Multicast packet transmission

A method for multicast packet transmission by a second provider edge device in a virtual switching instance, the method comprising:

• the second provider edge device receiving, from a first provider edge device in the virtual switching instance, a packet having an address of a private network multicast group and an address of a public network multicast group associated with the private network multicast group;
• the second provider edge device determining whether a customer edge device connected to the second provider edge device is a receiver of a private network multicast group;
• and
• if the determination is affirmative, the second provider edge device transmitting a join request packet to the first device to join the public network multicast group to receive a multicast packet from the first device, but otherwise, not transmitting the join request packet;
• wherein the multicast packet is encapsulated with the address of the public network multicast group and transmitted by the first provider edge device according to the address of the public network multicast group and forwarding information relating to an interface over which the join request packet is received by the first provider edge device.

A network device for multicast packet transmission, the network device being capable of acting as a first provider edge device and comprising a transmission unit, a receiving unit and a processing unit, wherein:

• the transmission unit is to transmit, to a second provider edge device in the virtual switching instance, a packet having an address of a private network multicast group and an address of a public network multicast group associated with the private network multicast group;
• the receiving unit is to receive, from the second provider edge device, a join request packet to join the public network multicast group;
• the processing unit is to store forwarding information for the public network multicast group, wherein the forwarding information relates to an interface over which the join request packet is received by the first provider edge device and is stored in a memory;
• the processing unit is further to encapsulate a multicast packet for the private network multicast group with the address of the public network multicast group;
• and
• the transmission unit is further to transmit the encapsulated multicast packet according to the address of the public network multicast group and forwarding information.

A network device for multicast packet transmission, the network device being capable of acting as a second provider edge device and comprising a receiving unit, a processing unit and a transmission unit, wherein:

• the receiving unit is to receive, from a first provider edge device in the virtual switching instance, a packet having an address of a private network multicast group and an address of a public network multicast group associated with the private network multicast group;
• the processing unit is to determine whether a customer edge device connected to the second provider edge device is a receiver of a private network multicast group;
• and
• the transmission unit is to, if the determination is affirmative, transmit a join request packet to join the public network multicast group to receive a multicast packet from the first device, but otherwise, not transmit the join request packet;
• wherein the multicast packet is encapsulated with the address of the public network multicast group and transmitted by the first provider edge device according to the address of the public network multicast group and forwarding information relating to an interface over which the join request packet is received by the first provider edge device.