IP version 6 (IPv6 is often called) is a network addressing that is used on TCP / IP with a total length of 128-bits, and can theoretically put address 2128= 3.4 x 1038 host computers around the world. Examples of IP version 6 address is 21DA: 00D3: 0000:2 F3B: 02AA: 00FF: FE28: 9C5A.
Overview
In contrast to IPv4 only has a length of 32-bit (total number of addresses that can be accomplished to achieve 4,294,967,296 addresses), IPv6 address has a length of 128-bits. IPv4, although the total address reach 4 billion, in fact, not until the 4 billion addresses, because there are some limitations, so that its implementation is currently only reaches a few hundred million. IPv6, which has a length of 128-bit, has a total addresses that may be up to2128= 3.4 x 1038addresses. Total addresses a very big aim to provide the address space that will not run out (up to several days ahead), and form a routing infrastructure are arranged hierarchically, thus reducing the complexity of the process of routing and routing tables.
Just as IPv4, IPv6 also allows the DHCP server as a regulator of the automatic address. If the IPv4 addresses are dynamic and static address, then the IPv6 address configuration using DHCP Server named with stateful address configuration, whereas if the configuration of IPv6 addresses without a DHCP server is called a stateless address configuration.
As with IPv4 using the bits in the high-level (high-order bit) as a temporary network address bits at low levels (low-order bit) as host addresses, IPv6 also occur in similar terms. In IPv6, the bits at a high level will be used as identification type of IPv6 address, called the Format Prefix (FP). In IPv6, there is no subnet mask, there is only Format Prefix.
IPv6 addressing is defined in RFC 2373.
Address Format
In IPv6, a 128-bit addresses will be divided into 8 blocks, 16-bit, which can be converted into a hexadecimal 4-digit size. Each block will be hexadecimal numbers separated by colons (:). Therefore, the format of the notation used by IPv6 also often called colon-hexadecimal format, using a different IPv4 dotted-decimal format.
Here is an example IPv6 address in binary form:
0010000111011010000000001101001100000000000000000010111100111011000000101010101000000000
1111111111111110001010001001110001011010
To translate it into a form of colon-hexadecimal notation format, binary numbers above should be divided into 8 pieces sized 16-bit blocks:
0010000111011010 0000000011010011 0000000000000000 0010111100111011 0000001010101010
0000000011111111 1111111000101000 1001110001011010
Then, each sized 16-bit block is converted into hexadecimal and hexadecimal numbers each are separated by colons. The conversion results are as follows:
21DA: 00D3: 0000:2 F3B: 02AA: 00FF: FE28: 9C5A
Simplification of address forms
Address above can be further simplified by removing numbers from 0 at the beginning of each block of eight 16-bit on top, with a single digit. By removing the number 0, the address above simplifies to:
21DA:D3:0:2F3B:2AA:FF:FE28:9C5A
IPv6 addressing convention address also allow further simplification, namely by removing many of the character 0, at an address that many of his number 0. If an IPv6 address notation is represented in hexadecimal colon-format contains several blocks of 16-bit with value 0, then the address may be simplified by using a two colons (:). To avoid confusion, simplification of IPv6 addresses in this way should only be used once within a single address, because the possibility of later users can not determine how many 0 bits represented by each sign two colons (:) contained in the address. The following table illustrates how to use it.
| Oroginal Address | The original address of a simplified | addresses that have been compressed |
|---|
FE80:0000:0000:0000:02AA
:00FF:FE9A:4CA2 | FE80:0:0:0:2AA:FF:FE9A:4CA2 | FE80::2AA:FF:FE9A:4CA2 |
FF02:0000:0000:0000
:0000:0000:0000:0002 | FF02:0:0:0:0:0:0:2 | FF02::2 |
To determine how many bits is 0 is removed (and replaced with a two point two) in an IPv6 address, it can be done by calculating how many blocks are available in the address, which is then subtracted with the number 8, and the figure is multiplied by 16. For example, the address FF02:: 2 contains only two blocks of addresses (FF02 block and block 2). Thus, the number of bits that are discarded (8-2) x 16 = 96 bits.
Format Prefix
In IPv4, an address in dotted-decimal notation format can be represented using a prefix number that refers to the subnet mask. IPv6 also has a number prefix, but not didugnakan to refer to a subnet mask, because it does not support IPv6 subnet mask.
Prefix is a part of the IP address, where the bits have fixed values or bits are part of a route or subnet identifier. IPv6 prefixes are represented in the same way as IPv4 address prefixes, namely [address] / [number prefix length]. Prefix length determines the number of bits that makes the largest far left subnet prefix. For example, an IPv6 address prefix can be represented as follows:
3FFE:2900:D005:F28B::/64
In the example above, the first 64 bits of the address is regarded as an address prefix, while the remaining 64 bits are considered as the interface ID.
Types of IPv6 addresses
IPv6 supports some kind of prefix format, namely as follows:
1. Unicast address, the address provides communications in point to point, directly between two hosts in one network
2. Multicast address, the address provides a method for sending data to multiple hosts in a group with the same address is used in one to many communication
3. Anycast addresses, which provides a method of delivering data packets to the nearest member of a group. These addresses are used in communication one-to-one-of-many. This address is also used only as a destination address (destination address) and given only to the router, not the usual hosts.
When viewed from the coverage of her address, unicast and anycast addresses are divided into the following addresses:
1. Link-Local, is a type of address that allows a computer to communicate with other computers within a subnet.
2. Site-Local, is a type of address that allows a computer to communicate with other computers within an intranet.
3. Global Address, a type of address that allows a computer to communicate with other computers in the Internet based on IPv6.
Meanwhile, the scope multicast address is inserted into the structure of the address.
Unicast Address
IPv6 unicast addresses can be implemented in various types of addresses, namely:
1. Global unicast address
2. Site-local unicast address
3. Link-local unicast address
4. Unicast address is yet to be determined (unspecified unicast address)
5. Unicast loopback address
6. 6to4 unicast address
7. Unicast address ISATAP
Global unicast addresses
IPv6 global unicast addresses are similar to public address in IPv4. Also known as Aggregatable Global Unicast Address. Like the public IPv4 addresses that can be globally referenced by the hosts on the Internet by using the routing process, the address is also implementing something similar. The structure of global unicast IPv6 address is divided into three level topology (Public, Sites, and Node).
| Field | Long | Description |
|---|
001 | 3 bit | Berfungsi sebagai tanda pengenal alamat, bahwa alamat ini adalah sebuah alamat IPv6 Unicast Global. |
| Top Level Aggregation Identifier (TLA ID) | 13 bit | Berfungsi sebagai level tertinggi dalam hierarki routing. TLA ID diatur oleh Internet Assigned Name Authority (IANA), yang mengalokasikannya ke dalam daftar Internet registry, yang kemudian mengolasikan sebuah TLA ID ke sebuah ISP global. |
| Res | 8 bit | Direservasikan untuk penggunaan pada masa yang akan datang (mungkin untuk memperluas TLA ID atau NLA ID). |
| Next Level Aggregation Identifier (NLA ID) | 24 bit | Berfungsi sebagai tanda pengenal milik situs (site) kustomer tertentu. |
| Site Level Aggregation Identifier (SLA ID) | 16 bit | Mengizinkan hingga 65536 (216) subnet dalam sebuah situs individu. SLA ID ditetapkan di dalam sebuah site. ISP tidak dapat mengubah bagian alamat ini. |
| Interface ID | 64 bit | Berfungsi sebagai alamat dari sebuah node dalam subnet yang spesifik (yang ditentukan oleh SLA ID). |
Site-local unicast addresses
Site-local unicast addresses are similar to IPv6 private addresses in IPv4. The scope of an address contained in the internetwork in a site belonging to an organization. The use of a global unicast address and site-local unicast in a network is possible. Prefixes used by this address is fec0:: / 48.
| Field | Long | Descrption |
|---|
11111110100000000000000000000000
00000000000000000000000000000000 | 64 bit | Berfungsi sebagai tanda pengenal alamat unicast link-local. |
| Interface ID | 64 bit | Berfungsi sebagai alamat dari sebuah node dalam subnet yang spesifik. |
Unicast address unspecified
Unicast address is yet to be determined is the address that has not been determined by an administrator or not find a DHCP Server to request the address. This address is the same as the IPv4 address that has not been determined, ie, 0.0.0.0. The value of this address in IPv6 is 0:0:0:0:0:0:0:0 or can be shortened to two point two (::).
Unicast Loopback Address
Unicast loopback address is an address used for interprocess communication mechanism (IPC) in a host. In IPv4, addresses are assigned is 127.0.0.1, while in IPv6 is 0:0:0:0:0:0:0:1, or:: 1.
6to4 Unicast Address
6to4 unicast address is the address used by the two hosts IPv4 and IPv6 in the IPv4 Internet to communicate with each other. These addresses are often used instead of IPv4 public addresses. The original address using the address prefix 2002:: / 16, with an additional 32 bits of IPv4 public addresses to create a prefix with length 48-bit, with the format 2002: WWXX: YYZZ:: / 48, where WWXX and YYZZ is the representation in colon-decimal notation format of the dotted-decimal notation format WXYZ of public IPv4 addresses. For example the IPv4 address 157.60.91.123 is translated into an IPv6 address 2002:9 D3C: 5B7B:: / 48.
Nevertheless, these addresses are often written in the format of the global Unicast IPv6 address, ie 2002: WWXX: YYZZ: SLA ID: Interface ID.
ISATAP Unicast Address
Unicast Addresses ISATAP is an address used by the two hosts IPv4 and IPv6 in an IPv4 intranet to communicate with each other. It combines a prefix address link-local unicast address, site-local unicast address or a global unicast address (which can be a 6to4 address prefixes) are sized 64-bit with 32-bit ISATAP Identifier (0000:5 EFE), followed by 32-bit IPv4 addresses are owned by the interface or a host. Prefixes used in this address is called a subnet prefix. Although 6to4 addresses can only deal with public IPv4 addresses only, ISATAP addresses can handle IPv4 private addresses and IPv4 public addresses.
Multicast Address
IPv6 multicast address as well as the IPv4 multicast addresses. Packets addressed to a multicast address will be delivered to all interfaces identified by that address. Address prefix used by IPv6 multicast address is FF00:: / 8.
| Field | Long | Descrption |
|---|
11111111 | 8 bit | Tanda pengenal bahwa alamat ini adalah alamat multicast. |
| Flags | 4 bit | Berfungsi sebagai tanda pengenal apakah alamat ini adalah alamat transient atau bukan. Jika nilainya 0, maka alamat ini bukan alamat transient, dan alamat ini merujuk kepada alamat multicast yang ditetapkan secara permanen. Jika nilainya 1, maka alamat ini adalah alamat transient. |
| Scope | 4 bit | Berfungsi untuk mengindikasikan cakupan lalu lintas multicast, seperti halnya interface-local, link-local, site-local, organization-local atau global. |
| Group ID | 112 bit | Berfungsi sebagai tanda pengenal group multicast |
Anycast Address
Anycast addresses in IPv6 is similar to anycast addresses in IPv4, but is implemented in a way that is more efficient than with IPv4. Generally, anycast addresses are used by Internet Service Providers (ISPs) who has many clients. Although anycast address using unicast address space, but its function is different than a unicast address.
Using IPv6 anycast addresses to identify several different interfaces. IPv6 will deliver packages addressed to an anycast address to the nearest interface identified by that address. This is very different from the multicast address, which deliver packets to multiple recipients, because the anycast address would deliver the package to one of many recipients.
