Method and system for VLAN aggregation

• US 6,914,905 B1
• Filed: 06/16/2000
• Issued: 07/05/2005
• Est. Priority Date: 06/16/2000
• Status: Active Grant

• Current Assignee: Arista Networks, Inc.
• Original Assignee: Extreme Networks, Inc.
• Inventors: Merchant, Shehzad T., Yin, Kenneth T., Yip, Michael
• Primary Examiner(s): Yao, Kwang Bin
• Application Number:
  US09/595,608
• Time in Patent Office: 1,845 Days
• Field of Search: 370/389, 370/392, 370/395.2, 370/395.3, 370/395.31, 370/395.32, 370/395.52, 370/395.53, 370/401, 370/411
• US Class Current: 370/395.53
• 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 2101/604 Address structures or formats
• 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 45/586 of virtual routers
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/35 involving non-standard use of addresses for implementing network functionalities, e.g. coding subscription information within the address or functional addressing, i.e. assigning an address to a function

Abstract

A method and system for an aggregated virtual local area network (VLAN) architecture in which several VLANs in a network share the same default router address and subnet mask, but remain isolated from one another'"'"'s network traffic. Instead of the traditional method of assigning one subnet to a VLAN, each VLAN is assigned only a portion of a subnet'"'"'s IP address space, and is further grouped into a super-VLAN uniquely associated with that subnet. Intra-VLAN traffic is forwarded only to host IP addresses assigned to that same VLAN according to a VLAN identifier carried in the data packet. Inter-VLAN traffic is processed by a virtual router interface which routes the data packet by applying the routing configuration for the subnet uniquely associated with the super-VLAN, according to a super-VLAN identifier carried in the data packet. The routing configuration used by the virtual router interface includes routing protocols, static routes, redundant router protocols and access-lists. Since each VLAN shares the same virtual router interlace, the traditional address overhead of a subnet is minimized, requiring only one default router and subnet mask, as well as only one pair of subnet broadcast addresses for all hosts on the subnet and the subnet itself. The aggregated VLAN architecture provides for the efficient use and management of a network'"'"'s IP address space.

Claims

1. An aggregated virtual local area network (VLAN) architecture system comprising:

a network having at least one of a plurality of subnets, each subnet having a routing configuration;

a super-VLAN uniquely associated with a one of the plurality of subnets and the routing configuration, the super-VLAN aggregating a plurality of sub-VLANs, each sub-VLAN sharing a common virtual router interface that applies the routing configuration of the uniquely associated subnet of the super-VLAN to each sub-VLAN.

2. The aggregated VLAN architecture of claim 1 wherein a local area network (LAN) switch only forwards a data packet having a VLAN ID that matches a VLAN ID for a one of the plurality of sub-VLANs controlled by the LAN switch, and if not, routes the data packet according to a destination IP address specified in the data packet.

3. The aggregated VLAN architecture of claim 1 wherein multiple subnets of the plurality of subnets are uniquely associated with a super-VLAN, and wherein the virtual router interface routes data packets having a VLAN ID for a one of the super-VLANs controlled by a LAN switch interfacing the network in accordance with the routing configuration of the subnet uniquely associated with the super-VLAN identified in the data packet'"'"'s VLAN ID.

4. The aggregated VLAN architecture of claim 1 wherein the routing configuration of the subnet uniquely associated with the super-VLAN includes a common default gateway IP address, a first broadcast IP address for all hosts on the subnet and a second broadcast IP address for the subnet only.

5. The aggregated VLAN architecture of claim 4 wherein the routing configuration further includes a subnet mask shared by each of the super-VLAN'"'"'s sub-VLANs.

6. A method for an aggregated VLAN architecture comprising;

assigning a portion of a subnet IP address space to one of a plurality of VLANs;

grouping the plurality of VLANs assigned to portions of the same subnet IP address space into a super-VLAN uniquely associated with the same subnet IP address space;

propagating a data packet carrying a VLAN ID that identifies the VLAN and super-VLAN with which the data packet is associated;

forwarding an intra-VLAN data packet according to the VLAN identified in the data packet'"'"'s VLAN ID; and

routing an inter-VLAN data packet according to a destination IP address specified in the data packet.

7. The method of claim 6, wherein the VLAN ID comprises an identifier derived from at least one well known field in the data packet.

8. The method of claim 7, wherein the at least one well known field comprises a source IP address and a destination IP address, and the derived identifier is based on the subnet prefix of the source IP address and destination IP address.

9. The method of claim 6, wherein forwarding an intra-VLAN data packet includes forwarding data packets within a single switch coupled to the VLAN identified in the data packet'"'"'s VLAN ID and forwarding data packets across a plurality of switches coupled to the VLAN identified in the data packet'"'"'s VLAN ID.

10. The method of claim 6, wherein routing an inter-VLAN data packet is performed by a virtual router interface, the virtual router interface applying a routing configuration for the subnet uniquely associated with the super-VLAN identified in the data packet'"'"'s VLAN ID.

11. The method of claim 10 wherein the routing configuration of the subnet uniquely associated with the super-VLAN includes a common default gateway IP address, a first broadcast IP address for all hosts on the subnet, and a second broadcast IP address for the subnet only.

12. The method of claim 11 wherein the routing configuration further includes a subnet mask shared by each of the VLANs in the super-VLAN identified in the data packet'"'"'s VLAN ID.

13. The method of claim 10, wherein the virtual router interface resides on a LAN switch coupled to the super-VLAN identified in the data packet'"'"'s VLAN ID.

14. An article of manufacture comprising a machine-readable medium having stored thereon a plurality of instructions for generating an aggregated VLAN architecture, comprising:

assigning a portion of a subnet IP address space to one of a plurality of VLANs;

grouping the plurality of VLANs assigned to portions of the same subnet IP address space into a super-VLAN uniquely associated with the same subnet IP address space;

propagating a data packet carrying a VLAN ID that identifies the VLAN and super-VLAN with which the data packet is associated;

forwarding an intra-VLAN data packet according to the VLAN identified in the data packet'"'"'s VLAN ID; and

routing an inter-VLAN data packet according to a the super-VLAN identified in the data packet'"'"'s VLAN ID.