, node210may include one or more devices300and/or one or more components of the device300. As shown inFIG.3, the device300may include a bus310, a processor320, a memory330, an input component340, an output component350, and/or a communication component360.

The bus310may include one or more components that enable wired and/or wireless communication among the components of the device300. The bus310may couple together two or more components ofFIG.3, such as via operative coupling, communicative coupling, electronic coupling, and/or electric coupling. For example, the bus310may include an electrical connection (e.g., a wire, a trace, and/or a lead) and/or a wireless bus. The processor320may include a central processing unit, a graphics processing unit, a microprocessor, a controller, a microcontroller, a digital signal processor, a field-programmable gate array, an application-specific integrated circuit, and/or another type of processing component. The processor320may be implemented in hardware, firmware, or a combination of hardware and software. In some implementations, the processor320may include one or more processors capable of being programmed to perform one or more operations or processes described elsewhere herein.

The memory330may include volatile and/or nonvolatile memory. For example, the memory330may include random access memory (RAM), read only memory (ROM), a hard disk drive, and/or another type of memory (e.g., a flash memory, a magnetic memory, and/or an optical memory). The memory330may include internal memory (e.g., RAM, ROM, or a hard disk drive) and/or removable memory (e.g., removable via a universal serial bus connection). The memory330may be a non-transitory computer-readable medium. The memory330may store information, one or more instructions, and/or software (e.g., one or more software applications) related to the operation of the device300. In some implementations, the memory330may include one or more memories that are coupled (e.g., communicatively coupled) to one or more processors (e.g., processor320), such as via the bus310. Communicative coupling between a processor320and a memory330may enable the processor320to read and/or process information stored in the memory330and/or to store information in the memory330.

The input component340may enable the device300to receive input, such as user input and/or sensed input. For example, the input component340may include a touch screen, a keyboard, a keypad, a mouse, a button, a microphone, a switch, a sensor, a global positioning system sensor, a global navigation satellite system sensor, an accelerometer, a gyroscope, and/or an actuator. The output component350may enable the device300to provide output, such as via a display, a speaker, and/or a light-emitting diode. The communication component360may enable the device300to communicate with other devices via a wired connection and/or a wireless connection. For example, the communication component360may include a receiver, a transmitter, a transceiver, a modem, a network interface card, and/or an antenna.

The device300may perform one or more operations or processes described herein. For example, a non-transitory computer-readable medium (e.g., memory330) may store a set of instructions (e.g., one or more instructions or code) for execution by the processor320. The processor320may execute the set of instructions to perform one or more operations or processes described herein. In some implementations, execution of the set of instructions, by one or more processors320, causes the one or more processors320and/or the device300to perform one or more operations or processes described herein. In some implementations, hardwired circuitry may be used instead of or in combination with the instructions to perform one or more operations or processes described herein. Additionally, or alternatively, the processor320may be configured to perform one or more operations or processes described herein. Thus, implementations described herein are not limited to any specific combination of hardware circuitry and software.

The number and arrangement of components shown inFIG.3are provided as an example. The device300may include additional components, fewer components, different components, or differently arranged components than those shown inFIG.3. Additionally, or alternatively, a set of components (e.g., one or more components) of the device300may perform one or more functions described as being performed by another set of components of the device300.

FIG.4is a diagram of example components of a device400associated with RSVP-TE path computation across FR clusters of an IS-IS FR network. Device400may correspond to node210. In some implementations, node210may include one or more devices400and/or one or more components of device400. As shown inFIG.4, device400may include one or more input components410-1through410-B (B≥1) (hereinafter referred to collectively as input components410, and individually as input component410), a switching component420, one or more output components430-1through430-C (C≥1) (hereinafter referred to collectively as output components430, and individually as output component430), and a controller440.

Input component410may be one or more points of attachment for physical links and may be one or more points of entry for incoming traffic, such as packets. Input component410may process incoming traffic, such as by performing data link layer encapsulation or decapsulation. In some implementations, input component410may transmit and/or receive packets. In some implementations, input component410may include an input line card that includes one or more packet processing components (e.g., in the form of integrated circuits), such as one or more interface cards (IFCs), packet forwarding components, line card controller components, input ports, processors, memories, and/or input queues. In some implementations, device400may include one or more input components410.

Switching component420may interconnect input components410with output components430. In some implementations, switching component420may be implemented via one or more crossbars, via busses, and/or with shared memories. The shared memories may act as temporary buffers to store packets from input components410before the packets are eventually scheduled for delivery to output components430. In some implementations, switching component420may enable input components410, output components430, and/or controller440to communicate with one another.

Output component430may store packets and may schedule packets for transmission on output physical links. Output component430may support data link layer encapsulation or decapsulation, and/or a variety of higher-level protocols. In some implementations, output component430may transmit packets and/or receive packets. In some implementations, output component430may include an output line card that includes one or more packet processing components (e.g., in the form of integrated circuits), such as one or more IFCs, packet forwarding components, line card controller components, output ports, processors, memories, and/or output queues. In some implementations, device400may include one or more output components430. In some implementations, input component410and output component430may be implemented by the same set of components (e.g., and input/output component may be a combination of input component410and output component430).

Controller440includes a processor in the form of, for example, a CPU, a graphics processing unit (GPU), an accelerated processing unit (APU), a microprocessor, a microcontroller, a digital signal processor (DSP), a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), and/or another type of processor. The processor is implemented in hardware, firmware, or a combination of hardware and software. In some implementations, controller440may include one or more processors that can be programmed to perform a function.

In some implementations, controller440may include a RAM, a ROM, and/or another type of dynamic or static storage device (e.g., a flash memory, a magnetic memory, an optical memory, etc.) that stores information and/or instructions for use by controller440.

In some implementations, controller440may communicate with other devices, networks, and/or systems connected to device400to exchange information regarding network topology. Controller440may create routing tables based on the network topology information, may create forwarding tables based on the routing tables, and may forward the forwarding tables to input components410and/or output components430. Input components410and/or output components430may use the forwarding tables to perform route lookups for incoming and/or outgoing packets.

Controller440may perform one or more processes described herein. Controller440may perform these processes in response to executing software instructions stored by a non-transitory computer-readable medium. A computer-readable medium is defined herein as a non-transitory memory device. A memory device includes memory space within a single physical storage device or memory space spread across multiple physical storage devices.

Software instructions may be read into a memory and/or storage component associated with controller440from another computer-readable medium or from another device via a communication interface. When executed, software instructions stored in a memory and/or storage component associated with controller440may cause controller440to perform one or more processes described herein. Additionally, or alternatively, hardwired circuitry may be used in place of or in combination with software instructions to perform one or more processes described herein. Thus, implementations described herein are not limited to any specific combination of hardware circuitry and software.

The number and arrangement of components shown inFIG.4are provided as an example. In practice, device400may include additional components, fewer components, different components, or differently arranged components than those shown inFIG.4. Additionally, or alternatively, a set of components (e.g., one or more components) of device400may perform one or more functions described as being performed by another set of components of device400.

FIG.5is a flowchart of an example process500associated with RSVP-TE path computation across FR clusters of an IS-IS FR network. In some implementations, one or more process blocks ofFIG.5are performed by a head L2 node (e.g., a node210configured as a head L2 node) of an IS-IS FR network. In some implementations, one or more process blocks ofFIG.5are performed by another device or a group of devices separate from or including the network device, such as another node (e.g., that is configured as an L1 node, an L2 node, or an L1/L2 node) of the IS-IS FR network. Additionally, or alternatively, one or more process blocks of FIG.5may be performed by one or more components of device300, such as processor320, memory330, input component340, output component350, and/or communication component360; one or more components of device400, such as input component410, switching component420, output components430, and/or controller440; and/or one or more other components.

As shown inFIG.5, process500may include determining an end-to-end path from the head L2 node to a tail L2 node of the IS-IS FR network (block510). For example, the head L2 node may determine an end-to-end path from the head L2 node to a tail L2 node of the IS-IS FR network, as described above. In some implementations, the IS-IS FR network includes a plurality of L2 nodes and a plurality of FR clusters that each comprise a plurality L1 nodes and a plurality of L1/L2 nodes connected by a plurality of L1 links.

As further shown inFIG.5, process500may include sending information associated with the end-to-end path to another node identified in the end-to-end path (block520). For example, the head L2 node may send information associated with the end-to-end path to another node identified in the end-to-end path, as described above. In some implementations, this causes an LSP to be established from the head L2 node to the tail L2 node, wherein the LSP traverses one or more L1 links within an FR cluster of the IS-IS FR network.

Process500may include additional implementations, such as any single implementation or any combination of implementations described below and/or in connection with one or more other processes described elsewhere herein.

In a first implementation, the end-to-end path identifies a set of two or more L1/L2 nodes that are associated with a particular FR cluster of the IS-IS FR network and that are connected by one or more L2 FR links, and the information associated with the end-to-end path indicates the set of two or more L1/L2 nodes and that the set of two more L1/L2 nodes are connected by the one or more L2 FR links.

In a second implementation, alone or in combination with the first implementation, sending the information associated with the end-to-end path to the other node allows an ingress L1/L2 node, of the set of two or more L1/L2 nodes, to determine an L1 path from the ingress L1/L2 node to an egress L1/L2 node, of the set of two or more L1/L2 nodes, via a set of one or more L1 links of the particular FR cluster, modify the information associated with the end-to-end path to indicate the L1 path, and send the information associated with the end-to-end path to a node of the L1 path to facilitate establishment of the LSP from the head L2 node to the tail L2 node.

In a third implementation, alone or in combination with one or more of the first and second implementations, the end-to-end path identifies a particular FR cluster of the IS-IS FR network, and the information associated with the end-to-end path indicates the particular FR cluster.

In a fourth implementation, alone or in combination with one or more of the first through third implementations, sending the information associated with the end-to-end path to the other node allows an ingress L1/L2 node of the particular FR cluster to determine an L1 path from the ingress L1/L2 node to an egress L1/L2 node, of the particular FR, via a set of one or more L1 links of the particular FR cluster, modify the information associated with the end-to-end path to indicate the L1 path, and send the information associated with the end-to-end path to a node of the L1 path to facilitate establishment of the LSP from the head L2 node to the tail L2 node.

In a fifth implementation, alone or in combination with one or more of the first through fourth implementations, determining the end-to-end path comprises sending, to a path computation node associated with the IS-IS FR network, a path computation request for a path from the head L2 node to the tail L2 node, and receiving, based on sending the path computation request, the end-to-end path from the path computation node, wherein the end-to-end path traverses the one or more L1 links within the FR cluster that are traversed by the LSP.

In a sixth implementation, alone or in combination with one or more of the first through fifth implementations, the path computation request indicates that the path is to traverse at least one FR cluster of the IS-IS FR network.

In a seventh implementation, alone or in combination with one or more of the first through sixth implementations, the path computation request indicates that the path is to traverse at least one particular FR cluster of the IS-IS FR network, including the FR cluster.

In an eighth implementation, alone or in combination with one or more of the first through seventh implementations, the path computation request indicates that the path is to not traverse at least one particular FR cluster of the IS-IS FR network, and the end-to-end path does not traverse any L1 links within the at least one particular FR cluster.

AlthoughFIG.5shows example blocks of process500, in some implementations, process500includes additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted inFIG.5. Additionally, or alternatively, two or more of the blocks of process500may be performed in parallel.

The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementations to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the implementations.

As used herein, the term “component” is intended to be broadly construed as hardware, firmware, or a combination of hardware and software. It will be apparent that systems and/or methods described herein may be implemented in different forms of hardware, firmware, and/or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and/or methods is not limiting of the implementations. Thus, the operation and behavior of the systems and/or methods are described herein without reference to specific software code-it being understood that software and hardware can be used to implement the systems and/or methods based on the description herein.

Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various implementations. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various implementations includes each dependent claim in combination with every other claim in the claim set. As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiple of the same item.

When “a processor” or “one or more processors” (or another device or component, such as “a controller” or “one or more controllers”) is described or claimed (within a single claim or across multiple claims) as performing multiple operations or being configured to perform multiple operations, this language is intended to broadly cover a variety of processor architectures and environments. For example, unless explicitly claimed otherwise (e.g., via the use of “first processor” and “second processor” or other language that differentiates processors in the claims), this language is intended to cover a single processor performing or being configured to perform all of the operations, a group of processors collectively performing or being configured to perform all of the operations, a first processor performing or being configured to perform a first operation and a second processor performing or being configured to perform a second operation, or any combination of processors performing or being configured to perform the operations. For example, when a claim has the form “one or more processors to: perform X; perform Y; and perform Z,” that claim should be interpreted to mean “one or more processors to perform X; one or more (possibly different) processors to perform Y; and one or more (also possibly different) processors to perform Z.”

No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more.” Further, as used herein, the article “the” is intended to include one or more items referenced in connection with the article “the” and may be used interchangeably with “the one or more.” Furthermore, as used herein, the term “set” is intended to include one or more items (e.g., related items, unrelated items, or a combination of related and unrelated items), and may be used interchangeably with “one or more.” Where only one item is intended, the phrase “only one” or similar language is used. Also, as used herein, the terms “has,” “have,” “having,” or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Also, as used herein, the term “or” is intended to be inclusive when used in a series and may be used interchangeably with “and/or,” unless explicitly stated otherwise (e.g., if used in combination with “either” or “only one of”).