JP2005151059A - Router and address automatic providing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a router and an address automatic providing method capable of providing a unique address to all terminals in a sub network in the case of building up the sub network. <P>SOLUTION: In the case of building up the sub network and providing an address to all the terminals in the sub network, let the number of ports of the router be P1 and a prefix length of a host router be n-bits, then n+log<SB>2</SB>(P1+1) bits are selected for a prefix length of the sub network, and the address is provided to each terminal in the sub network on the basis of the prefix length of the sub network. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to an address automatic assignment method in a network, and more particularly to an address automatic assignment method and a router at the time of construction of a subnetwork.

  In computer networks such as the Internet, it is common to use an industry standard IP (Internet Protocol), and an IP address is assigned to each connected computer for management.

  Therefore, in order to construct a sub-network as a lower level via a router connected to the Internet, the system administrator allocates an IP address of the sub-network based on the network configuration.

In addition, when the subnetwork moves from the connected router, the new address is reassigned at the destination of the subnetwork, and the data transmitted to the original address destination of the subnetwork is transferred to the destination of the destination. It can be transferred to the sub-network (for example, see Patent Document 1).
JP 2000-341330 A

  However, in the above conventional example, it is complicated for the system administrator to design the address considering the entire sub-network, and the system administrator must grasp the entire sub-network without fail. There is a problem that it must be very burdensome.

An object of the present invention is to provide a router and an automatic address assignment method capable of assigning a unique address to all terminals in a subnetwork at the time of construction of the subnetwork.

In the present invention, when an address is assigned to all terminals in a subnetwork at the time of construction of the subnetwork, the number of router ports is P1, and the prefix length of the upper router is n bits, so that n + log ₂ (P1 + 1) ) Bit is used as a prefix of the subnetwork, and an address is given to each terminal in the subnetwork based on the prefix length of the subnetwork.

In the present invention, when the number of ports of the router is P1 and the prefix length of the upper router is n bits, n + log ₂ (P1 + 1) bits are used as a subnetwork prefix, and based on the prefix length of this subnetwork, Since an address is assigned to each terminal in the sub-network, a system administrator automatically assigns a different address to each terminal in the sub-network without having to design a sub-network considering the prefix length based on the network configuration. The effect that it can be given to is produced.

  The best mode for carrying out the invention is the following examples.

  FIG. 1 is a diagram showing an outline of a network system NS1 including a router 10 that is Embodiment 1 of the present invention.

  The network system NS1 includes routers 10 and 20 and computers 30 and 40.

  The router 10 is a router that connects the upper network NW1 and a subnetwork that is a lower network, and assigns a unique address to the port. The router 10 is a router having 4 ports and has ports 11, 12, 13 and 14, and the router 20 is a router having 2 ports and has ports 21 and 22.

  The router 10 includes prefix acquisition means, port number acquisition means, additional prefix length calculation means, subnetwork prefix length calculation means, and address assignment means.

  The prefix acquisition means is means for acquiring the prefix and the bit length n of the prefix from the upper network NW1.

  The port number acquisition means is means for acquiring the number of ports P1 of the router.

The additional prefix length calculation means is means for calculating the bit length na of the additional prefix to be added to the bit length n of the prefix by log ₂ (P1 + 1).

The subnetwork prefix length calculation means is a means for calculating the bit length of the prefix assigned to the subnetwork by adding the prefix length n and the additional prefix length na = log ₂ (P1 + 1). .

  The address assigning means is means for assigning an address to each terminal (router port) in the subnetwork based on the subnetwork prefix length.

  The operation when an address is assigned to each terminal in the subnetwork based on the subnetwork prefix length will be described by taking an IPv6 address as an example. The IPv6 address length is 128 bits, the prefix given from the upper network is 48 bits, and the number of ports accommodating the lower network is 4 (P1).

  In this case, the additional prefix length is calculated by the following formula and becomes 3 bits.

log ₂ (P1 + 1) = log ₂ (4 + 1) = 3 (rounded up)
Therefore, the prefix given from each port to the lower network is 51 bits, the upper 51 bits are fixed, and the lower 77 bits can be used as the address of the lower network.

  In the network system NS1, the router 10 is connected to the upper network NW1, and the ports 11, 12, 13, and 14 of the router 10 are connected to lower routers, computers, and the like to constitute a subnetwork.

  For example, the port 11 of the router 10 is connected to the router 20, and the ports 21 and 22 of the router 20 are connected to other routers and terminals (hereinafter also referred to as “computers”) and the like.

  Next, the subnetwork prefix length calculation operation in the router 10 will be described.

  FIG. 2 is a flowchart showing an operation of calculating the prefix length of the subnetwork in the router 10.

  First, the router 10 acquires a prefix and a length n (hereinafter referred to as “prefix length”) of the prefix from the upper network NW1 (S1). Hereinafter, it is assumed that the prefix length n is 48 bits.

  Next, the number of ports P1 of the router 10 is acquired (S2). In the following, it is assumed that the number of ports P1 of the router 10 is 4.

  Then, in order to obtain the prefix length n of the subnetwork, a prefix length (additional prefix length) na to be added to the prefix length n is calculated by the following equation (1) (S3).

Additional prefix length na = log ₂ (P1 + 1) (1)
The “additional prefix” is a prefix to be added to the prefix length n of the subnetwork. The “additional prefix length” is the length of the addition prefix, and when adding a plurality of times, it is called “first addition prefix length”, “second addition prefix length”,.

  Based on the number of bits obtained by the above equation (1), a unique additional prefix can be assigned to all ports provided in the router.

  In the above equation (1), the reason why 1 is added to the number of ports P1 is to secure the subnet router anycast address of the router 10 itself. The “subnet router anycast address” is an address of all “0” after the subnet (prefix), and is an address used by a router to which the subnet is assigned. In the case of the above example, after the upper 48 bits x, the remaining 80 bits are all 0 addresses.

Here, since P1 = 4, the additional prefix length na = log ₂ (P1 + 1) = log ₂ (4 + 1) = 3, that is, the additional prefix length is 3 bits. In the above formula (1), the decimal part is rounded up.

  Since the prefix length n = 48 bits as described above, the number of bits obtained by adding the 48 bits and the additional prefix length na = 3 bits is set as the prefix length (= 51 bits) of the subnetwork ( S4).

  Further, the sub-network prefix length 51 bits obtained here is notified to the lower router 20 (S5).

  In the router 20, the additional prefix length na obtained by the router 10 is set as the first additional prefix length, and the second additional prefix length na2 is calculated by the following equation (2) in the same manner as the above processing.

Second additional prefix length na2 = log ₂ (P2 + 1) (2)
Here, assuming that the number of ports of the router 20 is P2, as shown in FIG. 1, since the number of ports P2 of the router 20 is 2, the second additional prefix length na2 = log ₂ (P2 + 1) = log ₂ (2 + 1) = 2 and therefore the second additional prefix length na2 is 2 bits. In the above formula (2), the decimal part is rounded up.

  Therefore, the prefix length in the subnetwork connected to the router 20 is 51 + 2 = 53 bits.

  As described above, the prefix length of the subnetwork can be automatically calculated regardless of how large and complicated the subnetwork is.

  Next, a specific operation of the above embodiment will be described.

  Hereinafter, in order to express the prefix in a simplified manner, as shown in the following example, one hexadecimal digit (ie, 4 bits) is indicated by X, and every 4 digits of the prefix represented by these characters, Insert the delimiter symbol “:”.

  Furthermore, “:: / n” is described at the end of the prefix, and “n” at the end indicates the number of bits of the prefix. For example, it is expressed as “xxxx: xxxx :: / 32”, and the number of prefix bits in this case is 32.

  When the prefix length is not a multiple of 4 bits or 16 bits, it is expressed as a number in which all the lower bits are “0”. That is, in the case of IPv6, 128 bits of the IP address are divided into 4 bits and expressed in hexadecimal numbers (0 to 9 and A to F), and are described as 4 blocks from the top, with: Since it becomes a digit character / number string and it is complicated to write as many as 32 digits, if the prefix is 48 bits, describe only 12 characters / number strings, and indicate the bit length of the prefix with / n. .

  For example, when the prefix length n is “6” and the bit representation is “0110 01”, “0110 0100 0000 0000” in which all the lower bits are “0”, “6400 :: / 6” It represents as follows.

  Next, address assignment processing in the above embodiment will be described.

  FIG. 3 is a flowchart showing the address assignment processing in the above embodiment.

  As described above, by assigning the prefix length n, the computer 30 on the sub-network connected to the router 10 is started and receives an address acquisition request (S11), and the port of the router to which the computer 30 is connected It is determined whether or not an additional prefix is assigned (S12).

  If a port prefix is assigned in this determination (S12), the prefix is determined (S31) and the address of the computer whose address is requested is assigned (S32).

  When assigning an address based on the determined prefix, taking the above IPv6 as an example, address assignment for the lower 77 bits is possible, so one bit at a time is added in order from the least significant bit and given as a 128-bit address. To do.

  If a port prefix is not assigned in the determination (S12), it is determined whether or not a prefix is assigned to the router 10 (S13). Here, if a prefix is assigned to the router 10, a prefix is acquired (S21), and if not assigned, the router 10 is inquired whether a port prefix is assigned (S14). Further, the host router determines whether or not a prefix is assigned (S15), and repeats the operation of querying the host router (S14) until the router to which the prefix is assigned is reached.

  An inquiry is made to the upper router, and if a prefix is assigned, the prefix is acquired (S21), and the prefix of the corresponding port is assigned (S22).

  Next, it is confirmed that the port of the router 10 is a port to which the computer 30 is connected (S23). If the port is not the port to which the computer 30 is connected, an inquiry is made to a lower router (S24). A port prefix is assigned (S22). The above inquiry is repeated until the port to which the computer 30 is connected. When the port becomes the corresponding port, the prefix is determined (S31), and the address of the requested computer is assigned (S32).

  Through the above processing, a unique address can be automatically assigned to all terminals (terminals such as computers) on the sub-network.

  Next, an operation for specifically assigning addresses to the computer 30 connected to the port 12 of the router 10 and the computer 40 connected to the port 21 of the router 20 will be described.

  The prefix of the router 10 is assumed to be “C0A8: 0186: 0101 :: / 48”.

  First, when the computer 30 connected to the port 12 of the router 10 is started and an address acquisition request is made (S11), the port 12 of the router 10 has not yet been assigned an additional prefix (S12). The prefix is confirmed (S13), and the prefix “C0A8: 0186: 0101 :: / 48” of the router 10 is acquired (S21).

  Next, 3 bits of the additional prefix “011” are allocated to the port 12 of the router 10 (S22), and the prefix “C0A8: 0186: 0101: 3000 :: / 51” of the port 12 is determined (S31). Based on this prefix, the address of the computer 30 is assigned (S32).

  Next, when the computer 40 connected to the port 21 of the router 20 is started and an address acquisition request is made (S11), an additional prefix has not yet been assigned to the port 21 of the router 20 (S12). Is confirmed (S13).

  Here, since the prefix of the router 20 has not yet been assigned, the host router 10 is inquired (S14). Since the prefix is assigned to the router 10 (S15), the router 20 acquires the prefix “C0A8: 0186: 0101 :: / 48” of the router 10 (S21).

  Next, 3 bits “001” are assigned to the additional prefix of the port 11 of the router 10 (S22), and the prefix “C0A8: 0186: 0101: 2000 :: / 51” of the port 11 is determined. Subsequently, returning to the processing of the lower router 20 (S23, S24), 2 bits “01” are assigned to the additional prefix of the port 21 of the router 20 (S22).

  Since the prefix given by the router 20 from the upper network (router 10) is 51 bits and the number of ports of the router 20 is two, if the same calculation as described above is performed, the additional prefix length is 2 Bit, these 2 bits are used as “01” in port 21 and “11” in port 22, so the prefix given from each port of the router 20 to the lower network is 53 bits. 2 bits (“01”) are added to 3 bits (“001”). Therefore, in binary, it becomes 0010 1000 0000 0000, and in hexadecimal notation, it becomes 2800, and together with the upper 48 bits, COA 8: 186: 0101: 2800 :: / 53.

  Next, since this port 21 is the port 21 of the router 20 to which the computer 40 is connected (S23), the prefix "C0A8: 0186: 0101: 2800 :: / 53" of this port 21 is determined ( S31). Based on this prefix, the address of the computer 40 is assigned (S32).

  In other words, the above-described embodiment is an embodiment in which propagation is performed in a lower order so as to maintain uniqueness within a given allowable address space. For example, in the case of a six-digit telephone number, assuming that 03 *** is given to the general exchange in Tokyo as an allowable address space and there are three subordinate exchanges (switches AC), 030 ** * Is the telephone number of the general exchange (the router needs its own address), 031 *** is the telephone number of the exchange A, 032 *** is the telephone number of the exchange B, and 033 * Allocate an acceptable address for the telephone number such that ** is the telephone number of switch C. If there is an exchange a under the exchange A, 0310 ** is the telephone number of the exchange A, and 0311 ** is the telephone number of the exchange a.

  According to the above embodiment, a unique address can be automatically assigned to all terminals on the sub-network. That is, in the above-described embodiment, the system administrator automatically assigns different addresses to each terminal in the subnetwork without designing the subnetwork in consideration of the prefix length based on the network configuration.

  Further, according to the above embodiment, all the ports of the router are represented by different additional prefixes by the number of bits of the additional prefix length, and the prefix added with the additional prefix is subordinate to each port. Since it is used as a sub-network prefix, a different additional prefix can be allocated to each port of the router and a hierarchical prefix can be assigned, and different addresses can be assigned to all terminals in the sub-network easily and reliably.

  In the above example, the “different additional prefix” means that three additional prefix bits are assigned to each of the four ports as follows. Note that x is a 48-bit fixed value given from the upper level.

That means
Port 1 contains xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx001
In port 2, xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx011
Port 3 contains xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx101
Port 4 has xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx111
It is.

It is a figure which shows the outline of network system NS1 including the router 10 which is Example 1 of this invention. 5 is a flowchart showing an operation of calculating a subnetwork prefix length in the router 10. It is a flowchart which shows the address provision process in the said Example.

Explanation of symbols

10, 20 ... router,
30, 40 ... Computer.

Claims (4)

In a router that connects an upper network and a sub-network that is a lower network, and that assigns a unique address to the port of the router,
Prefix acquisition means for acquiring the prefix of the upper network and the bit length n of the prefix from the upper network;
Port number acquisition means for acquiring the number of ports P1 of the router;
An additional prefix length calculating means for calculating the bit length of the additional prefix to be added to the bit length n of the prefix by log ₂ (P1 + 1);
Sub-network prefix length calculating means for calculating a bit length of a prefix to be given to the sub-network by adding the prefix length n and the additional prefix length log ₂ (P1 + 1);
Address assigning means for assigning an address to each terminal in the subnetwork based on the subnetwork prefix length;
A router characterized by comprising: In claim 1,
All ports of the router are the number of bits of the additional prefix length, represented by different additional prefixes, and the prefix added with the additional prefix as the prefix of the subnetwork connected to each port A router characterized by use. In the automatic address assignment method that assigns a unique address to the router port that connects the upper network and the subnetwork that is the lower network,
A prefix obtaining step of obtaining the prefix of the upper network and the bit length n of the prefix from the upper network;
A port number acquisition stage for acquiring the port number P1 of the router;
An additional prefix length calculating step of calculating the bit length of the additional prefix to be added to the prefix bit length n by log ₂ (P1 + 1);
A sub-network prefix length calculating step of calculating a bit length of a prefix added to the sub-network by adding the prefix length n and the additional prefix length log ₂ (P1 + 1);
An address assigning step of assigning an address to each terminal in the subnetwork based on the subnetwork prefix length;
An address auto-assignment method characterized by comprising: In claim 3,
All ports of the router are the number of bits of the additional prefix length, represented by different additional prefixes, and the prefix added with the additional prefix as the prefix of the subnetwork connected to each port An address auto-assignment method characterized by being used.

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