RPF multi-party reliable transport

• US 20080077710A1
• Filed: 05/01/2003
• Published: 03/27/2008
• Est. Priority Date: 10/28/2002
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Kouvelas, Isidor, Vicisano, Lorenzo
• Granted Patent: US 7,546,380 B2
• Time in Patent Office: Days
• US Class Current: 709/250
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 12/1854 with non-centralised forwarding system, e.g. chaincast
• CPC Class Codes: H04L 12/1868 Measures taken after transmission, e.g. acknowledgments
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/164 Adaptation or special uses of UDP protocol
• CPC Class Codes: H04L 69/165 Combined use of TCP and UDP protocols; selection criteria therefor
• CPC Class Codes: H04L 69/326 in the transport layer [OSI layer 4] H04L69/16 takes precedence
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users

Abstract

A multi-party reliable transport protocol for use by a higher layer application. A single session source distributes database updates to multiple receivers via a distribution tree. A node desiring to join a session selects a directly-connected node on a path upstream to a source by accessing unicast routing protocol information and sends a “Join” message to this upstream neighbor. Each node participating in the scheme handles retransmission requests from its directly-connected downstream neighbors. A supported application provides storage of previously transmitted information for potential retransmission.

Claims

1. A method for operating a selected node to distribute database updates within a network, said method comprising:

identifying one or more directly-connected next-hop or previous-hop neighboring nodes that participate in a transport layer session;

receiving an application data unit from an application operating at said selected node;

encapsulating said application data unit within a transport protocol data unit;

transmitting said transport protocol data unit to only said identified one or more directly-connected neighboring nodes as a part of said transport layer session; and

retransmitting said application data unit to one of said directly-connected neighboring nodes if a request for retransmission is received from said directly-connected neighboring node;

wherein said one or more directly-connected neighboring nodes are routers.

2. The method of claim 1 wherein identifying comprises:

receiving join messages from directly-connected neighboring nodes that wish to begin participating in said transport layer session;

receiving prune messages from directly-connected neighboring nodes that no longer wish to participate in said transport layer session.

3. The method of claim 1 wherein receiving comprises assigning a sequence number to said application data unit, said sequence number configured for consistent use across all of said nodes participating in said transport session.

4. The method of claim 1 wherein said selected node is a source node for said transport layer session.

5. The method of claim 1 wherein said transport protocol data unit is propagated by said one or more identified neighboring nodes to other nodes.

39. The method of claim 1 wherein transmitting comprises utilizing an unreliable datagram protocol.

40. The method of claim 1 wherein said request for retransmission is a negative acknowledgement.

6. A method for operating a selected node to support a transport layer session, said method comprising:

identifying a directly-connected node on a path toward a transport layer session source, said directly-connected node being an upstream node on said path;

receiving a transport protocol data unit from said upstream node;

extracting an application data unit from said transport protocol data unit and an associated sequence number;

delivering said application data unit and said sequence number to an application operating at said selected node;

tracking said sequence numbers; and

requesting retransmission of one or more of said application data units from said upstream node if one or more of said sequence numbers are missing;

wherein said directly-connected node is a router.

7. The method of claim 6 wherein identifying comprises:

based on a routing information base (RIB), determining a path from said selected node toward said transport layer session source.

8. The method of claim 6 further comprising:

prior to receiving said transport protocol data unit, sending a join message to said upstream node.

10. The method of claim 6 further comprising:

identifying at least one directly-connected node other than said upstream node as a downstream node;

forwarding contents of said transport layer data unit to said downstream node.

11. The method of claim 10 wherein identifying comprises:

receiving a join message from said downstream node.

12. The method of claim 10 further comprising:

receiving a request for retransmission of said application data unit from said downstream node;

retrieving said application data unit from said application; and

retransmitting said application data unit to said downstream node.

13. The method of claim 10 further comprising:

receiving a request for retransmission of said application data unit from said downstream node;

forwarding said request to said upstream node;

receiving a retransmission of said application data unit from said upstream node; and

forwarding said retransmission to said downstream node.

14. The method of claim 6 further comprising:

receiving a join message from a downstream node, said downstream node being a directly-connected node other than said directly-connected node on said path toward said transport session source;

in response to said join message, retrieving all stored application data units of said transport session from said application; and

forwarding said retrieved application data units of said transport session to said downstream node.

9. (canceled)

15. A method for operating a selected node to support a transport layer session having at least three parties, said method comprising:

identifying a first directly-connected node on a path toward a transport layer session source;

receiving a transport protocol data unit from said first directly-connected node;

forwarding contents of said transport protocol data unit to a second directly-connected node that is downstream from said transport layer session source and said selected node;

storing contents of said transport protocol data unit in a local cache;

receiving a request for retransmission from said second directly-connected node; and

retransmitting said contents of said transport protocol unit to said second directly-connected node in response to said request by retrieving from said local cache.

16. The method of claim 15 further comprising:

forwarding said request for retransmission to said first directly-connected node; and

receiving retransmitted data from said first directly-connected node.

17. A computer program product for operating a selected node to distribute database updates within a network, said computer program product comprising:

code that identifies one or more directly-connected next-hop or previous-hop neighboring nodes that participate in a transport layer session;

code that receives an application data unit from an application operating at said selected node;

code that encapsulates said application data unit within a transport protocol data unit;

code that transmits said transport protocol data unit to only said identified one or more directly-connected neighboring nodes as a part of said transport layer session;

code that retransmits said application data unit to one of said directly-connected neighboring nodes if a request for retransmission is received from said directly-connected neighboring node; and

a computer-readable storage medium that stores the codes;

wherein said one or more directly-connected neighboring nodes are routers.

18. The apparatus of claim 17 wherein said code that identifies comprises:

code that receives join messages from directly-connected neighboring nodes that wish to begin participating in said transport layer session; and

code that receives prune messages from directly-connected neighboring nodes that no longer wish to participate in said transport layer session.

19. The computer program product of claim 17 wherein said code that receives comprises code that assigns a sequence number to said application data unit.

20. The computer program product of claim 17 wherein said selected node is a source node for said transport layer session.

21. The computer program product of claim 17 wherein said transport protocol data unit is propagated by said one or more identified neighboring nodes to other nodes.

22. A computer program product for operating a selected node to support a transport layer session, said computer program product comprising:

code that identifies a directly-connected node on a path toward a transport layer session source, said directly-connected node being an upstream node on said path;

code that receives a transport protocol data unit from said upstream node;

code that extracts an application data unit from said transport protocol data unit and an associated sequence number;

code that delivers said application data unit and said sequence number to an application operating at said selected node;

code that tracks said sequence numbers;

code that requests retransmission of one or more of said application data units from said upstream node if one or more of said sequence numbers are missing; and

a computer-readable storage medium that stores the codes;

wherein said directly-connected node is a router.

23. The computer program product of claim 22 wherein said code that identifies comprises:

code that, based on a routing information base (RIB), determines a path from said selected node toward said transport layer session source.

24. The computer program product of claim 22 further comprising:

code that, prior to receiving said transport protocol data unit, sends a join message to said upstream node.

26. The computer program product of claim 22 further comprising:

code that identifies at least one directly-connected node other than said upstream node as a downstream node; and

code that forwards contents of said transport layer data unit to said downstream node.

27. The computer program product of claim 26 wherein said code that identifies comprises:

code that receives a join message from said downstream node.

28. The computer program product of claim 26 further comprising:

code that receives a request for retransmission of said application data unit from said downstream node;

code that retrieves said application data unit from said application; and

code that retransmits said application data unit to said downstream node.

29. The computer program product of claim 26 further comprising:

code that receives a request for retransmission of said application data unit from said downstream node;

code that forwards said request to said upstream node;

code that receives a retransmission of said application data unit from said upstream node; and

code that forwards said retransmission to said downstream node.

30. The computer program product of claim 22 further comprising:

code that receives a join message from a downstream node, said downstream node being a directly-connected node other than said directly-connected node on said path toward said transport session source;

code that, in response to said join message, retrieves all stored application data units of said transport session from said application; and

code that forwards said retrieved- application data units of said transport session to said downstream node.

25. (canceled)

31. A computer program product for operating a selected node to support a transport layer session having at least three parties, said computer program product comprising:

code that identifies a first directly-connected node on a path toward a transport layer session source;

code that receives a transport protocol data unit from said first directly-connected node;

code that forwards contents of said transport protocol data unit to a second directly-connected node that is downstream from said transport layer session source and said selected node;

code that stores contents of said transport protocol data unit in a local cache;

code that receives a request for retransmission from said second directly-connected node;

code that retransmits said contents of said transport protocol unit to said second directly-connected node in response to said request by retrieving from said local cache; and

a computer-readable storage medium that stores the codes.

32. The computer program product of claim 31 further comprising:

code that forwards said request for retransmission to said first directly-connected node; and

code that receives retransmitted data from said first directly-connected node.

33. Apparatus for operating a selected node to distribute database updates within a network, said apparatus comprising:

means for identifying one or more directly-connected next-hop or previous-hop neighboring nodes that participate in a transport layer session;

means for receiving an application data unit from an application operating at said selected node;

means for encapsulating said application data unit within a transport protocol data unit;

means for transmitting said transport protocol data unit to only said identified one or more directly-connected neighboring nodes as a part of said transport layer session; and

retransmitting said application data unit to one of said directly-connected neighboring nodes if a request for retransmission is received from said directly-connected neighboring node;

wherein said one or more directly-connected neighboring nodes are routers.

34. Apparatus for operating a selected node to support a transport layer session, said apparatus comprising:

means for identifying a directly-connected node on a path toward a transport layer session source, said directly-connected node being an upstream node on said path;

means for receiving a transport protocol data unit from said upstream node;

means for extracting an application data unit and an associated sequence number from said transport protocol data unit;

means for delivering said application data unit and said sequence number to an application operating at said selected node;

tracking said sequence numbers; and

requesting retransmission of one or more of said application data units from said upstream node if one or more of said sequence numbers are missing;

wherein said directly-connected node is a router.

35. Apparatus for operating a selected node to support a transport layer session having at least three parties, said apparatus comprising:

means for identifying a first directly-connected node on a path toward a transport layer session source;

means for receiving a transport protocol data unit from said first directly-connected node;

means for forwarding contents of said transport protocol data unit to a second directly-connected node that is downstream from said transport layer session source and said selected node;

means for storing contents of said transport protocol data unit in a local cache;

means for receiving a request for retransmission from said second directly-connected node; and

means for retransmitting said contents of said transport protocol unit to said second directly-connected node in response to said request by retrieving from said local cache.

36. Apparatus for operating a selected node to distribute database updates within a network, said apparatus comprising:

a processor that executes instructions; and

a memory device having said instructions stored thereon, said instructions comprising;

code that identifies one or more directly-connected next-hop or previous-hop neighboring nodes that participate in a transport layer session;

code that receives an application data unit from an application operating at said selected node;

code that encapsulates said application data unit within a transport protocol data unit;

code that transmits said transport protocol data unit to only said identified one or more directly-connected neighboring nodes as a part of said transport layer session; and

retransmitting said application data unit to one of said directly-connected neighboring nodes if request for retransmission is received from said directly-connected neighboring node;

wherein said one or more directly-connected neighboring nodes are routers.

37. Apparatus for operating a selected node to support a transport layer session, said apparatus comprising:

a processor that executes instructions; and

a memory device having said instructions stored thereon, said instructions comprising;

code that identifies a directly-connected node on a path toward a transport layer session source, said directly-connected node being an upstream node on said path;

code that receives a transport protocol data unit from said upstream node;

code that extracts an application data unit from said transport protocol data unit and an associated sequence number;

code that delivers said application data unit and said sequence number to an application operating at said selected node;

code that tracks said sequence numbers; and

code that requests retransmission of one or more of said application data units from said upstream node if one or more of said sequence numbers are missing;

wherein said directly-connected node is a router.

38. Apparatus for operating a selected node to support a transport layer session having at least three parties, said apparatus comprising:

a processor that executes instructions; and

a memory device having said instructions stored thereon, said instructions comprising;

code that identifies a first directly-connected node on a path toward a transport layer session source;

code that receives a transport protocol data unit from said first directly-connected node;

code that forwards contents of said transport protocol data unit to a second directly-connected node that is downstream from said transport layer session source and said selected node;

code that stores contents of said transport protocol data unit in a local cache;

code that receives a request for retransmission from said second directly-connected node; and

code that retransmits said contents of said transport protocol unit to said second directly-connected node in response to said request by retrieving from said local cache.