Cisco Technology, Inc.

Cisco Systems Inc.

Arjen Boers

Ijsbrand Wijnands

Toerless Eckert

Yiqun Cai

Alton Lo

Lorenzo Vicisano

Daniel A Alvarez

Stefano Benedetto Previdi

Dino Farinacci

Jacob Ijsbrand Wijnands

John S Meylor

Nidhi Bhaskar

Eric C Rosen

Luca Martini

Christopher Metz

Giovanni Meo

Tony Speakman

Swapna Yelamanchi

A method is provided for pruning an MP2MP tree. The method includes, in a first node of an MP2MP LSP tree, determining whether the first node has only a single replication branch for the MP2MP LSP tree, the single replication branch representing a downstream path to only a second node of the plurality of nodes. In response to determining that the first node has only a single replication branch for the MP2MP LSP tree, sending a message to the second node indicating that the second node should refrain from sending upstream traffic towards the first node, and in response to determining that the first node does not have only a single replication branch for the MP2MP LSP tree, refraining from sending a message to the second node indicating that the second node should refrain from sending upstream traffic of the MP2MP LSP tree towards the first node.

Preventing traffic flooding to the root of a multi-point to multi-point label-switched path tree with no receivers

A method of routing multicast traffic in a computer network is disclosed. The method comprises associating a plurality of multicast group addresses on a network device with respective multicast routing topologies. A network device and a network are also disclosed.

Method of routing multicast traffic

An apparatus and method for emulating a shared or source distribution tree within an MPLS network. In one embodiment of the method, a router receives a multicast data packet. The router transmits the multicast data packet to a first router via a first point-to-point label switched path (LSP). The router replicates the multicast data packet to produce a replicated multicast data packet. Then the router transmits the replicated multicast data packet to a second router via a second point-to-point LSP. The first point-to-point LSP is distinct from the second point-to-point LSP.

PIM sparse-mode emulation over MPLS LSP's

A method, system and an apparatus to transport bidir PIM over a multiprotocol label switched network are provided. The method may comprise receiving a multicast packet at a network element, the multicast packet including an upstream label. The method may further comprise identifying, from the upstream label, a Multicast Distribution Tree (MDT) rooted at a rendezvous point. The packet may be forwarded along the MDT towards the RP based on the upstream label. The MDT may be identified from a downstream label and the packet may be forwarded along the MDT away from the RP based on the downstream label.

Method to transport bidir PIM over a multiprotocol label switched network

An apparatus or method for upstream label allocation on LANs for multipoint (MP) label switched paths (LSPs). In one embodiment of the method, a first router receives a first incoming labeled data packet, wherein the first incoming labeled data packet comprises a first data packet and one or more first labels. The first router creates a first outgoing labeled data packet, wherein creating the first outgoing labeled data packet includes the step of swapping the one or more first labels of the first incoming labeled data packet with a context label and a forwarding label, wherein the first outgoing labeled data packet comprises the first data packet, the context label, and the forwarding label. Ultimately, the first router transmits the first outgoing labeled data packet to second and third routers via a LAN.

Upstream label allocation on ethernets for MP2MP LSPS

A mechanism is provided to configure a plurality of transport trees in a transport network, each of which correspond to a native tree (e.g., a bidirectional multicast tree). In embodiments of the present invention, each of the plurality of transport trees has a unique root node so that in the event of a failure of any root node, the transport trees with surviving root nodes can be used to transport traffic from the native tree. The present invention provides for each transport network edge router being independently responsible for selection of a transport tree that the edge router will use to transmit a datastream, while also being capable of receiving packets from any transport tree. Through the use of such configured transport trees along with independent selection of a transport tree, the present invention provides a reduction in the disruption of datastream transmission due to a root node failure.

Root node redundancy for multipoint-to-multipoint transport trees

A method of using a point-to-point (P2P) label switched path (LSP) to transmit multicast data packets partially through a multiprotocol label switched (MPLS) network when one or more label switched routers (LSRs) of the MPLS are not multicast label distribution protocol (mLDP) enabled. The P2P LSP can be used to transmit multicast data packets to the head end of a point-to-multipoint (P2MP) LSP created with mLDP enabled LSRs. The P2MP LSP can be used to transmit the multicast data packets through the MPLS network to intended receivers that are external to the MPLS network. The P2MP LSP can be built from an egress edge LSR towards an ingress edge LSR, by mLDP enabled LSRs. The P2P LSP can be built from a core mLDP enabled LSR to the ingress edge LSR, across a non-mLDP enabled LSR between the core mLDP enabled LSR and the ingress edge LSR.

Automation fallback to P2P LSPs for MLDP built multipoint-trees

Various devices and methods for implementing multicast over a label-switched core network are disclosed. For example, an edge node can include a physical interface, which is not enabled for multicast, that is configured to be coupled to a core network and a packet rewrite module coupled to the physical interface. The packet rewrite module is configured to encapsulate a multicast packet with a label and to send the encapsulated multicast packet to the physical interface. The label identifies a unicast label switched path (LSP) through the core network. The edge node can also include a virtual interface creation configured to create a virtual interface that is enabled for multicast. The packet rewrite module can encapsulate the multicast packet in response to detecting that the multicast packet is being sent via the virtual interface.

System and method for implementing multicast over a label-switched core network

Various techniques for exchanging control messages in order to gracefully reroute multicast traffic are disclosed. For example, one method involves sending a join message for a multicast group towards a root of a new multicast tree and forwarding multicast traffic, addressed to the multicast group, on a current multicast tree until an acknowledgment corresponding to the join message is received. The new multicast tree can be identified in response to detection of a topology change within the network. Until the acknowledgment is received, multicast traffic that is received via the new multicast tree can be dropped.

Acknowledgement-based rerouting of multicast traffic

A method is provided for pruning an MP2MP tree. The method includes (a) in a first node of an MP2MP LSP tree, the MP2MP LSP tree including a plurality of nodes, determining whether the first node has only a single replication branch for the MP2MP LSP tree, the single replication branch representing a downstream path to only a second node of the plurality of nodes, (b) in response to determining that the first node has only a single replication branch for the MP2MP LSP tree, sending a message to the second node indicating that the second node should refrain from sending upstream traffic towards the first node, and (c) in response to determining that the first node does not have only a single replication branch for the MP2MP LSP tree, refraining from sending a message to the second node indicating that the second node should refrain from sending upstream traffic of the MP2MP LSP tree towards the first node. Apparatus are also provided for use in practicing certain embodiments.

A mechanism is provided in which multicast reverse path forwarding can be performed at a provider network egress edge router wherein core routers of the provider network are not configured to support multicast protocols or point-to-multipoint LSPs. An embodiment of the present invention provides for the creation of virtual interfaces in the egress edge router element during configuration of a multicast connection in response to a subscriber request. A virtual interface will be associated with an upstream ingress edge router element and that ingress edge router element is provided a label associated with the virtual interface. Such a label can then be included in datastream packets transmitted through the provider network and be used by reverse path forward checking at the egress edge router element to ascertain whether the multicast datastream is being received by the correct upstream interface.

Transporting multicast over MPLS backbone using virtual interfaces to perform reverse-path forwarding checks

Techniques reliably provide the switchover from a default MDT to the data MDT by using reliable signaling and reliable building of a data MDT. The message notifying of the pending switchover to the data MDT is reliably sent using signaling that is reliable. Also, the switchover from the default MDT to the data MDT does not happen until all egress routers have responded to the message. Egress routers join the data MDT if associated receivers are interested in receiving the multicast stream from a source. The router does not send another response upstream until all egress routers downstream from it respond to the message in the positive or the negative.

Techniques for reliable switchover to a date multicast distribution tree (MDT)

A method is provided in one example embodiment and includes receiving a label-mapping message at a first router. The first router does not record the label-mapping message. The method further includes sending the label mapping message toward a root router of a Multipoint Label Switched Path (MPLSP) in a network and, further, evaluating a path vector sent from the root router to identify whether a first router's address is part of the path vector. If the first router's address is present in the path vector then a label mapping associated with the path vector is not installed by the first router. In more detailed embodiments, the first router identifies that if the first router's address is part of the path vector, a loop is present in the network. If the first router's address is not part of the path vector, the label mapping associated with the path vector is recorded.

Growing community of inventors

Sitges, Spain

Arjen Boers