Device for partitioning ports of a bridge into groups of different virtual local area networks

• US 5,963,556 A
• Filed: 10/22/1996
• Issued: 10/05/1999
• Est. Priority Date: 06/23/1993
• Status: Expired due to Term

• Current Assignee: Extreme Networks, Inc.
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Thomas, Robert Eugene, Bassett, John, Varghese, George, Simcoe, Robert, Spinney, Barry A., Cobb, Graham, Higginson, Peter
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US08/731,905
• Time in Patent Office: 1,078 Days
• Field of Search: 370/401, 370/402, 370/403, 370/409, 370/420, 370/471, 370/389, 370/397, 370/399, 370/243, 370/254
• US Class Current: 370/401
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 12/462 LAN interconnection over a bridge based backbone
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge
• CPC Class Codes: H04L 12/467 Arrangements for supporting untagged frames, e.g. port-based VLANs

Abstract

A network device for interconnecting computer networks, the device including a bridge having a plurality of ports through which network communications pass to and from the bridge, the bridge also including a first interface enabling a user to partition the plurality of bridge ports into a plurality of groups, wherein each group represents a different virtual network, wherein the bridge treats all ports within a given group as part of the virtual network corresponding to that group and the bridge isolates said virtual networks from each other, whereby any communications received at a first port of the bridge are directly sent by the bridge to another bridge port only if the other bridge port and the first bridge port are part of the same group.

Claims

1. A network device for interconnecting computer networks, said device comprising:

a bridge having a plurality of ports through which network communications pass to and from said bridge, said bridge comprising;

a first interface enabling a user to partition the plurality of ports of said bridge into a plurality of groups, wherein each group represents a different one of a plurality of virtual networks, wherein said bridge treats all ports within a given group as part of the virtual network corresponding to that group and said bridge isolates the groups of said plurality of virtual networks from each other, whereby any communications received at a first port of said bridge are directly sent by said bridge to another port of said bridge only if said other port and said first port are part of the same group; and

a second interface for enabling the user to designate one or more of said plurality of ports as client ports, wherein said bridge sends to said client ports communications that are received from a station on one virtual network of said plurality of virtual networks and ultimately destined for a station on another virtual network of said plurality of virtual networks.

2. The network device as defined in claim 1 further comprising a router connected to said bridge through one or more said client ports, said router including a plurality of ports through which network communications pass to and from said router.

3. The network device of claim 2 wherein said router includes an interface enabling said user to designate which one or more of said router ports as server ports, said server ports being the router ports through which the router is connected to said bridge.

4. The network device of claim 3 wherein said router further comprises a source table that contains a mapping of source addresses to said virtual networks, said source addresses representing locations of stations that are connected to said virtual networks and that send communications to said bridge.

5. The network device of claim 4 wherein upon receipt of a unicast packet from a first station on a first one of said virtual networks and destined for a second station on a second one of said virtual networks, said bridge forwards said unicast packet to said router, said forwarded unicast packet containing a source address identifying the first station, and wherein said router upon receipt of the forwarded unicast packet from said bridge learns the source address in the forwarded unicast packet and through said source table determines that said source address corresponds to said first one of said virtual networks.

6. The network device of claim 3 wherein said router is assigned a different router address for each of said virtual networks and wherein a unicast packet from a first station on a first one of said virtual networks and destined for a second station on a second one of said virtual networks contains the router address corresponding to said first one of said virtual networks.

7. The network device of claim 3 wherein said router comprises a table assigning a different router address to the router for each of the virtual networks and wherein a unicast packet sent to said router by said bridge contains a router address corresponding to a first one of said virtual networks and wherein upon receipt of said unicast packet from said bridge, said router identifies the router address in said unicast packet and through said table determines that the router address in said unicast packet corresponds to said first one of said virtual networks.

8. The network device of claim 3 wherein said router includes a database identifying each of the virtual networks by a different network identifier and wherein when said router sends to said bridge a multicast packet that is intended for one of said virtual networks, said router adds a network identifier to said multicast packet, the network identifier added to said multicast packet being obtained from said database and identifying the virtual network for which said multicast packet is intended.

9. The network device of claim 8 wherein said bridge upon receipt of the multicast packet sent by said router removes the network identifier from the multicast packet sent by said router to produce a modified multicast packet and then forwards the modified multicast packet to the virtual network identified by said network identifier.

10. The network device of claim 9 wherein said bridge further comprises a database mapping said plurality of ports on said bridge to said virtual networks and wherein said bridge uses said database to identify the ports on said bridge to which said bridge forwards the modified multicast packet.

11. The network device of claim 3 wherein said bridge includes a database mapping ports said bridge to the virtual networks of said plurality of virtual networks and wherein said bridge upon receipt of a multicast packet from any of said virtual networks adds source information to the received multicast packet to produce a modified multicast packet and then forwards said modified multicast packet through one of said one or more client ports to said router, the source information added to the received multicast packet being obtained from said database and identifying the virtual network from which said multicast packet was received.

12. The network device of claim 3 wherein said bridge includes a forwarding table which maps addresses of stations to bridge ports and wherein upon receipt at said bridge of a unicast packet sent by said router and having a destination address located on one of said virtual networks, said bridge determines from said forwarding table through which bridge port that destination address is reachable and then forwards said unicast packet through the identified bridge port.

13. The network device of claim 3 wherein said router includes a memory storing a server record that identifies the bridge to the router and that also identifies one or more said server ports.

14. The network device of claim 13 wherein said server record identifies which of said one or more server ports is operational.

15. The network device of claim 13 wherein said router memory also stores a virtual network record for each of said virtual networks, wherein each of said virtual network records identifies the virtual network with which it is associated.

16. The network device of claim 15 wherein each of said virtual network records also identifies a particular one of said one or more server ports as the port through which said router sends communications to the virtual network associated with that virtual network record.

17. The network device of claim 3 wherein said bridge includes a memory storing a virtual network record for each of said virtual networks, wherein each virtual network record stored in said memory identifies a virtual network with which it is associated.

18. The network device of claim 17 wherein each of said virtual network records also identifies a particular one of said one or more client ports as the client port through which said bridge sends communications to the virtual network associated with that virtual network record.