Mobile IP

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What Does Mobile IP Mean?

Mobile IP communication protocol refers to the forwarding of Internet traffic with a fixed IP address even outside the home network. It allows users having wireless or mobile devices to use the Internet remotely.


Mobile IP is mostly used in WAN networks, where users need to carry their mobile devices across different LANs with different IP addresses. Mobile IP is not a wireless protocol. However, it could be employed for the IP infrastructure of cellular networks.

Techopedia Explains Mobile IP

A simple analogy to understand the concept is a person who has left vacation and set his a forwarding address for his mail.

When a mobile terminal enters a visited area, it requires the services of a foreign agent. The foreign agent provides registration and packet-forwarding services to the visiting terminals. Each mobile IP host uses one permanent IP address (home address) and one temporary address (care-of address) if away from the home network. Thus, the IP packet exchange consists of three mechanisms:

  1. Discovering the care-of address.
  2. Registering the care-of address with the home agent.
  3. The home agent redirecting the received datagrams to the foreign network using care-of address.

Care-of IP addresses are temporary IP addresses are given by the network outside the home network so devices can stay connected while on the move. The device gets a new care-of address if the user moves to another network.


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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.