Method and apparatus for forwarding packets

• US 7,583,665 B1
• Filed: 10/02/1998
• Issued: 09/01/2009
• Est. Priority Date: 10/03/1997
• Status: Expired due to Fees

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent Canada Incorporated (Nokia Corporation)
• Inventors: Duncan, Ian H., Watt, James, Hall, Grant, Young, Ken
• Primary Examiner(s): NGUYEN, STEVEN H D
• Application Number:
  US09/509,872
• Time in Patent Office: 3,987 Days
• Field of Search: 370400-409, 370/389, 370/392, 370/395.5, 370/395.52, 370/395.53, 370351-356, 709/232, 709/247
• US Class Current: 370/389
• CPC Class Codes: H04L 2012/5617 Virtual LANs; Emulation of LANs
• CPC Class Codes: H04L 2012/5618 Bridges, gateways [GW] or interworking units [IWU]
• CPC Class Codes: H04L 2012/5631 Resource management and allocation
• CPC Class Codes: H04L 2012/5667 IP over ATM
• CPC Class Codes: H04L 2012/5669 Multiprotocol over ATM [MPOA]
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

An internetworking system operating over an ATM backbone. The physical internetworking devices within the system are shared to provide the internetworking functions while servicing two or more distinct and isolated user networks. This is accomplished by logically partitioning the devices into distinct sub-elements which provide all or part of the internetworking functions. These sub-elements are uniquely allocated to independent realms which are then assigned to specific user networks.

Claims

1. A method of forwarding packets in a communication system having multiple incoming service interfaces and multiple output service interfaces for providing service to multiple distinct and isolated user networks, said method comprising:

providing at least one route server to compute forwarding rules based on routing topology and policing information relevant to each of said distinct and isolated user networks;

providing edge forwarders for terminating said incoming service interfaces and for forwarding received packets, said forwarders relying for routing services on forwarding information received from said at least one route server;

transferring said computed forwarding rules from said at least one route server to said edge forwarders;

receiving said packets at one of said incoming service interfaces;

selecting an appropriate forwarding rule based on a source address in said packets and on the incoming service interface from which the packets are received; and

the corresponding edge forwarder for said one incoming service interface forwarding said packets to one of said output service interfaces, the decision as to which output service interface to forward the packets to being based on a destination address in said packets and information in said selected forwarding rule.

2. The method as defined in claim 1 wherein said service interfaces support realms, each realm relating to a specific instance of an internetworking service function.

3. The method as defined in claim 2 wherein said specific instance is a public Internet access service.

4. The method as defined in claim 2 wherein said specific instance is a virtual private network (VPN) service.

5. The method as defined in claim 4 wherein said VPN service is a bridged and/or routed connectivity service.

6. The method as defined in claim 4 wherein said VPN service is a network layer connectivity service.

7. The method as defined in claim 1 wherein said communication system includes an ATM transport fabric.

8. A packet forwarding entity for a communication system comprising:

multiple service interfaces providing instances of service to one of a plurality of distinct and isolated user networks;

edge forwarders terminating said service interfaces and forwarding received packets based on received routing information;

at least one route server for computing multiple forwarding rules relating to instances of service to which said service interfaces belong based on routing, topology and policing information, the multiple forwarding rules being particular to their respective service interfaces, and said at least one route server being configured to transfer the forwarding rules to said edge forwarders; and

said edge forwarders being configured to direct said service interfaces to user networks based on a destination address and information in an appropriate forwarding rule selected on the basis of a source address in packets received on an incoming service interface.

9. The packet forwarding entity as defined in claim 8 wherein said service interfaces related to physical and logical connections.

10. The packet forwarding entity as defined in claim 9 wherein said logical connections include multiple traffic flows from one or more ingress ports.

11. The packet forwarding entity as defined in claim 8 wherein one of said instances of service is an internetworking service function.

12. The packet forwarding entity as defined in claim 11 wherein said internetworking service function is a Public Internet access service.

13. The packet forwarding entity as defined in claim 11 wherein said internetworking service function is a virtual private network (VPN) service.

14. The packet forwarding entity as defined in claim 13 wherein said VPN service is a bridged and/or routed connectivity service.

15. The packet forwarding entity as defined in claim 14 wherein said internetworking service function is provided over an ATM network.

16. The packet forwarding entity as defined in claim 14 wherein said internetworking service function supports multiple protocols.

17. The packet forwarding entity as defined in claim 16 wherein said internetworking service function provides services at both the packet and frame levels.

18. The packet forwarding entity as defined in claim 17 wherein said internetworking service function is managed by a single service provider.

19. The packet forwarding entity as defined in claim 16 wherein said multiple protocols include Multi-protocol over ATM (MPOA) service via a MPOA client lookup cache management function.