Methods and apparatus to support routing of information

• US 7,698,456 B2
• Filed: 09/29/2003
• Issued: 04/13/2010
• Est. Priority Date: 09/29/2003
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Hanzl, Robert, Smit, Henk, Guichard, James N.
• Primary Examiner(s): Blair; Douglas B
• Application Number:
  US10/674,079
• Publication Number:
  US 20050083955A1
• Time in Patent Office: 2,388 Days
• Field of Search: 709/238, 709/243
• US Class Current: 709/238
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/302 Route determination based on requested QoS
• CPC Class Codes: H04L 63/0892 by using authentication-authorization-accounting [AAA] servers or protocols
• CPC Class Codes: H04L 67/63 Routing a service request depending on the request content or context
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]

Abstract

A first network node maintains separate routing policy information to forward network traffic depending on a direction of the network traffic. Upstream routing policy information at the first node identifies a second node to forward upstream traffic received from at least a first client communicating through the first node. Downstream routing policy information at the first node identifies how to forward downstream network traffic received from another node to the first client. By preventing use of the downstream policy routing information by the first client to route upstream network traffic, the first node is able to forward traffic along a path that the network traffic otherwise would have not traveled. For example, network traffic communicated through the first node can be forced to travel through another network node through which it would have not otherwise have passed if the downstream policy information was available to route the network traffic.

Claims

1. In the network supporting virtual network connections associated with clients communicating through a first node, a method comprising:

maintaining separate upstream routing policy information and downstream routing policy information at the first node, the upstream routing policy information being configured at the first node to identify a second node to forward upstream traffic received from at least a first client communicating through the first node, the downstream routing policy information being configured at the first node to forward downstream traffic received from the first client; and

for traffic transmitted by the first client through the first node intended for receipt by a second client downstream of the first node, preventing use of the downstream routing policy information to route the traffic intended for receipt by the second client and instead utilizing the upstream routing policy information in the first node to ensure forwarding of the traffic transmitted by the first client intended for receipt by the second client from the first node to the second node.

2. A method as in claim 1 further comprising:

receiving a session initiation request from the second client to establish a session to communicate through the first node;

from an address server, obtaining network address assignment information for the second client that generated the session initiation request, the assignment information including network address information to be used for identifying the second client; and

populating the downstream routing policy information at the first node to include the network address information identifying the second client.

3. A method as in claim 2 further comprising:

receiving a network message from the second client coupled to communicate through the first node, the network message intended for receipt by the first client;

utilizing the upstream routing policy information in the first node to identify a path on which to forward the network message; and

forwarding the network message from the first node along the path to the second node.

4. A method as in claim 3 further comprising:

based on routing policy information at the second node, establishing a return path between the second node and the first node on which to forward the network messages to the first client through the first node.

5. A method as in claim 1 further comprising:

based on use of the upstream routing policy information and downstream policy information at the first node, establishing a VPN (Virtual Private Network) connection between the first node and the second node on which to forward traffic from the first client.

6. A method as in claim 1, wherein the second node is part of a service provider network and the traffic between the first and second node is at least partly supported by a core network supporting a label switching protocol.

7. A method as in claim 1, wherein the upstream routing policy information and downstream policy information at the first node are each half duplex VRFs (Virtual Routing and Forwarding Instances) supporting forwarding of network messages generated by multiple clients communicating with each other through the first node of the second node.

8. A method as in claim 1 further comprising:

at the second node, applying a target-specific packet processing technique to the traffic from the first client forwarded through the second node.

9. A method as in claim 1 further comprising:

populating the downstream policy information at the first node with network address information of each new client associated with a given service supported by a corresponding service provider.

10. A method as in claim 9 further comprising:

after the downstream policy information is populated in the first node for a new client, distributing the network address information populated in the downstream policy information at the first node to the second node via use of a notification message distributed according to a system routing protocol.

11. A method as in claim 10, wherein the system routing protocol is based on BGP (Border Gateway Protocol).

12. A computer system at a first node of a network that at least partially supports a virtual network connection, the computer system comprising:

a processor;

a memory unit that stores instructions associated with an application executed by the processor;

a communication interface that supports communication with other nodes of the physical network; and

an interconnect coupling the processor, the memory unit, and the communication interface, enabling the computer system to execute the application and perform operations of;

maintaining separate upstream routing policy information and downstream routing policy information at the first node, the upstream routing policy information being configured at the first node to identify a second node to forward upstream traffic received from at least a first client communicating through the first node, the downstream routing policy information being configured at the first node to forward downstream traffic received from the first client; and

for traffic transmitted by the first client through the first node intended for receipt by the second client downstream of the first node, preventing use of the downstream routing policy information to route the traffic intended for receipt by the second client and instead utilizing the upstream routing policy information in the first node to ensure forwarding of the traffic transmitted by the first client intended for receipt by the second client from the first node to the second node.

13. A computer system as in claim 12 that additionally performs operations of:

receiving a session initiation request from the second client to establish a session to communicate through the first node;

from an address server, obtaining network address assignment information for the second client that generated the session initiation request, the assignment information including network address information to be used for identifying the second client; and

populating the upstream routing policy information at the first node to include the network address information identifying the second client.

14. A computer system as in claim 12 that additionally performs operations of:

receiving a network message from the second client coupled to communicate through the first node, the network message intended for receipt by the first client;

utilizing the downstream routing policy information in the first node to identify a path on which to forward the network message; and

forwarding the network message from the first node along the path to the second node.

15. A computer system as in claim 12 that additionally performs operations of:

based on routing policy information at the second node, establishing a return path between the second node and the first node on which to forward the network messages to the first client through the first node.

16. A computer system as in claim 13 that additionally performs operations of:

based on use of the upstream routing policy information and downstream policy information at the first node, establishing a VPN (Virtual Private Network) connection between the first node and the second node on which to forward traffic from the first client.

17. A computer system as in claim 12, wherein the second node is part of a service provider network and the traffic between the first and second node is at least partly supported by a core network supporting a label switching protocol.

18. A computer system as in claim 12, wherein the upstream routing policy information and downstream policy information at the first node are each half duplex VRFs (Virtual Routing and Forwarding Instances) supporting forwarding of network messages generated by multiple clients communicating with each other through the first node and the second node.

19. A computer system as in claim 12 that additionally performs operations of:

at the second node, applying a target-specific packet processing technique to the traffic from the first client forwarded through the second node.

20. A computer system as in claim 12 that additionally performs operations of:

populating the downstream policy information at the first node with network address information of each new client associated with a given service supported by a corresponding service provider.

21. A computer system as in claim 20 that additional performs operations of:

after the downstream policy information is populated in the first node for a new client, distributing the network address information populated in the downstream policy information at the first node to the second node via use of a notification message distributed according the a system routing protocol.

22. A computer system as in claim 21, wherein the system routing protocol is based on BGP (Border Gateway Protocol).

23. In a network supporting virtual network connections associated with clients communicating through a first node, a method comprising:

maintaining separate upstream routing policy information and downstream policy information at the first node, the upstream routing policy information being associated with a first path for traffic transmitted from a first client to a destination and the upstream routing policy information being used at the first node to identify a second node along the first path to forward upstream traffic received from the first client communicating through the first node, the downstream routing policy information being associated with a second path for traffic transmitted from the first client to the destination different from the first path; and

for traffic transmitted by the first client through the first node, preventing use of the downstream policy routing information to route the traffic along the entire second path and instead utilizing the upstream routing policy information in the first node to ensure forwarding of the traffic transmitted by the first client from the first node to the second node.

24. A method as in claim 23, wherein the destination is a second client;

and

wherein, the traffic transmitted by the first client through the first node intended for receipt by the second client is forwarded to the second node.

25. A method as in claim 23 further comprising:

receiving a session initiation request from a second client to establish a session to communicate through the first node;

from an address server,

obtaining network address assignment information for the second client that generated the session initiation request, the assignment information including network address information to be used for identifying the second client; and

populating the downstream routing policy information at the first node to include the network address information identifying the second client.

26. A method as in claim 25 further comprising:

receiving a network message from the second client coupled to communicate through the first node, the network message intended for receipt by the first client;

utilizing the upstream routing policy information in the first node to identify a third path on which to forward the network message; and

forwarding the network message from the first node along the third path to the second node.