Computer Network (xii) IPv6 Introduction

The necessity 1.IPv6

1.IPv6 to fundamentally solve the problem of IPv4 address exhaustion and standardized Internet Protocol.
2.IPv4 address length is four 8-bit bytes, i.e. 32 bits. And the IPv6 address length is four times the original, i.e. 128 bits, is generally written eight 16-bit bytes.
3. Switch from IPv4 to IPv6 is extremely time consuming, requires an IP address in the network all hosts and routers are reset.

2.IPv6 features

1.IP expanded polymeric address and routing control table
2. performance
3. supports plug and play
4 using authentication and encryption
5. multicast, Mobile IP extensions become

The method of marking the IP address 3.IPv6

1. It will be typically 128 bits per 16-bit IP addresses of a group, each with a colon ( ":") separated labeled.
2. If consecutive 0 0 These can have omitted, and two with a colon ( "::") apart appears.
3. An IP address is allowed only once in two consecutive colons appear.

Structure 4.IPv6 address

IPv6 is similar to IPv4, but also by several former identifies the type of IP addresses IP addresses.
1. In the Internet communication, the use of a global unicast address. It is the only Internet address, no official assigned IP addresses.
2. restrictions networks, namely those not directly access the Internet and private networks, use a unique local address.
3. The router is not used or when the same Ethernet network segment to communicate can use link-local unicast address.
4. When a plurality of types constructed to allow the network IP address, on the same link may be used as well as a unique global unicast address is a local address for communication.
5. In an IPv6 environment, these IP addresses can all be simultaneously disposed on the same one the NIC, demand flexibility.

The global unicast address

In Internet communications, the use of a global unicast address. It is the only Internet address, no official assigned IP addresses.
Global unicast address refers to a unique address in the world. It is the Internet communications and communications in the most commonly used within an IPv6 address each section.

Now format of an IPv6 network is used, n = 48, m = 16 and a 128-nm = 64. I.e., the first 64 bits network identification, after the identifier 64 bits for the host.
Typically, the interface ID value stored in 64-bit MAC address version.
However, because of the inherent MAC address belonging to the device information, and sometimes I do not want to let know to end. At this interface ID may be set to a MAC address is not related to the "temporary address."
This is usually a temporary address randomly generated and updated regularly.
View positioning devices become not so simple from IPv6 addresses. Competing research will be what kind of information, all determined by the specific device operating system.

6. The link-local unicast address

When not in use to communicate with a router or a Ethernet network segment, may be a link-local unicast address.
Unicast link-local address is unique within the same data link address. It is used without a router, a communication link of the same. 64-bit version is typically stored MAC address interface ID.

7. The only local addresses

Restrictive network, that is, those not directly access the Internet and private networks, use a unique local address.
The only local address is the Internet address not used for communication.
Device control restrictive network and the core network and other financial institutions will be isolated from the Internet. In order to improve the security of Internet communications network, within the enterprise and is usually performed by NAT or gateway (proxy) the time.
It does not address the unique local network or through NAT and proxy networking environment used in this.
The only local addresses, although not connected to the Internet, but also randomly generate a unique global ID as possible.

8.IPv6 segmentation process

Fragment processing of IPv6 only on the sending host as a starting point, a router not participating in a sheet.
IPv6 in the "Path MTU Discovery" function is essential.
However 1Pv6 minimum MTU is 1280 bytes. Thus, the embedded systems in those devices have certain limitations of system resources, the need for "Path MTU Discovery", but rather directly to 1280 bytes when sending out the IP packet fragmentation unit.