JP2000078194A - Network system - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the amount of software processing of switches / routers in an existing network, to reduce the cost of network equipment and to reduce the price, and to improve the processing speed of each switch. Network system that can be used. SOLUTION: Switches A to D configuring a network
Has a plurality of connection ports ~, and a transmission line, an end system ES, and a network server S which form a network are connected to these ports. Before performing the data transfer, the ES notifies the server of the address of the partner ES to calculate the route information, and transfers the data based on the route information. The path information has a format at the head of the transfer data that can be used and erased by each switch in the path. The ES holds the route information to the partner ES with which the communication has been performed in the past.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network system, and more particularly to a network system in which the amount of software processing of a switch / router is reduced and the cost of the network system is reduced by making the network equipment inexpensive.

[0002]

2. Description of the Related Art FIG. 12 is a block diagram showing the configuration of a network system according to the prior art. Hereinafter, the configuration and connection operation of the network system according to the prior art will be described with reference to FIG. In FIG. 12, ES is an end system, and A to D are routers.

The network system shown in FIG. 12 is configured by connecting a plurality of routers A to D for controlling connections in a network in a loop by a transmission line, and each router has an end system ES having an IP address. Is connected. In the illustrated example, end systems ES1 to ES3 having IP addresses IPA1, IPA2, and IPA3 are connected to the routers A, B, and D, respectively. Each of the routers A to D has a routing table for associating a plurality of connection ports of its own router with the IP addresses of devices connected to these ports. The connection is being controlled.

In the network system configured as described above, the network protocol is now T
End systems ES1 to ES3 using CP / IP
The IP packet is sent to In this case, router A
Searches the routing table from the destination IP address received from ES1, selects a port for sending out an IP packet, and sends to router D connected to that port an IP address.
Send a packet. The router D receiving the IP packet also searches the routing table in its own router in the same manner as described above, selects the port to which the destination ES3 is connected, and transmits the IP packet.

There is also known a network system using an ATM switch for switching data cells by hardware in place of a router. This network system performs connection-oriented communication in which connection is set prior to communication. In this case, in which connection is set by ATM, a routing of a signaling message by an ATM address is performed by each ATM switch.

[0006]

The above-described network system according to the prior art has an IP address from ES1 to ES3.
All routers on the packet transfer path perform route calculation, and there is a problem that the software processing performance of network devices such as routers directly affects the performance of the network system. Similarly, ATM
The network system using the switch also has a problem that the processing performance directly affects the performance of the network system in the switch similarly to the TCP / IP router in the connection setting.

That is, in the above-mentioned conventional technology, each device in a network calculates an address to a destination and transfers data such as a packet. The route calculation is performed by routers and switches which are devices in the network. Must increase the load on the devices in the network, increase the cost of network equipment by requiring software for route calculation and high-performance hardware to process the software at high speed. Has been invited.

In addition, the above-described prior art has a problem that a delay time until data transfer is increased because processing by software occurs for each device.

An object of the present invention is to solve the above-mentioned problems of the prior art, reduce the amount of software processing of switches / routers in an existing network, and reduce the cost of network equipment. It is an object of the present invention to provide a network system capable of reducing the price of the entire system.

It is another object of the present invention to provide a network system capable of simplifying a route selection process and improving a processing speed in each switch.

[0011]

According to the present invention, an object of the present invention is to provide a network system in which a plurality of switches are connected to each other and an end system for transmitting and receiving data is connected to the switches. The end system includes a network server that performs generation, management, and maintenance. When transferring data, the end system attaches path information to a transfer destination including path information in the switch to a data transfer unit to transfer data. Is achieved.

[0012] Further, the above object is attained by the switch controlling switching within its own switch based on the path information at the head of the path information added to the data, and discarding the used path information.

Further, the object is that the end system requests route information to the transfer destination from the network server prior to data transfer, and the network server sends the route information based on a request from the end system. This is achieved by calculating and returning the calculated route information to the end system that made the request.

Since the above-mentioned route information can be read by each switch by hardware and used for direct switching, the switch does not need to perform a route calculation by software, and can perform high-speed switching. Transfer of data becomes possible.

Each switch only needs to have software for notifying the server of the line status, its own switch configuration, and the port connection status, and does not need to have a routing function. No hardware required.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a network system according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a network system according to an embodiment of the present invention, FIG. 2 is a diagram for explaining a method of using path information in a switch, and FIG. 3 is path information in one switch. FIG. 4 illustrates the configuration of FIG.
FIG. 5 is a view for explaining data transfer between end systems via one switch, FIG. 5 is a view for explaining a flow of processing from an application in the end system to packet transmission, and FIG.
9 is a diagram for explaining information held in the server, FIG. 7 is a diagram for explaining information held in the switch A, FIG. 8 is a diagram for explaining information held in the end system ES1, and FIG.
FIG. 10 is a diagram for explaining message exchange from registration of an end system to data transfer, FIG. 10 is a diagram for explaining message exchange when a server is down, and FIG. 11 is a diagram for explaining a connection form in data transmission to another network. It is.
In FIG. 1, S1 and S2 are network servers, and other symbols are the same as those in FIG. In addition, A ~
D is a router in FIG. 12, but is a switch in FIG.

A network system according to an embodiment of the present invention shown in FIG. 1 is configured by connecting a plurality of switches A to D for controlling connection in a network in a loop by a transmission line. An end system ES having an IP address and a network server are connected. In the illustrated example, end systems ES1 to ES3 having IP addresses IPA1, IPA2 and IPA3 are connected to switches A, B and D, respectively, and network servers S1 and S2 having IP addresses IPAS1 and IPAS2 to switches C and D. Is connected.

Each of the switches A to D has a plurality of (eight in FIG. 1) connection ports to which transmission lines, end systems, and network servers constituting a network are connected. In the embodiment shown in FIG. 1, the network server S1 is used as an active server, and S2 is used as a spare server. The end systems ES1 to ES3 may be configured by a workstation, a personal computer, or the like. In addition,
Servers, switches, and end systems are identified by IP addresses for explanation. Further, in the following description, the term “server” means an active server.

Next, an example of data transfer based on path information in a switch will be described with reference to FIGS.

In the embodiment of the present invention, instead of the conventional address, route information is added to the data of the IP packet, and the data can be transferred based on the route information. The route information in this case is information indicating a route from an input port to an output port, which is how to pass a cross point in each switch, and is calculated by a network server as described later, This is given to the end system.

Next, a switch having four cross points as shown in FIG. 2 will be described as an example of a circuit for transferring data based on path information. Each crosspoint is
It is possible to connect between any two of the four routes, each route being directed by two bits. FIG.
In the example shown in FIG. 6, "00", "10", "10", "10", "0" are respectively assigned to the leftward route, the rightward route, the upward route, and the downward route of each of the cross points a to d. 01 ",
“11” is given. Therefore, the route information at each cross point is represented by 4-bit information of the input side route and the output side route.

Now, it is assumed that the connection ports of the switch are connected using cross points a, b, and d, and data is transferred using this route. In this case, as shown in FIG. 2, the direction in which data is transferred from the connection port to the connection port is defined as path 1, and the direction in which data is transferred from the connection port to the connection port is defined as path 2, and data is transferred to these paths. The following describes the route information in the case of performing.

The route information is added before data such as IP packets to be transmitted as shown in FIG. 3, and in the order of cross points passing through the switch, the input side route and output side route of the cross point are provided. Each information is arranged and constituted. In the case of the route 1 described above, the route information a at the first cross point a is the input side route “00” and the output side route “10”, and the route information b at the next cross point b is the input side route Route “00”, output side route “11”, and further route information c at the next cross point c.
Is the input side route “01” and the output side route “10”, so that the route information given to the transfer data for this switch is, as shown in FIG. It becomes "00100011010" in which the road information is arranged. Also,
In the case of the route 2, the process is reversed, and the route information added to the transfer data is “10011” as shown in FIG.
1001000 ".

In the switch shown in FIG. 2, the above-mentioned route information at each cross point is processed as follows. 1. At the cross point a, switching based on the route information a is performed. 2. The route information a is deleted. 3. The route information b, the route information d, and the data part are transferred to the cross point b.

Thereafter, the data is stored at the cross points b and d.
However, the same processing is performed, and the data is transferred to another network device such as a switch, an end system, or a server connected to the subsequent stage.

As described above, the route information is deleted every time the vehicle passes through the cross point in the switch.
At each cross point, the processing may be performed by reading the bit from the beginning, and the switching processing can be simplified. Further, since the path information is shortened each time the signal passes through each switch, it is possible to prevent a decrease in the transfer efficiency of the network due to an overhead due to the addition of the path information.

Next, an example in which data is transferred between end systems via a plurality of switches will be described with reference to FIG.

When data is transmitted from the end system ES1 to the end system ES3, the data is transmitted through the route 1 shown in FIG. In this case, the route information A of the switch A,
The path information D of the switch D is created in the same manner as the path information of the switch described above, and these are sequentially
(IP packet) before sending. The route information in this case is as shown in FIG. Similarly,
Transmission of data from the end system ES3 to ES1
This is performed by the route 2, and the route information in this case is as shown in FIG.

In the end system, route information is given as shown in FIG. That is, in the end system, the TCP / IP processing unit attaches an IP header to the transfer data
/ IP packet is generated, and route information is added thereto.
The data to which the path information has been added is transmitted to the connection port of the switch to which the own end system is connected. Since the path information is used only by each switch, the path information A of the path 1 shown in FIG. 4 is deleted at the time of passing the switch A, and the switch D can read the path information D from the head of the data. Will be possible.

Next, information stored in the network server will be described with reference to FIG.

As shown in FIG. 6, the information possessed by the network server includes, as shown in FIG. 6, the configuration of each switch in the network managed by the server itself, the connection topology and line status, the connection information of the end system, the connection information between switches, the spare server , Connection information to a network server of another network, path information to an end system that has already replied the path information, and path information between the end systems that have already replied.

The configuration of the switch is sent from the switch to the server when the switch is connected to the network. The connection information of the end system and the connection information between the switches are sent from the switch to the server when the end system or the switch is connected to the switch. The connection topology is calculated by the server when the configuration of the newly connected network device is completed.

The network server, except when newly connecting,
The following processing is performed.

A. Reply of route information to end system, b. Information exchange with a network managed by another network server; c. Reception of the line usage rate, status, and port connection status transmitted from the switch, and maintenance of each data in the server based on the received data, d. Change notification of answered route information based on line utilization / state.

Since the network server performs the above-described processing, the routing processing which has been distributed to each network device in the existing network is concentrated. By retaining the information and making it possible to transfer data to a destination whose path information is already known without making an inquiry to the server, it is possible to prevent the performance from being reduced due to an increase in the processing amount of the server. it can. Also,
Although the reliability of the network system may be degraded due to the network server going down, unless the end system sends a new connection request to the server and asks for route information, the end system sends data to the connection destination whose route information is known. Since the transfer can be performed, the effect of the down of the network server on the network is small.

Now, in the network system shown in FIG. 1, the end system and the switch need to obtain route information to the server for information exchange with the network server when connected to the network. for that reason,
The existing switch notifies the end system or the switch of the path information to the server when the end system or the switch is newly connected to the own switch. The end system and the switch hold the route information to the server and the route information to the spare server.

The switch receives the path information from the existing switch to the server and the spare server when newly connected to the existing switch, and receives the path information from the server when newly connected to the server. The switch holds the route information to the server as shown in FIG. That is, as path information to the server, it has path information corresponding to the IP address of the server, and corresponding to the connection port number of its own switch, the name of the switch connected to that port and the connection port number, the end system or It has the IP address of the server. Then, when a switch or end system is newly connected to the own switch, the switch notifies the connected switch or end system of path information to the server.

When the end system is newly connected to the switch, the end system notifies the switch of its own IP address, and the switch notifies the server of the connection port, the IP address, and the device name. The end system has, for example, information as shown in FIG. That is, the end system has the route information to the server including the spare by the IP address of the server and the corresponding route information, and also obtains the route information between the end system obtained by inquiring the server. With the IP addresses of those end systems and the route information.

When the end system receives the data transmission instruction and the transfer destination IP address from the upper-level protocol, it searches the above-described route information table as shown in FIG. 8 and finds that the route information has been registered. For example, the packet is transmitted to the destination end system using the route information. When the route information to the destination end system is not registered in the table shown in FIG. 8, the end system makes an inquiry to the server, and uses the route information transmitted as a reply to send the IP data. Send the packet to the destination end system.

Now, it is assumed that the end system ES1 transfers data to the end system ES3 in a state where the end system ES1 does not yet have path information for transferring data to the end system ES3. In this case, the end system ES1 is
First, using the route information to the server held in the own system, the server is queried for the route information to ES3.

The server manages the connection information sent from each device as described with reference to FIG. 6, and includes, in response to the inquiry about the path information, the connection information managed by the server itself and the inquiry request. And the route information from the destination data to the destination. In the case of the above example, the end system ES
1 sends the IP address IPA3 of the end system ES3 to be connected to the server. The server searches the connection information table described with reference to FIG. 6 to determine that the requested IP address IPA3 is connected to the fifth connection port of the switch D. Further, the server selects a route from the switch A to the switch D based on the traffic situation of the line and the number of hops from the connection topology and the line state described with reference to FIG.

After determining the route on the topology, the server calculates the route information from the configuration of each switch and the network configuration. In this case, in FIG. 1, the server calculates a path from the end system ES1 to the end system ES3 through the connection port and the connection port 6 of the switch A, and the connection port and the connection port of the switch D to the end system ES3, and transmits the calculated path to the end system ES1. . In addition, the server sends an end system E3 to the end system ES3 to send a reply to the end system ES1.
Also in S3, the route information obtained by reversing the route information transmitted to the ES1 is notified, and the route information transmitted as a response is stored in the route information table in the server described with reference to FIG.

The end system ES1 transmits data to the end system ES3 according to the route information based on the response from the server. In addition, the end system ES1 additionally registers the path information based on the response from the server in the table shown in FIG. 8 and makes the path information available for transmission to the next same destination.

Next, message exchange from registration of an end system to data transfer will be described with reference to FIG. In this example, the end system ESa is newly connected to a certain switch in the network, and the end system Ea
An example of message exchange until data transfer to Sb becomes possible is shown.

(1) When ESa is connected to the switch,
The switch transmits the path information to the server and the spare server to the end system ESa (steps a and b).

(2) The end system ESa transmits its own IP address to the switch (step c).

(3) The switch reports the IP address of the end system ESa and the connection port of the switch to the server (step d).

(4) The server, based on the report from the switch, determines the device name of the end system ESa, the connection port,
Register an IP address. Thus, the registration of the newly connected end system is completed (step e).

(5) Thereafter, when the end system ESa attempts to transfer data to the end system ESb, the end system ESa still transmits the end system ESa.
Since it does not have the route information to the end system ESb, it requests the server for the route information to the end system ESb (step f).

(6) The server, as described above,
The route information from the end system ESa to the end system ESb is calculated, and the route information is calculated.
a and notifies the end system ESb of the route information from the end system ESb to the end system ESa.
(Steps g and h).

(7) The server transmits the path information from the end system ESa to the end system ESb, the path information from the end system ESb to the end system ESa, and the path information from the own server to the end systems ESa and ESb by IP. It is registered in its own server in combination with the address (step i).

(8) The end system ESa, based on the route information notified from the server,
After completion of the data transfer, the route information to the end system ESb is registered in the own system (steps j and k).

(9) On the other hand, the end system ESb also registers the route information to the end system ESa after completing the data transfer from the end system ESa (step 1).

As described above, each switch monitors the line status between the switches and has a table of the route information and the port status as shown in FIG. 7, but as described above, the new end system has its own switch. When it is added to the network via, the server is notified to that effect. In addition, each switch notifies the server of the line usage rate and state at a fixed time unit, and immediately notifies the server of the failure when the adjacent switch goes down and the port becomes unavailable due to a line failure. Each switch notifies the server of the connection status of the port when an end system and another switch are newly connected to its own port.

The server responds to the inquiry about the path information from the end system based on the information. In addition, when the line usage rate is increased on a certain line, the server notifies the end system of path information for bypassing the line. The end system receives the notice from FIG.
Is re-registered in the new route information.

A network down due to a server down and a switch connected to the server down can be avoided by installing a spare server. The spare server S2 has a copy of the information in the server S1 as the working server, and every time the information in the server S1 is changed, the information in the spare server S2 is similarly changed. The switch and the end system also register and have the route information to the spare server S2, and when the answer to the request for the route information to the active server S1 cannot be obtained, request the route information to the spare server S2. .

Next, with reference to FIG. 10, a description will be given of message exchange when the active server is down, that is, when a reply from the server times out in response to a path information request from the end system.

(1) It is assumed that the active server S1 has received the report that the end system ES1 has been connected, and has already reported the route information to the server S1 to the end system ES1 (steps a and b).

(2) In the state described above, the end system ES
1 requests the server S1 for path information for data transfer, and when a reply of the path information from the server S1 is not obtained for a predetermined time, that is, when the reply from the server times out, To notify the server down (steps c and d).

(3) The spare server S2 notifies the end server ES and the switch that are newly connected while the active server is down that not only all the end systems ES but also all the switches that the active server S1 is down. Then, the own server is started as the active server (step e).

(4) After reporting the active server down to the standby server S2, the end system ES1 requests the route information transmitted to the active server S1 again, and
The data is transferred using the route information obtained from (step g).

(5) When the active server S1 recovers from the server failure, it sends a recovery notification to the spare server S2 and copies information in the spare server such as path information and network connection status into its own server (step h, i).

(6) The spare server S2 operating as the active server then notifies all end systems ES and the switches that the active server S1 has been restored, and returns to the standby server (steps j and k).

The server has only a limited range of data under the control of its own server. By exchanging information with another server, data transfer between end systems connected to another network is possible. It can be performed.

The example shown in FIG. 11 is an example of a network system configured by connecting a switch A to another switch E constituting another network. In this example, the switches A and E belong to different servers, and usually, the switch A is managed by the server S1, and the switch E is managed by the server S3. And
In this example, the switches A and E mutually exchange route information to a server managed by themselves, and notify the server of the connection port and the network address of the other party.

Assume that the end system ES4 has made a request for path information to the end system ES1 to the server S3. In this case, the server S3 calculates the route information of the network managed by the server S1 and requests the server S1 to calculate the route information in the network managed by the server S1 via the switches E and A. . The server S2 compares the route calculation result of the server S1 with its own server S2.
The route information from the end system ES4 to the ES1 is created together with the route calculation result of the above, and the route information is notified to the end system ES4. Thus, the end system ES4 can transfer data to and from the end system ES1 housed in a different network.

As shown in FIG. 6, the server has a correspondence between the route information to the other server and the network address as a table. If there is no data in the connection information table, the route to the other server is stored. By searching the information table and querying the adjacent server,
As mentioned above, get route information to other networks,
This can be registered in the table.

In the above-described embodiment of the present invention, since the calculation of the routing (route) and the network of the route of the transfer data are separated, the software processing amount of the switch / router in the existing network can be reduced. ,
It is possible to reduce the cost of the network system as a whole by making the previously expensive network equipment cheaper.

Further, according to the present invention described above, the path information is always placed at the head of the packet at a fixed length and each switch sequentially consumes the path information. The processing speed at the switch can be improved.

Further, according to the above-described embodiment of the present invention, when the end system inquires of the server about the route information,
Software processing is required, which causes the same delay as conventional routing.However, when data is transmitted using known route information stored in the end system, high-speed data transfer at the hardware level is possible. It is.

In the above-described embodiment of the present invention, the configuration of the switch has been described as having four 2 × 2 cross points. However, the present invention uses a switch having a larger number of cross points as a switch. Can also. Also,
In the above-described embodiment of the present invention, the route information defines the route of each cross point in the switch. However, the present invention creates the route information based on the input and output port numbers of the switch, and The switch itself may perform the transfer control inside the switch.

[0073]

As described above, according to the present invention, since the network server calculates the route information for the transfer data, it is not necessary for each switch / router in the network to perform the route calculation. The amount of software processing in the switch / router is reduced, and the network equipment can be made inexpensive, whereby the price of the entire network system can be reduced.

Further, according to the present invention, the switch in the network erases only the portion required by the own switch from the head of the route information, thereby simplifying the route selection process and simplifying the process at each switch. Speed can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a network system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a method of using path information in a switch.

FIG. 3 is a diagram illustrating a configuration of route information in one switch.

FIG. 4 is a diagram illustrating data transfer between end systems via two switches.

FIG. 5 is a diagram illustrating a flow of processing from an application in an end system to packet transmission.

FIG. 6 is a diagram illustrating information held in a server.

FIG. 7 is a diagram illustrating information held in a switch A.

FIG. 8 is a diagram illustrating information held in an end system ES1.

FIG. 9 is a diagram for explaining message exchange from registration of an end system to data transfer.

FIG. 10 is a diagram for explaining message exchange when a server goes down.

FIG. 11 is a diagram illustrating a connection mode in data transmission to another network.

FIG. 12 is a block diagram showing a configuration of a network system according to the related art. A to D are routers.

[Explanation of symbols]

 ES End system A to D Router or switch E Switch S1 to S3 Network server

Claims (3)

[Claims] 1. A network system in which a plurality of switches are connected to each other and an end system for transmitting and receiving data is connected to the switches, comprising a network server for generating, managing, and maintaining path information, A network system, wherein the end system transfers data by transferring path information to a transfer destination including path information in the switch to a data transfer unit when transferring data. 2. The network according to claim 1, wherein the switch controls switching within the switch based on path information at the head of the path information added to the data, and discards the used path information. system. 3. The end system requests route information to a transfer destination from the network server prior to data transfer, and the network server calculates and calculates route information based on a request from the end system. 3. The network system according to claim 1, wherein the route information is returned to the end system that made the request.