IEEE 802.21
802.21 is an
IEEE emerging standard. 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). The standard provides information to allow handing over to and from
cellular,
GSM,
GPRS,
WiFi,
Bluetooth and
802.11 networks through different handover mechanisms.
The IEEE 802.21
working group started work in March 2004 and is chaired by
Ajay Rajkumar from
Lucent Technologies. More than 30 companies have joined the working group and the group plans to vote on a first draft of the protocol in May
2005. The first draft of the protocol is already available in [
1].
Cellular networks and 802.11 networks employ handover mechanisms for handover within the same network and mobile IP employs handover mechanisms for handover across different networks of the same type. However, current
802 standards do not support handover between different types of networks. 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.
*Allow
roaming between
802.11 networks and
3g cellular networks.
*Allow users to engage in
ad hoc teleconferencing.
*Apply to both wired and wireless networks.
*Allow for use by multiple vendors and users.
*Compatibility and conformance with other
IEEE 802 standards.
*Include definitions for managed objects that are compatible with management standards like
SNMP.
*Although security
algorithms and security
protocols will not be defined in the standard
authentication,
authorization, and
network detection and
selection will be supported by the protocol.
Many vendors are building wireless products and participating in the development of the 802.21 standard. Current technologies such as
802.11 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
hotspot and be seamlessly handed off from a
GSM network to the 802.11 network and back again when leaving the hotspot.
Similar technologies
(UMA) technology is basically a private version of 802.21. UMA is said to provide roaming and handover between
GSM,
UMTS,
Bluetooth and
802.11 networks. However providers of the technology and standards do not guarantee interoperability. For more information on UMA you can go to http://www.umatechnology.org/.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 "Seamless Handover between Multi-Provider Networks" on
IEEE Explore.
*
IEEE 802.21 web site *
Is Cellular Handoff Nigh? article
