How can I determine if an IP packet is a MIPV6 packet?

Mobile IP is a network service designed to meet the needs of mobile nodes to maintain their connectivity during the move, and to achieve roaming across different network segments.

With the widespread use of mobile terminal devices, mobile computers and mobile terminals and other devices have begun to need to access the Internet, but the traditional IP design does not take into account the problem that mobile nodes will change Internet access points in the connection. Traditional IP addresses have two meanings: on the one hand, they are used to identify a unique host, and on the other hand, they also play an important role in the routing of data as the address of the host.

However, in the case of mobile nodes, because the Internet access point is constantly changing, its IP address is separated in two ways, one is that the mobile node needs a mechanism to uniquely identify itself, and the other is that it needs to be used for routing. Mobile IP is designed to enable mobile nodes to separate the two functions of IP addresses without completely changing the structure of the existing Internet.

Attribution IP addresses (fixed addresses) and mobile addresses (which change as computers move). When the device moves to another region, it needs to send its new address to the home, so that it can communicate to its new address in a timely manner.

In order to meet the needs of society, the IETF has developed a mobile IP (Mobile IP) protocol, which makes mobile access on the Internet possible.

To put it simply, the role of MIP technology is that a mobile node usually sets its address by its "home IP address", which is assigned to the mobile node on the "home subnetwork", and the subnet prefix of this address is the subnet prefix of the "home subnet". Use the home IP address to send the packets to the mobile node, first reach the home agent (HA), find the registration information of the mobile node, obtain the foreign agent (FA) address of the subnet where the user is currently located, and then access the FA, so as to finally find the mobile node and continue to communicate. Since the "home IP address" of the mobile node remains the same, its movement is transparent to the transport layer and beyond.

MIP is not a technology specifically designed for cellular mobile communication systems. The implementation of mipv4 and mipv6 is different. To implement the MIPV4 feature, GGSN needs to support the FA function.

IPv6 is an abbreviation for Internet Protocol Version 6, also known as the Next Generation Internet Protocol, which is a new IP protocol designed by the IETF (Internet Engineering Task Force) to replace the current IPv4 (current IP) protocol.

As we know, the host of the Internet has a unique IP address, and the IP address represents a host number with a 32-bit binary number, but the 32-bit address has limited resources and can no longer meet the needs of users, so the Internet Research Organization released a new host identification method, that is, IPv6. In RFC1884 (RFC is an abbreviation for Request for Comments Document. RFC is actually some of the standards for Internet services), the standard syntax of the regulations recommends that the 128-bit (16 bytes) of an IPv6 address be written as eight 16-bit unsigned integers, each represented by four hexadecimal bits, and the numbers are separated by a colon (:

separate, for example: 3ffe:3201:

1401:1280:c8ff:

fe4d:db39:1984 Extended addressing capability.

IPv6 extends the length of IP addresses from 32 bits to 128 bits, supporting more levels of address hierarchies, more addressable nodes, and simpler address auto-configuration. The scalability of multicast routing is improved by adding a "range" domain to the multicast address. A new address type, called an "arbitrcast address", is also defined to send packets to any one of a set of nodes;

Simplified header format.

Some IPv4 header fields have been removed or made optional to reduce the consumption of routine processing in packet processing and limit the bandwidth consumed by IPv6 headers;

Improvements to extended header and options support.

Changes to the encoding of IP header options can improve efficiency, make the length of options more restrictive, and provide greater flexibility to introduce new options in the future;

The ability to identify flows.

A new capability has been added that makes it possible to identify packets that belong to a specific communication "stream" that the sender requires special handling, such as a non-default quality of service to obtain a "live" service;

Authentication and encryption capabilities.

Extended features to support authentication, data integrity, and (optionally) data confidentiality are specified in IPv6.

Multicast: Point-to-multipoint communication, where packets are delivered to each of a group of computers. Multicast makes network communication more efficient, and IPv6 has a very large multicast address space.

IPv6 does not use broadcast terminology, but rather sees broadcast as a special case of multicast. Anycast: Anycast means that multiple routers share the same unicast address (a group of multicast routers), all multicast sources send packets to the unicast address, and the router automatically selects the nearest multicast router to reach the destination.

Anycast is a type added to IPv6 where the destination station is a group of computers, but packets are delivered to only one of them, usually the closest one. In order to make the representation of addresses more concise, IPv6 uses the colon hexadecimal method, which represents each 16-bit in the corresponding hexadecimal system, and separates the groups by a colon. For example:

686e：8c64：ffff：ffff：0：1180：96a：ffff

The colon hexadecimal notation allows zero compression, i.e. a string of consecutive zeros can be replaced by a pair of colons, for example:

ff05:0:0:0:0:0:0:b3 can be set to: ff05::b3

In order to ensure that there is a clear explanation of zero compression, the recommendations state that zero compression can only be used once in any address. This technique is particularly useful for the proposed allocation strategy, where there will be many addresses that contain consecutive zero strings.

The colon hexadecimal notation is combined with a bit of a decimal notation suffix. This combination is particularly useful in the transition from IPv4 to IPv6. For example, the following string is a valid colon hexadecimal notation:

In this notation, although each value separated by a colon is a 16-bit quantity, the value of the decimal part of each equinox indicates the value of one byte. Then use zero compression to get the following:

The leading bit 0 in each segment can be left unwritten;

In the same address, several consecutive 0 segments can be abbreviated as'::'。Multiple address prefixes can be aggregated into a single address prefix.

Address aggregation increases the efficiency and scalability of routing.

6. IPv6 address auto-configuration function.

Ability to use data-link addresses for addressing.

Ability for conflict-free address auto-provisioning.

Plug and play (automatically request and advertise address prefixes between the host and router) By modifying the lifetime of the old prefix advertised by the router (reducing its lifetime), a new prefix is advertised.

If you change the prefix for the entire network, you may need to change the DNS

IPv6 is the abbreviation of Internet Protocol Version 6"Internet Protocol"。IPv6 is the next generation of IP protocol designed by the IETF (Internet Engineering Task Force) to replace the current version of the IP protocol (IPv4), claiming to be able to weave a ** for every grain of sand in the world.

The biggest problem of IPv4 is that the network address resources are limited, which seriously restricts the application and development of the Internet. The use of IPv6 can not only solve the problem of the number of network address resources, but also solve the obstacles of multiple access devices to connect to the Internet.

IPv6 has several advantages over IPv4:

1. IPv6 has a larger address space. IPv4 specifies that the length of an IP address is 32, and the maximum number of addresses is 2 32. In IPv6, the length of an IP address is 128, that is, the maximum number of addresses is 2 128. Compared to the 32-bit address space, its address space has increased by 2 128-2 32.

Second, IPv6 uses smaller routing tables. IPv6 address allocation follows the principle of aggregation at the beginning, which enables the router to represent a ** network with a record (entry) in the routing table, which greatly reduces the length of the routing table in the router and improves the speed of the router's ** packet.

3. IPv6 adds enhanced multicast support and flow control, which gives the network an opportunity for the development of multiple applications and provides a good network platform for quality of service (QoS) control.

4. IPv6 adds support for Auto Configuration. This is an improvement and extension of the DHCP protocol, which makes the management of networks, especially LANs, easier and faster.

6. Expansion is permitted. IPv6 allows protocol extensions if required by new technologies or applications.

7. Better header format. IPv6 uses a new header format with options separate from the base header that can be inserted between the base header and the underlying data if desired. This simplifies and speeds up the routing process, as most options do not need to be routed.

8. New options. IPv6 has some new options for implementing additional features.