Virtual local area network with trunk stations

• US 6,469,987 B1
• Filed: 01/13/1998
• Issued: 10/22/2002
• Est. Priority Date: 01/13/1998
• Status: Expired due to Term

• Current Assignee: Extreme Networks, Inc.
• Original Assignee: Enterasys Networks Incorporated (Extreme Networks, Inc.)
• Inventors: Rijhsinghani, Anil G.
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): HYUN, SOON D
• Application Number:
  US09/006,242
• Time in Patent Office: 1,743 Days
• Field of Search: 370/389, 370/390, 370/391, 370/392, 370/393, 370/401, 370/402, 370/400, 370/432, 370/445, 370/395, 370/254, 370/255, 370/256, 370/257, 370/258, 709/220, 709/221, 709/223, 709/245, 709/249
• US Class Current: 370/254
• CPC Class Codes: H04L 12/1836 with heterogeneous network architecture
• CPC Class Codes: H04L 12/1886 with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains
• 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 12/4645 Details on frame tagging routing of packets H04L45/00; support for virtual LAN H04L49/354
• CPC Class Codes: H04L 12/467 Arrangements for supporting untagged frames, e.g. port-based VLANs

Abstract

A switch for use in a virtual area network communications system having multiple local area networks interconnected by multiple switches which are connected by a trunk having one or more trunk stations connected directly thereto, includes a first communications port, i.e., an access port, which connects to a first local area network. The first local area network is configured within a virtual area network which also includes a second local area network and a trunk station. The switch also includes a second communications port, i.e. a trunk port, connected to the trunk to which the trunk station is connected by another trunk port. A switch control console detects a multicast communication from the first local area network, duplicates the multicast communication to form a first communication and a second communication, appends a VLAN header to the first communication to form a VLAN communication, and directs transmission of the VLAN communication and the second communication to the second communication port, thereby facilitating delivery of the multicast communication to both the second local area network and the trunk station.

Claims

1. A switch for use in a virtual communications system having multiple local area networks interconnected by multiple switches that are connected by a trunk having one or more trunk stations connected directly thereto, the switch comprising:

a first communications port to be connected to a first local area network of a virtual area network that includes the first local area network a second local area network and at least one of the trunk stations;

a second communications port to be connected to the trunk; and

a control console to detect a multicast communication from the first local area network, to duplicate the multicast communication to form a first communication and a second communication, to append a VLAN header to the first communication to form a VLAN communication, and to direct transmission of the VLAN communication and the second communication to the second communications port.

2. The switch according to claim 1, wherein:

the multicast communication is addressed to at least one member of the second local area network; and

addressees of the multicast communication do not include any trunk stations included in the virtual area network.

3. The switch according to claim 1, wherein:

the multicast communication is addressed to at least one of the trunk stations included in the virtual area network; and

addressees of the multicast communication do not include members of any local area networks included in the virtual area network.

4. The switch according to claim 1, wherein the control console is further operative to detect a unicast communication from the first local area network, to identify the addressee of the unicast message as one of the trunk stations included in the virtual area network, and to direct transmission of the unicast communication, without appending a VLAN header thereto, to the second communications port.

5. A switch according to claim 1, wherein:

the switch is a multiported reconfigurable switch;

the first communications port is an access port;

the second communications port is a first trunk port; and

each of the one or more trunk stations is connected to the trunk by a distinct trunk port.

13. The switch according to claim 1, wherein the multicast communication is addressed to at least the second local area network and at least one of the trunk stations of the virtual area network.

24. The switch according to claim 1, wherein the control console is further operative to direct transmission of the second communication to the second communications port without a VLAN header appended thereto.

6. A method of communicating messages in a virtual area network having multiple local area networks interconnected by multiple switches that are connected by a trunk having one or more trunk stations connected directly thereto, the method comprising:

detecting a multicast communication from a first local area network of a virtual area network that includes the first local area network, a second local area network and at least one of the trunk stations;

duplicating the multicast communication to form a first communication and a second communication;

appending a VLAN header to the first communication to form a VLAN communication; and

directing transmission of the VLAN communication and the second communication to the trunk.

7. The method of communicating messages in a virtual area network according to claim 6, wherein:

the multicast communication is addressed to at least one member of the second local area network; and

addressees of the multicast communication do not include any trunk stations included in the virtual area network.

8. The method of communicating messages in a virtual area network according to claim 6, wherein:

the multicast communication is addressed to at least one of the trunk stations included in the virtual area network; and

addressees of the multicast communication do not include members of any local area network included in the virtual area network.

9. The method of communicating messages in a virtual area network according to claim 6, further comprising:

detecting a unicast communication from the first local area network;

identifying the addressee of the unicast message as one of the trunk stations included in the virtual area network; and

directing transmission of the unicast communication, without appending a VLAN header thereto, to the trunks.

14. The method according to claim 6, wherein the multicast communication is addressed to at least the second local area network and at least and one of the trunk stations of the virtual area network.

25. The switch according to claim 6, wherein the transmission of the second communication is directed to the trunk without a VLAN header appended thereto.

10. A switch for use in a virtual communications system having multiple local area networks interconnected by multiple switches which are connected by a trunk having one or more trunk stations connected directly thereto, the switch comprising:

a first communications port to be connected to a first local area network of a virtual area network that includes the first local area network, at least one of the trunk stations and one or more other local area networks;

a second communications port to be connected to the trunk; and

a control console to detect a unicast communication from the first local area network, to append a VLAN header to the unicast communication in the event that the unicast communication is addressed to one of the other local area networks of the virtual area network, to refrain from appending a VLAN header in the event that the unicast communication is addressed to one of the trunk stations of the virtual area network, and to direct transmission of the unicast communication to the second communications port and on to the trunk .

11. The switch according to claim 10, wherein:

the switch is a multiported reconfigurable switch;

the first communications port is an access port;

the second communications port is a first trunk port; and

each of the trunk stations is connected to the trunk by a distinct trunk port.

15. The switch according to claim 10, wherein the control console is further operative to determine whether the unicast communication is addressed to one of the trunk stations included within the virtual area network or one of the other local area networks included within the virtual area network.

12. A method of communicating messages in a virtual area network having multiple local area networks interconnected by multiple switches which are connected by a trunk having one or more trunk stations connected directly thereto, the method comprising:

detecting a unicast communication from the first local area network of a virtual area network that includes the first local area network, at least one of the trunk stations and one or more other local area networks;

appending a VLAN header to the unicast communication if the unicast communication is addressed to one of the other local area networks included within the virtual local area network;

refraining from appending a VLAN header to the unicast communication if the unicast communication is addressed to one of the trunk stations included within the virtual local area network; and

directing transmission of the unicast communication on to the trunk.

16. The method according to claim 12, wherein the method further comprises:

determining whether the unicast communication is addressed to one of the trunk stations included within the virtual area network or one of the other local area networks included within the virtual area network.

17. A system for communicating messages in a virtual area network having multiple local area networks interconnected by multiple switches that are connected by a trunk having one or more trunk stations connected directly thereto, the system comprising:

means for detecting a multicast communication from a first local area network of a virtual area network that includes the first local area network, a second local area network and at least one of the trunk stations;

means for duplicating the multicast communication to form a first communication and a second communication;

means for appending a VLAN header to the first communication to form a VLAN communication; and

means for directing transmission of the VLAN communication and the second communication to the trunk.

18. The system according to claim 17, wherein:

the multicast communication is addressed to at least one member of the second local area network; and

addressees of the multicast communication do not include any of the trunk stations included in the virtual area network.

19. The system according to claim 17, wherein:

the multicast communication is addressed to at least one of the trunk stations included in the virtual area network; and

addressees of the multicast communication do not include members of any local area networks included in the virtual area network.

20. The system according to claim 17, further comprising:

means for detecting a unicast communication from the first local area network;

mean for identifying the addressee of the unicast message as one of the trunk stations of the virtual area network; and

means for directing transmission of the unicast communication, without appending a VLAN header thereto, to the trunk.

21. The system according to claim 17, wherein the multicast communication is addressed to at least the second local area network and at least one of the trunk stations of the virtual area network.

26. The system according to claim 17 wherein the means for directing transmission is operative to direct transmission of the second communication is transmitted to the trunk without appending a VLAN header thereto.

22. A system for communicating messages in a virtual area network having multiple local area networks interconnected by multiple switches which are connected by a trunk having one or more trunk stations connected directly thereto, the system comprising:

means for de detecting a unicast communication from the first local area network of a virtual area network that includes the first local area network, at least one of the trunk stations and one or more other local area networks;

means for appending a VLAN header to the unicast communication in the event that the unicast communication is addressed to one of the other local area networks included within the virtual local area network;

means for refraining from appending a VLAN header to the unicast communication in the event that the unicast communication is addressed to one of the trunk stations included within the virtual local area network; and

means for directing transmission of the unicast communication on to the trunk.

23. The system according to claim 22, wherein the system further comprises:

means for determining whether the unicast communication is addressed to one of the trunk stations included within the virtual area network or one of the other local area networks included within the virtual area network.