Telefonaktiebolaget Lm Ericsson (Publ)

Srikanth Narayanan

Sriganesh Kini

Wenhu Lu

Arunkumar M Desigan

Vikram Guleria

Matias Cavuoti

Exemplary techniques for architecture-independent dynamic flow learning in a packet forwarder are described. A packet forwarder includes a plurality of forwarding threads and a plurality of provisioning threads, and can implement three functional blocks to learn new flows&#x2014;an admission control block, a forwarding database building block, and a notification path block. An admission control module can control the ability for forwarding threads to place flow operation requests in operation queues. Provisioning threads independently manage particular operation queues, and can update corresponding portions of a control database and a forwarding database. Flow operation notifications can be managed through notification queues, which can be drained back into the operation queues for the provisioning threads to later process. The packet forwarder thus can benefit from a highly-parallel, highly-efficient software-based approach to flow learning operations that does not require specialized hardware support.

Techniques for architecture-independent dynamic flow learning in a packet forwarder

A first network element in an MPLS network receives a first label advertised from a second network element in the network. The first network element computes a shortest path tree (SPT) to reach a destination network element under a potential failure condition. The second network element is a nexthop of the first network element in the computed SPT and is not upstream from the potential failure condition in the computed SPT. The first network element determines that a third network element in the network is a Point of Local Repair (PLR) when the potential failure condition is realized. The first network element distributes a second label to the third network element for a backup LDP Label Switched Path (LSP) that will serve as a backup path when the potential failure condition is realized. The first network element installs a swap action from the second label to the first label.

MPLS fast re-route using LDP (LDP-FRR)

MPLS (Multiprotocol Label Switching) fast re-routing using LDP (Label Distribution Protocol) is described. A first network element in a MPLS network receives a first label advertised from a second network element in the MPLS network. The first network element computes a shortest path tree (SPT) to reach a destination network element under a potential failure condition. The second network element is a nexthop of the first network element in the computed SPT and is not upstream from the potential failure condition. The first network element advertises a second label to one or more third network elements for a backup LDP LSP (Label Switched Path) that will serve as a backup when the potential failure condition is realized. The third network element(s) are upstream neighbors on the computed SPT with respect to the first network element. The first network element installs a swap action from the second label to the first label.

Computing a constraint-based label switched path (LSP) that spans multiple areas is described. In one embodiment, a router in a first one of the multiple areas computes a path segment that meets a set of one or more constraints to at least one border router of the first area that lies in a path necessary to reach the destination. The router transmits a path computation request message to a path computation element (PCE) in a second one of the areas, which includes a set of one or more attributes for each computed path segment that are used by the PCE to compute one or more path segments towards the destination of the constraint-based LSP. The router receives a path computation reply message from the PCE that specifies a set of one or more computed path segments that meet the set of constraints and that were computed by one or more PCEs downstream from the router. The router stitches at least one of the set of computed path segments that are specified in the path computation reply message with the path segment computed by the router to form at least part of the constraint-based LSP.

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San Jose, CA, United States of America

Srikanth Narayanan