KR100669030B1 - Ethernet Link Protector for Fast Path Recovery - Google Patents

Abstract

The present invention relates to an Ethernet link protector for rapidly detecting a link failure between an Ethernet switch or a switch and a terminal and switching the backup path to a backup path.

In general, the Ethernet switch and the terminal is connected by one Ethernet link, so when the switch or link failure, the terminal is unable to communicate. In the case of a terminal that seriously affects service interruption, an Ethernet link protector is needed to duplicate the link so that communication can be performed in a bypass path in case of failure.

The Ethernet link protector separates the switch connection link into two and connects each to the Ethernet switch, but communicates with any one of the two. If the link in use fails, the Ethernet link protector bypasses the other link. However, even if the path is changed from the Ethernet link protector to the bypass link, the switching table of the Ethernet switch remains in the previous state until the Ethernet frame is transferred to the bypassed path and the changed MAC address is registered. Therefore, communication is lost for a long time. do.

In order to prevent this, in the present invention, when the path is changed to the bypass link, the control frame for address registration including the address of the terminal in the destination address area is transmitted to the Ethernet switch so that the changed state can be quickly registered in the switching table of the Ethernet switch. It was. Therefore, the communication path can be set up hundreds of times faster than the conventional method.

Ethernet Link Protector, Ethernet Frame, Ethernet Switch, Redundancy, Active Link

Description

Ethernet Link Protector for Fast Path Recovery {Ethernet Link Protector for Fast Path Recovery}

Diagram of Redundancy of Transmission Path Using Ethernet Link Protector

2 is a configuration example 1 of the Ethernet link protector of the present invention

3 is a configuration example 2 of the Ethernet link protector of the present invention

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The present invention is to change the contents of the Ethernet switch switch table in the Ethernet link protector to detect the link failure between the Ethernet switch or the switch and the terminal when switching to the backup path to enable fast end-to-end communication recovery There is a purpose.
The Ethernet link protector separates the switch connection link into two and connects each to the Ethernet switch, but communicates with any one of the two. If the link in use fails, the Ethernet link protector bypasses the other link. However, even if the path is changed from the Ethernet link protector to the bypass link, the switching table of the Ethernet switch remains in the previous state until the Ethernet frame is transferred to the bypassed path and the changed MAC address is registered. Therefore, communication is lost for a long time. do.

In order to prevent this, the present invention transfers a control frame for address registration to the Ethernet switch so that the changed state can be quickly registered in the switching table of the Ethernet switch to set the communication path hundreds of times faster than the conventional method. The purpose is to make this possible.

The present invention is a technique for quickly changing the switching table of the Ethernet switch when there is a communication link change in the protector of the Ethernet link. As shown in FIG. 1, when communication between the terminal-1 and the terminal-2 is performed through the communication path 1, and the link 1 is disconnected, the link link is switched to the link 3 by the Ethernet link protector-1. Communication should be made via communication path 2.

The conventional Ethernet link protector performs a function of simply changing the connection of a terminal to a spare link (link 3) when an error occurs in the main link (link 1). In this case, even if link abnormality detection and path change are performed at high speed, the switching table of the Ethernet switch cannot be changed, and thus, a large delay may occur until normal communication is performed. That is, the Ethernet switch searches the transmission address of the frame received through each port, finds the MAC address of the terminal connected to the corresponding port, and records it in the switching table. Therefore, when communication is performed through the link 1-Ethernet switch 1-link 2 and the link 1 is disconnected, before the frame transmitted from the terminal 1 is transmitted to the link 3-Ethernet switch 2-link 5-Ethernet switch 1 In the switching table of the Ethernet switch 1, it is recorded that the terminal 1 is connected to the link 1. Therefore, the Ethernet frame transmitted from the terminal 2 to the terminal 1 is transmitted to the port connected to the link 1 from the Ethernet switch 1 and discarded. When the terminal 1 only responds to the request of the terminal 2, in the worst case, the communication is performed after the storage period (usually 5 minutes) of the MAC address stored in the switching table of the Ethernet switch 1 has passed.

In another conventional technique, a method of periodically transmitting an address registration broadcast frame whose MAC address is a transmission address to the active port may be used. In this case, communication interruption can be prevented from occurring for an extremely long time as described above, but it has a limitation that it can be applied only to a terminal built-in Ethernet link protector having a MAC address. In addition, the longer the transmission period of the address registration broadcast frame, the longer the communication recovery time, the shorter the transmission period has the disadvantage that the address registration broadcast frame acts as a heavy load on the network, thereby reducing network performance.

Definitions of terms used in the present invention are as follows.

Ethernet Switch Port: In a fault tolerance network, there are two redundant Ethernet switches, and the Ethernet link protector defines two connection ports that can be connected to two Ethernet switches (primary and spare) as Ethernet switch ports. The Ethernet port has a main Ethernet switch port for connection with the main Ethernet switch and a spare Ethernet switch port for connection with the main Ethernet switch.

□ Terminal Ethernet port: Ethernet port to which terminal is connected to Ethernet link protector

Primary / Spare Ethernet Switch: Defines one of the two redundant Ethernet switches as the primary Ethernet switch and the other as the spare Ethernet switch.

□ Active link: A link in which two communication links between an Ethernet link protector and a primary / preliminary Ethernet switch are communicating, and the link that is not communicating is defined as a standby link.

□ Active port: It means the port that is communicating among two Ethernet switch ports of Ethernet link protector.

□ MAC Address: Means the address of Ethernet's Medium Access Control (MAC) layer.

□ ARP Request / ARP Response: ARP (Address Resolution Protocol) frame to find MAC address corresponding to Internet Protocol (IP) address. ARP request frame is defined as ARP request frame.

In order to solve the above problems, when the Ethernet link protector detects a link failure state and changes the transmission path, the switching table of the Ethernet switch must also be changed in accordance with the changed path.

In the Ethernet link protector of the present invention, a function of transmitting an address registration control frame to an Ethernet switch is immediately added to the changed link when a change of the active link occurs in order to change the switching table of the Ethernet switch. Therefore, compared to the method of periodically transmitting the address registration frame, it is possible to establish a communication path within a certain time faster and predictable. To this end, since the Ethernet link protector must have the MAC address of the terminal, it has a function of extracting and storing the MAC address of the terminal in the header of the Ethernet frame transferred from the terminal to the Ethernet switch.                         

This method can reduce the time required to change the communication path after switching from hundreds of milliseconds to several seconds by several tens of microseconds. Recovery is possible. Therefore, the total communication disconnection time from link failure to recovery can be shortened to within several hundred microseconds, so it can be utilized for important servers, military fire control systems, etc., in which the communication failure time should be extremely short.

The present invention analyzes the header of a frame transmitted by the terminal and recognizes the address of the terminal, thereby requiring no change in the interface hardware or driver software of the terminal, and having the advantage of a configuration independent of the terminal.

According to the present invention, a terminal Ethernet matching unit for transmitting and receiving an Ethernet frame with a terminal, a main Ethernet switch matching unit and a spare Ethernet switch matching unit, an Ethernet matching unit or an address registration frame for transmitting and receiving Ethernet frames with a primary Ethernet switch and a spare Ethernet switch, respectively Path switch for setting the communication path between the generator and the main Ethernet switch matching unit or the spare Ethernet switch matching unit, MAC address extraction unit for extracting the MAC address of the terminal from the Ethernet frame transmitted from the terminal, MAC storing the extracted MAC address Active frames that transmit and receive frames by monitoring the link status of the address registration frame generator, main Ethernet switch matching unit, and spare Ethernet switch matching unit that generate address registration frames having MAC addresses stored in the address table and MAC address table, and transmit them to the active port. Determine port and set forwarding path to this active port Is made so that a redundant configuration control unit for controlling the frame address generation unit and a path switch

If an abnormal condition is detected on the main Ethernet switch or the spare Ethernet switch link that was active, the standby port is changed to active and an address registration frame with the MAC address stored in the MAC address table is sent to the active link. It is an Ethernet link protector that allows the terminal to communicate with the connected port to establish a fast communication link.

If the terminal Ethernet port, main Ethernet switch port, and spare Ethernet switch port are all in a normal state, the Ethernet link protector transparently redirects the Ethernet frame to either of the terminal Ethernet port, the main Ethernet switch port, or the spare Ethernet switch port set to active. It serves to pass.

If a redundant state is detected on the Ethernet switch link that is set to active, the redundant control unit immediately activates the Ethernet switch port in the standby state and activates the MAC address table in the address registration frame generator. Generates an address registration frame with the address value that is present and sends it to the active Ethernet switch port. Also, when the address registration frame transmission is completed, the path between the active Ethernet switch port and the terminal Ethernet port is established immediately so that normal communication between the terminal and the Ethernet switch is performed.

In addition, the redundancy control unit may additionally set an active Ethernet switch port through an external monitor port or additionally perform functions such as monitoring the MAC address value stored in the MAC address table.

Whenever the frame transmitted by the terminal is received by the Ethernet link protector, the MAC address extractor stores the time tag value representing the address value of the transmitting MAC address area and the stored relative time value in the MAC address table. When a frame with the same MAC address is received, the time tag value stored with the corresponding MAC address value is changed to a new value, and the time tag value is used to remove the MAC address value that has elapsed from the table.

The address registration frame generator generates an "Oxffffffffffff" value for broadcasting in the destination address area, an MAC address stored in the MAC address table in the destination address area, and an Ethernet frame with a specific value defined by itself in the type area. It makes the MAC address of the terminal re-registered in the switching table of the Ethernet switch by transmitting it to the Ethernet switch port that is set as active through the path switch. If multiple MAC addresses are stored in the MAC address table, one Ethernet frame must be created and transmitted separately for each MAC address.

In another modified example of the present invention, an ARP frame extracting unit for copying an ARP (Address Resolution Protocol) request frame for querying a MAC address corresponding to an internet protocol address and an ARP frame for storing the copied ARP frame as shown in FIG. A buffer and an Ethernet link protector comprising an ARP frame transmitter for transmitting ARP frames stored in an ARP frame buffer to a changed port when an active port is changed. This is because the ARP request frame transmitted from the terminal contains information on the counterpart terminal to which the terminal wants to communicate, and the terminal receiving the ARP request frame transmits the ARP response frame so that the address registration frame is transmitted in both directions when the active port is changed. Will have Therefore, Ethernet switch has an advantage that a faster communication path can be set to a changed port.
The ARP frame extracting unit replaces the ARP request frame stored with the latest ARP request frame when the transmission address of the ARP request frame is the same as the transmission address of the stored ARP request frame, and the ARP request in which the transmission address of the ARP request frame is stored. If different from the destination address of the frame, it is additionally stored. The ARP frame transmitter transmits all the frames stored in the ARP frame buffer to the changed active port when the active port is changed.

The Ethernet link protector of the present invention can support an improved fault tolerance by additionally having a relay such that a physical connection is maintained between the terminal Ethernet port and the main Ethernet switch port or the spare Ethernet switch port even when the power supply is cut off.

The present invention has an effect of speeding up communication recovery by quickly changing the switching table value according to the change of the communication link of the Ethernet switch when constructing an Ethernet-based fault-tolerant communication network. That is, even if a path failure is detected and a path is changed to a normal link, end-to-end communication is not performed unless the switching table value of the Ethernet switch is changed. Since the switch table of the Ethernet switch is automatically changed by the transmission address value of the received Ethernet frame, in the present invention, the control frame for registering the switching table address is transferred to the switch at the same time as the link change, compared to the conventional method. The communication path is restored more than 100 times faster.

In addition, this method has the advantage that the Ethernet link protector itself does not have a MAC address and recognizes the MAC address of the terminal and thus uses the terminal internal type as well as an external configuration independent of the terminal.

Claims (7)

Terminal Ethernet matching unit for transmitting / receiving Ethernet frame with the terminal, main Ethernet switch matching unit and spare Ethernet switch matching unit, Ethernet terminal matching unit or address registration frame generating unit for transmitting and receiving Ethernet frame with primary Ethernet switch and spare Ethernet switch, respectively A route switch for establishing a communication path between the main network and the main Ethernet switch matching unit or the spare Ethernet switch matching unit, a MAC address extraction unit for extracting the MAC address of the terminal from the Ethernet frame transmitted from the terminal, and a MAC address table for storing the extracted MAC address The active port that transmits and receives frames by monitoring the link status of the address registration frame generator, the main Ethernet switch matching unit, and the spare Ethernet switch matching unit which generates and transmits an address registration frame having the MAC address stored in the MAC address table to the active port. And set the forwarding path to this active port. Such that it consists of a control unit for controlling the redundant address frame generating section and a path switch If an abnormal status is detected on the active or primary Ethernet switch link, change the ready Ethernet switch port to the active port and replace the address registration frame with the MAC address stored in the MAC address table with the active port. Ethernet link protector, characterized in that the path is set so that the Ethernet frame is transparently transmitted between the terminal Ethernet port and the Ethernet switch port in the active state after transmission. The address registration frame generator of claim 1 defines "Oxffffffffffff", which means broadcasting, in the destination address area, the MAC address value stored in the MAC address table in the destination address area, and a specific value defined by itself in the type area. Ethernet link protector, characterized in that for generating an address registration frame (insert address frame) The Ethernet link protector of claim 1, wherein the address registration frame generator generates and transmits one address registration frame separately for each MAC address when a plurality of MAC addresses are stored in the MAC address table. Terminal Ethernet matching unit for transmitting / receiving Ethernet frames with the terminal, main Ethernet switch matching unit and spare Ethernet switch matching unit, Ethernet terminal matching unit or ARP frame transmitter and main unit for transmitting and receiving Ethernet frames with the main Ethernet switch and the spare Ethernet switch, respectively. Path switch for setting communication path between Ethernet switch matching unit or spare Ethernet switch matching unit, ARP frame extracting unit for extracting ARP (Address Resolution Protocol) request frame for inquiring MAC address corresponding to internet protocol address An ARP frame buffer that stores ARP frames, and an ARP frame transmitter that transmits ARP frames stored in the ARP frame buffer to a changed port when the active port is changed.It monitors the link status of the main Ethernet switch matching unit and the spare Ethernet switch matching unit. Determines which active port is made and forwards to this active port It is composed of redundancy control part that controls ARP frame transmitting part and path switch so that setting is done. When abnormal status is detected in the active or primary Ethernet switch link, the Ethernet switch port is changed to the active port. Ethernet link protector characterized in that the path is set so that the Ethernet frame is transparently transmitted between the Ethernet port and the Ethernet switch port in the active state after transmitting the ARP request frame stored in the ARP frame buffer. The ARP frame extracting unit of claim 4 replaces the ARP request frame stored with the latest ARP request frame if the sender address of the ARP request frame is the same as the sender address of the stored ARP request frame, and the sender address of the ARP request frame. If the ARP request frame is different from the destination address of the stored ARP request frame, it is additionally stored. The ARP frame transmitter transmits all the frames stored in the ARP frame buffer to the changed active port when the active port is changed. The Ethernet link protector according to claim 1, wherein the redundancy control unit has a monitor port for monitoring the link state of the Ethernet switch port and the terminal Ethernet port, the address value stored in the MAC address table, and changing the active port. The Ethernet link protector according to claim 4, wherein the redundant control unit has an Ethernet switch port and a monitor port for monitoring a link state of the terminal Ethernet port, a frame stored in the ARP frame buffer, and changing an active port.

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