US 5,835,723 A · Dynamic assignment of multicast addresses

Abstract

A distributed protocol for allocation of multicast addresses. A first node of a network sends an address request message identifying (1) a requested in multicast address, and (2) a multicast group identifier to which the requestor belongs. The request is in multicast on a network address reserved for address resolution. All other nodes of the network monitor the reserved network address for address request messages. If a second node receiving the address request message has already allocated the requested multicast address, then the second node sends an acknowledgment message identifying (1) the already allocated in multicast address, and (2) the multicast group for which the address has been allocated. This acknowledgment is transmitted on the same reserved network address on which the address request was sent. The first node, monitoring the reserved network address, receives the acknowledgment message. If the multicast group identified in the acknowledgment message matches the multicast group to which the first node belongs, then the first node also allocates the requested network address. If the multicast group identified in the acknowledgment message does not match the multicast group to which the first node belongs, then the first node abandons the requested network address. If the first node does not receive an acknowledgment message in response to any number of address request messages repeated for the same requested multicast address, then the first node either (1) allocates the requested network address, or (2) abandons the requested network address, if the node is not the first member of a multicast group to request allocation of the address. If address allocation succeeds, then the first node uses the allocated network address for multicasting. If address allocation fails, then the first node is free to select a different multicast address to request.

Claims36

Dependent claims

A computer-implemented process for allocating multicast addresses, comprising the steps of:

(a) selecting a potential multicast address by a first node of a network;
(b) transmitting by the first node an address request message on a reserved address of the network, wherein:
the address request message identifies the potential multicast address as a requested multicast address;
the address request message identifies a requested handle associated with the requested multicast address, wherein the requested handle comprises a unicast address for the first node and a unique value generated by the first node, whereby the requested handle is different from any other requested handle ever generated by any node of the network including the first node;
one or more other nodes of the network monitor the reserved address for address request messages;
at least one other node of the network transmits an acknowledgment message on the reserved address, if the requested multicast address is already allocated by the other node;
the acknowledgment message identifies the requested multicast address as an already allocated multicast address;
and
the acknowledgment message identifies an already allocated handle associated with the already allocated multicast address;
(c) monitoring the reserved address by the first node for the acknowledgment message;
and
(d) abandoning the requested multicast address by the first node, if the first node receives the acknowledgment message from at least one other node of the network.

9 more elements

An apparatus for allocating multicast addresses, comprising:

(a) means for selecting a potential multicast address by a first node of a network;
(b) means for transmitting by the first node an address request message on a reserved address of the network, wherein:
the address request message identifies the potential multicast address as a requested multicast address;
the address request message identifies a requested handle associated with the requested multicast address, wherein the requested handle comprises a unicast address for the first node and a unique value generated by the first node, whereby the requested handle is different from any other requested handle ever generated by any node of the network including the first node;
one or more other nodes of the network monitor the reserved address for address request messages;
at least one other node of the network transmits an acknowledgment message on the reserved address, if the requested multicast address is already allocated by the other node;
the acknowledgment message identifies the requested multicast address as an already allocated multicast address;
and
the acknowledgment message identifies an already allocated handle associated with the already allocated multicast address;
(c) means for monitoring the reserved address by the first node for the acknowledgment message;
and
(d) means for abandoning the requested multicast address by the first node, if the first node receives the acknowledgment message from at least one other node of the network.

9 more elements

A storage medium encoded with machine-readable computer program code for allocating multicast addresses, comprising:

(a) means for causing a computer to select a potential multicast address by a first node of a network;
(b) means for causing the computer to transmit by the first node an address request message on a reserved address of the network, wherein:
the address request message identifies the potential multicast address as a requested multicast address;
the address request message identifies a requested handle associated with the requested multicast address, wherein the requested handle comprises a unicast address for the first node and a unique value generated by the first node, whereby the requested handle is different from any other requested handle ever generated by any node of the network including the first node;
one or more other nodes of the network monitor the reserved address for address request messages;
at least one other node of the network transmits an acknowledgment message on the reserved address, if the requested multicast address is already allocated by the other node;
the acknowledgment message identifies the requested multicast address as an already allocated multicast address;
and
the acknowledgment message identifies an already allocated handle associated with the already allocated multicast address;
(c) means for causing the computer to monitor the reserved address by the first node for the acknowledgment message;
and
(d) means for causing the computer to abandon the requested multicast address by the first node, if the first node receives the acknowledgment message from at least one other node of the network.

9 more elements

Dependencies are inferred from the claim text.

Dynamic assignment of multicast addresses

Life of this patent

Dynamic assignment of multicast addresses

Life of this patent

Abstract

Claims36