Control apparatus, communication system, relay apparatus control method, and program

A communication system, comprising:

• a control apparatus;
• and
• a relay apparatus(es) that operates in accordance with control information set by the control apparatus;
• wherein the control apparatus includes:
• a first control unit that configures a first virtual network by setting the control information in the relay apparatus(es);
• a multicast group management unit that holds a configuration(s) of a multicast group(s) configured by an apparatus(es) connected to the relay apparatus(es);
• a multicast path calculation unit that calculates a path(s) for transmitting a multicast packet(s) to the apparatus(es) that belongs to the multicast group(s) on the basis of information about a topology representing a connection relationship about the relay apparatus(es);
• and a second control unit that sets control information instructing forwarding of the multicast packet(s) along the path(s) in the relay apparatus(es).

A relay apparatus control method, comprising:

• causing a control apparatus, which includes:
• a first control unit that configures a first virtual network by setting control information in a relay apparatus(es);
• and a multicast group management unit that holds a configuration(s) of a multicast group(s) configured by an apparatus(es) connected to the relay apparatus(es), to calculate a path(s) for transmitting a multicast packet(s) to an apparatus(es) that belongs to the multicast group(s) on the basis of the configuration(s) of the multicast group(s) and information about a topology representing a connection relationship about the relay apparatus(es);
• and
• causing the control apparatus to set control information instructing forwarding of the multicast packet(s) along the path(s) in the relay apparatus(es).