KR980013128A - Layer 3 routing method and device using Ethernet switch - Google Patents

Abstract

The present invention provides an Ethernet switch capable of high-speed processing of an Ethernet frame input at a line speed by combining a header processor for converting an address area of an Ethernet packet header to a controller and a controller with a header processor control function added to a function of a normal router. The present invention relates to a three-layer routing processing method and apparatus using a combination of an Ethernet switch and a router, wherein the first packet of several packets destined for the same destination is processed by the router, and the routing information is stored in a cache in the header processor. Packets of the same forwarding path are delivered to the destination directly through the switch without passing through the router, thereby improving the overall routing processing capacity. Also, the broadcast function of the switch performs the three-layer multicasting function using the broadcast function.

Therefore, the present invention has the effect of configuring the router at a lower price than the router while performing the three-layer routing function using the high-speed processing capability of the switch.

Description

Layer 3 routing method and device using Ethernet switch

The present invention combines the high-speed switching function of the Ethernet switch, the broadcasting function, and the three-layer processing function of the router, and has a low-cost, high-performance switch router (three-layer switch) that supports three-layer point-to-point and multicasting communication. The present invention relates to a three-layer routing processing method and apparatus for fast processing frames.

The present invention relates to a router configuration that can be applied to an Ethernet-based LAN backbone, and stores some recently used information of the router's routing information in a hardware cache and based on the Ethernet address corresponding to a three-layer address in hardware. By providing input frames directly from the Ethernet switch, the overall routing performance can be increased.

Conventional techniques for high-speed routing maximize the processing performance by using the first packet stored in the cache when the first packet performs all routing procedures while the first packet performs all routing procedures through the same path. One Cisco NetFlow technology, which improves performance by streamlining packet processing in continuous flows, does not take advantage of the high-speed switching capabilities of Ethernet switches.

Technologies that provide three-layer switching using LAN switches include 3COM's FastIP technology, CableTron's SecureFast technology, and Enbei's DirectIP technology.

FastIP technology connects subnets of a hand switch to improve the routing performance in a LAN where multiple subnets are connected to routers. The network is increasing the routing throughput by passing it through.

However, this method has a problem in that a control function for transmitting a packet through a switch path through a subnet must be added to all terminals. There is a problem in that a software for performing the control function must be separately developed for each terminal type.

SecurFast technology intercepts a broadcasting packet transmitted by a terminal to a LAN switch to obtain a LAN address corresponding to the layer 3 address, and transmits the packet to a separate controller, and a controller providing a LAN address corresponding to the layer 3 address. In addition, it is a technology that configures a LAN into a plurality of virtual three-layer subnets.

This scheme can perform the three-layer switching function relatively easily, but it has the disadvantage that it cannot use the standard three-layer routing protocol adopted by most routers. There will be restrictions on the application.

DirectIP technology adds a function that processes Layer 3 packets to a LAN switch and a control device that provides a LAN address corresponding to the Layer 3 address, so that the first packet is processed in the same way as a normal router in the controller. It is delivered to the terminal.

In this process, a direct path is established between the two terminals via the LAN switch, and the remaining packets are delivered through the direct path. This method operates the LAN switch as a virtual high-speed router, but cannot use the standard 3-layer routing protocol. Not only has the problem of lacking compatibility with the router, there is a disadvantage that the change of the software due to the direct path to all terminals are required.

In addition, all of the FastIP, SecureFast, and DirectIP technologies have difficulty in supporting three-layer multicasting.

Furthermore, the Ethernet switch of the prior art performs a two-layer switch function that determines the output port by the destination address value of the header of the Ethernet frame, while the router performs a three-layer (network layer, e.g. Internet protocol) packet input. A packet forwarding function that determines the output port according to the destination address and a routing protocol that exchanges control information with neighboring routers and determines the forwarding path information according to the layer 3 address value should be performed.

Therefore, the switch which handles the second layer adopts a hardware processing method, but the software which is adopted by the router which handles the conventional three layer does not only slow down the battery speed but also the price is about 10 times higher than the switch of the same speed. .

In order to solve the disadvantages of the prior art, an object of the present invention is to provide a three-layer routing processing method and apparatus for an Ethernet switch for processing a high-speed Ethernet frame by combining a header processor and a routing controller in the Ethernet switch.

Another object of the present invention is to provide a three-layer routing processing method and apparatus using an Ethernet switch by combining a standard routing protocol, a broadcast function of a RenSwitch and a three-layer multicasting function of a router.

It is still another object of the present invention to provide a three-layer routing processing method and apparatus using an Ethernet switch which combines an Ethernet switch and a router with a first packet, a control packet, and routing protocols of consecutive packets at a high speed in a routing controller.

It is another object of the present invention to provide a multicasting function of a three-layer packet that broadcasts an Ethernet frame from an Ethernet switch to all ports, so that the three-layer address, Ethernet address, and multicasting control information are included in the header handler's address translation table and multicast. The present invention provides a three-layer routing processing method and apparatus using an Ethernet switch that allows a multicast frame to be delivered to a designated port only when registered in an identifier table.

Accordingly, the present invention transmits a frame to a designated port if the destination address value of the Ethernet frame is an individual address, and a frame having a multicasting address includes an Ethernet switch having a plurality of ports broadcasting to all ports, and the remaining Ethernet switches except one port. Header processor for converting destination address and destination address of frame connected to each port to input and output value, routing of Layer 3 packet while processing Ethernet frame connected to Ethernet switch in the same way as a normal router Layer 3 routing processor using an Ethernet switch consisting of a routing controller that writes the resulting layer 3 address, Ethernet address, and multicasting control information into a header processing address translation table and a multicast identifier table. The frame's destination when entered into the handler If the address is a broadcast address, it checks whether it is a broadcast address and delivers it to the routing controller.If it is not a broadcast address, it extracts the destination address value of the 3rd layer packet included in the Ethernet frame and searches for an Ethernet address corresponding to the address translation table. If there is an existing Ethernet address, the Ethernet address is written in the destination address area of the frame, and then passed to the Ethernet switch. If the Ethernet address does not exist, the Ethernet frame is transmitted to the routing controller. Characterized by the layer routing method.

In the present invention, in configuring a router using an Ethernet switch, a standard routing protocol used in an existing router may be applied as it is, and a method in which a change of terminal software is not required is considered.

In addition, a method of providing a three-layer multicasting function provided by a conventional router by using a broadcasting function of a LAN switch is considered.

In the present invention, the first packet of a plurality of consecutive packets forwarded to the same destination and the control packets (eg, address translation request / response packets and routing protocol related packets) processed by the existing router are the same in the routing controller as in the conventional router. As the routing protocol used by the existing router can be applied as it is.

In addition, the LAN address (Ethernet address) corresponding to the third layer address is stored in the hardware cache in the header processor, and the existing terminal software can be used by changing the Ethernet address of the frame input to the Ethernet switch.

Since Ethernet frames with multicast addresses are broadcast to all ports on the Ethernet switch, this feature is used to provide multicasting of Layer 3 packets.

That is, the header processor delivers the multicast Ethernet address and the multicast identifier corresponding to the three-layer multicast address to the Ethernet frame and transfers them to the Ethernet switch. Pass only when registered in the multicast identifier table of the corresponding port so that the multicast frame is delivered only to the designated port.

1 is a block diagram showing a configuration of the present invention;

2 is an Ethernet frame diagram for delivering an Internet Protocol (IP) packet;

3 is a block diagram showing the configuration of the header processor of the present invention;

4 is a block diagram of an address translation table of a header processor;

5 is a flowchart of processing when an Ethernet frame is input to a header processor from an external network;

6 is a flowchart of processing when an Ethernet frame is input to a routing controller;

7 is a flowchart of processing when an Ethernet frame is input from the Ethernet switch to the header processor.

1 shows a configuration of a router using the Ethernet switch 101 according to the present invention.

According to the present invention, an Ethernet switch 101 having a plurality of ports for delivering a frame to a designated port according to a destination address value of an Ethernet frame, and a header for converting header values of a frame connected to each port of the Ethernet switch to input and output to a specified value Processor 102 is connected to a specific port of the Ethernet switch and processes the inputted Ethernet frame like a normal router, and transfers the three-layer address, Ethernet address, and multicasting control information, which is the result of packet routing, to the address translation table of the header processor. The routing control controller 103 writes the multicast table.

The Ethernet switch 101 transmits the frame to the port to which the terminal of the corresponding address value is connected according to the destination address value of the input Ethernet frame, and detects the sender address of the input frame and registers the addresses of the terminals connected to the corresponding port. .

If the destination address is a multicasting or broadcasting address, it has the function of copying and forwarding frames to all ports.This function is the basic function of general Ethernet switch. have.

1 shows that a broadcast frame input to a router having n-1 ports is a frame requesting an Ethernet address corresponding to a layer 3 address or a control packet transmitted to exchange routing information between routers.

Therefore, the Ethernet frame having the broadcast address must be delivered to and processed by the routing controller 103. To this end, the header processor 102 converts the destination address of the Ethernet frame having the broadcast address input from the outside into the Ethernet address value of the routing controller. By converting and forwarding, the frame is forwarded to the routing controller through the Ethernet switch.

When an Ethernet frame with an address value other than the broadcast address is input, the address translation table is searched for the destination address value of the 3rd layer packet (e.g. IP packet) included in the frame, and if there is a corresponding Ethernet address value, it is the destination of the Ethernet frame. Write it in the address field and pass it to the Ethernet switch.

If there is no Ethernet address value corresponding to the address translation table, the address value of the routing controller is written in the destination address area of the Ethernet frame, and then transmitted to the routing controller 103 for processing.

The address handler table 305 (see Fig. 3) of the header processor performs the role of a cache having routing information. Therefore, if the information exists and the cache exists, the frame is directly passed through the Ethernet switch using the information. If there is no information in the router, it is transmitted to the routing controller and processed like the general router, and then passes through the Ethernet switch directly. It was made.

The routing control 103 handles the input Ethernet frame in the same way as a normal router. If there is a three-layer packet to which the input frame is to be transmitted to another terminal, the routing control 103 should be output according to the routing table information in the routing controller. The port is determined and forwarded to the Ethernet frame destined for the corresponding Ethernet address.

At this time, the Ethernet address pairs corresponding to the layer 3 addresses are stored in the address translation table in the header processor so that the Ethernet frames transmitted to the same port destination are directly transmitted to the destination through the Ethernet switch without passing through the routing controller.

Even when a packet inputted to the routing controller is related to three-layer control, the packet is processed in the same manner as a normal router. However, when a multicasting group is newly created or deleted, an additional operation is required as follows.

When a new multicasting group is added, it assigns a multicast identifier corresponding to the 3-layer multicast address value and assigns the 3-layer address, Ethernet address, and multicast identifier to the address translation table of the port where the multicast frame of the corresponding address is input. Store in a multicast identifier table in the header handler connected to the ports on which the multicast frame should be output.

When the multicasting group is deleted, the corresponding entry is removed from the address translation table in which the corresponding layer 3 multicast address is stored, and the multicast identifier corresponding to the address is removed from the multicast identifier table of all ports.

2 shows a configuration of an Ethernet frame 200 carrying an IP packet.

The Ethernet frame includes a six-byte destination address 201 and a source address 202, a two-byte form field 203 indicating the type of information conveyed by the Ethernet frame, an information field of up to 1500 bytes, and error detection. It consists of a 4-byte Cyclic Redundancy Code (CRC) area 205.

Although various types of three-layer packets can be delivered according to the shape region value, this figure shows an example of delivering an IP packet. The 20-byte IP packet header 204 controls various types of data, including the destination IP address 206. Have information

3 shows the configuration of the header processor 102.

Broadcast frame header conversion function 303 for converting the destination address value of the Ethernet frame whose broadcast address is the broadcast address to the Ethernet address of the routing controller 103, and forwarding it to the Ethernet switch, Layer 3 packet contained in the Ethernet frame. Searches the Ethernet address corresponding to the destination in the address conversion table 305 and writes the address value in the destination address area of the Ethernet frame to the Ethernet switch.If the Ethernet address corresponding to the address conversion table does not exist, the Ethernet switch A destination address translation function 304 which writes the Ethernet address of the routing controller in the destination address area to be transmitted to the Ethernet switch, and an address conversion table 305 which stores the Ethernet address value corresponding to the three-layer address. The processing unit 301, the destination tide value of the frame input from the Ethernet switch is multicast If so, it extracts the multicast identifier included in the frame, searches the multicast identifier table 307, removes the multicast identifier if the identifier exists, and outputs the frame, and removes the multicast frame if the identifier does not exist in the table. A transmission processing unit 302 including a multicast packet filtering function 306 for performing a function, and a source address translation function 308 for converting and outputting the destination addresses of all input Ethernet frames by converting the Ethernet addresses of the routing controllers; Routing controller matching function 309 that allows the routing controller to access the multicast identifier table and the address translation table.

If the 3rd layer address value to be searched in the destination address translation function of the receiving processor is a multicast address, the multicast identifier along with the corresponding Ethernet address from the address translation table should be read and loaded into the Ethernet frame to be transmitted to the Ethernet switch.

Even if the frame received from the outside is directly transmitted through the Ethernet switch, the receiving terminal should recognize it as if it is delivered through the router. Convert to Ethernet address value.

4 shows an example of the configuration of the address translation table 305.

The table shows the three-layer address area 4010, the corresponding Ethernet address area 402, the multicast identifier area 403 used when the three-layer address value is a multicast address, and the time when the entry was most recently retrieved. It consists of a time stamp area 404.

This table is retrieved by layer 3 address values and outputs Ethernet addresses and multicast identifiers. The multicast identifier is valid only if the layer 3 address value is a multicast address. Stores the time at which it is retrieved and uses it to check if it has not been accessed for a specified time.

Fig. 5 is a flowchart showing the processing procedure when the Ethernet frame is input to the receiving processing unit of the header processor.

When the Ethernet frame is input, it is checked whether the destination address of the frame is a broadcast station (step 501). If the broadcast address is a broadcast address, the frame is transmitted to the routing controller (step 504). The destination address value is extracted to search for the existence of the Ethernet address corresponding to the address translation table (step 502).

If the corresponding Ethernet address exists, the Ethernet address is written in the destination address area of the frame and then transmitted to the Ethernet switch (step 505 and step 506). If not, the Ethernet frame is forwarded to the routing controller.

6 is a flowchart showing a processing procedure when an Ethernet frame is input to the routing controller.

When the Ethernet frame is input, the third layer packet contained in the frame is restored (step 601), and the type of packet is checked (step 602).

If the restored 3rd layer packet is an individual address packet to be delivered to another terminal, extract the Ethernet address corresponding to the destination address value of the packet, send the packet to the Ethernet switch by putting a packet on the Ethernet frame which is the destination address (Step 603), the address value corresponding to the third layer address of the packet is written to the address translation table of the header processor (step 604).

If the restored three-layer packet is a packet related to the configuration on the multicast group, a multicast identifier corresponding to the three-layer multicast address is allocated (step 607). The three-layer address, the corresponding Ethernet address, and the multicast identifier Is written into the address translation table (step 608), and at the same time, the identifier value is stored in the multicast identifier table in the header processing of ports allowed to output the multicast packet (step 609).

If the restored three-layer packet is a packet related to the deletion of the multicast group, if the packet is related to the deletion, the entry of the three-layer multicast address to be deleted is retrieved from the address translation table of the header processor and the corresponding entry is deleted (step 611). The multicast identifier corresponding to the multicast address is deleted from the multicast identifier table of all header processors (step 612).

If the restored three-layer packet is a control packet other than the above, the process is performed in the same manner as a normal router (610).

Fig. 7 is a flowchart showing the processing procedure when the Ethernet frame is input to the transmission processing unit of the header processor.

When the Ethernet frame is input, the destination address of the frame is checked (step 701), and if it is not a multicast frame, the Ethernet address value of the routing eliminator is written in the transmission address area of the Ethernet frame and transmitted (step 702).

If the input Ethernet frame is a multicast frame, the multicast identifier is retrieved from the multicast identifier table (step 703). If the identifier does not exist in the table, the frame is deleted (step 706). (Step 705). Subsequently, the Ethernet address of the routing controller is entered and transmitted in the destination address area (step 702).

The present invention can easily configure a large-capacity router having excellent price / performance ratio compared to a conventional router by combining a hardware that performs a header processing function on an Ethernet switch and a router controller having a header processor control function added to a router of communication. .

In the present invention, the overall packet processing performance has the advantage of having a processing capacity of 100M × (number of ports-1) when using an Ethernet switch having a 100M link speed, and easily expanding the capacity by increasing the number of Ethernet switching ports. Have

The routing controller handles only the first packet and the control packets related to the three-layer routing protocol among the plurality of packet flows passing through the same path. Therefore, the routing controller does not require high throughput and the standard three-layer routing protocol used in the existing router. As it is, using the Ethernet switch solves the compatibility problem of the prior art.

Therefore, there is an advantage that the change of the terminal software is not required.

In addition, in the present invention, three-layer multicasting processing with higher bandwidth is possible by processing three-layer multicasting using the broadcasting function and the hardware filtering function of the Ethernet switch.

Claims (6)

If the destination address of the Ethernet frame is an individual address, the frame is forwarded to the specified port. A frame with a multicasting address is connected to each port of the Ethernet switch except for one port. Header processor that converts destination address and source address of input / output frame to designated value, Layer 3 address which is the result of routing of Layer 3 packet while Ethernet frame connected to Ethernet switch is processed like normal router, Ethernet And a routing controller for writing address and multicasting control information into an address translation table and a multicast identifier table of a header processor. The header processor of claim 1, wherein the header processor converts a destination address value of an Ethernet frame whose broadcast address is a broadcast address into an Ethernet address of a routing controller, and a three-layer destination address value of the Ethernet frame. Ethernet address corresponding to Ethernet address is searched in the address conversion table and the Ethernet address value is found and written in the destination address area of Ethernet frame to Ethernet switch.If there is no Ethernet address in the address conversion table, the destination address of Ethernet frame Receiving processing unit consisting of the destination address translation function that writes the Ethernet address of the routing controller in the area and forwards it to the Ethernet switch, an address processing table that stores the Ethernet address value and the multicast identifier corresponding to the three-layer address, and is input from the Ethernet switch. The destination address of the frame is multicast If it is an address, it extracts the multicast identifier included in the frame, searches the multicast identifier table, and if the identifier exists, removes the multicast identifier and outputs the frame. If the identifier does not exist in the table, the function removes the multicast frame. Multicast packet filtering function to perform the multicast packet filtering function, a transmission processing unit configured to convert the source address of all the input Ethernet frames to the Ethernet address of the routing controller and output the output address, and the routing controller converts the multicast identifier table and the address. A three-layer routing process using an Ethernet switch, characterized by a routing controller matching function that allows access to a table. The 3rd layer using an Ethernet switch according to claim 2, wherein the destination address translation function additionally takes a multicast identifier value from an address translation table and loads it in an Ethernet frame when the layer 3 address value is a multicast address. Routing Processing Unit. When the Ethernet frame is input to the header processor from the outside, it checks whether the destination address of the frame is a broadcast address, and if it is a broadcast address, delivers it to the routing controller.If the broadcast frame is not a broadcast address, it extracts the destination address of the layer 3 packet contained in the Ethernet frame. If there is a corresponding Ethernet address in the address translation table, if there is a corresponding Ethernet address, the Ethernet address is written in the destination address area of the frame and forwarded to the Ethernet switch.If not, the Ethernet frame is forwarded to the routing controller. Routing processing method using an Ethernet switch, characterized in that consisting of receiving and processing the Ethernet frame. The method of claim 4, wherein when the Ethernet frame is input to the routing controller, the packet is restored by checking the type of the packet by restoring the layer 3 packet included in the frame, and when the restored layer 3 packet is an individual address packet to be delivered to another terminal, After extracting the Ethernet address corresponding to the destination address, the packet is loaded into the Ethernet frame with the destination address and transmitted to the Ethernet switch, and then forwarded to the destination. If the 3rd layer packet is a packet related to the setting of the multicast group, assign a multicast identifier corresponding to the 3rd layer multicast address, and then add the 3rd layer address, the corresponding Ethernet address, and the multicast identifier. Is written in the address translation table and at the same time header processing of the ports allowed to output the corresponding multicast packet. The identifier value is stored in the multicast identifier table in the table.If the restored layer 3 packet is a packet related to the deletion of the multicast group, the entry is deleted by searching the address handler table of the header handler for the layer 3 multicast address to be deleted. Routing control processing steps of deleting the multicast identifier corresponding to the multicast address from the multicast identifier table of all header processors and processing the same as a normal router when the restored layer 3 packet is a control packet other than the above Layer 3 routing processing method using an Ethernet switch, characterized in that consisting of. The method according to claim 4, wherein when the Ethernet frame is input to the header processor from the Ethernet switch, the destination address of the frame is checked, and if the multicast frame is not a multicast frame, the Ethernet address of the routing controller is written in the transmission address area of the Ethernet frame and transmitted. If the input Ethernet frame is a multicast frame, the multicast identifier is searched in the multicast identifier table, and if the identifier does not exist in the table, the corresponding frame is deleted. Three-layer routing processing method using an Ethernet switch, characterized in that consisting of a transmission processing unit processing step for transmitting to the outside by writing the Ethernet address. ※ Note: The disclosure is based on the initial application.