How does mobile IP and the transport layer work

IP packets do not require mechanisms to set up a dedicated bandwidth or channel. The IP address serves a dual purpose — for routing packets through the Internet and as an end-point identifier for applications in end-hosts. The connections in an IP network use sockets to communicate between clients and servers. A socket consists of source IP address, source port, destination IP address, and destination port. A TCP connection cannot survive any address change because it relies on the socket to determine a connection. However, when a terminal moves from one network to another, its address changes. A mobile node (MN) is a terminal than can change its location and thus its point of attachment. The partner for communication is called the correspondent node that can be either a fixed or an MN.

How does mobile IP and the transport layer work

Mobile IP is designed to support host mobility on the Internet. In order for an MN to move across different connection points while maintaining connectivity with other nodes on the Internet, the MN needs to maintain the same address. Two versions of MIP are defined depending on IP version used in the network: MIPv4 for IPv4 networks and MIPv6 for IPv6 networks.

Mobile IP implies that a user is connected to one or more applications across the Internet, that the user’s point of attachment changes dynamically, and that all connections are automatically maintained despite the change. When MN moves its attachment point to another network, it is considered a foreign network for this host. Once the mobile is reattached, it makes its presence known by registering with a network node, typically a router, on the foreign network known as a foreign agent (FA). The mobile then communicates with a similar agent on the user’s home network, known as a home agent (HA), giving the home agent the care-of address (CoA) of the mobile node; the care-of address identifies the foreign agent’s location. A home agent tracks a mobile host’s location. The mobile host is affiliated with a static IP address on the home network and a foreign agent supports mobility on a foreign network by providing routing to a visiting mobile host. Network supporting mobile IP will have to create foreign agents to deliver packets of information to the mobile host. Mobile IP is fundamental for the paradigm to provide the successful model for wireless data, which takes the connection one has into the corporate intranet and makes it wireless.