Broadcast isolation and level 3 network switch

• US 5,920,699 A
• Filed: 11/07/1996
• Issued: 07/06/1999
• Est. Priority Date: 11/07/1996
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Bare, Ballard C.
• Primary Examiner(s): Ramirez, Ellis B.
• Assistant Examiner(s): TITCOMB, WILLIAM D
• Application Number:
  US08/744,335
• Time in Patent Office: 971 Days
• Field of Search: 370/351, 370/431, 370/400, 370/402, 370/401, 395/500, 395/200.79, 395/200.55
• US Class Current: 709/225
• CPC Class Codes: H04L 12/1886 with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains
• CPC Class Codes: H04L 12/4604 LAN interconnection over a backbone network, e.g. Internet, Frame Relay
• 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 12/467 Arrangements for supporting untagged frames, e.g. port-based VLANs

Abstract

A network switch comprising a switching Application Specific Integrated Circuit (ASIC) and a Virtual Switching Engine (VSE) connected to a plurality of ports. The switching ASIC has a high-speed memory table which enables it to look up addresses that it has previously obtained and to forward unicast packets to said addresses. The VSE is a CPU that makes switching decisions outside of the ASIC and keeps track of any unknown addresses, forwarding the packets out the appropriate ports and answers broadcast packets by proxy for all known addresses without forwarding any of the packets down the VLANs, thereby freeing the VLAN bandwidth from excessive traffic. The system requires no user configuration because the switching methodology is self-adaptive to the network in which it is inserted and has the ability to perform router functions such as level 2 and 3 switching, spanning tree protocols and compatibility with Internetwork Packet and Internetwork Packet Exchange networks.

Claims

1. A process for reducing excessive packet traffic across a local area network segment, said process comprising the steps of:

receiving selected packets destined for the network segment;

checking the source address of said packets against a Media Access Control address table;

determining if said packets are broadcast packets;

determining if the destination address of said broadcast packets are known;

if said Level 3 addresses are known, then sending reply packet to source address; and

if said addresses are unknown, then flooding all appropriate ports with said broadcast packets; and

forwarding selected packets to a switch engine.

2. The process of claim 1, further comprising the steps of:

determining if said packets are unicast packets; and

forwarding non-unicast packets to said switch engine.

3. The process of claim 2, further comprising the steps of:

determining if the source of said packets is said switch engine; and

determining the destination ports for the packets received from said switch engine by using the Virtual Local Area Network mask in the packet header of said packets.

4. The process of claim 3, further comprising the step of:

determining if level 3 switching has been configured.

5. The process of claim 1, wherein said process is an application specific integrated circuit.

6. The process of claim 1, wherein said process is a software program.

7. The process of claim 1 further comprising the steps of:

recording packet source address and port number in said Media Access Control address table and Address Resolution Protocol cache;

determining if said packets are reply packets; and

if said packets are reply packets, then forwarding said reply packets to destination address.

8. The process of claim 7, further comprising the step of:

if said packets are not reply packets, then recording destination address in said Address Resolution Protocol cache and sending said packets out all appropriate ports.

9. The process of claim 8, further comprising the step of:

filtering broadcast packets for specific subnets configured by the user.

10. The process of claim 8, further comprising the step of:

performing router functions.

11. An apparatus for reducing excessive packet traffic across a local area network segment, comprising:

a plurality of network ports for sending and receiving packets;

a switching module for high-speed packet switching; and

a switch engine comprising;

a mechanism for receiving selected packets, determining if said packets are broadcast packets, sending reply packet to the source address for known destination addresses, and flooding all appropriate ports with said broadcast packets for unknown destination addresses;

wherein said switching module compares the source address of said received packets against a Media Access Control address table and forwards selected packets to said switch engine.

12. The apparatus of claim 11, wherein said switching module further comprising:

forwarding non-unicast packets to said switch engine.

13. The apparatus of claim 12, wherein said switching module further comprising:

sending the packets received from said switch engine to the destination ports using the Virtual Local Area Network mask in the packet headers of said packets.

14. The apparatus of claim 13, wherein said switching module further comprising:

determining if level 3 switching has been configured.

15. The apparatus of claim 11, wherein said switching module further comprises an application specific integrated circuit.

16. The apparatus of claim 11, wherein said switching module further comprises a software program.

17. The apparatus of claim 14, wherein said switch engine further comprising:

recording packet source address and port number in said Media Access Control address table and Address Resolution Protocol cache and forwarding reply packets to their destination address.

18. The apparatus of claim 17, wherein said switch engine further comprising:

recording packet destination address in said Address Resolution Protocol cache and sending non-reply packets out all appropriate ports.

19. The apparatus of claim 18, wherein said switch engine further comprising:

user configurable filter for broadcast packets.

20. The apparatus of claim 18, wherein said switch engine further comprising:

performing router functions.