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Information about Mobile Ip

Mobile IP is an Internet Engineering Task Force (IETF) standard communications protocol that is designed to allow mobile device users to move from one network to another while maintaining a permanent IP address. Mobile IPv4 is described in IETF RFC 3344 (Obsoleting both RFC 3220 and RFC 2002), and updates are added in IETF RFC 4721. Mobile IPv6 is described in IETF RFC 3775.

Introduction

Mobile IP provides an efficient, scalable mechanism for roaming within the Internet. Using Mobile IP, nodes may change their point-of-attachment to the Internet without changing their IP address. This allows them to maintain transport and higher-layer connections while moving. Node mobility is realized without the need to propagate host-specific routes throughout the Internet routing fabric.

Applications

Mobile IP is most often found in wired and wireless environments where users need to carry their mobile devices across multiple LAN subnets with different IP addresses. It may for example be used in roaming between overlapping wireless systems, for example IP over DVB, WLAN, WiMAX and BWA. Currently, Mobile IP is not required within cellular systems such as 3G, to provide transparency when internet users migrate between cellular towers, since these systems provide their own data link layer handover and roaming mechanisms. However, it is often used in 3G systems to allow seamless IP mobility between different Packet Data Serving Node (PDSN) domains. For Release 8, MIP and different variations like PMIP will be supported by the EPS (Evolved Packet System), at least for non-3GPP accesses.

In many applications (VPN and VoIP, to name a few), sudden changes in network and IP-address can cause problems.

How Mobile IP works

In brief, Mobile IP works as follows. A mobile node can have two addresses - a permanent home address and a care of address, which is associated with the network the mobile node is visiting. There are two kinds of entities in Mobile IP:
  • A home agent stores information about mobile nodes whose permanent address is in the home agent's network.
  • A foreign agent stores information about mobile nodes visiting its network. Foreign agents also advertise care-of addresses, which are used by Mobile IP.
A node wanting to communicate with the mobile node uses the home address of the mobile node to send packets. These packets are intercepted by the home agent, which uses a table and tunnels the packets to the mobile node's care-of address with a new IP header, preserving the original IP header. The packets are decapsulated at the end of the tunnel to remove the added IP header and delivered to the mobile node.

When acting as sender, mobile node simply sends packets directly to the other communicating node through the foreign agent. If needed, the foreign agent could employ reverse tunneling by tunneling mobile node's packets to the home agent, which in turn forwards them to the communicating node.

The Mobile IP protocol defines the following:
  • an authenticated registration procedure by which a mobile node informs its home agent(s) of its care-of-address"(es);
  • an extension to ICMP Router Discovery, which allows mobile nodes to discover prospective home agents and foreign agents; and
  • the rules for routing packets to and from mobile nodes, including the specification of one mandatory tunneling mechanism and several optional tunneling mechanisms.

Future

Enhancements to the Mobile IP technique, such as Mobile IPv6 and Hierarchical Mobile IPv6 (HMIPv6), are being developed to improve mobile communications in certain circumstances by making the processes more secure and more efficient.

Researchers are also working to create support for mobile networking without requiring any pre-deployed infrastructure as required by MIP. One such example is Interactive Protocol for Mobile Networking (IPMN) which promises supporting mobility on a regular IP network just from the network edges by intelligent signaling between IP at end-points and application layer module with improved quality of service.

See also

External links

Internet Engineering Task Force (IETF) develops and promotes Internet standards, cooperating closely with the W3C and ISO/IEC standard bodies; and dealing in particular with standards of the TCP/IP and Internet protocol suite.
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protocol is a convention or standard that controls or enables the connection, communication, and data transfer between two computing endpoints. In its simplest form, a protocol can be defined as the rules governing the syntax, semantics, and synchronization of communication.
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Roaming is a general term in wireless telecommunications that refers to the extending of connectivity service in a location that is different from the home location where the service was registered.
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IP over DVB or IP over MPEG implies that Internet Protocol datagrams are transferred over the MPEG transport stream, and are distributed using some digital television system, for example DVB-H, DVB-T, DVB-S or DVB-C.
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WiMAX, the Worldwide Interoperability for Microwave Access, is a telecommunications technology aimed at providing wireless data over long distances in a variety of ways, from point-to-point links to full mobile cellular type access.
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Wireless Broadband is a fairly new technology that provides high-speed wireless internet and data network access over a wide area.

The Term Broadband

According to the 802.
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    3G is the third generation of mobile phone standards and technology, after 2G. It is based on the International Telecommunication Union (ITU) family of standards under the International Mobile Telecommunications programme, "IMT-2000".
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    For the telecommunication usage, see .


    Handover, in the political-historical sense, often refers to the transfer of power of former colonies (particularly those of former British colonies) to the local people.
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    Roaming is a general term in wireless telecommunications that refers to the extending of connectivity service in a location that is different from the home location where the service was registered.
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      3G is the third generation of mobile phone standards and technology, after 2G. It is based on the International Telecommunication Union (ITU) family of standards under the International Mobile Telecommunications programme, "IMT-2000".
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      The Packet Data Serving Node, or PDSN, is a component of a CDMA2000 mobile network. It acts as the connection point between the Radio Access and IP networks. This component is responsible for managing PPP sessions between the mobile provider's core IP network and the mobile
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      virtual private network (VPN) is a communications network tunneled through another network, and dedicated for a specific network. One common application is secure communications through the public Internet, but a VPN need not have explicit security features, such as
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      Voice over Internet Protocol, also called VoIP, IP Telephony, Internet telephony, Broadband telephony, Broadband Phone and Voice over Broadband is the routing of voice conversations over the Internet or through any other IP-based network.
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      Used in Internet routing, a care-of-address (usually referred to as CoA) is a temporary IP address for a mobile device. This allows a Home Agent to forward messages to the mobile device.
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      ICMP Internet Router Discovery Protocol (IRDP) uses Internet Control Message Protocol (ICMP) router advertisements and router solicitation messages to allow a host to discover the addresses of operational routers on the subnet.
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      Mobile IPv6 is a network layer IP standard used by electronic devices to exchange data across a packet-switched internetwork. Mobile IPv6 allows an IPv6 node to be mobile—to arbitrarily change its location on an IPv6 network—and still maintain existing connections.
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      In cellular telecommunications, the term handoff refers to the process of transferring an ongoing call or data session from one channel connected to the core network to another.
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      Roaming is a general term in wireless telecommunications that refers to the extending of connectivity service in a location that is different from the home location where the service was registered.
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        Mobility Management is one of the major functions of a GSM or a UMTS network that allows mobile phones to work. The aim of mobility management is to track where the subscribers are, so that calls, SMS and other mobile phone services can be delivered to them.
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        Mobile IPv6 is a network layer IP standard used by electronic devices to exchange data across a packet-switched internetwork. Mobile IPv6 allows an IPv6 node to be mobile—to arbitrarily change its location on an IPv6 network—and still maintain existing connections.
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        Vertical handoff refers to a network node changing the type of connectivity it uses to access a supporting infrastructure, usually to support node mobility. For example, a suitably equipped laptop might be able to use both a high speed wireless LAN and a cellular technology for
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