IEEE 802.21
Encyclopedia
802.21 is an IEEE standard published in 2008. The standard supports algorithms enabling seamless handover
between networks of the same type as well as handover between different network types also called Media independent handover (MIH) or vertical handover. The standard provides information to allow handing over to and from 802.3, 802.11, 802.15, 802.16, 3GPP
and 3GPP2 networks through different handover mechanisms.
The IEEE 802.21 working group
started work in March 2004. More than 30 companies have joined the working group. The group produced a first draft of the standard including the protocol definition in May 2005. The standard was published January 2009.
standards do not support handover between different types of networks. They also do not provide triggers or other services to accelerate mobile IP based handovers. Moreover, existing 802 standards provide mechanisms for detecting and selecting network access points, but do not allow for detection and selection of network access points in a way that is independent of the network type.
that accomplish handover use software to accomplish handovers and suggest that software will also be the way that handover will be implemented by 802.21. The use of software as a means to implement 802.21 should not cause large increases in the cost of networking devices.
(UMA) technology is basically a mobile-centric version of 802.21. UMA is said to provide roaming and handover between GSM, UMTS, Bluetooth
and 802.11 networks
. For more information on UMA you can go to http://www.umatoday.com/.
Since June 19 2005, UMA is a part of the ETSI 3GPP standardization process under the GAN (Generic Access Network) Group.
WiOptiMo technology enables any application running on a device to use the best internet connection among all the wired/wireless access providers available, guaranteeing persistence in case of weak or no signal and managing the switch among them (when needed/convenient) in a transparent way, without interrupting the active application/session.
For more information you can read A Cross-Layering and Autonomic Approach to Optimized Seamless Handover or "WiSwitch: Seamless Handover between Multi-Provider Networks" on IEEE Explore.
Handover
In cellular telecommunications, the term handover or handoff refers to the process of transferring an ongoing call or data session from one channel connected to the core network to another...
between networks of the same type as well as handover between different network types also called Media independent handover (MIH) or vertical handover. The standard provides information to allow handing over to and from 802.3, 802.11, 802.15, 802.16, 3GPP
3GPP
The 3rd Generation Partnership Project is a collaboration between groups of telecommunications associations, known as the Organizational Partners...
and 3GPP2 networks through different handover mechanisms.
The IEEE 802.21 working group
Working group
A working group is an interdisciplinary collaboration of researchers working on new research activities that would be difficult to develop under traditional funding mechanisms . The lifespan of the WG can last anywhere between a few months and several years...
started work in March 2004. More than 30 companies have joined the working group. The group produced a first draft of the standard including the protocol definition in May 2005. The standard was published January 2009.
Reasons for 802.21
Cellular networks and 802.11 networks employ handover mechanisms for handover within the same network type (aka horizontal handover). Mobile IP provides handover mechanisms for handover across subnets of different types of networks, but can be slow in the process. Current 802IEEE 802.11
IEEE 802.11 is a set of standards for implementing wireless local area network computer communication in the 2.4, 3.6 and 5 GHz frequency bands. They are created and maintained by the IEEE LAN/MAN Standards Committee . The base version of the standard IEEE 802.11-2007 has had subsequent...
standards do not support handover between different types of networks. They also do not provide triggers or other services to accelerate mobile IP based handovers. Moreover, existing 802 standards provide mechanisms for detecting and selecting network access points, but do not allow for detection and selection of network access points in a way that is independent of the network type.
Some of the expectations
- Allow 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...
between 802.11IEEE 802.11IEEE 802.11 is a set of standards for implementing wireless local area network computer communication in the 2.4, 3.6 and 5 GHz frequency bands. They are created and maintained by the IEEE LAN/MAN Standards Committee . The base version of the standard IEEE 802.11-2007 has had subsequent...
networks and 3G cellular networks. - Allow users to engage in ad hocAd hocAd hoc is a Latin phrase meaning "for this". It generally signifies a solution designed for a specific problem or task, non-generalizable, and not intended to be able to be adapted to other purposes. Compare A priori....
teleconferencing. - Apply to both wired and wireless networks.
- Allow for use by multiple vendors and users.
- Compatibility and conformance with other IEEE 802IEEE 802.11IEEE 802.11 is a set of standards for implementing wireless local area network computer communication in the 2.4, 3.6 and 5 GHz frequency bands. They are created and maintained by the IEEE LAN/MAN Standards Committee . The base version of the standard IEEE 802.11-2007 has had subsequent...
standards especially 802.11u unknown user authentication and 802.11s ad hoc wireless mesh networking. - Include definitions for managed objects that are compatible with management standards like SNMPSimple Network Management ProtocolSimple Network Management Protocol is an "Internet-standard protocol for managing devices on IP networks. Devices that typically support SNMP include routers, switches, servers, workstations, printers, modem racks, and more." It is used mostly in network management systems to monitor...
. - Although security algorithms and security protocols will not be defined in the standard, authenticationAuthenticationAuthentication is the act of confirming the truth of an attribute of a datum or entity...
, authorizationAuthorizationAuthorization is the function of specifying access rights to resources, which is related to information security and computer security in general and to access control in particular. More formally, "to authorize" is to define access policy...
, and network detection and selection will be supported by the protocol.
Implementation
Many vendors are building wireless products and participating in the development of the 802.21 standard. Current technologies such as 802.11IEEE 802.11
IEEE 802.11 is a set of standards for implementing wireless local area network computer communication in the 2.4, 3.6 and 5 GHz frequency bands. They are created and maintained by the IEEE LAN/MAN Standards Committee . The base version of the standard IEEE 802.11-2007 has had subsequent...
that accomplish handover use software to accomplish handovers and suggest that software will also be the way that handover will be implemented by 802.21. The use of software as a means to implement 802.21 should not cause large increases in the cost of networking devices.
Examples
- A user should be able to unplug from an 802.3 network and get handed off to an 802.11 network.
- A cellular phone user in the midst of a call should be able to enter an 802.11 network hotspotHotspot (Wi-Fi)A hotspot is a site that offers Internet access over a wireless local area network through the use of a router connected to a link to an Internet service provider...
and be seamlessly handed off from a GSM network to the 802.11 network and back again when leaving the hotspot.
Similar technologies
Unlicensed Mobile AccessGeneric Access Network
Generic Access Network or GAN is a telecommunication system that extends mobile voice, data and IP Multimedia Subsystem/Session Initiation Protocol applications over IP networks...
(UMA) technology is basically a mobile-centric version of 802.21. UMA is said to provide roaming and handover between GSM, UMTS, Bluetooth
Bluetooth
Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
and 802.11 networks
IEEE 802.11
IEEE 802.11 is a set of standards for implementing wireless local area network computer communication in the 2.4, 3.6 and 5 GHz frequency bands. They are created and maintained by the IEEE LAN/MAN Standards Committee . The base version of the standard IEEE 802.11-2007 has had subsequent...
. For more information on UMA you can go to http://www.umatoday.com/.
Since June 19 2005, UMA is a part of the ETSI 3GPP standardization process under the GAN (Generic Access Network) Group.
WiOptiMo technology enables any application running on a device to use the best internet connection among all the wired/wireless access providers available, guaranteeing persistence in case of weak or no signal and managing the switch among them (when needed/convenient) in a transparent way, without interrupting the active application/session.
For more information you can read A Cross-Layering and Autonomic Approach to Optimized Seamless Handover or "WiSwitch: Seamless Handover between Multi-Provider Networks" on IEEE Explore.
See also
- 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....
- Mobile IPMobile IPMobile IP is an Internet Engineering Task Force 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...
- HandoverHandoverIn cellular telecommunications, the term handover or handoff refers to the process of transferring an ongoing call or data session from one channel connected to the core network to another...
- Radio resource managementRadio resource managementRadio resource management is the system level control of co-channel interference and other radio transmission characteristics in wireless communication systems, for example cellular networks, wireless networks and broadcasting systems...
- 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...
- 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...
External links
- IEEE 802.21 web site
- Is Cellular Handoff Nigh? article
- Internet Protocol Journal Introduction to IEEE 802.21