Abstract: Techniques are described for multicast flow prioritization in protocol independent multicast (PIM) networks with multicast flow limits. According to the disclosed techniques, once a router has reached its multicast flow limit, the router may preempt an installed lower priority multicast flow with a newly requested higher priority multicast flow. For example, if a maximum number of multicast flows are installed on the router, then, upon receiving a PIM join for a higher priority flow as compared to the installed flows, the router replaces one of the installed lower priority flows with the received higher priority flow. Furthermore, according to the disclosed techniques, priority values for multicast flows are consistent across a PIM domain and each of the routers within the PIM domain is configured to use the priority values to select a higher priority flow over a lower priority flow.

Abstract: An example method includes exchanging targeted hello messages to establish a targeted neighbor connection between a first routing device and a second routing device, wherein one of the routing devices comprises a central routing device, and wherein another one of the routing devices comprises an ingress routing device. The example method further includes processing a source-active register message that specifies a source address and an identifier that are collectively associated with a multicast stream, and wherein the source-active register message further indicates whether the multicast stream is active or withdrawn.

Abstract: A network device may identify first interfaces used by the network device to communicate with other network devices. The network device may use second interfaces to communicate with multicast receiver devices that are different from the other network devices. The network device may store information that identifies the first interfaces used to communicate with the other network devices. The network device may receive a packet, and may determine that the packet includes a bidirectional forwarding detection message, associated with a bidirectional forwarding detection protocol, to be used to verify multicast connectivity with a multicast source device. The network device may identify the first interfaces based on the stored information and based on determining that the packet includes the bidirectional forwarding detection message, and may transmit the packet via the first interfaces without transmitting the packet via the second interfaces.

Abstract: Techniques are described for multicast flow prioritization in protocol independent multicast (PIM) networks with multicast flow limits. According to the disclosed techniques, once a router has reached its multicast flow limit, the router may preempt an installed lower priority multicast flow with a newly requested higher priority multicast flow. For example, if a maximum number of multicast flows are installed on the router, then, upon receiving a PIM join for a higher priority flow as compared to the installed flows, the router replaces one of the installed lower priority flows with the received higher priority flow. Furthermore, according to the disclosed techniques, priority values for multicast flows are consistent across a PIM domain and each of the routers within the PIM domain is configured to use the priority values to select a higher priority flow over a lower priority flow.

Abstract: Techniques are described for enhancements to multicast Label Distribution Protocol (mLDP) to support multicast only fast re-route (MoFRR) over a remote loop free alternate (RLFA) backup path. An egress router is configured to generate a modified mLDP control message to signal the RLFA backup path in which an address of a RLFA node is included in an LSPRoot field and an address of an ingress router is included in an opaque data field. In addition, the RLFA node of the RLFA backup path is configured to recognize that it is identified in the LSPRoot field of the modified mLDP control message, and, in response, look up the ingress router identified in the opaque data field of the modified mLDP control message. The RLFA node is further configured to send an mLDP control message that includes the address of the ingress router in the LSPRoot field towards the ingress router.

Abstract: An example method includes exchanging targeted hello messages to establish a targeted neighbor connection between a first routing device and a second routing device, wherein one of the routing devices comprises a central routing device, and wherein another one of the routing devices comprises an ingress routing device. The example method further includes processing a source-active register message that specifies a source address and an identifier that are collectively associated with a multicast stream, and wherein the source-active register message further indicates whether the multicast stream is active or withdrawn.

Abstract: A network device may identify first interfaces used by the network device to communicate with other network devices. The network device may use second interfaces to communicate with multicast receiver devices that are different from the other network devices. The network device may store information that identifies the first interfaces used to communicate with the other network devices. The network device may receive a packet, and may determine that the packet includes a bidirectional forwarding detection message, associated with a bidirectional forwarding detection protocol, to be used to verify multicast connectivity with a multicast source device. The network device may identify the first interfaces based on the stored information and based on determining that the packet includes the bidirectional forwarding detection message, and may transmit the packet via the first interfaces without transmitting the packet via the second interfaces.

Abstract: An example method includes exchanging targeted hello messages to establish a targeted neighbor connection between a first routing device and a second routing device, wherein one of the routing devices comprises a central routing device, and wherein another one of the routing devices comprises an ingress routing device. The example method further includes processing a source-active register message that specifies a source address and an identifier that are collectively associated with a multicast stream, and wherein the source-active register message further indicates whether the multicast stream is active or withdrawn.

Abstract: Techniques are described for enhancements to Protocol Independent Multicast (PIM) to enable a last hop router (LHR) to perform source discovery and directly build or join a source tree. According to the techniques of this disclosure, the LHR builds a communication channel with a rendezvous point (RP) router and requests source information for at least one multicast group for which the LHR has interested receivers. The RP responds to the request by looking into a register database maintained by the RP and sending source information indicating at least one source that is actively providing traffic for the at least one multicast group. Based on the response, the LHR initiates a (S,G) PIM Join message toward the at least one source for the at least one multicast group to directly build or join at least one source tree.

Abstract: Techniques are described for providing robust control plane asserts in a network using Protocol Independent Multicast (PIM) or other routing protocols for controlling delivery of multicast traffic. In one example, a router includes a control unit having a hardware-based processor executing a Protocol Independent Multicast (PIM) protocol. The control unit, when executing the PIM protocol, initiates an election process for selecting, from a plurality of routers, a forwarding router to forward multicast traffic to a shared media computer network. In addition, the control unit determines whether the multicast traffic has been received by the router and outputs, in association with the election process, a PIM assert message that includes an indication as to whether the router has successfully received the multicast traffic.

Abstract: Techniques are described for enhancements to Protocol Independent Multicast (PIM) in an Any Source Multicast (ASM) mode in order to effectively implement Multicast only Fast Re-Route (MoFRR). According to the PIM ASM mode, a router operating as a last hop router connected to a receiver may initiate establishment of both a shared tree and a shortest path tree over which to receive multicast traffic for a given multicast group. According to the disclosed techniques, the router may use the shortest path tree as a primary path on which to receive the multicast traffic, and may use the shared tree as a secondary or backup path for MoFRR in case a failure occurs on the primary path. The techniques enable the router to perform MoFRR for PIM ASM mode without pruning the multicast traffic from the shared tree, and without building additional trees as secondary paths for MoFRR.

Abstract: In one example, a method includes exchanging, by a first routing device and with a second routing device, targeted hello messages using a Protocol Independent Multicast (PIM) protocol to establish a targeted neighbor connection between the first routing device and the second routing device, wherein the first routing device exchanges the targeted hello messages with the second routing device via at least one intermediate routing device, and wherein at least one of the first or second routing device comprises a rendezvous point (RP). The example method further includes processing, by the first routing device using the targeted neighbor connection, a register message that includes multicast stream data elements, wherein each multicast stream data element identifies a source address and a group address that are collectively associated with a respective multicast stream, and wherein each multicast stream data element further indicates whether the respective multicast stream is active or withdrawn.

Abstract: Techniques are described for enhancements to multicast Label Distribution Protocol (mLDP) to support multicast only fast re-route (MoFRR) over a remote loop free alternate (RLFA) backup path. An egress router is configured to generate a modified mLDP control message to signal the RLFA backup path in which an address of a RLFA node is included in an LSPRoot field and an address of an ingress router is included in an opaque data field. In addition, the RLFA node of the RLFA backup path is configured to recognize that it is identified in the LSPRoot field of the modified mLDP control message, and, in response, look up the ingress router identified in the opaque data field of the modified mLDP control message. The RLFA node is further configured to send an mLDP control message that includes the address of the ingress router in the LSPRoot field towards the ingress router.

Abstract: An example method includes exchanging targeted hello messages to establish a targeted neighbor connection between a first routing device and a second routing device, wherein one of the routing devices comprises a central routing device, and wherein another one of the routing devices comprises an ingress routing device. The example method further includes processing a source-active register message that specifies a source address and an identifier that are collectively associated with a multicast stream, and wherein the source-active register message further indicates whether the multicast stream is active or withdrawn.

Abstract: Techniques are described for enhancements to Protocol Independent Multicast (PIM) to enable a last hop router (LHR) to perform source discovery and directly build or join a source tree. According to the techniques of this disclosure, the LHR builds a communication channel with a rendezvous point (RP) router and requests source information for at least one multicast group for which the LHR has interested receivers. The RP responds to the request by looking into a register database maintained by the RP and sending source information indicating at least one source that is actively providing traffic for the at least one multicast group. Based on the response, the LHR initiates a (S,G) PIM Join message toward the at least one source for the at least one multicast group to directly build or join at least one source tree.

Abstract: In one example, a method includes exchanging, by a first routing device and with a second routing device, targeted hello messages using a Protocol Independent Multicast (PIM) protocol to establish a targeted neighbor connection between the first routing device and the second routing device, wherein the first routing device exchanges the targeted hello messages with the second routing device via at least one intermediate routing device, and wherein at least one of the first or second routing device comprises a rendezvous point (RP). The example method further includes processing, by the first routing device using the targeted neighbor connection, a register message that includes multicast stream data elements, wherein each multicast stream data element identifies a source address and a group address that are collectively associated with a respective multicast stream, and wherein each multicast stream data element further indicates whether the respective multicast stream is active or withdrawn.

Abstract: Techniques are described for providing robust control plane asserts in a network using Protocol Independent Multicast (PIM) or other routing protocols for controlling delivery of multicast traffic. In one example, a router includes a control unit having a hardware-based processor executing a Protocol Independent Multicast (PIM) protocol. The control unit, when executing the PIM protocol, initiates an election process for selecting, from a plurality of routers, a forwarding router to forward multicast traffic to a shared media computer network. In addition, the control unit determines whether the multicast traffic has been received by the router and outputs, in association with the election process, a PIM assert message that includes an indication as to whether the router has successfully received the multicast traffic.