IPv6 address expression, addressing models, and address space gmccf
This chapter describes IPv6 addressing, first introduced with the use of IP addressing number to identify and locate the node on the IP network related issues.
years, IP addresses are considered to be in the end, the only IP network and persistent node identifier. In recent years, especially with the next-generation IP technology, IP address for this view is changing. If we continue as in the past 20 years, the method used to allocate network and node address, it would be an unnecessary and inefficient approach.
This chapter describes the RFC 2373 (IPv6 Addressing Architecture) described in the IP addressing architecture,
nfl wholesale jerseys, the will first introduce some related issues with IP addressing. And will introduce several possible address allocation. IPv6 addressing in this chapter will be divided into the following sections: 128-bit address of the structure and the naming and the different types of IPv6 addresses (unicast, multicast and anycast).
IPv6 designers can simply addressing architecture in IPv4 address space to expand. But this way will we lose a great opportunity to improve IP. Architecture for the entire addressing the tremendous opportunities for change, not only in improving the efficiency of address allocation, but also in improving IP routing performance. This chapter describes these improvements, Chapter 8, issues for IPv6 routing will be described in greater detail. The address allocation, the mobile network technology and auto-configuration in Chapter 11 to explain in detail.
RFC 2373 in the July 1998 publication, and abandoned as early as December 1995 published in RFC 1884 (IPv6 Addressing Architecture). Most of which change from the initial two and half years after the release of RFC is considered necessary in the need for clarification, correction and modification of the Department.
address
IPv4 and IPv6 addresses the most obvious difference is between the length: IPv4 address length is 32 bits, the IPv6 address length is 128 bits. RFC 2373 explains not only the expression of these addresses, but also describes the different address types and their structure. IPv4 addresses can be divided into 2-3 different parts of the (network identifier, node identifier, and sometimes subnet identifier), IPv6 address has a larger address space can support more fields.
There are three types
IPv6 addresses, unicast, multicast and anycast addresses. The next section describes this in more detail. Unicast and multicast IPv4 address and the address is very similar; but no longer support IPv6 in the IPv4 broadcast address, and the addition of a pan-broadcast address. This section describes the IPv6 addressing model, address type, address and address in the expression of a special case.
address expression
IPv4 address generally points to 4 points between the methods, ie 4 numbers separated by dots. For example, the following are some valid IPv4 addresses are expressed with a decimal integer:
10.5.3.1
127.0.0.1
201.199.244.101
IPv4 addresses are also often in a group of four 2-bit hexadecimal integer or four 8-bit binary integer, but the latter rare.
IPv6 address length of 4 times the IPv4 address, in expressing the complexity of the IPv4 address is 4 times. The basic expression of IPv6 address is X: X: X: X: X: X: X: X, where X is a 4-bit hexadecimal integer (16 bits). Each figure contains four, each containing 4 integer numbers,
twins jerseys cheap, each address includes eight integers, Total 1 2 8 (4 × 4 × 8 = 128). For example, the following are some valid IPv6 address:
CDCD: 910A: 2222:5498:8475:1111:3900:2020
1030:0:0:0: C9B4: FF12: 48AA: 1A2B
2000:0:0:0:0:0:0:1
Please note that these integers are hexadecimal integer, which represents A to F is 1 0 to 1 5. Address each of the integers must be represented, but can not express the starting 0.
This is a relatively standard IPv6 address expression, in addition to two other more clear and easy to use way.
some IPv6 addresses may contain long string of 0 (as above as the second and third example). When this happens, the standard permits the use of \In other words, the address
2000:0:0:0:0:0:0:1
can be expressed as:
2000:: 1
that address both the colon that can be extended to a full 128-bit address. In this method, only when the 16 bit set to 0 only when all been replaced by two colons and two colons in the address only once.
IPv4 and IPv6
in a mixed environment may have a third method. IPv6 address of the lowest 32 bits can be used to represent IPv4 addresses, the address can be expressed by a hybrid, that is X: X: X: X: X: X: dddd, where X represents a 16 bit integer, and d represents an 8-bit decimal integer. For example, the address
0:0:0:0:0:0:10.0.0.1
is a valid IPv4 address. The expression of the two possible together, the address can also be expressed as:
:: 10.0.0.1
the IPv6 address is divided into two parts - the subnet prefix and interface identifier, so people can look forward to a IP node address CIDR address a similar way by being represented as an additional value to carry the address, which points out the address in How many bits are mask. That is, IPv6 node address that the prefix length, the length of the IPv6 address with a slash distinguish between,
wholesale jerseys, for example:
1030:0:0:0: C9B4: FF12: 48AA: 1A2B/60
this address prefix used for routing a length of 60 bits.
addressing model
IPv6 and IPv4 addressing model is very similar. Each unicast address identifies a single network interface. IP address is assigned to the network interface rather than nodes,
nfl jerseys for sale, so a node with multiple network interfaces can have multiple IPv6 addresses, IPv6 address any one of them can represent the node. Although a network interface with multiple unicast address associated, but only a unicast address is associated with a network interface. Each network interface must have at least a unicast address.
There is a very important statement and a very important exception. This statement and the use of point to point links. In IPv4, all the network interfaces, including the router connected to a node point to point links (dial-up Internet connection with many), we need a dedicated IP address. As many institutions began to use the point to point links to connect their branch offices, each link requires its own subnet, so that consumes a lot of address space. In IPv6, if any one end point to point link from non-neighboring nodes do not need to receive and send data, they can no special address. That is, if two nodes are mainly passing traffic, they do not need to have IPv6 addresses.
for each network interface is assigned a globally unique unicast address of the IPv4 address the requirements of the expansion of obstacles. Provide a common service of a server in the case of high demand may crash. Therefore, IPv6 address model also proposed an important exception: if the hardware is capable of multiple network interfaces to share the network load properly, then the multiple network interfaces can share a IPv6 address. This makes the extension from the server to the load sharing server group possible, and no longer need to increase the demand on the server hardware must be upgraded.
will be discussed below multicast and anycast address is also related with the network interface. A network interface can have any type of multiple addresses.
address space
RFC 2373 contains an IPv6 address space \the length of the address allocation.
IPv6 address allocation in the points that need attention. First, in RFC 1884, the address space of a quarter is used for two different addresses: one in eight is based on the unicast address of the supplier, while the other one in eight is based on the geographical unicast address. It is hoped that the network address assigned to the user where the service provider network or physical location. Based on the accumulation of suppliers, as it was originally called, requires the network to provide Internet access from the supplier get the IP address can be gathered. However,
tennessee titans jerseys, this approach has a distant branch offices for large organizations is not a perfect solution, since many offices may use different vendors. Will be based on the accumulation of suppliers to bring more of these large units IP address management problems.
Steve Deering proposed to address allocation method based on geographic location as the SIP (SIPP's predecessor,
st louis rams jerseys, in Chapter 4 in Introduction) in a way. Based on these addresses with the addresses of different suppliers, in a way very similar distribution of IPv4 addresses. These addresses are geographically related, and suppliers will have to keep an extra router to support IPv6 address space to gather some of those outside the network.
ISP does not actually agree with this solution, because the management of location-based addressing will greatly increase the complexity (and cost). On the other hand, is difficult to address vendor-based configuration and reconfiguration rise to a number of suppliers based on the distribution of program opposition. If there is no widespread use of IPv4-based auto-configuration (eg DHCP), then all agencies will be there is a huge network management problems. Although the IPv6 auto-configuration has the better support, but did not approach the ultimate integration of location into the distribution.
note that most of the address space is not assigned, address the first part of the distribution is preserved.
Hybrid Mode
