Learn the concept of IPv6 network address from the perspective of Installation

The commercialization of IPv6 networks has played a key role in promoting IPv6 networks. Now, as an IPv4-dominated network. Many of us are still unclear about the IPv6 network address. Now let's take a look at the knowledge of IPv6 network addresses based on its installation problems.

IPv6 and IPv4 are two completely different network protocols. Now that IPV4 is to be replaced by IPv6 in the future, what are its advantages? First, IPv6 has a large address capacity. IPv6 addresses use a length of 128 bits. For 32-bit IPV4 addresses, the added IP addresses can be described as massive IP addresses. An IPV4 address can only provide up to two 32-power addresses, but also some private addresses and reserved addresses. The actual number of available addresses is less than this number. IPv6 addresses can provide a maximum of 2 128 addresses. In the future, no matter what network devices are added to the network, enough addresses will be allocated. This is the biggest advantage of IPv6. Of course, IPv6 also has better Qos support than IPV4, and has a simpler IPv6 Header, which facilitates network devices to process IPv6 packets, it also provides streaming support and higher security.

Currently, IPV4 addresses are represented in dotted decimal notation. How can next-generation IPv6 addresses be expressed? Because the IPv6 address is 4 times longer than the IPv4 address, it is more complex to express than the IPV4 address. The basic expression of IPv6 network addresses is X: X, where X is a 4-bit hexadecimal INTEGER (1 6 digits ). Each number contains four digits, each integer contains four digits, and each address contains eight integers, totaling 1 2 8 bits (4 × 4 × 8 = 1 2 8 ). For example, the following are some valid IPv6 addresses:

CDCD: 901A: 2222: 5498: 8475: 1111: 3900: 2020

1030: 0: 0: 0: C9B4: FF12: 48AA: 1A2B

2000: 0: 0: 0: 0: 0: 0: 1

Note that these integers are hexadecimal integers, with A to F representing 10 to 15. Each integer in the address must be expressed, but the starting 0 does not need to be expressed.

This is a standard IPv6 network address expression, and there are two more clear and easy-to-use methods.

Some IPv6 addresses may contain a long string of 0 (as in the second and third examples above ). In this case, the "gap" is allowed in the standard to indicate the 0 of this long string. In other words, the address 2000: 0: 0: 0: 0: 0: 1 can be expressed as: 2000: 1. The two colons indicate that the address can be expanded to a complete 128-bit address. In this method, only when the first 6-digit group is 0 will be replaced by two colons, and the two colons can only appear once in the address to avoid confusion.

There may be a third expression method in the hybrid environment of IPv4 and IPv6. The minimum 32 bits in an IPv6 address can be used to represent an IPv4 address. The address can be expressed in a hybrid manner, that is, X: d. d. d. d, where X represents a 16-digit integer, while d represents an 8-digit decimal integer. For example, address 0: 0: 0: 0: 0: 0: 10.0.0.1 is a valid IPv4 address. Combine two possible expressions. This address can also be expressed as: 10.0.0.1.

There is also a major difference between an IPv6 network address and an IPv4 address, that is, the address type. As we all know, there are three types of ipv4 addresses: unicast address, multicast address, and broadcast address. Although IPv6 addresses are also of three types, they have already changed: unicast, multicast (multicast), and anycast ).

◆ Unicast address: the address of a network interface. Packets sent to a unicast address are sent to the interface identified by this address.

◆ Multicast address: The network address of a group of interfaces (generally different nodes. Packets sent to a multicast address are transmitted to all interfaces with the address ID.

◆ Wildcard address: The network address of a group of interfaces (generally different nodes. Packets sent to a wildcard IP address will be transmitted to one of the interfaces identified by this IP address (select the nearest one based on the distance calculation method of the routing protocol ).

◆ Broadcast address: All nodes in a CIDR block. Packets sent to a broadcast address are sent to all nodes in the CIDR block.

The reason why we need to remove the broadcast address from the IPv6 network address and redefine the anycast address is mainly because the existence of a large number of broadcast packets in the Network may cause network congestion, in addition, because each node in the network needs to process most of the broadcast packets that are not related to itself, the performance of the network nodes will also be affected.