Institute for Systems Research

Certain constraints of TDMA transmission in a wireless network requirescareful scheduling among the nodes in order to achieve conflict-free operations. These constraints also make the calculation of the end-to-end bandwidth along a path non-trivial. These calculationsare essential for QoS routing which requires a certain amount of bandwidth available on a route.

We prove the problem of calculating the maximal end-to-end bandwidth along a given a path in a TDMA network is NP-complete, and develop an efficient bandwidth calculation scheme. We also show how the bandwidth calculation scheme can be usedwith the Ad-hoc On-demand Distance Vector protocol (AODV) to perform QoSrouting.

This is a mixture of the traditional prefix-routed scenario fo the fixed Internet, and the classical edge mobility scenario that is today supported by cellularnetworks, primarily as part of the cellular technology elements (GSM, GPRS, etc.).

We outline a general architecture for the support of such edge mobility, and present an approach to FMC routing that fits within this architecture. We then present initial simulation resultsillustrating the potential scalability and routing efficiency of this approach.

We parameterize the group with a time-varying quantity that servesas a distributed mechanism for controlling key generation privilege.

Our scheme can be viewed as an alternative to polynomial schemes where, at the time of the secret construction step, there has to be a third party or a black box to combine the shares. Also, in polynomial schemes, at the time of combining, the individual shares of the secret have to be revealed to the third party. In our scheme, the common secret can be generated without ever exposing the individual shares constructing it.

We note that many of the recently proposed distributed key management~[2-4] schemes need such group keys for certification and signing purposes.

Our scheme can be viewed as an alternative to polynomial schemes where, at the time of the secret construction step, there has to be a third party or a black box to combine the shares. Also, in polynomial schemes, at the time of combining,the individual shares of the secret have to be revealed to the third party.

In our scheme, the common secret can be generated without ever exposing the individual shares constructing it. We note that many of the recently proposed distributed key management schemes need such group keys for certification and signing purposes.

3rd Annual Conference on Advanced Telecommunications and Information Distribution Research Program (ATIRP)

The proposed key generation approach allows entities whichmayhave only partial trust in each other to jointly generate a shared keywithout the aid of an external third party. The group collectivelygenerates and maintains a dynamic group parameter, and the shared key isgenerated using a strong, one-way function of this parameter.

This schemealso provides perfect forward secrecy. The validity of key generation canbe checked using verifiable secret sharing techniques. The key retrievalmethod does not require the keys to be stored in an external retrievalcenter.

We note that many Internet-based applications may have theserequirements. Fulfillment of these requirements is realized through theuse of fractional keys--a distributed technique recently developed toenhance the security of distributed systems in a non-cryptographicmanner.