Reliable transport protocol for internetwork routing

A method of reliably transmitting multicast packets and unicast packets in a network, comprising

• multicasting a first packet having a sequence number to a plurality of destinations;
• recording a set of ones of said plurality of destinations for which an acknowledgment is not received;
• when said set is nonempty, multicasting a second packet having an indicator representative of said set;
• multicasting a third packet having an indicator representative of conditional receipt, whereby destinations in said set ignore said third multicast packet;
• and
• unicasting said first packet and said third packet to each destination in said set.

A device for routing packets in a network, comprising

• means for reliably transmitting multicast packets and unicast packets in a network, said means for reliably transmitting comprising
• (a) means for multicasting a first packet having a sequence number to a plurality of destinations, (b) means for recording a set of ones of said plurality of destinations for which an acknowledgment is not received, (c) means, when said set is nonempty, for multicasting a second packet having an indicator representative of said set, (d) means for multicasting a third packet having an indicator representative of conditional receipt, whereby destinations in said set ignore said third packet, and (e) means for unicasting said first packet and said third packet to each destination in said set;
• and
• means for reliably receiving multicast packets and unicast packets in a network, said means for reliably receiving comprising
• (a) a recipient identifier, (b) means, upon receiving a packet having a sequence number from a source, for transmitting an acknowledgment to said source, said acknowledgment indicating said recipient identifier, (c) means, upon receiving a packet having an indicator representative of a set of destinations for which an acknowledgment was not received, for entering a conditional-receive mode if said indicator is not representative of said recipient identifier, and (d) means, for receiving a packet having an indicator representative of conditional receipt only when in said conditional-receive mode.

A method of routing packets in a network, comprising

• receiving a packet, said packet comprising an external header, said external header comprising a value representative of an external routing protocol, a metric assigned by said external routing protocol, a value representative of an autonomous system of routers, and a value representative of an administrative tag;
• routing said packet in response to said metric assigned by said external routing protocol;
• and
• routing said packet in response to an administrative policy indicated by said administrative tag.

Apparatus for reliably receiving multicast packets and unicast packets in a network, said apparatus comprising

• a recipient identifier;
• means for transmitting an acknowledgment to a source, said acknowledgment indicating said recipient identifier, upon receiving a packet having a sequence number from said source;
• means for entering a conditional-receive mode upon receiving a second packet having an indicator representative of a set of destinations for which an acknowledgment was not received, if said indicator is not representative of said recipient identifier;
• and
• means for receiving a packet having an indicator representative of conditional receipt only when in said conditional-receive mode.

Apparatus for reliably transmitting multicast packets and unicast packets in a network, said apparatus comprising

• means for multicasting a first packet having a sequence number to a plurality of destinations;
• means for recording a set of ones of said plurality of destinations for which an acknowledgment is not received;
• means responsive to said set for multicasting a second packet having an indicator representative of said set;
• means for multicasting a third packet having an indicator directing destinations in said set to ignore said third multicast packet;
• and
• means for unicasting said first packet and said third packet to each destination in said set.

Apparatus for routing packets in a network, said apparatus comprising

• means for receiving a packet, said packet comprising an external header, said external header comprising a value representative of an external routing protocol, a metric assigned by said external routing protocol, a value representative of an autonomous system of routers, and a value representative of an administrative tag;
• means for routing said packet in response to said metric assigned by said external routing protocol;
• and
• means for routing said packet in response to an administrative policy indicated by said administrative tag.