Protocol-independent multicast designated router (PIM-DR) failover in a multi-chassis environment

A method of protocol-independent multicast designated router (PIM-DR) failover, comprising:

• designate a PIM process of a first network device of a multi-chassis link aggregation group (MC-LAG) as a designated router responsible for forwarding all PIM data traffic in the MC-LAG, the PIM process of the first network device having an active route processor;
• designate a PIM process of a second network device of the MC-LAG as a proxy designated router, wherein the PIM process of the second network device is configured to operate in a same manner as the PIM process of the first network device except that a PIM data traffic forwarding function of the PIM process of the second network device is inactive;
• exchanging from the first network device to the second network device, over an interchassis link (ICL), information describing a plurality of multicast route states between an active route processor of the PIM process of the first network device and a plurality of neighbor network devices;
• storing, in a memory of the second network device, the information describing the plurality of multicast route states from the first network device;
• detecting, by the second network device, a PIM-related failure on the first network device;
• disabling a PIM data traffic forwarding function of the PIM process of the first network device;
• and
• activating, by the second network device, the PIM data traffic forwarding function of the PIM process of the second network device by sending a PIM-DR event message to the PIM process of the second network device;
• wherein one or more other networking components of the first network device remain in a functional state and only the PIM process of the second network device is affected by the PIM-DR event message.

A non-transitory machine-readable storage medium encoded with instructions, the instructions executable by a processor of a system to cause the system to:

• designate a PIM process of a first network device of a multi-chassis link aggregation group (MC-LAG) as a designated router responsible for forwarding all PIM data traffic in the MC-LAG, the PIM process of the first network device having an active route processor;
• designate a PIM process of a second network device of the MC-LAG as a proxy designated router, wherein the PIM process of the second network device is configured to operate in a same manner as the PIM process of the first network device except that a PIM data traffic forwarding function of the PIM process of the second network device is inactive;
• exchange from the first network device to the second network device, over an interchassis link (ICL), information describing a plurality of multicast route states between an active route processor of the PIM process of the first network device and a plurality of neighbor network devices;
• store, in a memory of the second network device, the information describing the plurality of multicast route states from the first network device;
• detect, by the second network device, a PIM-related failure on the first network device;
• disable a PIM data traffic forwarding function of the PIM process of the first network device;
• and
• activate, by the second network device, the PIM data traffic forwarding function of the PIM process of the second network device by sending a PIM-DR event message to the PIM process of the second network device;
• wherein one or more other networking components of the first network device remain in a functional state and only the PIM process of the second network device is affected by the PIM-DR event message.