Network relay device for relaying data in a network and control method for the same

• US 7,792,016 B2
• Filed: 03/03/2006
• Issued: 09/07/2010
• Est. Priority Date: 08/24/2005
• Status: Active Grant

• Current Assignee: Alaxala Networks Corporation (Fortinet Inc.)
• Original Assignee: Alaxala Networks Corporation (Fortinet Inc.)
• Inventors: Nozaki, Shinji, Arai, Masaya, Miyamoto, Takahisa
• Primary Examiner(s): Moe; Aung S
• Assistant Examiner(s): Mered; Habte
• Application Number:
  US11/366,837
• Publication Number:
  US 20070047436A1
• Time in Patent Office: 1,649 Days
• Field of Search: 370216-228, 370241-248, 370/254, 370/386, 370/392, 714 1- 4, 714 10- 13, 714/36, 714/55, 455/423, 455/428, 709/203, 709/208, 709/209, 398 1- 8
• US Class Current: 370/217
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches
• CPC Class Codes: H04L 49/552 by ensuring the integrity of packets received through redundant connections
• CPC Class Codes: H04L 49/557 Error correction, e.g. fault recovery or fault tolerance
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

In the case of detection of failure on a direct link interconnecting Master and Backup upstream switches, a control module of the Master upstream switch sends a partial failure message representing the occurrence of partial failure in the Master upstream switch via any of multiple lines connected to multiple ports of the Master upstream switch to the Backup upstream switch. Upon reception of the partial failure message from the Master upstream switch, a control module of the Backup upstream switch identifies partial failure occurring in the Master upstream switch and keeps the Backup operating status of the Backup upstream switch. Upon no reception of the partial failure message from the Master upstream switch, on the other hand, the control module of the Backup upstream switch identifies total failure occurring in the Master upstream switch and switches over the operating status of the Backup upstream switch from Backup to Master. In the event of failure occurring in the Master upstream switch, this arrangement effectively prevents unintentional interruption of data communication but ensures normal data communication in a network without causing the double-master state and the control loop in the network.

Claims

1. A network relay device that has a direct link and multiple ports, and works to relay data in a network, in combination with at least one specific network device among multiple network devices linked to the multiple ports via multiple lines,

the network relay device comprising:

a control module that receives and sends control messages from and to the specific network device via the direct link and switches over an operating status of the network relay device between master and backup; and

a communication module that is under control of the control module and, in the master operating status of the network relay device, sets a connection status of the multiple lines connected with the multiple ports to logic connection to enable transmission of both messages and the data, while in the backup operating status of the network relay device, setting the connection status of the multiple lines connected with the multiple ports to logic disconnection to enable only transmission of messages but disable transmission of the data,

in the case of detection of failure on the direct link in the backup operating status of the network relay device, the control module verifying reception of a partial failure message representing occurrence of partial failure in the specific network device from the specific network device via any of the multiple lines linked to the multiple ports and identifying partial failure occurring in the specific network device,

wherein upon identification of the partial failure occurring in the specific network device, the control module sends a switchover message to the specific network device to urge a switchover of an operating status of the specific network device from master to backup via a line connected to a port receiving the partial failure message, receives a return message from the specific network device, and switches over the operating status of the network relay device from backup to master.

2. An upstream network relay device that has a direct link and multiple ports, and works to relay data in a network, in combination with at least one specific upstream network device among multiple network devices linked to the multiple ports via multiple lines,

the upstream network relay device comprising:

a control module that receives and sends control messages from and to the specific upstream network device via the direct link and switches over an operating status of the network relay device between master and backup; and

a communication module that is under control of the control module and, in the master operating status of the upstream network relay device, sets a connection status of the multiple lines connected with the multiple ports to logic connection to enable transmission of both messages and the data, while in the backup operating status of the upstream network relay device, setting the connection status of the multiple lines connected with the multiple ports to logic disconnection to enable only transmission of messages but disable transmission of the data,

in the backup operating status of the upstream network relay device, the control module identifying each type of the multiple downstream network devices linked to the multiple ports via the multiple lines as either of a first downstream network device with a failure detection function of detecting failure occurring in the specific network device and a second downstream network device without the failure detection function and specifying number of the identified first downstream network devices and number of the identified second downstream network devices,

in the case of detection of failure on the direct link under the condition that the specified number of the second downstream network devices is equal to zero, the control module verifying reception of a failure occurrence message representing occurrence of failure in the specific upstream network device from all the specified number of the identified first downstream network devices via respective lines connected to relevant ports and identifying total failure occurring in the specific upstream network device.

3. The network relay device in accordance with claim 2, wherein in the case of detection of failure on the direct line, the control module identifies total failure occurring in the specific network device when no message is received via any of the multiple lines connected to the multiple ports within a preset time elapsed since a predetermined reference timing.

4. The network relay device in accordance with claim 2, wherein upon identification of total failure occurring in the specific network device, the control module switches over the operating status of the network relay device from backup to master.