Avoiding multicast traffic loss in networks having multi-homing designated routers

A method comprising:

• receiving, by a first network device, a request to join a multicast group from a receiver that is multi-homed to the first network device and a second network device by a layer two (L2) broadcast communication domain, wherein the second network device is a designated router (DR) for the L2 broadcast communication domain and the first network device is a non-DR for the L2 broadcast communication domain;
• monitoring, by the first network device, multicast virtual private network (MVPN) control traffic that is injected into the L2 broadcast communication domain by the second network device and received by the first network device via a border gateway protocol (BGP) session, wherein the MVPN control traffic comprises a MVPN type 1 route for the second network device;
• determining, by the first network device and based on the MVPN type 1 route for the second network device not being available in the first network device, that the second network device has lost a route to a source of the multicast group;
• and
• based on the determination that the second network device has lost the route to the source of the multicast group, sending, by the first network device as the non-DR, multicast data traffic for the multicast group to the receiver on the L2 broadcast communication domain without performing a DR switchover.

A network device comprising:

• a receiver-facing port coupled to a layer two (L2) broadcast communication domain by which a receiver is multi-homed to the network device and a designated router (DR) for the L2 broadcast communication domain, wherein the network device is a non-DR for the L2 broadcast communication domain;
• and
• a control unit comprising one or more processors configured to:
• receive a request to join a multicast group from the receiver;
• monitor traffic associated with the multicast group that is injected into the L2 broadcast communication domain by the DR and received by the network device;
• determine, based on the monitored traffic, that the DR has lost a route to a source of the multicast group;
• and
• based on the determination that the DR has lost the route to the source of the multicast group, send multicast data traffic for the multicast group to the receiver on the L2 broadcast communication domain without performing a DR switchover, wherein, to send the multicast data traffic for the multicast group, the control unit is configured to:
• send a join message for the multicast group toward the source of the multicast group;
• receive the multicast data traffic for the multicast group from the source of the multicast group;
• and forward the multicast data traffic for the multicast group to the receiver on the L2 broadcast communication domain.

A network device comprising:

• a receiver-facing port coupled to a layer two (L2) broadcast communication domain by which a receiver is multi-homed to the network device and a designated router (DR) for the L2 broadcast communication domain, wherein the network device is a non-DR for the L2 broadcast communication domain;
• and
• a control unit comprising one or more processors configured to:
• receive a request to join a multicast group from the receiver;
• monitor multicast virtual private network (MVPN) control traffic that is injected into the L2 broadcast communication domain by the DR and received by the network device via a border gateway protocol (BGP) session, wherein the MVPN control traffic comprises a MVPN type 1 route for the DR;
• determine, based on the MVPN type 1 route for the DR not being available in the network device, that the DR has lost a route to a source of the multicast group;
• and
• based on the determination that the DR has lost the route to the source of the multicast group, send multicast data traffic for the multicast group to the receiver on the L2 broadcast communication domain without performing a DR switchover.

A non-transitory computer readable medium storing instructions that when executed cause one or more processors to:

• receive, by a first network device, a request to join a multicast group from a receiver that is multi-homed to the first network device and a second network device by a layer two (L2) broadcast communication domain, wherein the second network device is a designated router (DR) for the L2 broadcast communication domain and the first network device is a non-DR for the L2 broadcast communication domain;
• monitor, by the first network device, traffic associated with the multicast group that is injected into the L2 broadcast communication domain by the second network device and received by the first network device;
• determine, by the first network device and based on the monitored traffic, that the second network device has lost a route to a source of the multicast group;
• and
• based on the determination that the second network device has lost the route to the source of the multicast group, send, by the first network device as the non-DR, multicast data traffic for the multicast group to the receiver on the L2 broadcast communication domain without performing a DR switchover, wherein the instructions further cause the one or more processors to:
• send, by the first network device, a join message for the multicast group toward the source of the multicast group;
• receive, by the first network device, the multicast data traffic for the multicast group from the source of the multicast group;
• and forward, by the first network device, the multicast data traffic for the multicast group to the receiver on the L2 broadcast communication domain.