1. The background of the emergence of mobile IP
1. With the rapid development of IP networks, people are no longer satisfied with a single, fixed Internet access method, but hope to provide flexible Internet access methods.
2. The development of wireless Internet requires IP network to provide good support for mobility.
3. With the advent of the era of personal communication, users are required to use one of their own dedicated addresses to surf the Internet anywhere.
4. In the future IPv6 network, the concept of network nodes is not only limited to traditional hosts, but also includes various smart devices, such as automobiles, etc. With the good support of IPv6 for mobile IP, mobile IP will be very useful.
2. The solution when the position of a node changes
1. Change the IP address of the node
If the communication is in progress while the node is moving to another network, changing the node address will cause communication interruption;
2. Adopt specific host routing The
routing table is highly inflated, which brings a great burden to the update of the routing table and is extremely unfavorable for routing query.
3. Mobile IP
enables the mobile host to maintain ongoing communications while switching links. It meets the needs of people accessing the Internet anytime, anywhere.
3. Advantages of Mobile IP
Uninterrupted communication without having to change addresses;
There is no need to use host routing, and it will not cause problems such as expansion of the routing table;
Can provide mobile functionality between multiple mediums;
Mobility support over an arbitrarily large range can be achieved.
4. The essence of mobile IP
1. Mobile IP is a network layer solution that supports host mobility
(1) Like IP, Mobile IP does not require any lower-layer transmission media, and can provide host mobility between networks with different media
(2) Mobile IP goes up to the upper layer The details of the host movement are shielded
(3) The upper-layer protocols and applications of the existing Internet do not need to be changed
2. Solve the problem of sending IP packets between the communication peer and the mobile host
(1) How does the communication peer send IP packets to the mobile host
(2) How does the mobile host send IP packets to the communication peer
3. Mobile IP is realized through tunnel technology