Multicasting a data message in a multi-site network

An apparatus for multicasting a data message in a multi-site network (MSN), said apparatus comprising:

• a processor;
• and
• a memory on which is store machine readable instructions that when executed by the processor cause the processor to:
• identify a designated router port in the apparatus corresponding to a virtual local area network (VLAN);
• and
• input a corresponding relation between the VLAN and the designated router port into a local multicast snooping table;
• receive a multicast data message that is to be communicated to another apparatus over the MSN and that includes VLAN information and group information of a multicast group to which the multicast data message relates, wherein the apparatus includes a MSN-link port through which data messages are to be communicated to the another apparatus;
• determine, from a table entry in the local multicast snooping table, that the received multicast data message is to be communicated to the another apparatus through the MSN-link port, by identifying a table entry in the local multicast snooping table that matches the VLAN information, the table entry including:
• a multicast router port corresponding to the designated router port, and a multicast member port corresponding to the group information and to the MSN-link port;
• replicate the received multicast data message according to the multicast router porter and the multicast member port;
• encapsulate the replicated multicast data message into a MSN message;
• and
• tunnel the MSN message to the another apparatus over the MSN-link port.

A non-transitory computer readable storage medium on which is stored machine readable instructions that when executed by a processor of an apparatus for multicasting a data message in a multi-site network (MSN) cause the processor to:

• identify a designated router port in the apparatus corresponding to a virtual local area network (VLAN);
• and
• input a corresponding relation between the VLAN and the designated router port into a local multicast snooping table;
• receive a multicast data message that is to be communicated to another apparatus over the MSN and that includes VLAN information and group information of a multicast group to which the multicast data message relates, the apparatus including a MSN-link port through which data messages are to be communicated to the another apparatus;
• determine, from a table entry in the local multicast snooping table, that the received multicast data message is to be communicated to the another apparatus through the MSN-link port, by identifying a table entry in the local multicast snooping table that matches the VLAN information, the table entry including:
• a multicast router port corresponding to the designated router port, and a multicast member port corresponding to the group information and to the MSN-link port;
• replicate the received multicast data message according to the multicast router porter and the multicast member port;
• encapsulate the replicated multicast data message into a MSN message;
• and
• tunnel the MSN message to the another apparatus over the MSN-link port.