Discovering network nodes

A system for discovering nodes of a network, comprising:

• a communication interface configured to:
• send to a multicast group of the network an Internet Protocol multicast packet that requires a receiver of the packet to provide a response packet, wherein the response packet is required to be provided as a direct reply to the Internet Protocol multicast packet and the Internet Protocol multicast packet specifies an invalid option that requires a recipient to provide the response packet in direct reply to the Internet Protocol multicast packet;
• and
• receive a plurality of Internet Control Message Protocol replies from all nodes that belong to the multicast group in reply to the single Internet Protocol multicast packet, wherein every one of the plurality of Internet Control Message Protocol replies identify a communication error associated with the Internet Protocol multicast packet;
• and
• a processor coupled with the communication interface and configured to:
• use the received communication error replies to the Internet Protocol multicast packet to determine a new listing of all nodes of at least the multicast group of the network that provided the communication error replies to the Internet Protocol multicast packet, wherein a previously undiscovered node provided at least one communication error reply of the communication error replies in direct reply to the Internet Protocol multicast packet that requires the receiver of the packet to provide the at least one communication error reply;
• and
• compare at least the new listing of all nodes that provided the communication error replies to the Internet Protocol multicast packet with a previous listing of nodes that provided a previous set of communication error replies to a previous Internet Protocol multicast packet to discover a change in a membership of nodes belong to the network.

A computer program product for discovering nodes of a network, the computer program product being embodied in a non-transitory computer readable storage medium and comprising computer instructions for:

• sending to a multicast group of the network an Internet Protocol multicast packet that requires a receiver of the packet to provide a response packet, wherein the response packet is required to be provided as a direct reply to the Internet Protocol multicast packet and the Internet Protocol multicast packet specifies an invalid option that requires a recipient to provide the response packet in direct reply to the Internet Protocol multicast packet;
• receiving a plurality of Internet Control Message Protocol replies from all nodes that belong to the multicast group in reply to the single Internet Protocol multicast packet, wherein every one of the plurality of Internet Control Message Protocol replies identify a communication error associated with the Internet Protocol multicast packet;
• determining, using the received communication error replies to the Internet Protocol multicast packet to determine a new listing of all nodes of at least the multicast group of the network that provided the communication error replies to the Internet Protocol multicast packet, wherein a previously undiscovered node provided at least one communication error reply of the communication error replies in direct reply to the Internet Protocol multicast packet that requires the receiver of the packet to provide the at least one communication error reply;
• and
• comparing at least the new listing of all nodes that provided the communication error replies to the Internet Protocol multicast packet with a previous listing of nodes that provided a previous set of communication error replies to a previous Internet Protocol multicast packet to discover a change in a membership of nodes belong to the network.