JP7585696B2 - Network system, communication system, and communication method - Google Patents

Description

The present invention relates to a network system, a communication system, and a communication method.

When there are a large number of client terminals, it may take time to change the settings associated with replacing the server. In such a case, both client terminals after the setting change and client terminals before the setting change will exist within the communication system. The client terminals before the setting change can communicate with the old server (hereafter referred to as the old server), but the client terminals after the setting change cannot communicate with the old server. Therefore, the client terminals after the setting change will be unable to communicate with the server until operation of the new server (hereafter referred to as the new server) begins.

Patent Document 1 discloses technology related to an update management system that manages application updates. If a problem occurs, a switchover to the old server is performed.

International Publication No. 2015/146355

As mentioned above, there was a problem in that client terminals that had their settings changed to communicate with the new server were unable to communicate with the old server until the new server began operation.

The present disclosure has been made to solve such problems. In other words, the objective is to provide a network system, a communication system, and a communication method that enable communication between a client terminal whose settings have been changed to communicate with a new server and an old server.

The network system according to the present disclosure includes a first network device that, when relaying a packet transmitted by a client terminal, transmits a packet having address information of a non-production server as destination information to a detour route and transmits a packet having address information of a production server as destination information to a direct route;
a second network device that performs at least one of a process of transmitting a packet transmitted by the operation server to both the detour route and the direct route when relaying the packet, and a process of transmitting the packet so that the routes of the outgoing packet and the return packet are the same based on route identification information assigned to the packet;
and a third network device that converts destination information of a packet sent by the client terminal into address information of the operational server, and converts source information of a packet sent by the operational server into address information of the non-operational server, on the detour route.

The communication system according to the present disclosure comprises:
A production server;
A client terminal;
A network system;
Equipped with
The network system includes:
a first network device that, when forwarding a packet transmitted by the client terminal, transmits a packet having address information of a non-operational server as destination information to a detour route and transmits a packet having address information of the operation server as destination information to a direct route;
a second network device that performs at least one of a process of transmitting a packet transmitted by the operational server to both the detour route and the direct route when forwarding the packet, and a process of transmitting the packet so that the routes of the outgoing packet and the return packet are the same based on route identification information assigned to the packet;
and a third network device that converts destination information of a packet sent by the client terminal into address information of the operational server on the detour route, and converts source information of a packet sent by the operational server into address information of the non-operational server.

The communication method according to the present disclosure includes:
When forwarding packets sent by a client terminal, packets whose destination information is the address information of a non-production server are sent via a detour route, and packets whose destination information is the address information of a production server are sent via a direct route.
When forwarding a packet transmitted by the operational server, at least one of a process of transmitting the packet via both the detour route and the direct route and a process of transmitting the packet so that the routes of the outgoing packet and the return packet are the same based on route identification information assigned to the packet,
In the detour route, destination information of a packet sent by the client terminal is converted to address information of the primary server, and source information of a packet sent by the primary server is converted to address information of the non-primary server.

According to the present disclosure, it is possible to provide a network system, a communication system, and a communication method that enable communication between a client terminal whose settings have been changed to communicate with a new server and an old server.

1 is a block diagram showing a configuration of a communication system according to a first embodiment; FIG. 11 is a block diagram showing a configuration of a communication system according to a second embodiment. FIG. 11 is a block diagram showing a configuration of a communication system according to a third embodiment.

(Embodiment 1)
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing a configuration of a communication system 1 according to the embodiment 1. The communication system 1 includes an operation server 11, a non-operation server 12, a client terminal 13, and a network system 14.

The operational server 11 is the server currently in operation, and is also called the old server. The non-operational server 12 is the new server following the server replacement, and has not yet begun operation. The client terminals 13 are communication terminals such as mobile phone terminals and PCs (Personal Computers). The settings of some of the multiple client terminals 13 have not been changed so that they can communicate with the non-operational server 12. In addition, the settings of some of the multiple client terminals 13 have been changed so that they can communicate with the non-operational server 12.

The operational server 11 and the client terminal 13 before the setting change can communicate with each other via the network system 14. On the other hand, since the operation of the non-operational server 12 has not started, the client terminal 13 after the setting change cannot communicate with the non-operational server 12. As described below, the client terminal 13 after the setting change can communicate with the operational server 11 via the network system 14.

The network system 14 includes a first network device 141, a second network device 142, and a third network device 143. Note that the network system 14 in FIG. 1 is omitted as appropriate, and switches, routers, etc. other than the first network device 141, the second network device 142, and the third network device 143 may be provided.

Each of the first network device 141, the second network device 142, and the third network device 143 has a relay function. The first network device 141, the second network device 142, and the third network device 143 may be, for example, a router, a firewall, or a computer. Furthermore, each of the first network device 141, the second network device 142, and the third network device 143 may be realized as a function of a computer, and may be, for example, a virtual router. Furthermore, each of the first network device 141, the second network device 142, and the third network device 143 may be a combination of multiple hardware devices.

There are two routes connecting the first network device 141 and the second network device 142. The route that goes through the third network device 143 is called the detour route, and the route that does not go through the third network device 143 is called the direct route.

When relaying packets sent by a client terminal, the first network device 141 sends packets whose destination information is the address information of the non-operational server 12 to a detour route, and sends packets whose destination information is the address information of the operational server to a direct route that does not detour. In other words, the first network device 141 transfers packets whose destination information is the address information of the non-operational server 12 to the third network device 143. The first network device 141 also transfers packets whose destination information is the address information of the operational server 11 to the second network device 142.

When relaying a packet sent by the operational server 11, the second network device 142 performs at least one of the following processes: sending the packet to both a bypass route and a direct route, and sending the packet so that the routes of the outgoing packet and the return packet are the same based on the route identification information assigned to the packet. An outgoing packet is a packet sent from the client terminal 13 to the operational server 11, and a return packet is a packet sent from the operational server 11 to the client terminal 13.

The route identification information is information indicating whether or not a packet should take a detour route, and any field included in the packet's header can be used as the route identification information. For example, if the route identification information is a predetermined value set by the third network device 143, the second network device 142 may transmit the packet to the detour route, and otherwise transmit the packet to the direct route.

The second network device 142 may also transmit a packet sent by the operational server 11 to either the detour route or the direct route, and copy the transmitted packet and transmit it to the other route. That is, the second network device 142 may transmit a packet to both the detour route and the direct route by performing port mirroring. The client terminal 13 that receives the two packets responds to the packet with the source information correctly set and ignores the other one. This establishes communication between the client terminal 13 and the operational server 11.

The second network device 142 may also transmit packets to both the detour route and the direct route in the case of certain communications, and transmit packets to either the detour route or the direct route based on the route identification information in other cases. For example, the second network device 142 may transmit packets to both the detour route and the direct route in the case of communications initiated from the server side.

The third network device 143 converts the destination information of the packet sent by the client terminal 13 into the address information of the operational server 11 on the detour route, and converts the source information of the packet sent by the operational server 11 into the address information of the non-operational server 12. In other words, the third network device 143 is a device that performs NAT (Network Address Transformation).

In addition, when converting the destination information of a packet sent by the client terminal 13, the third network device 143 may set the route identification information included in the packet header to a predetermined value. The second network device 142 can relay the return packet to take the same route as the outgoing packet depending on whether the route identification information is the predetermined value or not.

Therefore, the destination information of the packets sent by the client terminal after the setting change is converted and sent to the operation server 11. Then, at least one of the packets sent by the operation server 11 to the client terminal after the setting change has the source information converted to the non-operation server 12, so that the client terminal after the setting change can respond.

Note that the destination information of packets sent by a client terminal before the setting change is not converted. And, since the source information of at least one of the packets sent by the operation server 11 to a client terminal before the setting change is not converted, the client terminal before the setting change can respond.

Therefore, according to the network system 14 of the first embodiment, communication between the client terminal whose settings have been changed and the old server becomes possible.

(Embodiment 2)
The second embodiment is a specific example of the first embodiment, and transmits a packet to either a direct route or a detour route based on a precedence value. Fig. 2 is a configuration diagram showing a configuration of a communication system 1a according to the second embodiment.

The communication system 1a includes a client terminal 13, operational servers 11a and 11b, new servers 12a and 12b, and a network system 14a. The client terminal 13 may be an in-vehicle terminal mounted in a vehicle. The operational servers 11a and 11b have been migrated to the new servers 12a and 12b, but the new servers 12a and 12b have not yet started operation. Note that, although FIG. 2 shows a case in which there are two client terminals, two operational servers, and two new servers, the number of client terminals, etc. is not limited to this.

A part of the client terminals 13 (called the first client terminal 131) has been reconfigured to communicate with the new servers 12a and 12b, and is configured to ignore packets whose source information is not the IP address of the new servers 12a or 12b. A part of the client terminals 13 (called the second client terminal 132) has not yet been reconfigured, and is configured to ignore packets whose source information is not the IP address of the operational servers 11a or 11b. The IP address of the first client terminal 131 is "A1". The IP address of the second client terminal 132 is "A2". The IP address of the operational server 11a is "C1". The IP address of the operational server 11b is "C2". The IP address of the new server 12a is "C3". The IP address of the new server 12b is "C4".

The network system 14a includes a first network device 141, a second network device 142, a third network device 143, and an L2 switch 144. The network system 14a may further include a router, a switch, etc. The network system 14a may further include a path for the operational servers 11a and 11b to communicate with the client terminal 13, etc.

Each of the first network device 141, the second network device 142, and the third network device is, for example, a router, but may not be a router as long as it has a packet relay function, and may be, for example, a firewall or a virtual router. The first network device 141 and the second network device 142 have a function of performing policy-based routing, and transmit packets to a detour route or a direct route based on a policy.

The first network device 141 has ports 141a, 141b, and 141c. Port 141a receives packets sent by the first client terminal 131 and the second client terminal 132. The IP address of port 141a is "B1". Port 141b is connected to the second network device 142. The IP address of port 141b is "B2". Port 141c is connected to the third network device 143, and has an IP address of "B3".

The first network device 141 has a packet relay function. The first network device transmits packets sent by the first client terminal 131 to the third network device 143, and transmits packets sent by the second client terminal 132 to the second network device 142. That is, the first network device 141 transmits packets sent by the first client terminal 131 to a bypass route, and transmits packets sent by the second client terminal to a direct route. The first network device 141 may be configured to transmit packets whose destination information is the IP address of the new server 12a or 12b to the third network device 143.

The second network device 142 has ports 142a, 142b, and 142c. Port 142a is connected to the first network device 141 and has an IP address of "B4". Port 142b is connected to the third network device 143 and has an IP address of "B5". Port 142c is connected to the Layer 2 switch 144 and has an IP address of "B6".

The second network device 142 has a packet relay function. The second network device 142 receives a packet sent by the operation server 11a or 11b via the layer 2 switch 144, and determines whether the precedence value included in the ToS (Type of Service) field of the IP header is, for example, "7". The second network device 142 then sends packets with a precedence value of "7" to the third network device 143, and sends other packets to the first network device 141. Therefore, packets with a precedence value of "7" are sent to the detour route, and other packets are sent to the direct route. The second network device 142 may be a layer 3 switch.

The precedence value is set to "7" by the third network device 143, as described below. The second network device 142 may use identification information other than the precedence value to distribute packets. Any judgment condition using identification information may be used to distribute packets.

The third network device 143 has ports 143a and 143b. Port 143a is connected to the first network device 141 and has an IP address of "B7". Port 143b is connected to the third network device 143 and has an IP address of "B8".

The third network device 143 converts the destination information of the packet sent by the first client terminal 131 into the IP address of the operational server 11a or 11b, and sets the precedence value included in the packet header to "7." The third network device 143 also converts the source information of the packet sent by the operational server 11a or 11b into the IP address of the new server 12a or 12b.

The layer 2 switch 144 is connected to the operational servers 11a and 11b. The layer 2 switch 144 may also be connected to the new servers 12a and 12b before they start operation.

Next, the operation of the network system 14a will be described. First, a case will be described where the first client terminal 131 transmits a packet to the new server 12a. The transmitted packet is first sent by the first network device 141 to the third network device 143. Next, the third network device 143 converts the destination information of the packet to the address information of the operational server 11a and sets the precedence value of the header to "7". The packet is then transmitted to the operational server 11a via the second network device 142 and the Layer 2 switch 144.

The response packet sent by the operational server 11a is then sent to the second network device 142 via the L2 switch 144. Since the precedence value of the response packet is "7", the second network device 142 sends the response packet to the third network device 143. The third network device 143 converts the source information of the response packet and sends it to the first network device 141. The first network device 141 sends the response packet to the first client terminal 131. Since the source information of the response packet is the address information of the new server 12a, the first client terminal 131 is able to communicate.

Next, a case where the second client terminal 132 transmits a packet to the operational server 11a will be described. The transmitted packet is transmitted by the first network device 141 to the second network device 142, and then transmitted to the operational server 11a via the L2 switch 144. Since the precedence value of the response packet transmitted by the operational server 11a has not been rewritten, the second network device 142 transmits the response packet to the first network device 141. The first network device 141 then transmits the response packet to the second client terminal 132. Through the above operations, the second client terminal 132 is able to communicate with the operational server 11a.

In this way, the network system 14a converts the destination information of the packet sent by the first client terminal 131 into the address information of the operational server, and converts the source information of the response packet sent by the operational server 11 into the address information of the new server 12. Therefore, the first client terminal 131, which is set to communicate with the new server 12, can establish communication with the operational server 11. Note that the packet sent by the second client terminal 132 and its response packet are not address converted, so there is no effect on the communication between the second client terminal and the operational server.

It is also possible to establish communication when the second network device 142 transmits a response packet to both the first network device 141 and the third network device 143. In such a case, two response packets are transmitted to the client terminal 13. On the other hand, the network system 14a according to the second embodiment transmits only one response packet, thereby reducing the amount of communication. This is advantageous when the client terminal 13 performs wireless communication. This also reduces the processing load on the client terminal.

(Embodiment 3)
The third embodiment is also a specific example of the first embodiment, like the second embodiment. A network system 14b according to the third embodiment transmits a packet transmitted by the operation server 11 to both the first network device 141 and the third network device 143.

In the second embodiment, a case has been described in which the client terminal 13 initiates communication, but communication may also be initiated by the operational server 11a or 11b. Such communication is also called server-initiated communication. In addition, communication initiated by a client terminal is also called client-initiated communication.

According to the second embodiment, when communication is initiated from the server side, the second network device 142 cannot determine whether the destination is the first client terminal 131 or the second client terminal 132, and therefore cannot establish communication. The network system 14b can establish communication even in such a case.

Figure 3 is a block diagram showing the configuration of a communication system 1b and a network system 14b according to the third embodiment. The following mainly describes the differences from Figure 2. The second network device 142 further includes a port 142d. The third network device 143 further includes a port 143c. The IP address of the port 143c is "B9". As described below, a virtual IP address is set for the ports 143c and 141b. The virtual IP address is "D1".

The second network device 142 is configured to transmit a copy of a packet transmitted from port 142a from port 142d. Here, VRRP (Virtual Router Redundancy Protocol) technology is used, and the same virtual IP address "D1" is set for ports 141b and 143c. Also, since port 142c is a port that performs mirroring, no IP address is set. To transmit the same packet, it is necessary to set the same MAC (Media Access Control) address for ports 141b and 143c. For this reason, network system 14b uses VRRP.

Next, the operation of network system 14b will be described. First, a case will be described where operational server 11a transmits a packet to first client terminal 131. Second network device 142 transmits the packet to first network device 141, and transmits a copy of it to third network device 143. Third network device 143 converts the source information of the packet and transmits it to first network device 141. First client terminal 131 receives two packets from first network device 141, responds to the packet with the converted source information, and ignores the packet with the unconverted source information. Therefore, operational server 11 can establish communication with first client terminal 131.

Next, a case will be described where the operational server 11a sends a packet to the second client terminal 132. The second network device 142 sends the packet to the first network device 141, and sends a copy of it to the third network device 143. The third network device 143 converts the source information of the packet and sends it to the first network device 141. The second client terminal 132 receives two packets from the first network device 141, responds to the packet with unconverted source information, and ignores the packet with converted source information. Therefore, the operational server 11 can establish communication with the second client terminal 132.

In this way, network system 14b can establish server-triggered communication during server migration. Also, network system 14b can establish client-triggered communication, as in embodiment 2. In such a case, client terminal 13 may respond to only one of the two packets received.

In addition, in the network system 14b, route identification information may be set in the same manner as in the second embodiment. In such a case, as in the second embodiment, the second network device 142 transmits the packet to the third network device 143 when the precedence value satisfies a predetermined condition, and transmits the packet to the first network device 141 otherwise.

The second network device 142 may operate to mirror packets in server-triggered communications, but not mirror packets in client-triggered communications. In such a case, the amount of communication and processing load can be reduced because two packets are not sent in client-triggered communications. The second network device 142 may be configured to perform conditional port mirroring depending on the type of server-triggered communications, for example.

The present invention has been described above with reference to the embodiment, but the present invention is not limited to the above. The configuration and details of the present invention can be modified in various ways that are understandable to those skilled in the art within the scope of the invention. For example, in the above embodiment, the present invention has been described as a hardware configuration, but the present invention is not limited to this. Any processing in the present invention can also be realized by having a CPU (Central Processing Unit) execute a computer program.

The program can be stored and supplied to the computer using various types of non-transitory computer readable media. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R/Ws, and semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (random access memories)). The program may also be supplied to the computer by various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The transitory computer readable media can supply the program to the computer via wired communication paths such as electric wires and optical fibers, or wireless communication paths.

1, 1a, 1b Communication system 11, 11a, 11b Operational server 12, 12a, 12b Non-operational server (new server)
13 Client terminal 131 First client terminal 132 Second client terminal 14, 14a, 14b Network system 141 First network device 142 Second network device 143 Third network device 144 Layer 2 switch 141a, 141b, 141c, 142a, 142b, 142c, 142d, 143a, 143b, 143c Port

Claims (5)

a first network device that, when relaying a packet transmitted by a client terminal, transmits a packet having address information of a non-production server as destination information to a detour route and transmits a packet having address information of a production server as destination information to a direct route;
a second network device that performs at least one of a first process of transmitting a packet transmitted by the operational server to both the detour route and the direct route when relaying the packet, and a second process of transmitting the packet so that the routes of the outgoing packet and the return packet are the same based on route identification information assigned to the packet;
a third network device that converts destination information of a packet transmitted by the client terminal into address information of the primary server and converts source information of a packet transmitted by the primary server into address information of the non-primary server in the detouring route;
Equipped with
the third network device sets the route identification information included in a header of a packet transmitted by the client terminal to a predetermined value on the detour route;
the second process transmits the packet to the detour route if the route identification information is equal to the predetermined value, and otherwise transmits the packet to the direct route;
Network system. The first process includes transmitting the packet to one of the detour route and the direct route, and copying the transmitted packet and transmitting it to the other route.
The network system according to claim 1 . The first process transmits the same packet to both the detour route and the direct route by using a Virtual Router Redundancy Protocol (VRRP) technique.
The network system according to claim 2 . A production server;
A client terminal;
A network system;
Equipped with
The network system includes:
a first network device that, when forwarding a packet transmitted by the client terminal, transmits a packet having address information of a non-operational server as destination information to a detour route and transmits a packet having address information of the operation server as destination information to a direct route;
a second network device that performs at least one of a first process of transmitting a packet transmitted by the operational server to both the detour route and the direct route when the packet is forwarded, and a second process of transmitting the packet so that the routes of the outgoing packet and the return packet are the same based on route identification information assigned to the packet;
a third network device that converts destination information of a packet transmitted by the client terminal into address information of the primary server, and converts source information of a packet transmitted by the primary server into address information of the non-primary server, in the detouring route ;
the third network device sets the route identification information included in a header of a packet transmitted by the client terminal to a predetermined value on the detour route;
the second process transmits the packet to the detour route if the route identification information is equal to the predetermined value, and otherwise transmits the packet to the direct route;
Communication systems. When forwarding packets sent by a client terminal, packets whose destination information is the address information of a non-production server are sent via a detour route, and packets whose destination information is the address information of a production server are sent via a direct route.
When forwarding a packet transmitted by the operational server, at least one of a first process of transmitting the packet via both the detour route and the direct route and a second process of transmitting the packet so that the routes of a going packet and a returning packet are the same based on route identification information assigned to the packet,
converting destination information of a packet transmitted by the client terminal into address information of the primary server, and converting source information of a packet transmitted by the primary server into address information of the non-primary server, in the detouring route;
1. A communication method comprising:
setting the route identification information included in a header of a packet transmitted by the client terminal to a predetermined value on the detour route;
the second process transmits the packet to the detour route if the route identification information is equal to the predetermined value, and otherwise transmits the packet to the direct route;
Communication methods.

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