Internet protocol (IP) work group routing

• US 6,249,820 B1
• Filed: 05/06/1998
• Issued: 06/19/2001
• Est. Priority Date: 07/12/1995
• Status: Expired due to Term

• Current Assignee: Enterasys Networks Incorporated (Extreme Networks, Inc.)
• Original Assignee: Cabletron Systems Incorporated (Extreme Networks, Inc.)
• Inventors: Dobbins, Kurt A., Negus, Stephen H., Cullerot, David L., Haggerty, William T.
• Primary Examiner(s): Geckil, Mehmet B.
• Application Number:
  US09/073,557
• Time in Patent Office: 1,140 Days
• Field of Search: 709/238, 709/239, 709/245, 709/249, 709/250, 370/351, 370/401, 370/409
• US Class Current: 709/238
• CPC Class Codes: H04L 12/46 Interconnection of networks
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge
• CPC Class Codes: H04L 2101/677 Multiple interfaces, e.g. multihomed nodes
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/25 of the same type
• CPC Class Codes: H04L 61/5069 for group communication, multicast communication or broadcast communication
• CPC Class Codes: H04L 63/0236 Filtering by address, protocol, port number or service, e.g. IP-address or URL
• 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 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/165 Combined use of TCP and UDP protocols; selection criteria therefor
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

Apparatus and method wherein multiple router interfaces are assigned the same IP network address, creating an IP work group. This enhances host mobility by allowing, in one embodiment, a host to be relocated anywhere in the work group without requiring reconfiguration of the host. As a further option, host address ranges may be specified (i.e., locked) to designated interfaces of the work group, to enhance security by restricting the allowed host mobility within the work group. An additional advantage is a reduced consumption of network and subnet addresses, because now a single address is used for several physical networks.

Claims

1. A method of forwarding IP packets in a network device between a plurality of host based on IP addressing, wherein the network device has a plurality of network interfaces connecting a pluralty of host networks and the at least one host is coupled to at least one of the plurality of network interfaces, comprising:

assigning the plurality of network interfaces to an IP work group, each of the plurality of network interfaces of the IP work group having a single IP work group address and wherein the at least one host has an IP address assigned in the IP work group; and

the network device forwarding IP packets received from the host between the plurality of network interfaces if the at least one host is permitted to transmit packets to the at least one network interface to which the at least one host is coupled.

2. The method of claim 1, including assigning one or more of the plurality of network interfaces in the IP work group to a designated range of host IP addresses, and wherein forwarding of IP packets is restricted to hosts complying with the designated range.

3. The method of claim 2, wherein select network interfaces are assigned to the same host IP address range.

4. The method of claim 2, wherein select network interfaces are assigned to different host IP address ranges.

5. The method of claim 1, including assigning one or more of the plurality of the network interfaces in the IP work group to a designated level of security, and wherein forwarding of IP packets is restricted to compliance with the designated level of security.

6. The method of claim 5, wherein one security level identifies hosts as “

free”

in order to permit forwarding to/from any network interface in the IP work group, and another security level identifies hosts as “

secured”

in order to permit forwarding to/from one or more designated network interfaces in IP work group.

7. The method of claim 5, wherein the secured level includes a “

low”

security work group wherein a host with any physical address is free to reside on any network interface as long as its IP address not lie within a specified host address range, but if it does fall in the specified range then it must reside on a designated network interface for that range.

8. The method of claim 5, wherein the secured level includes a “

medium”

security work group wherein a host'"'"'s IP address must fall within a specified host address range for a designated network interface, but unless a physical address is also specified, the physical address is not constrained.

9. The method of claim 5, wherein the secured level includes a “

high”

security work group when a host must have a specified host IP address for a designated network interface and have a designated physical address.

10. The method of claim 1, including assigning one or more of the plurality of network interfaces in the IP work group a designated range of host physical address(es), and wherein forwarding of IP packets is restricted to hosts complying with the designated range.

11. The method of claim 2, including assigning one or more of the plurality of network interface in the IP work group a designated range of host physical address(es), and wherein forwarding of IP packets is restricted to hosts complying with the designated range.

12. The method of claim 10, wherein the designated range is for a single physical address.

13. The method of claim 1, wherein if an IP packet contains source and destination host addresses within the same IP work group, forwarding of the IP packet occurs without performing header and address validation.

14. The method of claim 1, further including configuring a forwarding information base (FIB) with a route for the IP work group.

15. The method of claim 1, including maintaining a host table of IP host addresses and their associated interfaces.

16. The method of claim 15, further comprising reviewing the host table for duplicate IP host addresses and associated interfaces.

17. The method of claim 1, further comprising maintaining a count of host network interfaces within the IP work group.

18. The method of claim 15, further comprising monitoring the hosts heard on each network interface and maintaining the host table of IP host addresses and the associated network interfaces on which each host is heard.

19. The method of claim 15, wherein the host table is maintained as a cache memory accessible by each of the network interfaces.

20. The method of claim 2, further comprising:

providing a work group forwarding agent for each IP work group.

21. The method of claim 20, further comprising:

maintaining a host table of IP host addresses and their associated network interfaces; and

wherein the work group forwarding agent, prior to forwarding an IP packet, accesses the host table for the associated network interface.

22. The method of claim 21, wherein:

the work group forwarding agent sends ARP requests to all network interfaces in the IP work group to resolve an unknown host physical address.

23. The method of claim 22, further comprising:

providing an ARP forwarding agent at each network interface in the work group, for accessing the host table.

24. The method of claim 2, further comprising:

maintaining a range table of host IP addresses and associated network interfaces on which the hosts may reside; and

prior to forwarding an IP packet, accessing the range table to validate at least one of a source host and a destination host.

25. The method of claim 1, wherein a host is attachable to any network interface in the IP work group without requiring reconfiguration of the host IP address.

26. The method of claim 25, including assigning one or more of the plurality of network interfaces in the IP work group to a designated range of host IP addresses, and wherein forwarding of IP packets is restricted to hosts complying with the designated range.

27. The method of claim 25, including assigning one or more of the plurality of network interfaces in the IP work group to a designated level of security, and

wherein forwarding of IP packets is restricted to compliance with the designated level of security.

28. The method of claim 25, including assigning one or more of the plurality of network interfaces in the IP work group to a designated range of host physical address(es), and

wherein forwarding of IP packets is restricted to hosts complying with the designated range.

29. A network device for forwarding IP packets between a plurality of hosts based on IP addressing wherein the network device has a plurality of network interfaces connecting a plurality of host networks and, the improvement comprising:

means for assigning the plurality of network interfaces to an IP work group, each of the plurality of network interfaces of the IP work group having a single IP work group address and wherein the at least one host has an IP address assigned in the IP work group; and

means for forwarding IP packets received from the host between the plurality of network interfaces if the at least one host is permitted to transmit packets to the at least one network interface to which the at least one host is coupled.

30. The network device of claim 29, wherein the assigning means assigns one or more of the plurality of the network interfaces in the IP work group to a designated range of host IP addresses, and wherein forwarding of IP packets by the forwarding means is restricted to hosts complying with the designated range.

31. The network device of claim 30, wherein the assigning means assigns select network interfaces to the same host IP address range.

32. The network device of claim 30, wherein the assigning means assigns select network interfaces to different host IP address ranges.

33. The network device of claim 29, wherein the assigning means assigns one or more of the plurality of network interfaces in the IP work group to a designated level of security, and wherein forwarding of IP packets by the forwarding means is restricted to compliance with the designated level of security.

34. The network device of claim 29, wherein the assigning means assigns one or more of the plurality of host network interfaces in the IP work group a designated range of host physical address(es), and wherein forwarding of IP packets by the forwarding means is restricted to hosts complying with the designated range.

35. The network device of claim 30, wherein the assigning means assigns one or more of the plurality of network interfaces in the IP workgroup a designated range of host physical address(es), and

wherein forwarding of IP packets by the forwarding means is restricted to hosts complying with the designated range.