KR100667783B1 - Communication adapter switching method and apparatus - Google Patents

Abstract

According to the present invention, a method and apparatus for switching a communication adapter in a system environment equipped with a plurality of communication adapters is disclosed.

In the switching method according to the present invention, a method of switching the communication adapter in a system environment equipped with a plurality of communication adapters, the address of the plurality of communication adapters to the address of the first communication adapter of the plurality of communication adapters Setting the same, setting the packet filtering mode of the other communication adapters except the first communication adapter to a mode that can accept all packets, and communicating through one communication adapter of the plurality of communication adapters. And switching to another communication adapter when the communication is disconnected. According to the present invention, since only one virtual adapter is visible to protocol drivers such as TCP / IP, even when the communication adapter is switched, the session of TCP / IP with the same IP address is almost never disconnected. One handoff is possible.

Description

Communication adapter switching method and apparatus

1 is a configuration diagram of a network driver system according to the prior art;

2 is a configuration of a network driver according to the prior art,

3 is a configuration diagram of a network driver system according to the present invention;

4 is a configuration of the virtual driver shown in FIG. 3;

5A and 5B are flowcharts of a virtual driver loading process according to the present invention;

6 is a flowchart illustrating operations at the time of connecting according to the present invention;

7 is a flowchart illustrating operations during disconnection according to the present invention.

The present invention relates to the field of networks, and more particularly to a method and apparatus for switching communication adapters.

 You can install multiple communication physical adapters in the Windows OS. In addition, each of the plurality of physical adapters may be assigned an IP address for communication. When establishing a session with the other party, basically, the IP address of the network layer and the port address of the transport layer are paired. If any of these pairs change, the session will be immediately disconnected.

 If there are two physical adapters of the same type (eg 802.3), then each physical adapter will be given a different IP address. When the communication application connects to the communication session, it selects one IP address according to an optimal routing path and communicates with the other party through a physical adapter to which the corresponding IP address is assigned. For example, other physical adapters such as 802.3 and 802.11 will communicate in the same way.

 However, if a user activates both a wired LAN and a wireless LAN at the same time on a PC with a Windows OS having a heterogeneous physical adapter and communicates with each other, and if both are connected to the same domain, a fast wired LAN is generally faster. Will communicate. That is, the IP address used at this time will be an IP address assigned to the wired LAN. However, when the wired LAN is disconnected, Windows OS automatically terminates the session of the application using TCP / UDP communication. This is because the assigned IP address is no longer available.

1 illustrates a kernel-level library provided by Microsoft for providing a networking function of a Windows OS. This is called NDIS (Network Driver Interface Specification). If a real physical adapter is connected to a PCI interface, the driver to drive it will develop a miniport driver for that physical adapter in accordance with NDIS's Miniport Spec. Then, the actual physical adapter operates, receives and forwards packets at an upper level, and receives packets from an upper level and transmits the packets to a local area network (LAN).

 Commonly known TCP / IP and NETBIOS are actually protocol drivers that run on top of NDIS. The protocol driver is usually at the kernel level of the operating system, and the application is at the user level.

Referring to FIG. 1, a network driver system includes a WIN32 packet driver 110, a LAN protocol driver 120, an NDIS 130, an intermediate driver 140, a miniport driver 150, and a miniport driver 160. NIC 170, NIC 180.

The device driver is the means by which the operating system and its input / output devices are connected, interpreting general requests received from the operating system and converting them into commands that a particular peripheral controller can understand.

Network interface cards (NICs) 170 and 180 are physical devices that act as gateways that allow data frames to be transmitted and received over a network.

Network Driver Interface Specification (NDIS) 130 describes an interface that allows one or more NIC drivers to communicate with one or more protocol drivers and operating systems thereon. In other words, NDIS provides a library of functions (called wrappers) that can be used by NIC drivers as well as high-level (TCP / IP) protocol drivers. The NIC driver relies on NDIS for all external functions, including communication with protocol drivers, registering and intercepting NIC hardware interrupts, and communication with underlying NICs.

NDIS drivers include network interface card (NIC) drivers, intermediate protocol drivers, and high-level protocol drivers.

The network interface card driver manages network interface cards (NICs). The NIC driver interfaces directly with the hardware (NIC) at its lower edge, and provides an interface at the upper edge that allows higher-level drivers to:

One of the NIC drivers, miniport driver 150 and 160, implements the hardware specific operations required to manage the NIC, including sending and receiving data to and from the NIC. The miniport driver does not call the operating system directly, but instead can call functions exported by NDIS. It interfaces with higher level drivers such as intermediate drivers and transport protocol drivers.

The intermediate driver 140 exists between the existing protocol driver and the miniport driver. To the high-level transport driver, the intermediate driver looks like a miniport drive. To the miniport driver, the intermediate driver looks like a protocol driver. The main reason for using the intermediate driver is to convert media between the existing protocol driver and the miniport driver that manages the new media types unknown to these protocol drivers.

Due to its intermediate position in the driver layer, the intermediate driver communicates with both the miniport driver below and the protocol driver above. At the lower edge, the intermediate driver provides the protocol entry point and at the upper edge the miniport entry point. This is used by NDIS to forward requests to the protocol driver above it. To the protocol driver at the top, it appears to be a miniport driver.

The high level protocol driver 120 implements a TDI interface or an application specific interface to provide services to its users. Such a driver sends these packets to the lower level driver by allocating packets, copying data into the packets, and calling NDIS. It also provides a protocol interface at that lower level to receive packets from the next lower level driver. The transport protocol driver also forwards the received data to the appropriate client application.

As shown in Figure 2, in the current Windows OS, not only heterogeneous physical adapters, but also a single physical communication line is disconnected from the same type of physical adapter, the session itself is automatically disconnected. This is because TCP stores information about the media in the TCB (Tcp Control Block), because when the information about the interface is lost, TCP automatically disconnects the session. This is done because it is obvious that the interface is broken and the IP address assigned to that interface will no longer be available. Even if the session is not disconnected from TCP, Windows cannot assign the same IP address to different interfaces at the same time. If you want to change to the same IP for a while, all other existing sessions will be disconnected because the TCP / IP protocol driver itself is down / up.

 Because of these problems, in order to make sure that there is only one interface in the real protocol driver stage, you can use a bridge called Windows to create a virtual adapter. Although the Bridge provides the same IP address, the handoff time is basically about 30 seconds. In other words, when a bridge loses communication with one physical adapter, the bridge automatically sends a signal to the virtual adapter created by the bridge. This automatically disconnects all sessions from the TCP / IP protocol driver. And another problem with the bridge method is that it takes too much time to switch from one media to another. The experiment takes about 30 seconds, which is the TCP timeout time. Even if you block the information that the connection is lost, the session will eventually be disconnected due to TCP timeout.

Disclosure of the Invention It is an object of the present invention to provide a communication adapter switching method and apparatus for maintaining a communication session of a higher application and providing the same without interruption in switching between heterogeneous communication adapters.

One feature of the present invention for solving the above problems is a method for switching the communication adapter in a system environment equipped with a plurality of communication adapters, the address of the plurality of communication adapters the plurality of communication adapters Setting the same as the address of the first communication adapter, setting the packet filtering mode of the other communication adapters except the first communication adapter to a mode that can accept all packets, and the plurality of communication adapters. Switching to another communication adapter when the communication is disconnected while communicating through one of the communication adapters.

Another aspect of the present invention provides a method for switching the communication adapter in a system environment equipped with a plurality of communication adapters, wherein the MAC address of the wired LAN communication adapter of the plurality of communication adapters is set to the MAC address of the WLAN communication adapter Setting the packet filtering mode of the wired LAN communication adapter to a promiscuous mode to accept all packets; and when the wired LAN communication is disconnected while communicating through the wired LAN communication adapter, wireless LAN information is transmitted. And switching to the WLAN communication adapter using the wireless LAN.

The switching method may further include switching to the wired LAN communication adapter using the wired LAN information when an event indicating the wired LAN communication connection occurs while communicating through the wireless LAN communication adapter.

The switching method may further include setting a packet filtering mode of the WLAN communication adapter to a direct, multicast or broadcast mode.

The switching method may further include mapping the WLAN information to a virtual adapter when the wired LAN communication adapter is not connected.

Another aspect of the present invention provides a device for switching the communication adapter in a system environment equipped with a plurality of communication adapters, wherein the address of the plurality of communication adapters is the same as the address of the first communication adapter of the plurality of communication adapters. And setting the packet filtering mode of the other communication adapters except the first communication adapter to a mode that can accept all packets, and communicating through one communication adapter of the plurality of communication adapters. And a virtual protocol driver that switches to another communication adapter when the communication is disconnected.

In still another aspect of the present invention, in the apparatus for switching the communication adapter in a system environment equipped with a plurality of communication adapters, the MAC address of the wired LAN communication adapter of the plurality of communication adapters is set as the MAC address of the WLAN communication adapter. And a virtual adapter that sets a packet filtering mode of the wired LAN communication adapter to a promiscuous mode to accept all packets, and when the wired LAN communication is disconnected while communicating through the wired LAN communication adapter, It includes a virtual protocol driver for switching to the WLAN communication adapter using the information.

The virtual protocol driver preferably includes a link state detector for providing a connected or disconnected state whenever a connected or disconnected event occurs.

Preferably, the virtual protocol driver further includes an optimal adapter selecting unit that determines an optimal adapter for communication based on the information provided by the link state detection unit.

Packets received from the physical adapter are unconditionally sent to the virtual adapter, and packets to be sent to the physical adapter are preferably sent to the determined optimal adapter.

The present invention will now be described in detail with reference to the accompanying drawings.

3 is a configuration diagram of a network driver system according to the present invention.

According to the present invention, the actual miniport driver only binds to the virtual protocol driver belonging to the intermediate driver. Then, we create a virtual miniport driver, and the protocol driver and miniport driver also bind to each other. Real protocol drivers such as TCP / IP then bind only to the virtual miniport driver. By doing this, the real protocol driver knows the connection status only by information informed by the virtual driver and sends and receives all packets.

Referring to FIG. 3, the network driver system includes an intermediate driver 400, a NIC 350, 360, an 802.3 miniport 330, an 802.11 miniport 340, a LAN protocol driver 310, and an NDIS. 320.

The intermediate driver according to the present invention includes a virtual protocol driver at the bottom and a virtual miniport driver at the top. In other words, the relationship between the virtual protocol driver and the miniport driver at the bottom of the intermediate driver acts as a protocol driver, and the relationship between the virtual miniport driver and the LAN protocol driver at the top of the intermediate driver. The intermediate driver acts as a miniport driver. This virtual miniport driver is seen as one adapter by the upper real protocol driver. The reason for creating the virtual adapter is that the session of the TCP / IP protocol driver is immediately disconnected because of the disconnection information of the actual physical adapter. If the information is filtered by the intermediate driver stage according to the present invention, it is possible to prevent transmission of information that is disconnected from the physical adapter to the actual protocol driver stage. In other words, the TCP session is maintained.

Also, if there are two actual physical adapters, the continuity of communication cannot be given because the IP addresses must be continuously assigned to each adapter. For this reason, the intermediate driver is used as a virtual adapter at the bottom of the two physical adapters. In this case, the application layer above the protocol driver of communication communicates with one virtual adapter, so that it is in a state where the physical adapter under the virtual driver is in a state and the physical adapter is actually communicating with the virtual adapter.

Therefore, the intermediate driver stage according to the present invention may change the routing of packets at will. Therefore, the intermediate driver stage then selects the communication media according to the situation and sends and receives packets to and from the physical adapter. This allows switching of wired / wireless communication to occur in near real time without affecting the higher real protocol drivers.

Referring to FIG. 4, the intermediate driver 400 according to the present invention includes a virtual miniport driver 410 and a virtual protocol driver 420.

The virtual miniport driver 410 includes a virtual adapter controller 411.

The virtual adapter control unit 411 generates a virtual adapter and controls to bind and use the virtual adapter in the protocol driver or higher.

In addition, when the virtual protocol driver attempts to set the properties of each adapter at the time of binding with the lower physical adapter, the virtual adapter controller sets all the physical adapters bound below to the same address. When setting the packet filtering value in Promiscous mode, which allows all packets to be accepted in the case of wired LAN, and direct / multicast / broadcast (Direct | Multicast) which is generally used in the case of WLAN. BroadCast) mode. Thereafter, the MAC address of the virtual adapter is used as the MAC address of the WLAN. That is, in the wired LAN address is set to the Promise Cure's (promiscuous) mode accepts all packets, so substantially in the case of oil seonraen has the same as not setting the address, since a WLAN address using a normal mode As it is, the general MAC address of the WLAN is used. Therefore, it appears to the protocol driver in the upper stage that only one MAC address of the WLAN is set for the wired LAN and the WLAN.

By using the same MAC address, you can avoid having to retransmit ARP packets to update the ARP table of the hub. In addition, MAC address is used as one option of DHCP protocol when assigning dynamic addresses using DHCP. In this case, DHCP server is recognized as the same PC by using the same MAC address. It can be used without any problem. Finally, the next-generation Internet Protocol Version 6 (IPv6) uses MAC addresses to assign IPv6 addresses using Syateless Auto Configulation, so the MAC addresses are the same.

In addition, the virtual adapter controller 411 reports the optimal adapter information selected by the optimal adapter selector 421 to the higher protocol driver when information is requested from the higher protocol drivers. Select the link status information below to inform the protocol drivers. In addition, the virtual adapter controller 411 sends the packet through the binding handle of the optimal adapter selected by the optimal adapter selector 421.

The virtual protocol driver 420 includes an optimal adapter selecting unit 421, a link state detector 422, and an adapter binding unit 423.

The optimal adapter selector 421 determines which physical adapter to transmit / receive according to the connection information of the wired / wireless LAN received from the link state detector 422.

The link state detector 422 detects link state information of the wired / wireless LAN and provides the link state information to the optimum adapter selector 421.

The adapter binding unit 423 binds all enabled adapters to generate a binding list 424. Each bound physical adapter then has a binding handle to control it. The present invention includes an 802.3 binding handle 425 and an 802.11 binding handle 426 for a wireless LAN. The binding handle is similar to the key used by the virtual adapter to communicate with the miniport drivers below. In addition, the adapter binding unit 423 unconditionally receives the packet and sends it to the virtual adapter.

5A and 5B illustrate an initialization process of an intermediate driver as a DriverEntry function according to the present invention. DriverEntry allocates packet pools and buffer pools for ARP, registers driver handles for miniport drivers, protocol handles for protocol drivers, and informs NDIS of associations between driver handles and protocol handles. Figure 5a is shown in the center of the process of initializing the intermediate driver in accordance with the present invention.

Referring to FIG. 5A, the initialization of the intermediate driver is initiated by the operating system by invoking a DriverEntry function that serves as the entry point of the intermediate driver (510).

Next, the virtual adapter controller 411 binds the 802.3 adapter (520). A virtual adapter data structure is a data structure that is created to store information about a physical adapter whenever a binding is made with a physical adapter. Therefore, this data structure is generated by the number of actual physical adapters. The virtual adapter data structure is bound to this data structure by the actual real protocol drivers. This binding with the physical adapter results in the binding handle of the physical adapter.

The binding handle data structure is responsible for storing a list of the lower number of data structures in the upper virtual adapter data structure.

In the 802.3 adapter binding process, the packet filtering property of the 802.3 wired LAN adapter is set to a promiscuous mode (521). Adapters placed in promiscuous mode are configured to accept any incoming packet.

The address of the wired LAN adapter is set to the MAC address of the 802.11 layer 2 WLAN adapter (522).

In this configuration, the 802.3 wired LAN adapter has the MAC address of the 802.11 wireless LAN adapter and can receive all the packets coming into the wired LAN.

Next, the virtual adapter controller 411 binds the 802.11 adapter (530).

The packet filtering property for the 802.11 WLAN adapter is set to direct, multicast, and broadcast modes (531). This is a commonly used mode setting method.

Direct mode has the physical address (Ethernet address) of the destination machine where a frame destined for a particular machine is specified as its destination address. The machine with such a physical address will accept the frame, and all other machines will not accept it.

Multicast mode is a form in which a frame transmitted to a set of specific machines is transmitted in a multicast frame having a multicast address designated as its destination address. These sets of machines make up a multicast group. Thus, any machine that is a member of this multicast group can accept a frame with a multicast destination address. Although the NIC is not part of a multicast group, the NIC can be set programmatically in a multicast mode that accepts all multicast frames.

The broadcast mode is a form in which frames transmitted to all machines on the network are broadcast on the network with a destination address of 0xffffff. 0xffffff is considered the broadcast address for the frame. The NIC placed in this broadcast mode accepts frames with this destination address. Typically all NICs are configured to accept broadcast frames.

After binding as many physical adapters as described above, the virtual adapter controller 411 generates a virtual adapter (540) and initializes the virtual adapter (550). Initializing a virtual adapter includes allocating a binding handle data structure to store binding handle information, generating a binding handle list, storing the binding adapter's point information and binding handle information in the generated binding handle list, and the like. .

Next, the connection status is queried by the virtual protocol driver 420 (560).

The connection state detection unit 422 of the virtual protocol driver 420 receiving the query detects the 802.3 connection state information and the 802.11 connection state information (570). The detected connection state information is transmitted to the optimum adapter selector 421.

Then, the optimal adapter selector 421 selects an optimal adapter (580). When both wired LAN and wireless LAN are connected, the wired LAN is faster, so choose the optimal adapter for the wired LAN. If the wired LAN is not connected, select the optimal adapter for the wireless LAN. Then, the information on the optimal adapter selected in this way is transmitted to the virtual adapter control unit 411.

Upon receiving this, the virtual adapter controller 411 maps information of the selected optimal adapter (590). When this operation is completed, it is ready to communicate.

6 is a flowchart illustrating operations at the time of connecting according to the present invention.

First, when a connect event occurs in the disconnected state 601 in both the wired LAN of 802.3 and the wireless LAN of 802.11 (602), the virtual miniport driver reports the connection state to the upper protocol driver (603). The upper protocol driver determines whether the connected adapter is 802.3 (604), and in case of 802.3, communicates with 802.3 (607). If an 802.11 connect event occurs while communicating with 802.3 (605), the connection information of 802.11 is updated (606).

Next, if the connected adapter is 802.11 instead of 802.3, 802.11 information is mapped to the virtual adapter (608). In operation 609, communication with 802.11 is performed.

If an 802.3 connect event occurs during communication with 802.11 (610), 802.3 information is mapped to the virtual adapter (611). It then communicates with 802.3 (612).

7 is a flowchart illustrating operations during disconnection according to the present invention.

Referring to FIG. 7, while communicating with 802.3 (701), when a disconnect event occurs (702), the virtual adapter controller determines whether the disconnected adapter is 802.3 (703), and if it is 802.3, the virtual adapter. Remapping 802.11 information at 704. Then, communication with 802.11 is performed (705).

If the disconnected adapter is not 802.3, the connection state of the 802.3 is checked (706).

If the check result is the connected state, the communication with 802.3 is performed (707).

If the result of the check is disconnected, the disconnection status is reported to the upper protocol driver (708), and 802.3 information is remapped to the virtual adapter (709). In this case, all of them are disconnected.

The switching method as described above can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. In addition, functional programs, codes, and code segments for implementing the switching method can be easily inferred by programmers in the art to which the present invention belongs.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

According to the present invention as described above, to make the communication medium between heterogeneous to one unique virtual adapter, to give a virtual adapter made one IP address, when both wired / wireless LAN is connected to use a fast wired LAN, If the wired LAN is disconnected, it automatically detects this and changes the routing of packets in the WLAN, so that only one virtual adapter is visible to protocol drivers such as TCP / IP. Since the address does not change, the session can continue.                     

In other words, when handing off wirelessly in a wired connection, a seamless seamless handoff is possible without disconnecting a session of TCP / IP with the same IP address. Also, since the same Mac address is used, IP address assigned by DHCP ensures continuity of communication. In addition, even in an IPv6 environment, seamless communication is possible even in a stateless auto configuration environment in which an IPv6 address is generated with a Mac address.

Claims (10)

A method for switching the communication adapter in a system environment equipped with a plurality of communication adapters, Setting an address of the plurality of communication adapters equally to an address of a first communication adapter of the plurality of communication adapters; Setting a packet filtering mode of the other communication adapters except the first communication adapter to a mode that can accept all packets; And switching to another communication adapter when the communication is disconnected while communicating through one of the plurality of communication adapters. A method for switching the communication adapter in a system environment equipped with a plurality of communication adapters, Setting the MAC address of the wired LAN communication adapter among the plurality of communication adapters to the MAC address of the wireless LAN communication adapter, and setting the packet filtering mode of the wired LAN communication adapter to a promiscuous mode that can accept all packets. Wow, And switching to the wireless LAN communication adapter using wireless LAN information when the wired LAN communication is disconnected while communicating through the wired LAN communication adapter. The method of claim 2, And switching to the wired LAN communication adapter using the wired LAN information when an event informing the wired LAN communication connection occurs while communicating through the wireless LAN communication adapter. The method of claim 2, And setting the packet filtering mode of the WLAN communication adapter to a direct, multicast, or broadcast mode. The method of claim 2, And if the wired LAN communication adapter is not connected, mapping the wireless LAN information to a virtual adapter. An apparatus for switching the communication adapter in a system environment equipped with a plurality of communication adapters, A mode in which the addresses of the plurality of communication adapters are set to be the same as the address of the first communication adapter among the plurality of communication adapters, and the packet filtering mode of the other communication adapters except the first communication adapter can accept all packets. The virtual adapter to set to And a virtual protocol driver for switching to another communication adapter when the communication is disconnected while communicating through one of the plurality of communication adapters. An apparatus for switching the communication adapter in a system environment equipped with a plurality of communication adapters, A virtual address setting the MAC address of the wired LAN communication adapter of the plurality of communication adapters to the MAC address of the wireless LAN communication adapter, and setting the packet filtering mode of the wired LAN communication adapter to a promiscuous mode that can accept all packets. With the adapter, And a virtual protocol driver for switching to the wireless LAN communication adapter using wireless LAN information when the connection of the wired LAN communication is lost while communicating through the wired LAN communication adapter. The method of claim 7, wherein The virtual protocol driver, And a link state detector for providing a connected or disconnected state whenever a connected or disconnected event occurs. The method of claim 8, The virtual protocol driver, And an optimum adapter selection unit for determining an optimum adapter for communication based on the information provided by the link state detection unit. The method of claim 9, And a packet received from a physical adapter is unconditionally sent to the virtual adapter, and a packet to be sent to the physical adapter is sent to the determined optimal adapter.

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