Node discovery involving multiple node enumerators

• US 20060168276A1
• Filed: 12/14/2005
• Published: 07/27/2006
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Black, Richard John, Sverrisson, Heimir Thor
• Granted Patent: US 7,870,247 B2
• Time in Patent Office: Days
• US Class Current: 709/230
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 67/60 Scheduling or organising the servicing of application requests, e.g. requests for application data transmissions using the analysis and optimisation of the required network resources admission control or resource allocation H04L47/70
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding

Abstract

A network node discovery method allows multiple enumerators to concurrently accept and interpret the same enumeration responses from responder nodes on a network. In this manner, the responder nodes do not have to issue individual responses for each enumerator. Each responder maintains a discovery state and one or more per-enumerator session states to manage when the responder should transmit enumeration responses. The enumeration, therefore, proceeds at a target network load, irrespective of the number of enumerators present, and completes in a short time by making efficient use of the network capacity available. Furthermore, an enumerator can determine that it need only wait for responses solicited by other enumerators, rather than requesting them, thereby reducing network traffic in the presence of many concurrently enumerating nodes.

Claims

1. A method of managing transmission of one or more enumeration responses by a network node to enumeration requests received from a plurality of enumerators in a computer network, the method comprising:

maintaining a session state for each of the plurality of enumerators; and

transmitting the one or more enumeration responses if the session states for the plurality of enumerators indicate that the plurality of enumerators have not acknowledged a previous enumeration response by the network node.

2. The method of claim 1 wherein the maintaining operation comprises:

maintaining a session state table having a session state record for each of the plurality of enumerators.

3. The method of claim 2 wherein the session state record includes a sequence identifier provided by a corresponding one of the plurality of enumerators.

4. The method of claim 2 wherein the session state record includes an active time value indicating a time at which a corresponding one of the plurality of enumerators last requested an enumeration response.

5. The method of claim 1 further comprising:

maintaining a retransmission counter to limit the one or more enumeration responses relative to a retransmission threshold; and

terminating transmission of the enumeration responses if the retransmission counter satisfies the retransmission threshold.

6. The method of claim 1 wherein the maintaining operation comprises:

receiving an enumeration request from one of the plurality of enumerators; and

transitioning the session state associated with the enumerator to a new state, responsive to receipt of the enumeration request, wherein the network node waits in the new state for an acknowledgement from the enumerator.

7. The method of claim 1 wherein the maintaining operation comprises:

receiving an acknowledgement of the one or more enumeration responses from one of the plurality of enumerators; and

transitioning the session state associated with the enumerator to a new state, responsive to receipt of the acknowledgement from the enumerator, wherein the new state indicates that the network node has received an acknowledgement from the enumerator.

8. The method of claim 1 further comprising:

maintaining a discovery state that indicates whether the session states for the plurality of enumerators indicate that no further enumeration responses are to be sent.

9. The method of claim 1 further comprising:

maintaining a discovery state that indicates whether the plurality of enumerators have acknowledged a previous enumeration response by the network node.

10. The method of claim 1 wherein the transmitting operation comprises:

transmitting the one or more enumeration responses until a threshold number of enumeration responses are transmitted.

11. The method of claim 1 wherein the transmitting operation comprises:

transmitting the one or more enumeration responses, wherein transmission of each enumeration response is temporally separated from transmission of another enumeration response by a determined delay.

12. The method of claim 11 wherein the delay depends on an estimate of a number of active network nodes remaining to respond to enumeration requests in the computer network.

13. The method of claim 1 further comprising:

scheduling transmission of the one or more enumeration responses based on an estimate of a number of active network nodes remaining to respond to enumeration requests in the computer network.

14. The method of claim 13 wherein the estimate is enhanced in a round following receipt of an enumeration request from a new enumerator.

15. A computer-readable medium having computer-executable instructions for performing a computer process implementing the method of claim 1.

16. A method of managing transmission of enumeration requests by a network node in a computer network, the method comprising:

detecting a number of active enumerators making enumeration requests in the computer network;

computing an estimate interval as a function of the number of active enumerators;

computing an enumeration load in the computer network as a function of all enumeration responses observed during the estimated interval; and

transmitting enumeration requests unless the network node does not observe a previously-unacknowledged enumeration response during the estimate interval and the enumeration load is below a predetermined fractional threshold of a target load in the computer network.

17. A computer-readable medium having computer-executable instructions for performing a computer process implementing the method of claim 16.

18. A network node that manages one or more enumeration responses to enumeration requests received from a plurality of enumerators in a computer network, the network node comprising:

a session state datastore that records a session state for each of the plurality of enumerators; and

a responder module that transmits the one or more enumeration responses if the session states for the plurality of enumerators indicate that the plurality of enumerators have not acknowledged a previous enumeration response by the network node.

19. The network node of claim 18 further comprising:

a discovery state datastore that records a discovery state indicating whether the plurality of enumerators have acknowledged a previous enumeration response by the network node.

20. The network node of claim 18 wherein transmission of each enumeration response is temporally separated from transmission of another enumeration response by a determined delay.