The Domain Name System (DNS) is an existing and implemented network service in Internet providing host and service reachability, which is essential to every IP connection setup. Merge of mobile networks with Internet results in large flow of frequent updates to the DNS database, which is a threat for DNS database consistency, because of strong caching it uses. Even though DNS wasn't originally designed for networks supporting host mobility, it gets enabled, if caching of resource records, carrying mobile host's locator information, is disabled by setting the time-to-live (TTL) field to 0 and by enabling dynamic DNS updates from mobile hosts to authoritative name servers. In this paper we are interested in the impact of TTL value 0 on DNS system performance. Based on the modeling of DNS caching behavior, we have a quantitative evaluation of the TTL value 0 impact on DNS performance of the mobile enhanced Internet.

The Domain Name System (DNS) is an existing and implemented network service in Internet providing host and service reachability, which is essential to every IP connection setup. Merge of mobile networks with Internet results in large flow of frequent updates to the DNS database, which is a threat for DNS database consistency, because of strong caching it uses. Even though DNS wasn't originally designed for networks supporting host mobility, it gets enabled, if caching of resource records, carrying mobile host's locator information, is disabled by setting the time-tolive (TTL) field to 0 and by enabling dynamic DNS updates from mobile hosts to authoritative name servers. In this paper we are interested in the impact of TTL value 0 on DNS system performance. Based on the modeling of DNS caching behavior, we have a quantitative evaluation of the TTL value 0 impact on DNS performance of the mobile enhanced Internet.

Today's cellular networks make access evaluation and selection based on pre-defined rudiment policies and rules. It works in the current networking environment that is fairly homogeneous. However, it would not be feasible anymore for the heterogeneous networking environment in the future. The future wireless networking environment will consist of diversified radio access technologies. Similar phenomenon could be foreseen to happen for mobile services and business environment as well. In such diversified environment, it is important that users are easily and efficiently able to exploit their mobile devices' multiaccess capabilities. We thus study new distributed handover strategies that perform the access selection according to a richer set of criteria ranging from end user's preferences to network/service provider capabilities. The initial simulation analysis on these new handover strategies for multi-service and multi-operator environment indicates that the new strategies provide improvements in all measured areas of network and service utilization rates, uptime of mobile terminals, and other various connectivity statistics.

Battery-powered multiaccess devices, with their increased flexibility and reachability, are becoming common. Such devices would have to disassociate their radio accesses from the surrounding networks whenever they are left unused, in order to address battery lifetime limitations. In single-access networks, paging has been proven an effective method for minimizing power consumption. In a heterogeneous multiaccess environment, a paging function may be even more important in extending battery lifetimes. This study investigates the issues at hand, presents related work, analyzes the paging issues in multiaccess scenarios, and proposes two multiaccess paging schemes, which utilize (but do not replace) existing paging functions in access technologies as a foundation to realize multiaccess paging. We further specify how to realize multiaccess paging in Ambient Networks, and present numerical analysis results on the different degrees of battery lifetime savings under different communication, network and device use settings.