Dial-out link selection via static route redistribution

• US 6,738,824 B1
• Filed: 01/07/2000
• Issued: 05/18/2004
• Est. Priority Date: 03/30/1999
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Blair, Dana
• Primary Examiner(s): Dharia, Rupal
• Assistant Examiner(s): MIRZA, ADNAN M
• Application Number:
  US09/479,527
• Time in Patent Office: 1,593 Days
• Field of Search: 709/227, 709/228, 709/238, 709/235, 709/239, 370/352, 370/260, 340/352, 359/352
• US Class Current: 709/238
• CPC Class Codes: H04L 12/2876 Handling of subscriber policies group policies management H04L41/0893
• CPC Class Codes: H04L 12/462 LAN interconnection over a bridge based backbone
• CPC Class Codes: H04L 45/125 based on throughput or bandwidth
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04M 3/367 Traffic or load control
• CPC Class Codes: H04M 7/122 where the PSTN/ISDN access is used as an access to networks other than PSTN/ISDN access arrangements to networks other than PSTN/ISDN H04M7/0066; access arrangements to public data networks H04L12/2856
• CPC Class Codes: H04M 7/1285 Details of finding and selecting a gateway for a particular call

Abstract

Dial-out route service is forwarded by a gateway to reduce congestion in a data communication network. The first gateway determines availability of it ports to provide dial-out service to a dial-out route. If the first gateway is unable to provide dial-out service to the dial-out route, then the first gateway transfers information corresponding to the dial-out route to a second gateway. The second gateway may access a central database storing static routes corresponding to the transferred dial-out route information. The central database is typically stored on a server providing security services, which may include access, authentication, and authorization. The second gateway advertises the transferred dial-out route and a respective priority level to effectuate the dial-out route transfer. The dial-out route may be terminated based on one or more termination parameters. In an alternate embodiment, a network node determines the first gateway'"'"'s state of congestion corresponding to the first gateway'"'"'s ability to provide dial-out route service. The node transfers the dial-out route to a second gateway. The node may continually monitor the first gateway to determine when to restore the transferred dial-out route. Forwarding dial-out route service may be used to dynamically scale dial-out service provided by a gateway.

Claims

1. A method for scaling dial-out services provided by gateways in a data communication network to reduce congestion in the data communication network, the method comprising the steps of:

for network nodes that access a first gateway for dial-out services, determining an availability of ports in the first gateway to provide dial-out services;

transferring dial-out route information, corresponding to at least one dial-out route from the first gateway to a second gateway in the event the ports are not available to provide dial-out sevices by the first gateway to provide services for the network nodes; and

after determining a dial-out route is available by the second gateway, updating a routing table in the second gateway and advertising the dial-out route to the network via a routing protocol.

2. The method according to claim 1 further including the step of accessing a central database storing static routes corresponding to the transferred dial-out route information.

3. The method according to claim 2 wherein the central database is stored on a server providing security services.

4. The method according to claim 1, further including the step of:

issuing a request to the second gateway to transfer a dial-out route corresponding to the dial-out route information prior to transferring the dial-out route.

5. The method according to claim 4, further including the step of identifying whether the second gateway chooses to accept the dial-out route.

6. The method according to claim 1, wherein the step of transferring the dial-out route information includes transferring a respective priority level parameter associated with the dial-out route information.

7. The method according to claim 6 further including the step of advertising the transferred dial-out route and a respective priority level by the second gateway to effectuate transferring the dial-out route.

8. The method according to claim 1, wherein the step of transferring further includes transferring at least one transfer termination parameter to limit dial-out route transfer time.

9. The method according to claim 8, wherein the termination parameters include at least one of the parameters:

time-to-live, delete-after-complete, or delete-upon-reboot.

10. In a second gateway being used to expand dial-out services in a data communication network, a method for dynamically scaling dial-out services provided by a first gateway to reduce congestion in the data communication network, the method comprising the steps of:

from a first gateway, receiving a dial-out route transfer request including dial-out route information;

determining to accept the dial-out route transfer request;

updating a routing table in the second gateway; and

issuing an advertisement via a routing protocol to effectuate the dial-out transfer request to expand dial-out services in the data communication network.

11. The method according to claim 10 further including the step of asserting the dial-out route information to a respective gateway port in a manner supporting dial-out services.

12. The method according to claim 10 further including the step of assigning a higher priority to the dial-out route than the dial-out route has in another gateway.

13. The method according to claim 10 further including the step of:

accessing a database, having records of routing information for network nodes reachable by the network, for a record corresponding to the transferred dial-out route information.

14. The method according claim 13 wherein the step of accessing the database includes the step of communicating with a server providing security services.

15. The method according to claim 14 wherein the server is an access, authentication, and authorization server.

16. The method according to claim 10 further including the step of receiving a static route transfer duration parameter.

17. The method according to claim 10 further including the step of terminating the transferred route according to at least one termination parameter.

18. The method according to claim 17 wherein the termination parameter includes at least one parameter:

time-to-live, delete-after-complete, or delete-upon-reboot.

19. A system for dynamically scaling dial-out services provided by gateways in a data communication network to reduce congestion in the data communication network, the system comprising:

in the data communications network, a first gateway transferring to a second gateway at least one parameter related to a static dial-out route; and

the second gateway determining a dial-out route is available and applying the dial-out route corresponding to the transferred parameter via a routing protocol to reduce congestion in the data communication network.

20. The system according to claim 19 further including a server providing a reachability database, the reachability database including static routes accessible by the gateways.

21. The system according to claim 20 wherein the server provides security services.

22. The system according to claim 21 wherein the server is an access, authentication, and authorization server.

23. The system according to claim 19 wherein the second gateway retrieves the dial-out route from the reachability database.

24. The system according to claim 19 wherein the first gateway transfers the static route parameters in response to determining a reduced number of gateway ports being able to provide dial-out route services for a static route corresponding to the static route parameters.

25. The system according to claim 19 wherein the second gateway advertises the transferred dial-out route on the data communication network to effectuate dial-out services for the respective static route.

26. The system according to claim 25 wherein the second gateway includes a dial-out route priority parameter in advertisements about the static route dial-out services to other network nodes.

27. The system according to claim 26 wherein the static route priority parameter is calculated in the second gateway.

28. The system according to claim 26 wherein the static route priority parameter is provided by the first gateway.

29. The system according to claim 26 wherein a server includes the static route priority parameter in a database.

30. The system according to claim 19 wherein one of the gateways terminates dial-out services of the transferred static route by the second gateway.

31. The system according to claim 30 wherein the second gateway terminates the transferred static route based on a termination parameter transferred from the first gateway.

32. An apparatus for dynamically forwarding scaling dial-out services provided by gateways in a data communication network to reduce congestion in a the data communication network, the apparatus comprising:

means for sharing dial-out gateway routes between at least two gateways including (i) means for determining a dial-out route is available by a given one of the at least two gateways, (ii) means for updating a routing table in the given gateway, and (iii) means for advertising the dial-out route to the network via a routing protocol; and

means for coordinating priority of dial-out gateway routes between the gateways.

33. The apparatus according to claim 32 wherein said means for coordinating priority of gateway routes informs reachable network nodes of respective gateway routes and corresponding gateway route priorities to reduce data flow congestion in the data communication network.

34. The apparatus according to claim 32 wherein said means for sharing the dial-out gateway routes includes means for transferring a gateway route from a first gateway to a second gateway.

35. The apparatus according to claim 32 wherein said means for sharing dial-out gateway routes includes means for terminating the transferred dial-out route from the second gateway according to a gateway route termination parameter.

36. A method for dynamically providing dial-out services for a first gateway by a network node, the method comprising:

determining a state of dial-out route services of a first gateway;

retrieving at least one dial-out route reachable from the first gateway from a central database storing dial-out routes for the first gateway;

assigning the retrieved dial-out route to a second gateway to provide services to the dial-out route;

updating a routing table in the second gateway; and

advertising the dial-out route to the network via a routing protocol.

37. The method according to claim 36 further including the step of re-assessing the state of dial-out route services of the first gateway to restore the retrieved dial-out route.

38. A computer program product comprising:

a computer usable medium for storing data; and

a set of computer program instructions embodied on the computer usable medium, including instructions to;

determine a dial-out route is available by a second gateway;

transfer a dial-out route from a first gateway to the second gateway in a data communications network;

update a routing table in the second gateway; and

effectuate the dial-out route via a routing protocol by the second gateway to reduce congestion for nodes in the data communications network.

39. The computer program product according to claim 38 wherein the set of computer program instructions further includes instructions to terminate dial-out route services of the transferred dial-out route by the second gateway.