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NS-2 NIST add-on

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IEEE 802.21
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Publications

Neves, P.; Sargento, S.; Melo, M.; Fontes, F.; Pentikousis, K.; "Enhanced Media Independent Handover Framework", Proc IEEE Vehicular Technology Conference-(VTC-Spring), Barcelona, Spain, Vol. N/A, pp. N/A - N/A, April, 2009.

Neves, P.; Soares, J.; Sargento, S.; "Media Independent Handovers: LAN, MAN and WAN Scenarios", Proc IEEE Global Telecommunications Conf. - GLOBECOM, Honolulu (Hawaii), United States, Vol. N/A, pp. N/A - N/A, November, 2009

Contacts

Abstract

The IEEE 802.21 working group started developing in March 2004 a mobility optimization framework, independent from the access network or technology. After several companies joined this group and eight drafts, the first standard was released in January of 2009, IEEE 802.21-2008. This recent release will provide mechanisms that allow seamless handovers, whether horizontal handovers (between networks of the same technology) or vertical handovers (networks of different technologies). This standard provides information allowing mobility to and from cellular GSM, GPRS, Wi-Fi, Bluetooth, 802.11 and 802.16 networks through different handover mechanisms. 
As we know, new technologies take time to be ready for experimentation. In order to evaluate the performance of handovers between heterogeneous networks (Wi-Fi, WiMAX, UMTS) through the mechanisms presented in the IEEE 802.21 protocol, the Network Simulator 2 (NS-2) tool was used.

Modifications to an already available NS-2 implementation of the IEEE 802.21 protocol developed by the NIST group were made in order to improve the protocol implementation as well as to allow its integration with the different technologies.

The content presented in this page was carried out under a master's thesis work at the Instituto de Telecomunicações de Aveiro/Universidade de Aveiro in collaboration with PT Inovação.

 

NIST logoThe NIST group supported for over two years the IEEE 802.21 working group on Media Independent Handovers (MIH), making important contributions on the IEEE 802.21 standard specifications.
Important contributions were also made in the simulation field, where NIST developed NS-2 models of IEEE 802.21 MIH architecture components (Events, Commands, Information Services and transport of Layer 2 trigger information to higher layers) based on the IEEE 802.21-draft 3 specifications. This contribution was entitled The Network Simulator NS-2 NIST add-on.
The integration of UMTS (UTRAN)*, Bluetooth, 802.16 technologies are other upgrades provided by the NIST add-on, as well as a design for nodes (network nodes, in this case a mbile node) with multiple interfaces and the support for subnet discovery and change of address. All the wireless technologies allow heterogeneous handovers, including the 802.11 that was modified to support it.
This add-on does not have an implementation of the MIH Users on the network, therefore there is no interaction between MIH Users from the network and MN.
More information regarding the NIST add-on the can be found here.

*The UMTS model was developed by the EURANE organization. NIST only perform the integration with its models.

 

Technical developments


The current state of the simulator only allowed handovers between Wi-Fi- WiMAX. Even though the NIST add-on provides the UMTS technology, their definition of MIH with UMTS is very poor, probably because the UMTS code was not developed by NIST, but by an organization named EURANE. So, the concept of handover between UMTS and other technologies is not well defined in the simulator, and in order to implement it, was necessary a very deep analysis of both the add-ons, as well as the NS-2 implementation.

 

More information regarding the technical development of this implementation can be found here.