JP2000092098A - Name server and name solution data generation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a name server capable of demonstrating a name solution function in a short time after supplying power again even in the case of storing a name solution table in a volatile memory. SOLUTION: After power is supplied again, at the time of receiving a message including the IP address of a pertinent computer and a NetBIOS name regularly broadcasted inside a LAN 2 by computers 31 and 32, this name server 4 uses the received message, generates the name solution table 6 for indicating the correspondence relation of the IP address of the computers 31 and 32 and the NetBIOS name and stores it in a DRAM 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a name server for performing name resolution on a network and a method for generating name resolution data.

[0002]

2. Description of the Related Art In the Internet, TCP / IP (Transport C) is a protocol for communication between computers.
ontrol Protocol / Internet Protocol) and identify each host computer by assigning a fixed 4-byte unique length IP address to each of a plurality of host computers (primary master name servers) existing on the network. I have. This IP address is a series of numbers, which is inconvenient for humans to remember.
Instead of an address, a hierarchical domain name (host computer name) convenient for human memory is used, and a correspondence between the domain name and the IP address is defined by a name resolution server called DNS (Domain Name Server). We have solved it. Domain names are determined to be unique throughout the Internet.

In recent years, many personal computers have, for example, NetBIOS (Network Basic Input Out), which is a basic protocol for a small LAN.
OS (Opera such as Microsoft's Windows 95 (trade name) and Windows NT (trade name) that adopts putSystem: network basic input / output system)
application program running on the ting system). These OSs are, as shown in FIG.
NetBIOS is realized on TCP / IP. That is, as shown in FIGS. 4A and 4B, the network layer and the transport layer of the OSI reference model are set to TCP.
/ IP, and the session layer is realized by NetBIOS. As shown in FIG. 4B, NetBIOS operating in the session layer is a NetBT (NetBIOS o).
ver TCP / IP).

A computer using an OS employing NetBT as described above is not a DNS but a WI.
A name server called an NS (Windows Internet Name Service) server is used. This name server is
When defining a group of computers with shared resources connected over a network,
A computer belonging to the group is assigned a NetBIOS computer name unique within the group, and the correspondence between the NetBIOS computer name and the IP address is registered and checked. The WINS server assigns an IP address to a computer in a group each time the computer is started.
Protocol) can be used. By using DHCP, a user can use a complicated I / O when starting up a computer.
There is no need to set the P address.

The NetBIOS computer name and I
As a method of resolving a name with a P address, in addition to a name server, a method of inquiring each computer using a broadcast packet, or a method in which each computer uses a NetBIOS computer name and an IP address of another computer having a shared resource. LMHOS correspondence
There is a method of statically saving in a TS file. However, the latter method cannot realize the DHCP described above. In the former method, name resolution via a router cannot be performed.

Hereinafter, the name server (WINS) will be described in detail. The name server stores a name resolution table indicating the correspondence between the NetBIOS computer names and the IP addresses of the computers in the group in a nonvolatile memory such as a hard disk or a flash memory, and receives an inquiry packet including the NetBIOS computer name. Then, an entry corresponding to the NetBIOS computer name is searched, and a response packet including the IP address in the entry is returned.

[0007] The name resolution table of the name server is generated as follows. That is, when a new computer joins the group, the name server receives a registration packet from the computer and adds the NetBIOS computer name and the IP address included in the registration packet to the name resolution table.

Further, the name server periodically receives an update packet from a computer belonging to the group, searches the name resolution table for an entry corresponding to the NetBIOS computer name and the IP address included in the update packet, and It is determined whether or not the content should be updated. If the content needs to be updated, the content of the entry is added to the NetBIO included in the update packet.
Update with S computer name and IP address. The update packet is periodically transmitted from the computer to the name server, for example, every three days. Also, the name server is
When the computer belonging to the group is removed, the release packet is received from the computer, and the entry in the name resolution table corresponding to the NetBIOS computer name and the IP address included in the release packet is deleted. The above-described registration packet, update packet, and release packet are transmitted from computers belonging to the group by explicitly specifying the address of the name server.

In such a name server, the name resolution table is stored in the non-volatile memory as described above. Therefore, even if the power of the name server is turned off, if the power is turned on next, the non-volatile memory is used. Can be used.

[0010]

By the way, there is a name server that stores a name resolution table in a volatile memory such as a DRAM from the viewpoint of reducing the price and providing various models. In such a name server, for example, when the power is turned off, the power supply to the DRAM stops, and the name resolution table stored in the DRAM disappears. Therefore, the next time the power is turned on, there is no name resolution table, and the name resolution function cannot be exhibited. Therefore, it is necessary to newly create a name resolution table using an update packet received from each computer in the group. However, the update packet is, for example, 3 as described above.
Since the data is often transmitted at relatively long intervals such as every day, there is a problem that the system cannot be operated for a long time from when the power is turned on to when a new name resolution table is created.

In particular, a router or the like that also functions as a name server usually has only a built-in volatile memory.
The problem as described above has occurred.

The present invention has been made in view of the above-mentioned problems of the prior art. Even when a name resolution table is stored in a volatile memory, a name resolution function can be exhibited in a short time after the power is turned on again. An object of the present invention is to provide a name server and a method for generating name resolution data.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art and to achieve the above-mentioned object, a name server of the present invention comprises one or more connected servers in a network capable of broadcasting messages. A name server that manages the correspondence between the address and name of the processing device as name resolution data, and a receiving unit that receives a message containing the address and name of the processing device that the processing device periodically broadcasts, Data for generating name resolution data indicating the correspondence between the address and the name of the processing device using the address and name of the processing device included in the received message other than the message for updating the name resolution data. Generating means, and a volatile memory for storing the generated name resolution data.

In the name server according to the present invention, for example, when the power supply to the volatile memory is stopped and then restarted, the receiving unit includes the address and name of the processing device broadcasted in the network by the receiving device. A message is received. Then, the data generating means indicates the correspondence between the address and the name of the processing device by using the address and the name of the processing device included in the received message other than the message for updating the name resolution data. Name resolution data is generated, and the generated name resolution data is stored in the volatile memory.

Further, in the name server of the present invention, preferably, the data generation means is configured such that when power supply to the volatile memory is started, a time corresponding to a time interval for broadcasting the message has elapsed. Then, the generation of the name resolution data ends.

In the name server of the present invention, preferably, the address is an address uniquely determined on the Internet.

Further, the name resolution data generation method according to the present invention is a name resolution data generation method for indicating a correspondence relationship between addresses and names of one or more processing devices connected in a network capable of broadcasting a message. And generating name resolution data indicating the correspondence between the address and the name of the processing device using the address and the name of the processing device included in the message that the processing device periodically broadcasts.

[0018]

Hereinafter, a network system according to an embodiment of the present invention will be described. FIG. 1 is a configuration diagram of a network system 1 according to the present embodiment. FIG.
As shown in FIG. 1, the network system 1 has a LAN (Loc
computer 3 ₁ via al Area Network) 2, has a structure of connecting the master browser 3 ₂ and name servers 4. The computer 3 ₁ and master browser 3 _2, a name that is uniquely determined within the group consisting of a plurality of computers with shared resources "PC1" and "PC2" are assigned respectively. Further, the computer 3 ₁ and master browser 3 _2, IP address uniquely determined on the Internet is assigned.

Computer 3 _{1 The} computer 3 ₁ is, for example, Microsoft Windows 95 (trade name) employing NetBIOS.
OS (Operating System) such as Windows and Windows NT (trade name)
Run the application program on System).

[0020] In the computer 3 _1, as the IP address of the WINS server, and holds the IP address of the name server 4.

The computer 3 _1, when belonging to the group transmission, the registration packet including the NetBIOS computer name and IP address of the self, by specifying the IP address of the name server 4, the name server 4 via the LAN2 I do. Further, the computer 3 _1, except when registered, for example, every 3 days, an update packet including a NetBIOS computer name and IP address of the self, by specifying the IP address of the name server 4, the name server 4 via the LAN2 Send to Computer 3
For example, when being removed from the group, ₁ transmits a release packet including its own NetBIOS computer name and IP address to the name server 4 via the LAN 2 by designating the IP address of the name server 4.

Further, the computer 3 ₁ has a shared resource to be shared with other computers on the LAN2, given host announcement transmission time interval, e.g., at 12 minute intervals, its NetBIOS computer names and I
The host announcement packet including the P address is sent to L
Broadcasting within AN2.

Further, the computer 3 _1, when performing access to another computer, the name server 4 via the LAN2, transmits an inquiry packet containing the NetBIOS computer name to perform the access. Then, the computer 3 _1, using the IP address of the computer to perform the access received from the name server 4 performs access to the computer.

The master browser 3 ₂ master browser 3 ₂ has the same functions as a computer 3 ₁ which essentially described above, the following differences. That is, the master browser 3 _2, the computer 3 ₁ broadcasts receives host announcement packet including a NetBIOS computer name and IP address, determines whether NetBIOS computer name included in the packet exists in the browse list And
If not, add the computer name to the browse list.

[0025] In addition, the master browser 3 _2, a blouse list in response to the request, be sent to the requesting computer.

Further, the master browser 3 _2, given local master announcement transmission time interval, e.g., 10
At a minute interval, a local master announcement packet including its own NetBIOS computer name and IP address is broadcast in LAN2.

The name server 4 name server 4, as described above, functions as a WINS server, as shown in FIG. 1, the name resolution table showing the correspondence between the NetBIOS computer name and IP address (name resolution data) 6 With the volatile memory D
It is stored in the RAM 7. As described above, since the DRAM 7 is a volatile memory, when the power of the name server 4 is turned off and the power supply to the DRAM 7 is stopped, the stored contents including the name resolution table 6 are lost.

When the name server 4 receives the above-mentioned registration packet, the name server 4 includes the NetBI included in the registration packet.
The OS computer name and the IP address are added to the name resolution table 6. When the name server 4 receives the update packet, the name server 4 includes Ne included in the update packet.
An entry corresponding to the tBIOS computer name and the IP address is searched from the name resolution table 6, and it is determined whether or not the contents of the entry should be updated. If the entry needs to be updated, the contents of the entry are updated. NetBIOS computer name and I included in the packet
Update with P address. Further, upon receiving the release packet, the name server 4 receives N
The entry of the name resolution table 6 corresponding to the etBIOS computer name and the IP address is deleted.

The name server 4, the computer 3 ₁ receives a host announcement packet broadcast, NetBIOS computer name and IP address included in the packet name resolution table 6
If it is not registered in, register this. Also, the name server 4, if the master browser 3 ₂ receives the local master announcement packet broadcast, NetBIOS computer name and IP address included in the packet is not registered in the name resolution table 6, Register this.

Here, the name server 4 registers the name resolution table 6 using the host announcement packet and the local master announcement packet, for example, after the power of the name server 4 is turned on, the host announcement transmission time. Restrict within the longer of the interval and the local master announcement transmission time interval. In the present embodiment, the name server 4 limits the registration of the name resolution table 6 using the host announcement packet and the local master announcement packet to 13 minutes after the power of the name server 4 is turned on. This time limit can be changed according to the environment. Thus, by limiting the registration of the name resolution table 6 using the host announcement packet and the local master announcement packet, the CPU (Central Pro
The load of the "Sensor Unit" can be controlled to a minimum.

Hereinafter, the operation of the network system 1 will be described. First, an operation from turning off the power of the name server 4 to turning on the power until the name resolution table 6 is newly created will be described. When the power of the name server 4 is turned off, the power supply to the DRAM 7 is stopped and the DRA
The name resolution table 6 stored in M7 is deleted.

[0032] Thereafter, when the source of the name server 4 is again turned on, as shown in FIG. 2 (A), (B) , L from the computer 3 ₁ and master browser 3 ₂ at 12 minute intervals
The host announcement packet and the local master announcement packet broadcast on the AN 2 are received by the name server 4.

Ne included in the host announcement packet and the local master announcement packet
The tBIOS computer name and the IP address are registered in the name resolution table 6 of the name server 4. As a result, within 12 minutes after the power of the name server 4 is turned on, the same name resolution table 6 as before the power of the name server 4 was turned off last time is stored in the DRAM 7. Then, 13 minutes elapses after the power on the name server 4, by the host announcement packet and local master announcements packet, registration in the name resolution table 6 is not performed, from the computer 3 ₁ and master browser 3 ₂ In accordance with the received registration packet, update packet, and release packet, registration of a new entry in the name resolution table 6 and update and deletion of the entry are performed.

[0034] Next, the operation when a query packet is transmitted from the computer 3 _1. When accessing from the computer 3 ₁ to the computer 3 _2,
Through the LAN2, the name server 4 from the computer 3 _1, inquiry packet containing the NetBIOS computer name "PC2" is transmitted. In the name server 4, the Net included in the received inquiry packet is
Is retrieved entries for BIOS computer name "PC2", the response packet including the IP address of the entry is sent to the computer 3 _1.

[0035] Then, using the IP address included in the response packet received by the computer 3 _1, the access is made from the computer 3 ₁ master browser 3 _2.

As described above, according to the network system 1, a message other than an update packet, such as a host announcement packet and a local master announcement packet, is transmitted by the source device's NetBIOS.
Since the name resolution data is generated from the message including the computer name and the IP address, even if the name server 4 stores the name resolution table 6 in the volatile DRAM, the name server 4 must be turned off and then turned on again. Within 12 minutes, the same name resolution table 6 as before the last power-off can be created automatically. Therefore, the name server 4 can be restored in a short time after it is restarted, and the influence of turning off the power can be reduced. In addition, since the name server 4 does not use an expensive volatile memory, the price can be reduced, and the name server 4 can support various models.

The present invention is not limited to the above embodiment. For example, as shown in FIG.
May be provided with a DRAM 72 for storing the name resolution table 6 in the router 20, and the router 20 may play the role of the above-mentioned name server in addition to the role of the router. In this case, the name resolution table 6 is created by using the free area of the DRAM 72 that the router 20 originally has.
Can be stored, and a low-cost router with a name server function can be realized. In addition, since the router 20 also functions as a name server, an expensive server (W
Windows NT) is preferred because there is no need to purchase it.

Further, in the above embodiment, as shown in FIG. 1, the LAN2, a case has been exemplified that connect the computer 3 ₁ and master browser 3 _2, LAN2 2
The above-mentioned computers and shared resources such as printers other than the computers may be connected.

[0039]

As described above, according to the name server of the present invention, name resolution data can be generated and a name resolution function can be provided in a short time after power supply to the volatile memory is started. According to the name resolution data generation method of the present invention, for example, even when the name resolution data is stored in the volatile memory, the name resolution data is generated in a short time after the power supply to the volatile memory is started. Can be generated to provide a name resolution function.

[Brief description of the drawings]

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

FIG. 2 is a diagram for explaining a signal flow in the network system shown in FIG. 1;

FIG. 3 is a configuration diagram of an embodiment in which a router has a name server function.

FIG. 4 is a diagram for explaining Windows NT.

[Description of Signs] 1 ... Network system, 2 ... LAN, 3 ₁ ... Computer, 3 ₂ ... Master browser, 4 ... Name server, 5
... ISDN, 6 ... Name resolution table, 7 ... DRAM

Claims (3)

[Claims] 1. A name server which manages, as name resolution data, a correspondence relationship between addresses and names of one or more processing devices connected in a network capable of broadcasting a message, wherein the processing devices broadcast periodically. Receiving means for receiving a message including the address and name of the processing device; and using the address and name of the processing device included in a message other than a message for updating name resolution data in the received message, A name server comprising: data generation means for generating name resolution data indicating a correspondence between an address and a name; and a volatile memory for storing the generated name resolution data. 2. The data generation means terminates generation of the name resolution data when a time corresponding to a time interval for broadcasting the message has elapsed since the power supply to the volatile memory was started. The name server according to claim 1, wherein 3. A method for generating name resolution data indicating a correspondence between addresses and names of one or more processing devices connected in a network capable of broadcasting a message, wherein the processing devices periodically broadcast. A name resolution data generation method for generating name resolution data indicating a correspondence between an address and a name of the processing device using an address and a name of the processing device included in a message.