True Ring Networks With Gateway Connections Using MAC Source Address Filtering

• US 20100020798A1
• Filed: 07/25/2008
• Published: 01/28/2010
• Est. Priority Date: 07/25/2008
• Status: Active Grant

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Micrel Incorporated (Microchip Technology Incorporated)
• Inventors: Jones, Michael
• Granted Patent: US 7,801,141 B2
• Time in Patent Office: Days
• US Class Current: 370/392
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]
• CPC Class Codes: H04L 12/433 with asynchronous transmission, e.g. token ring, register insertion
• CPC Class Codes: H04L 12/4645 Details on frame tagging routing of packets H04L45/00; support for virtual LAN H04L49/354

Abstract

A method in a network device implements source address filtering, including gateway address filtering, to enable network devices to be configured in a true Ethernet ring network. By implementing source address filtering or source address filtering with gateway address filtering, a true ring network can be formed using Ethernet protocols where all the links between the network devices in the ring are active paths while avoiding data packets being switched endlessly around the ring. In one embodiment, a data packet in the true ring network is terminated when the source address of the data packet matches the local address of the network device. In another embodiment, a data packet in the true ring network is terminated when the source address of the data packet matches the address of the gateway switch connected to the network device.

Claims

1. A method in a network device configured in a true ring network with other network devices, the network device having a first port and a second port connected to the true ring network and a third port connected to a processor, the method comprising:

connecting the network device to transmit data packets in a single direction around the true ring network, the first port being an ingress port and the second port being an egress port;

enabling ingress source address filtering on the first port and the second port and not the third port;

receiving a data packet at the first port of the network device;

determining if the source address of the data packet matches the local address of the network device;

when the source address of the data packet matches the local address of the network device, terminating the data packet;

when the source address of the data packet does not match the local address of the network device, determining if the destination address of the data packet matches the local address of the network device;

when the destination address of the data packet matches the local address of the network device, transferring the data packet to the third port; and

when the data packet is a multicast data packet for a multicast group in which the network device belongs or a broadcast data packet, transmitting the data packet to the third port and through the egress port.

2. The method of claim 1, wherein the local address of the network device comprises a media access control (MAC) address of the network device and the source address of the data packet comprises a MAC address of the originating network device.

3. The method of claim 1, further comprising:

disabling address learning on the first port and the second port.

4. The method of claim 1, wherein the network device further includes a fourth port coupled to a gateway switch, the gateway switching being connected to a second network, the method further comprising:

enabling ingress gateway source address filtering on the first port and the second port and not the third port or the fourth port of the network device;

determining if the source address of the data packet matches the local address of the gateway switch;

when the source address of the data packet matches the local address of the gateway switch, terminating the data packet;

when the source address of the data packet does not match the local address of the gateway switch or the local address of the network device, determining if the destination address of the data packet matches the local address of the network device or the local address of the gateway switch;

when the destination address of the data packet matches the local address of the network device, transferring the data packet to the third port; and

when the destination address of the data packet matches the local address of the gateway switch, transferring the data packet to the fourth port.

5. The method of claim 4, wherein the local address of the gateway switch comprises a MAC address of the gateway switch.

6. The method of claim 1, wherein the network device comprises one of switches, hubs, gateways, bridges or routers.

7. The method of claim 1, wherein the network device comprises a layer 2 device.

8. The method of claim 1, wherein the network device comprises a layer 2 device with three or more ports.

9. The method of claim 4, wherein the network device comprises a layer 2 device with four or more ports.