Communication System and Network Relay Device

• US 20140226461A1
• Filed: 12/23/2013
• Published: 08/14/2014
• Est. Priority Date: 02/13/2013
• Status: Active Grant

• Current Assignee: APRESIA Systems, Ltd. (HC Networks Incorporated)
• Original Assignee: Hitachi Metals (Thailand) Ltd.
• Inventors: KUMAGAI, Wataru, HASHIMOTO, Nozomi
• Granted Patent: US 9,385,971 B2
• Time in Patent Office: Days
• US Class Current: 370/219
• CPC Class Codes: H04L 45/245 Link aggregation, e.g. trunking
• CPC Class Codes: H04L 49/555 Error detection
• CPC Class Codes: H04L 49/557 Error correction, e.g. fault recovery or fault tolerance

Abstract

In a multi-chassis link-aggregation device, each of first and second switch devices is provided with a relay condition, which defines prohibition of a predetermined relay path. If there is no link failure in each multi-chassis link-aggregation device, each of the first and second switch devices prohibits forwarding of a frame, which has been received by a bridge port, from each multi-chassis link-aggregation device. On the other hand, if a link failure is present in a second port (second multi-chassis link-aggregation device) of the first and second switch devices permits forwarding of the frame, which has been received by the bridge port, from the second port. In this case, if a destination port of the frame received by a first port includes the second multi-chassis link-aggregation device, the first switch device adds a port identifier representing the received port to the frame and forwards that toward the second switch device.

Claims

1. A communication system comprising:

first and second switch devices, each of the first and second switch devices having a plurality of ports including first and second ports and a bridge port, the first and second switch devices being connected to each other by a communication line via the bridge ports;

wherein each of the first and second switch devices has;

a relay condition defining prohibition of relaying of a frame from a predetermined relay-source port to a predetermined relay-destination port among the plurality of ports; and

a link table indicating that link aggregation is set for the first ports of the first and second switch devices and that link aggregation is set for the second ports of the first and second switch devices;

if no link failure is present at the first and second ports, each of the first and second switch devices prohibits forwarding of the frame, which has been received by the bridge port, from the first and second ports;

if a link failure is present at the second port of the first switch device, the second switch device permits forwarding of the frame, which has been received by the bridge port, from the second port; and

the first switch device adds a port identifier representing the received port to the frame received by the first port and forwards the frame from the bridge port, and the second switch device detects the port identifier from the frame received by the bridge port and, if the relay-source port having the relay condition is the port represented by the port identifier, prohibits relaying of the frame toward the relay-destination port.

2. The communication system according to claim 1,

wherein the plurality of ports owned by each of the first and second switch devices further include a general port for which link aggregation is not set;

and

the first switch device adds the port identifier representing the received port to the frame received by the general port and forwards the frame from the bridge port, and the second switch device detects the port identifier from the frame received by the bridge port and, if the relay-source port having the relay condition is the port represented by the port identifier, prohibits relaying of the frame toward the relay-destination port.

3. The communication system according to claim 2,

wherein each of the first and second switch devices is a box-type switch device.

4. A network relay device comprising:

a plurality of ports including first and second ports;

a bridge port for connecting to another network relay device via a communication line;

a relay condition defining prohibition of relaying of a frame from a predetermined relay-source port to a predetermined relay-destination port among the plurality of ports; and

a link table showing that link aggregation is set for the first port of its own and a first port of the second network relay device and that link aggregation is set for the second port of its own and a second port of the second network relay device;

wherein, if the first and second ports of the second network relay device have no link failure, forwarding of the frame, which has been received by the bridge port, from the first and second ports of its own is prohibited;

if the second port of the second network relay device has a link failure, forwarding of the frame, which has been received by the bridge port, from the second port of its own is permitted;

if the first port receives the frame, a port identifier representing the received port is added to the frame and the frame is forwarded from the bridge port;

if the frame to which the port identifier is added by the second network relay device is received by the bridge port, the port identifier is detected from the frame, and, if the relay-source port of the relay condition is the port represented by the port identifier, relaying of the frame toward the relay-destination port is prohibited.

5. The network relay device according to claim 4,

wherein the plurality of ports further include a general port for which link aggregation is not set;

if the frame is received by the general port, a port identifier representing the received port is added to the frame and the frame is forwarded from the bridge port; and

,

if the frame to which the port identifier is added by the second network relay device is received by the bridge port, the port identifier is detected from the frame, and, if the relay-source port having the relay condition is the port represented by the port identifier, relaying of the frame toward the relay-destination port is prohibited.