KR20020051191A - Packet switching method for virtual local area network - Google Patents

Abstract

PURPOSE: A packet switching method between VLANs(Virtual Local Area Networks) is provided to execute communication without using a router by making a 2-layer switch cover routing execution. CONSTITUTION: If a packet is received from the first host(A)(S10), the second host(B) judges whether the subnet of the source of the received packet is identical to the subnet of the destination(S11). If identical, the second host judges that the received packet is an intra traffic that belongs to the same VLAN. If an ARP(Address Read Protocol)_Request signal to read the MAC address of the second host is transmitted from the first host(S12), the second host judges whether it is a new MAC address(S14). In case that it is a new MAC address, the second host registers the source MAC address and port number of the packet in a MAC address table and transmits the registered MAC address to a CPU and the VLAN of the first host at the same time(S15,S16). If an ARP_Request packet is received(S17), the second host judges whether it is a new MAC address(S18,S19). If it is a new MAC address, the second host executes the above steps(S15,S16) again(S20,S21) and transmits an ARP_Response packet to the first host so that the first host can transmit a data packet to the second host through the MAC address of the second host(S22,S23).

Description

PACKET SWITCHING METHOD FOR VIRTUAL LOCAL AREA NETWORK}

The present invention relates to a packet switching method between virtual local area networks, and in particular, in a communication between different virtual local area networks, a packet between virtual local area networks that enables a layer 2 switch to perform routing without communicating through a router. It relates to a switching method.

Currently, all forms of local area networks that conform to the local area network approach and protocol standard (IEEE 802) can be connected to each other by means of a medium access control (MAC) bridge specified in ISO / IEC 15802-3. It defines the operation of virtual local area network bridges for the definition, operation and management of virtual local area network (VLAN) topologies within a bridged local area network.

The virtual local area network (hereinafter, referred to as a 'VLAN') refers to a local area network that is virtually divided by physically or logically divided conditions such as a port, a medium access control address, and an Internet Protocol Subnet (IP Subnet) Ethernet protocol.

In addition, the IEEE 802.1Q standard switches the data frame between the ports of the VLAN according to the VLAN tag according to the port-based VLAN configuration, and if the frame does not include the VLAN tag, the frame is based on the received port. Assign a default tag to the frame.

There are two ways of configuring VLANs: port-based VLANs, MAC address-based VLANs, IP subnet-based VLANs, protocol-based VLANs, and multicast-based VLANs.

First of all, protocol-based VLAN follows the IEEE 802.1Q standard and is most commonly used in a way that is logically bounded by ports. This method is bounded by ports and is not limited to the number or movement of terminals. This has the advantage of being very easy to set up and manage.

In the MAC address based VLAN, a VLAN constituting unit is a MAC address assigned to each terminal, and may pre-specify a VLAN member constituting a VLAN, and may limit a terminal having an unregistered MAC address. Therefore, it is suitable when network security is required for a specific VLAN. However, VLAN configuration is more complicated than port-based VLAN and performance is degraded.

The IP subnet-based VLAN does not use the physical properties of the second layer like the port-based VLAN or the MAC address-based VLAN, but sets the VLAN based on the IP subnet information of the third layer. It is necessary to refer to the information, and accordingly, it takes a long time to learn VLAN.

The protocol-based VLAN configures a VLAN according to the Ethernet protocol type field following the destination MAC address and source MAC address fields in the Ethernet frame, and the protocol fields include IP, packet exchange (IPX), address derivation protocol (ARP), It is used to distinguish between protocols such as Reverse Address Resolution Protocol (RARP) and AppleTalk (APPLE-TALK), which is suitable for networks that use many specific protocols such as IPX or APPLTALK.

Finally, the multicast-based VLAN monitors Internet Group Management Protocol (IGMP) packets to form multicast groups formed on the network into a single logical VLAN, and IGMP is a network timer server in the Internet and other networks. It is possible to dynamically form groups by terminals in a multimedia environment used for network resource grasping or using video on demand (VOD), video conferencing and the like.

Referring to the accompanying drawings, the operation process of the prior art on the technical basis as described above is as follows.

1 is a diagram illustrating a configuration for communication between a conventional virtual local area network, and as shown in FIG. 1, a switch is a device for processing a layer 2 frame at high speed, and processing of a layer 3 frame such as an IP frame is separately performed. Because the processing is possible only if the function of, the communication between the different VLAN through the router (connecting the local area network, using the same protocol between the similar or different communication network) is performed.

However, in the prior art as described above, the switch is a device for processing a layer 2 frame at high speed, and processing of a layer 3 frame such as an IP frame can only be processed with a separate function. It is not possible for equipment without a central processing unit, so it is not possible to communicate even two-layer frames between groups divided into VLANs, and three-layer frame communication surrounded by two-layer frames is also impossible. Compared to the switch, the router requires a lot of time to process the received traffic. As the traffic throughput increases, the router generates a load, thereby degrading the performance of the router, thereby degrading the overall performance of packet switching.

Accordingly, the present invention has been made to solve the above-mentioned conventional problem, and in a communication between different virtual local area networks, a layer 2 switch is responsible for performing routing so that communication can be performed without passing through a router. The purpose is to provide.

1 is an exemplary view showing a configuration for communication between a conventional virtual local area network.

Figure 2 is an exemplary view briefly showing the configuration of a system for applying the present invention.

3 is an exemplary view showing a flow of intra traffic operation according to the present invention.

4 is an exemplary view illustrating a flow of inter and WAN traffic operations according to the present invention.

In order to achieve the above object, the packet switching method between the virtual local area networks of the present invention determines whether the source and the subnet of the destination are the same when the packet is received from the host to be transmitted. a traffic determining step of selecting one of an inter) and a traffic operation of a wide area network (WAN); An intra traffic execution step of transmitting a packet through a predetermined process to a segment composed of the same virtual local area network (VLAN) according to the determination result of the traffic determination step; An inter traffic execution step of transmitting a packet to a segment composed of different VLANs according to a determination result of the traffic determination step through a predetermined process; Wide area network traffic performing step of transmitting to the network by a predetermined operation through the router rather than the virtual local area network traffic, characterized in that consisting of.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is an exemplary view briefly showing a configuration of a system for applying the present invention. As shown in FIG. 2, a logical IP is configured based on a port-based VLAN that is logically bounded by ports according to the IEEE 802.1Q standard. The default gateway is configured by configuring the subnet (LIS) as one VLAN, and the CPU is set as the default gateway of all VLANs (as many IPs as the number of VLAN settings are allocated). Accordingly, the CPU performs routing to deliver a packet to a corresponding destination address when communicating between different VLANs, and forwards packing to a port of a VLAN corresponding to the destination address.

Referring to the accompanying drawings, the operation of an embodiment according to the present invention configured as described above will be described.

3 is a flowchart illustrating a packet switching operation between a virtual local area network according to the present invention. As shown in FIG. 3, when a packet is received from a host (hereinafter, referred to as 'host A') to be transmitted, a source and a destination of the packet are received. It is determined whether the subnet is the same (S10), and if the result is the same, the medium access control (MAC) of the host (hereinafter referred to as 'host B') to be transmitted is determined as intra traffic belonging to the same VLAN. When an address derivation protocol request signal (hereinafter referred to as 'ARP_Request') for knowing an address is transmitted, it is determined whether it is a new MAC address (S11 to S14). As a result of this determination, in case of a new MAC address, the source MAC address and port number of the packet are registered in the MAC address table, and then the registered MAC address is simultaneously transmitted to the CPU of the CPU and Host A and registered in each table. (S15 ~ S16), the ARP_Request packet is then transmitted to the VLAN of the host A, the host B receives the ARP_Request packet, and then the host B transmits a response (hereinafter referred to as 'ARP_Response') to determine whether the new MAC address In operation S17 to S19, if it is determined that the MAC address is a new MAC address, the same operations (S20 to S21) are repeated. Then, the ARP_Response packet is transmitted to the host A to inform the host B's MAC address. Transmits the data packet to the host B (S22 to S23).

If it is not the same as the determination result of step S10, if it is determined as inter traffic and transmits ARP_Request for determining the MAC address of host B to be transmitted from host A as shown in FIG. It is determined whether the new MAC address (S30 ~ S31). As a result of this determination, in case of a new MAC address, the source MAC address and port number of the packet are registered in the MAC address table, and then the registered MAC address is simultaneously used as the VLAN of the CPU and Host A set as the default gateways. It transmits and registers each table (S32 to S33). After the CPU receives the ARP_Request packet, if the CPU transmits ARP_Response, it is determined whether it is a new MAC address (S34 to S36).

If the determination result is a new MAC address, the operation of steps S32 to S33 is repeated, and then the ARP_Response packet is transmitted to the host A to inform the MAC address of the default gateway (CPU) and transmitted from the host A to the host B. The data packet is transmitted to the CPU (S37 to S38), and after the CPU receives the transmitted data packet, it is determined whether there is an entry corresponding to the IP subnet of the destination address in the routing table (S39 to S40). ).

If there is an entry as a result of the determination, after performing routing to the corresponding destination address, the CPU transmits an ARP_Rquest packet to the VLAN of the corresponding host B (S42 to S43) and determines whether it is a new MAC address. After repeating the operation of S33), the host B receives the ARP_Rquest packet (S44 to S45).

Thereafter, when the host B transmits the ARP_Response (S45-1), the host B performs a predetermined operation according to whether the ARP_Response packet is transmitted (S46).

After the CPU receives the ARP_Response packet (S47), the CPU determines whether an entry of the host B exists in the MAC table of the CPU to transmit the data packet received from the host A (S48), and if the entry does not exist, the host B After transmitting a query message to find the device number and port number of the device, a read message is transmitted (S50), the MAC address table is searched according to the inquiry message, the corresponding entry is stored in a register, and then read. When the message is input, the corresponding information is loaded into the message (S51), and the CPU receives the device number and the port number corresponding to the MAC address of the host B in the MAC table (S52).

If it is determined that the entry exists, it is determined whether it is a new MAC address, and if it is determined that the entry is a new MAC address, the operation of steps S32 to S33 is repeated (S49), and then the data packet received from the host A is host. Transfer to B (S53).

In addition, if there is no entry as a result of the determination in step S40, the controller determines that the traffic is wide area network (WAN) traffic, transmits the packet to the router, performs routing, and then transmits the packet to the host B (S41).

As described above, in the packet switching method between the virtual local area networks of the present invention, when a server of one VLAN attempts to connect to another VLAN, the router can access the router through a switch functioning as a routing function. By reducing the load due to the throughput, the performance of the router is improved, and the performance of the entire packet switching operation is also improved.

Claims (5)

When a packet is received from a host to be transmitted, it is determined whether the source and the subnet of the destination are the same to select one of the traffic operations of the intra, inter and wide area network (WAN). A decision step; An intra traffic execution step of transmitting a packet through a predetermined process to a segment composed of the same virtual local area network (VLAN) according to the determination result of the traffic determination step; An inter traffic execution step of transmitting a packet to a segment composed of different VLANs according to a determination result of the traffic determination step through a predetermined process; A method for switching packets between virtual local area networks, comprising performing a wide area network traffic performing step of transmitting to a network by a predetermined operation through a router instead of the virtual local area network traffic. The method of claim 1, wherein the intra traffic execution step includes an address for determining a MAC address of a host (hereinafter, referred to as 'host B') to be transmitted from a host (hereinafter, referred to as 'host A'). Transmitting a derived protocol request signal (hereinafter referred to as 'ARP_Request') to determine a new MAC address; According to the determination result of the first step, the source MAC address and port number of the packet are registered in the MAC address table, and then the registered MAC address is simultaneously transmitted to the CPU of the CPU and the host A to be registered in each table. A second step; Transmitting the ARP_Request packet to the VLAN of the host B when the execution of the second step is completed, and then determining whether a new MAC address is received when a response (hereinafter referred to as 'ARP_Response') is received from the host B; After repeating the operation of the second step according to the determination result of the third step, the ARP_Response packet is transmitted to the host A to inform the host B's MAC address to transmit the data packet from the host A to the host B. Packet switching method between the virtual local area network, characterized in that consisting of a fourth step. The method of claim 1, wherein the performing of the wide area network traffic comprises: a first step of determining whether there is an entry corresponding to an IP subnet of a destination address in a routing table when a packet is received from the host A; A virtual local area network comprising a second step of performing a predetermined step of the inter-tracking step according to the determination of the first step, or transmitting a packet to a router, and then transmitting the packet to the host B How packets are switched between. The method of claim 1, wherein the performing of the inter traffic comprises: a first step of determining whether a new MAC address is transmitted by transmitting an ARP_Request for identifying a medium access control (MAC) address of the host B to be transmitted from the host A; According to the determination result of the first step, the source MAC address and port number of the packet are registered in the MAC address table, and then the registered MAC address is simultaneously transmitted to the CPU of the CPU and the host A and registered in each table. A second step; When the execution of the second step is completed, the ARP_Request packet is transmitted to the VLAN of the host B, the ARP_Response transmitted from the host B is received by the CPU set as the default gateway (default gateway) and transmitted to the host A, and then a new MAC A third step of determining whether the address is an address; After repeating the operation of the second step according to the determination result of the third step, the ARP_Response packet is transmitted to the host A to inform the MAC address of the default gateway (CPU) to transmit data from the host A to the host B. A fourth step of sending a packet to the CPU; A fifth step of determining whether there is an entry corresponding to the IP subnet of the destination address in the routing table after receiving the data packet transmitted by performing the fourth step; After performing the wide area network traffic execution step or routing to the corresponding destination address according to the determination result of the fifth step, transmitting the ARP_Rquest packet to the VLAN of the corresponding host B, and then receiving the ARP_Response from the host B, ARP_Response A sixth step of performing a predetermined operation or determining whether a packet is a new MAC address according to whether a packet is received; A seventh step of repeating the operation of the second step according to the determination result of the sixth step and then transmitting an ARP_Response packet to the CPU; An eighth step of transmitting a data packet received from the host A to the host B after performing the predetermined operation of the sixth step or performing the seventh step of the wide area network; Switching method. The method of claim 4, wherein the sixth step comprises: a first step of determining whether a corresponding entry exists in a MAC table of a CPU; A second step of transmitting a read message after transmitting a query message for determining a device number and a port number of the host B according to the determination result of the first step; A third step of retrieving the MAC address table according to the inquiry message of the second step, storing the corresponding entry in a register, and transmitting the corresponding information to the message when a read message is input; And receiving a message containing the information of the third step and storing a device number and a port number corresponding to the MAC address of the host B in a table.