JP3570506B2 - Network server and control method thereof - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a network server for connecting a client terminal on a local area network (hereinafter, LAN) to the Internet and a control method therefor, and more particularly to a server connectable to the Internet via a plurality of paths. The present invention relates to a network server that is a load distribution processing server that transfers packets intermittently transmitted from a plurality of paths in a distributed manner, and a control method thereof.
[0002]
[Prior art]
FIG. 4 is a block diagram showing an example of a conventional network for connecting a client terminal on a LAN to the Internet. As shown in FIG. 4, the network, the provider ₂ 1, _{2 2,} and router ₄ 1, _{4 2,} and the load distribution processing server 6 is a network server, the LAN 7, and a client ₈ 1 to 8 _n, public The network includes lines 9 ₁ and 9 ₂ , networks 10 ₁ and 10 ₂ , and servers 11 ₁ and 11 ₂ .
[0003]
In this network, the clients 8 ₁ to 8 _n are connected to the LAN 7, and can transmit a third packet to the load distribution processing server 6 similarly connected to the LAN 7. ing.
[0004]
The routers 4 ₁ and 4 ₂ are connected to the load distribution processing server 6 via the networks 10 ₁ and 10 ₂ , respectively. Provider 2 ₁ is connected to the router 4 ₁ via the public line 9 _1, provider 2 ₂ is connected to the router 4 ₂ via the public line 9 _2. Provider 2 _1, 2 ₂ is an Internet Service Provider that provides a connection service to the Internet 1. The servers 11 ₁ and 11 ₂ are servers such as DNS servers of the providers 2 ₁ and 2 ₂ .
[0005]
In this network, a client can connect to the Internet 1 via the load distribution processing server 6. The path from the load distribution processing server 6 to the Internet 1 includes the path of the load distribution processing server 6-network 10 ₁ -router 4 ₁ -provider 21 ₁ -internet 1 and the path of the load distribution processing server 6-network 10 ₂ -router 4 ₂ -Provider 2 ₂ -Internet 1 route. That is, in this network, the route to the Internet 1 is redundantly configured, and the load distribution processing server 6 distributes the packets intermittently transmitted from the clients 8 ₁ to 8 _n to the respective routes and transmits the packets. This distributes the load of routers on each route.
[0006]
The load distribution processing server 6 has a fault-tolerant function of monitoring whether each path is operating normally. However, conventional fault tolerant capabilities of the load distribution processing server 6, the state of the router ₄ 1, _{4 2,} and the state of the network ₁₀ 1, 10 ₂ between the load distribution processing server 6 router ₄ 1, _{4 2} However, the state of the public lines 9 ₁ and 9 ₂ between the routers 4 ₁ and 4 ₂ and the providers 2 ₁ and 2 ₂ is not monitored. Therefore, even if any one of the public lines 9 ₁ and 9 ₂ is not operating, the load distribution processing server 6 does not detect the fact, and the load distribution processing server 6 Packets are also transferred to the router connected to the network, and eventually the packets cannot be delivered to the communication destination.
[0007]
[Problems to be solved by the invention]
As described above, the fault tolerant function of the conventional network server only monitors the status of each router and the status of the network between the network server and each router, and monitors the status of each router and each provider. Did not monitor the status of each public line. Therefore, even if any one of the public lines is not operating, the network server does not detect this, and the network server also sends the packet to the router connected to the inactive public line. There is a problem that the packet is forwarded and the packet cannot be finally delivered to the communication destination.
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to provide a network server and a control method thereof that can make the fault-tolerant function more reliable.
[0009]
[Means for Solving the Problems]
In order to solve the above problem, in the network server of the present invention, a plurality of routes that are connected to a LAN to which at least one client terminal is connected and that pass through at least one of the plurality of routers and an Internet service provider are provided. A network server that can connect to the Internet by periodically transmitting a first packet to each of the routers and checking whether a response to the first packet is received from each of the routers. A second packet is periodically transmitted to the server of the Internet service provider by a route via a router that has responded to the first packet among the routers, and the Internet for the second packet is transmitted. Service provider server response Whether to confirm, among the each router, the operating level of the router no response to the first packet is a first level, of said each router, to the first packet The second level is the operation level of the router that has responded and has not responded to the server of the Internet service provider. The third router has an operation level of the third level, and among the routers, a router whose operation level is the third level is selected as a router for transferring a third packet from each of the client terminals. The third packet is transferred from the client terminal.
[0010]
The network server of the present invention not only checks whether packets can be normally transmitted to each router, but also checks whether packets can be normally transmitted to an Internet service provider via those routers. By doing so, the network server of the present invention can prevent the third packet from being transmitted on a path that cannot transmit the third packet from the client to the Internet. Therefore, in the network server of the present invention, the fault tolerant function can be made more reliable.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, a network server and a control method thereof according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a network centered on a network server according to the present embodiment. As shown in FIG. 1, this network differs from the network of FIG. 4 in that a load distribution processing server 3 which is a network server of the present embodiment is provided instead of the load distribution processing server 6. In FIGS. 1 and 4, components denoted by the same reference numerals all indicate the same components.
[0012]
Router 4 _1, 4 _2, a router R to be fault-tolerant, is registered in the load distribution processing server 3. 1 shows, for simplicity of explanation, the router 4 ₁ as a router _R, 4 ₂ of Although only two shown, the number of routers R may be three or more.
[0013]
Further, the load distribution processing server 3, a router ₄ 1, _{4 2} of the IP address, port number, priority, server ₁₁ 1, 11 IP address such as ₂ are registered. The priority of the routers 4 ₁ and 4 ₂ means that when the load distribution processing server 3 receives a packet from the client 8 ₁ to 8 _n , the packet is distributed to the routers 4 ₁ and 4 ₂ and transmitted. This is the priority as the transfer destination. If towards the router 4 ₁ Router 4 ₂ than the higher priority, the packet is first sent to the router 4 _1, then each packet received, alternating router 4 _2, the router 4 1 _... order Sent to. Note that these registrations are executed by the administrator of the load distribution processing server 3.
[0014]
Further, the load distribution processing server 3, in the presence of periodically transmits to the router ₄ 1, _{4 2,} router ₄ 1, _{4 2} responses to that request an ARP request or the like which is the first packet, the router _{4 1} , ₄ or ₂ is operating, the network ₁₀ 1, 10 ₂ of the cable is checked or not broken. A protocol such as ARP used for checking the routers 4 ₁ and 4 ₂ and the networks 10 ₁ and 10 ₂ is referred to as a protocol Pr. Other protocols that can be used as such a protocol Pr include a protocol using a PING command. Which protocol is used as the protocol Pr needs to be registered in the load distribution processing server 3 in advance.
[0015]
Furthermore, the load distribution processing server 3 monitors the server ₁₁ 1, 11 ₂ by executing the PING command OS or the like itself is supported, i.e., server ₁₁ 1, 11 to ₂ transmits a second packet , by checking whether or not there is a response to the second packet periodically checks whether the public line 9 _1, 9 ₂ are operating properly. Such server ₁₁ 1, 11 ₂ and the server Sip. A protocol using a PING command used for checking the public lines 9 ₁ and 9 ₂ is referred to as a protocol Ps. Other protocols that can be used as such a protocol Ps include ARP and the like. Which protocol is used as the protocol Ps needs to be registered in the load distribution processing server 3 in advance. In this network, per each router R (Router ₄ 1, _{4 2),} (server 11 ₁ to the router _{4 1,} the router _{4 2} server 11 ₂₎ server as a server Sip only by the one of each shown Although not performed, there may be a plurality of servers Sip for each router R (routers 4 ₁ and 4 ₂ ). In this case, each server Sip naturally has a different IP address, and an IP address is set for each server Sip in the routing table of each router R.
[0016]
Further, the load distribution processing server 3 determines the operation level A of the router R (routers 4 ₁ , 4 ₂ ) that is considered to be operating normally by checking with the above-mentioned protocol Pr and protocol Ps. The operation level A is a level indicating the operation state of each route passing through the router, and is set to determine whether or not the router is to be subjected to the above-described packet distribution. Level.
[0017]
If there is no response from the router R in the check by the protocol Pr, it is considered that there is some failure in the router R or the network between the router R and the load distribution processing server 3, and the operation level A of the router R is the first. Is set to the level “0”.
[0018]
If there is no response from the server in the check by the protocol Ps, it is considered that there is some failure in the public line between the router R and the provider, and the operation level A of the router R is the second level “1”. Is set to
[0019]
If it is determined that the router R is operating normally by the check by the protocol Pr and the protocol Ps, the operation level A of the router R is set to the third level “2”.
[0020]
In the network server of the present embodiment, the three operation levels A are “0” to “2”, but the network control system of the present invention is not limited to this, and the three operation levels A It may be expressed in such a format. The operation level A may be a two-stage level of a level indicating that there is some kind of trouble and a level indicating that transfer is possible. Since it is possible to determine whether a failure has occurred in a part, a better embodiment is achieved.
[0021]
Client 8 ₁ to 8 _n is, sending intermittently packet to the default route of the load distribution processing server 3 to access the Internet 1, the load distribution processing server 3, the operation level A is "2" The packets are transmitted to the router R. For example, if only the operation level A of each router 4 ₁ is "2", the load distribution processing server 3 transfers the packets only to the router 4 _1. When the operation level A of each of the routers 4 ₁ and 4 ₂ is “2”, the load distribution processing server 3 sets each of the routers 4 ₁ and 4 _{2 in} accordance with the previously set priority. To forward those packets. If there are three or more routers R, of which two or more routers R have the operation level A of “2”, the load distribution processing server 3 sets the priority according to the previously set priorities. , And forwards those packets to each router R whose operation level A was “2” in turn. The router R that has received the packet transfers the packet to a provider connected via a public line. The packet is forwarded on the Internet 1 via the provider.
[0022]
Thus, in this network, for example, it is a public line 9 ₁ is a system down, if normal public line 9 _2, the load distribution processing server 3 forwards the packet only to the router 4 _2, clients 8 _{1 8n} can normally communicate with the communication destination on the Internet 1.
[0023]
Next, an operation of the network server of the present embodiment, that is, a method of controlling the network server will be described. FIG. 2 is a flowchart illustrating the operation of the fault tolerant function of the load distribution processing server 3 that is the network server of the present embodiment.
[0024]
As shown in FIG. 2, first, the load distribution processing server 3 performs setting for the connected router R (Step A0). As described above, the router R to be connected, if FIG. 1, is that of the router 4 _1, 4 ₂ of any of the routers. Note that what is set in step A1 is the priority of each router R, the setting of the protocol Pr, the IP address of each server Sip (servers 11 ₁ and 11 ₂ ), the setting of the protocol Ps, and the like. The priorities of the routers are not duplicated.
[0025]
The IP address of each server Sip is set in the routing table of each router R, and the protocol Ps can be set for each IP address of each server Sip. Next, the load distribution processing server 3 selects one of the routers R (Step A1).
[0026]
Further, the load distribution processing server 3 transmits a packet based on the protocol Pr to the router R (hereinafter simply referred to as router R) selected in step A1 according to the protocol Pr, and the router R responds to the packet. It is checked whether or not there is (Step A2). If there is a response from the router R in step A2, it is considered that the network between the router R and the load distribution processing server 3 is operating, and the operation level A of the router R is set to 1 (step A3). ). If there is no response from the router R in step A2, the operation level A of the router R is set to "0" (step A4). After executing step A3, a packet of the protocol Ps addressed to the IP address of the server Sip set in the router R is transmitted to the router R, and it is checked whether or not there is a response from the server Sip (step A5).
[0027]
If there is a response from the server Sip in step A5, the operation level A of the router R is set to "2" (step A7). In step A4, if there is no response from the server Sip, it is checked whether or not all the servers Sip have been checked (step A6). If the check has not been completed for all servers Sip in step A6, the process returns to step A5. In step A6, if the check is completed for all the servers Sip without any response from all the servers Sip, it is considered that some trouble has occurred in the public line of the router R, and the operation of the router R The level A setting remains "1".
[0028]
After the execution of steps A4 and A7, or when the check on all the servers Sip is completed in step A6, the load distribution processing server 3 determines whether or not the check on the state of all the routers R is completed. A judgment is made (step A8). In step A8, if the check of the status of all routers R has not yet been completed, the process of the load distribution processing server 3 returns to step A2, and if the check of the status of all routers R has been completed, Then, the processing of the load distribution processing server 3 ends. When returning to step A2, the load distribution processing server 3 executes steps A2 to A8 at regular intervals. As described above, the check by the protocol Pr and the protocol Ps is performed periodically.
[0029]
3, when receiving the packet from the client 8 ₁ to 8 _n, is a flowchart showing the operation of the load distribution processing server 3 is a network server of the embodiment. As shown in FIG. 3, when receiving packets from the clients 8 ₁ to 8 _n in step B1, the load distribution processing server 3 continues to check the operation levels A of all the routers R in descending order of priority. The router R is selected (step B2), the operation level A of the selected router R (hereinafter simply referred to as router R) is checked, and it is checked whether the operation level A is "2" (step B2). Steps B3 and B4). In step B3, if the operation level A of the router R is "2", to the router R, and transfers the packet received from the client 8 ₁ to 8 _n (step B5), the flow returns to step B1 . In step B4, if the operation level A all the routers R is not "2", and discards the packet received from the client 8 ₁ to 8 _n (step B6), the flow returns to step B1.
[0030]
As described above, the network server according to the present embodiment not only checks whether packets can be normally transmitted to each of the fault-tolerant routers, but also checks the Internet service provider 2 via those routers. It is confirmed whether packets can be transmitted normally to ₁ , 2 and ₂ . By doing so, the network server of the present embodiment, the path can not send packets from the client 8 ₁ to 8 _n to the Internet 1, it is possible not to transmit the packet. Therefore, the network server can make its fault-tolerant function more reliable.
[0031]
【The invention's effect】
As described above, the network control system of the present invention not only checks whether packets can be normally transmitted to each router, but also can normally transmit packets to the Internet service provider via those routers. Have confirmed. By doing so, the network server of the present invention can prevent a packet from being transmitted on a path that cannot transmit a packet from a client to the Internet. Therefore, in the network server of the present invention, the fault tolerant function can be made more reliable.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a network centered on a network server according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating an operation of a fault tolerant function of a load distribution processing server which is a network server according to an embodiment of the present invention.
FIG. 3 is a flowchart illustrating an operation of a load distribution processing server that is a network server according to an embodiment of the present invention when a packet is received from a client.
FIG. 4 is a block diagram showing a configuration of a conventional network centered on a conventional network server.
[Explanation of symbols]
1 Internet 2 ₁ , 2 ₂ Provider 3, 6 Load distribution processing server 7 LAN
8 ₁ , 8 _n Client 9 ₁ , 9 ₂ Public line 10 ₁ , 10 ₂ Network 11 ₁ , 11 ₂ Servers A0-A8, B1-B6 Step

Claims (6)

A network server connected to a LAN to which at least one client terminal is connected, and capable of connecting to the Internet via a plurality of routes through at least one of the plurality of routers and an Internet service provider. A network server that transmits a first packet to each of the routers and checks whether a response to the first packet is received from each of the routers,
A second packet is periodically transmitted to the server of the Internet service provider by a route via a router that has responded to the first packet among the routers, and the Internet for the second packet is transmitted. Check whether there is a response from the server of the service provider, and, among the routers, set the operation level of the router that has not responded to the first packet to the first level, and among the routers, An operation level of a router that has responded to the first packet and has not responded to the server of the Internet service provider is set to a second level, and among the routers, the operation level of the Internet service provider is The operation level of the router on the route to which the server responded is set to the third level, and Among the features to transfer the router with the operation level as the third, the third packet from the third said client terminal to select as a router to forward packets from the client terminal Network server to do. When the third packet is intermittently received, the third packet is transferred to a router whose operation level is the third level in a preset order of priority of the routers. 2. The network server according to 1 . Wherein in the operation level of each server, the operating level of all routers, wherein when the non-3 level, the third network server the packet discarding according to claim 1 or 2 wherein. A method for controlling a network server connected to a LAN to which at least one client terminal is connected and connectable to the Internet by a plurality of routes through at least one of the plurality of routers and an Internet service provider, A method of controlling a network server, comprising: periodically transmitting a first packet to each of the routers; and confirming whether or not a response to the first packet is received from each of the routers.
A second packet is periodically transmitted to the server of the Internet service provider by a route via a router that has responded to the first packet among the routers, and the Internet for the second packet is transmitted. Checking whether there is a response from the service provider's server;
Setting an operation level of a router that has not responded to the first packet among the routers to a first level;
Setting the operation level of the router that has responded to the first packet among the routers that has not responded to the server of the Internet service provider to a second level;
Setting the operation level of the router on the route to which the server of the Internet service provider has responded to the third level among the routers;
Selecting a router whose operation level is the third level from among the routers as a router that forwards a third packet from each of the client terminals;
Transferring the third packet from the client terminal to only the router selected as the router for transferring the third packet from each of the client terminals among the routers. , Network server control method. Transferring the third packet to a router whose operation level is the third level when the third packet is received intermittently in the order of the priorities of the routers set in advance. The method for controlling a network server according to claim 4 , further comprising: Of operating level of each router, the operating level of all routers, wherein when the non-third level further comprises a discarding step the third packet by the network server, according to claim 4 or 5, wherein How to control the network server.

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