Mobile IP
Encyclopedia
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 IP for IPv4
is described in IETF RFC 5944, and extensions are defined in IETF RFC 4721. Mobile IPv6, the IP mobility implementation for the next generation of the Internet Protocol
, IPv6
, is described in RFC 6275.
Mobile IP was designed to support seamless and continuous Internet connectivity.
Mobile IP is most often found in wired and wireless environments where users need to carry their mobile devices across multiple LAN subnets. Examples of use are in roaming between overlapping wireless systems, e.g., IP over DVB, WLAN
, WiMAX
and BWA
.
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.
A node wanting to communicate with the mobile node uses the permanent home address of the mobile node as the destination address to send packets to. Because the home address logically belongs to the network associated with the home agent, normal IP routing mechanisms forward these packets to the home agent. Instead of forwarding these packets to a destination that is physically in the same network as the home agent, the home agent redirects these packets towards the remote address through an IP tunnel
by encapsulating the datagram with a new IP header using the care of address of the mobile node.
When acting as transmitter, a mobile node sends packets directly to the other communicating node, without sending the packets through the home agent, using its permanent home address as the source address for the IP packets. This is known as triangular routing. If needed, the foreign agent could employ reverse tunneling by tunneling the mobile node's packets to the home agent, which in turn forwards them to the communicating node. This is needed in networks whose gateway routers check that the source IP address of the mobile host belongs to their subnet or discard the packet otherwise.
HMIPv6 explanation can be found at Hierarchical-Mobile-IPv6.
Researchers create support for mobile networking without requiring any pre-deployed infrastructure as it currently is 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 signalling between IP at end-points and application layer module with improved quality of service.
Researchers are also working to create support for mobile networking between entire subnets with support from Mobile IPv6. One such example is Network Mobility (NEMO) Network Mobility Basic Support Protocol by the IETF Network Mobility Working Group which supports mobility for entire Mobile Networks that move and to attach to different points in the Internet. The protocol is an extension of Mobile IPv6 and allows session continuity for every node in the Mobile Network as the network moves.
Home address: The home address of a mobile device is the IP address assigned to the device within its home network.
Foreign network: A foreign network is the network in which a mobile node is operating when away from its home network.
Care-of address: The care-of address of a mobile device is the network-native IP address of the device when operating in a foreign network.
: A home agent is a router on a mobile node’s home network which tunnels datagrams for delivery to the mobile node when it is away from home. It maintains current location (IP address) information for the mobile node. It is used with one or more foreign agents.
: A foreign agent is a router that stores information about mobile nodes visiting its network. Foreign agents also advertise care-of-addresses which are used by Mobile IP.
Binding: A binding is the association of the home address with a care-of address.
Internet Engineering Task Force
The Internet Engineering Task Force develops and promotes Internet standards, cooperating closely with the W3C and ISO/IEC standards bodies and dealing in particular with standards of the TCP/IP and Internet protocol suite...
(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 IP for IPv4
IPv4
Internet Protocol version 4 is the fourth revision in the development of the Internet Protocol and the first version of the protocol to be widely deployed. Together with IPv6, it is at the core of standards-based internetworking methods of the Internet...
is described in IETF RFC 5944, and extensions are defined in IETF RFC 4721. Mobile IPv6, the IP mobility implementation for the next generation of the Internet Protocol
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
, IPv6
IPv6
Internet Protocol version 6 is a version of the Internet Protocol . It is designed to succeed the Internet Protocol version 4...
, is described in RFC 6275.
Introduction
The Mobile IP protocol allows location-independent routing of IP datagrams on the Internet. Each mobile node is identified by its home address disregarding its current location in the Internet. While away from its home network, a mobile node is associated with a care-of address which identifies its current location and its home address is associated with the local endpoint of a tunnel to its home agent. Mobile IP specifies how a mobile node registers with its home agent and how the home agent routes datagrams to the mobile node through the tunnel.Applications
In many applications (e.g., VPN, VoIP), sudden changes in network connectivity and IP address can cause problems.Mobile IP was designed to support seamless and continuous Internet connectivity.
Mobile IP is most often found in wired and wireless environments where users need to carry their mobile devices across multiple LAN subnets. Examples of use are in roaming between overlapping wireless systems, e.g., IP over DVB, WLAN
Wireless LAN
A wireless local area network links two or more devices using some wireless distribution method , and usually providing a connection through an access point to the wider internet. This gives users the mobility to move around within a local coverage area and still be connected to the network...
, WiMAX
WiMAX
WiMAX is a communication technology for wirelessly delivering high-speed Internet service to large geographical areas. The 2005 WiMAX revision provided bit rates up to 40 Mbit/s with the 2011 update up to 1 Gbit/s for fixed stations...
and BWA
Broadband wireless access
Wireless Broadband refers to technology that provides high-speed wireless Internet access or computer networking access over a wide area.-The term broadband:...
.
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
Packet Data Serving Node
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 station...
(PDSN) domains.
Operational principles
A mobile node has two addresses - a permanent home address and a care-of address (CoA), which is associated with the network the mobile node is visiting. Two kinds of entities comprise a Mobile IP implementation:- A home agent stores information about mobile nodes whose permanent home 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. If there is no foreign agent in the host network, the mobile device has to take care of getting an address and advertising that address by its own means.
A node wanting to communicate with the mobile node uses the permanent home address of the mobile node as the destination address to send packets to. Because the home address logically belongs to the network associated with the home agent, normal IP routing mechanisms forward these packets to the home agent. Instead of forwarding these packets to a destination that is physically in the same network as the home agent, the home agent redirects these packets towards the remote address through an IP tunnel
IP tunnel
An IP tunnel is an Internet Protocol network communications channel between two networks. It is used to transport another network protocol by encapsulation of its packets....
by encapsulating the datagram with a new IP header using the care of address of the mobile node.
When acting as transmitter, a mobile node sends packets directly to the other communicating node, without sending the packets through the home agent, using its permanent home address as the source address for the IP packets. This is known as triangular routing. If needed, the foreign agent could employ reverse tunneling by tunneling the mobile node's packets to the home agent, which in turn forwards them to the communicating node. This is needed in networks whose gateway routers check that the source IP address of the mobile host belongs to their subnet or discard the packet otherwise.
Performance
A performance evaluation of Mobile IPv6 can be found in Additionally, a performance comparison between Mobile IPv6 and some of its proposed enhancements (Hierarchical Mobile IPv6, Fast Handovers for Mobile IPv6 and their Combination) is available at .Development
Enhancements to the Mobile IP technique, such as Mobile IPv6 and Hierarchical Mobile IPv6 (HMIPv6) defined in RFC 5380, are being developed to improve mobile communications in certain circumstances by making the processes more secure and more efficient.HMIPv6 explanation can be found at Hierarchical-Mobile-IPv6.
Researchers create support for mobile networking without requiring any pre-deployed infrastructure as it currently is 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 signalling between IP at end-points and application layer module with improved quality of service.
Researchers are also working to create support for mobile networking between entire subnets with support from Mobile IPv6. One such example is Network Mobility (NEMO) Network Mobility Basic Support Protocol by the IETF Network Mobility Working Group which supports mobility for entire Mobile Networks that move and to attach to different points in the Internet. The protocol is an extension of Mobile IPv6 and allows session continuity for every node in the Mobile Network as the network moves.
Changes in IPv6 for Mobile IPv6
- A set of mobility options to include in mobility messages
- A new Home Address option for the Destination Options header
- A new Type 2 Routing header
- New Internet Control Message Protocol for IPv6 (ICMPv6) messages to discover the set of home agents and to obtain the prefix of the home link
- Changes to router discovery messages and options and additional Neighbor Discovery options
Definition of terms
Home network: The home network of a mobile device is the network within which the device receives its identifying IP address (home address).Home address: The home address of a mobile device is the IP address assigned to the device within its home network.
Foreign network: A foreign network is the network in which a mobile node is operating when away from its home network.
Care-of address: The care-of address of a mobile device is the network-native IP address of the device when operating in a foreign network.
: A home agent is a router on a mobile node’s home network which tunnels datagrams for delivery to the mobile node when it is away from home. It maintains current location (IP address) information for the mobile node. It is used with one or more foreign agents.
: A foreign agent is a router that stores information about mobile nodes visiting its network. Foreign agents also advertise care-of-addresses which are used by Mobile IP.
Binding: A binding is the association of the home address with a care-of address.
See also
- Handoff
- RoamingRoamingIn wireless telecommunications, roaming is a general term referring to the extension of connectivity service in a location that is different from the home location where the service was registered. Roaming ensures that the wireless device is kept connected to the network, without losing the...
- Mobility managementMobility managementMobility management is one of the major functions of a GSM ora UMTS network that allows mobile phones to work. The aim of mobility management is to track where the subscribers are, allowing calls, SMS and other mobile phone services to be delivered to them....
- GPRS Tunneling ProtocolGPRS Tunnelling ProtocolGPRS Tunneling Protocol is a group of IP-based communications protocols used to carry General Packet Radio Service within GSM, UMTS and LTE networks. In 3GPP architectures, GTP and Proxy Mobile IPv6 based interfaces are specified on various interface points.GTP can be decomposed into separate...
- Vertical handoffVertical handoffVertical handover or 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...
- Proxy Mobile IPProxy Mobile IPProxy Mobile IPv6 is a network-based mobility management protocol standardized by IETF and is specified in RFC 5213. It is a protocol for building a common and access technology independent of mobile core networks, accommodating various access technologies such as WiMAX, 3GPP, 3GPP2 and WLAN based...
- Host Identity ProtocolHost Identity ProtocolThe Host Identity Protocol is a host identification technology for use on Internet Protocol networks, such as the Internet. The Internet has two main name spaces, IP addresses and the Domain Name System. HIP separates the end-point identifier and locator roles of IP addresses...
External links
- RFC 6275 -Mobility support for IPv6
- RFC 5944 - IP Mobility Support for IPv4, Revised
- RFC 4721 - Mobile IPv4 Challenge/Response Extensions
- RFC 3024 - Reverse Tunneling for Mobile IP
- Inside Mobile IP
- Protocols for Adaptive Mobile and Wireless Networking
- Mobile IP explained (a tutorial)
- Mobility Extensions for IPv6 (mext) IETF Working Group Web site
- Mobile IPv6 -- A short introduction by Holger Zuleger
- Linux Mobile IPv6 HOWTO on the Linux Documentation ProjectLinux Documentation ProjectThe Linux Documentation Project is an all-volunteer project that maintains a large collection of GNU and Linux-related documentation and publishes the collection online. It began as a way for hackers to share their documentation with each other and with their users, and for users to share...
- D. Johnson, C. Perkins, J. Arkko. Mobility Support in IPv6. RFC 6275. June 2011
- J. Arkko, V. Devarapalli, F. Dupont. Using IPsec to Protect Mobile IPv6 Signaling Between Mobile Nodes and Home Agents. RFC 3776. June 2004