A comparison of IPV4 and IPV6

Introduction

The IPv6 mode that ordinary users can use is the tunnel connection. In the tunnel connection, the scarce fixed global IPv4 addresses must be allocated by the ISP so an ISP service charge is relatively expensive. In a native connection, many low-cost consumer broadband routers do not support IPv6, or if so, they are expensive. ADSL services are the core of current broadband connections and those that support IPv6 native communication are extremely limited. In the existing IPv4 network, NAT is used with private addresses because of the IP address depletion problem. Under the development of a wireless LAN environment, most existing IPv6 connection services are being provided through a wired connection.

Description

IPv4

IPv6

Address

32 bits long (4 bytes). Address is composed of a network and a host portion, which depend on address class. Various address classes are defined: A, B, C, D, or E depending on initial few bits. The total number of IPv4 addresses is 4 294 967 296.

The text form of the IPv4 address is nnn.nnn.nnn.nnn, where 0<=nnn<=255, and each n is a decimal digit. Leading zeros can be omitted. Maximum number of print characters is 15, not counting a mask. (Bragg, 22)

128 bits long (16 bytes). Basic architecture is 64 bits for the network number and 64 bits for the host number. Often, the host portion of an IPv6 address (or part of it) will be derived from a MAC address or other interface identifier.

Depending on the subnet prefix, IPv6 has a more complicated architecture than IPv4.

The number of IPv6 addresses is 1028 (79 228 162 514 264 337 593 543 950 336) times larger than the number of IPv4 addresses. The text form of the IPv6 address is xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx, where each x is a hexadecimal digit, representing 4 bits. Leading zeros can be omitted. The double colon (::) can be used once in the text form of an address, to designate any number of 0 bits. For example, ::ffff:10.120.78.40 is an IPv4-mapped IPv6 address. (Abley, Black, & Gill, 10)

Address lifetime

Generally, not an applicable concept, except for addresses assigned using DHCP. (Thomson, & Narten, 81)

IPv6 addresses have two lifetimes: preferred and valid, with the preferred lifetime always <= valid.

After the preferred lifetime expires, the address is not to be used as a source IP address for new connections if an equally good preferred address is available. After the valid lifetime expires, the address is not used (recognized) as a valid destination IP address for incoming packets or used as a source IP address. (Crawford, 209)

Address prefix

Sometimes used to designate network from host portion. Sometimes written as /nn suffix on presentation form of address. (Dupont, 102)

Used to designate the subnet prefix of an address. Written as /nnn (up to 3 decimal digits, 0 <= nnn <= 128) suffix after the print form. An example is fe80::982:2a5c/10, where the first 10 bits comprise the subnet prefix. (Hinden, O'Dell, & Deering, 45)

Address Resolution Protocol (ARP)

Address Resolution Protocol is used by IPv4 to find a physical ...