Active networks

Proxies, Active Networks, Re-configurable Terminals: The Cornerstones of Future Wireless Internet1
Adam Wolisz, Christian Hoene, Berthold Rathke, Morten Schläger
Technical University of Berlin, Telecommunication Networks Group, email {wolisz|hoene|rathke|morten}@ee.tu-berlin.de Abstract: After discussing basic issues related to both wireless data transmission and internet principles we identifyand discuss fundamental problems of their merge. Following this discussion, a vision of a specific approach and architecture for improving wireless internet access called AMICA is outlined. Furthermore, we analyse the need for re-configurable terminals and active networks to enable advanced wireless Internet services and the support of hierarchical, heterogeneous wireless access, which are indeedthe fundamentals of AMICA.

1. Introduction
Using internet services not only becomes a habit, in fact both in their professional and everyday life people become increasingly dependent on access to these services. Or they might achieve significant profit – both in the business and quality of life sense – if such access would be possible frequently enough. In fact, there are good reasons toconsider moving all the communication solutions to the internet platform. Wireless transmission technologies have definitely a potential to contribute to the deployment of easy accessible, flexible internet access. The merger of wireless transmission with the already established internet paradigm appears, however, to be more complex than it might have been expected at first glance. Therefore, thismerger is recently one of the hottest research topics in the area of telecommunication networks. Our further considerations will be structured as follows: In section 2, we will discuss some basic scenarios and identify major general differences between wireless and wired access. In section 3, we will recall basic internet paradigms, consider what are the implication of introducing a wireless hop ininternet, and discuss the different possible meanings of the notion of internet access. Finally in section 4 we will outline AMICA reflecting our approach on wireless internet access.

2. Mobility and Wireless Access
In general, the usage of wireless access can be described by mobility scenarios [25]. We concentrate our discussion with a scenario called true mobile access. Terminals can be movedwithin and between the range of multiple access points. Dynamic changes of the supporting access point during a session are expected to appear. Such changes are usually called handover. For mobile access to be attractive, deployment of access points should be dense; usually a significant (although not necessarily all) part of the area will be in the range of at least one of these access points.The degree of service continuity in spite of handover is one of the essential quality features. Continuity of service might be expressed in terms of the amount of information during handover. The case of frequent, possibly interruption-less handover usually implies a homogeneous system concept in which all the access points (and the end-system) are incorporated. In addition, it seems almost natural(although not necessary!) to assume that also the transmission techniques will be identical. In fact, this
1

This work has been supported in part by the German Ministry of Research (BMBF) within the Project IBMS in the research area ATM Mobile, as well as by grants from German Telecom, DFG within the Graduate College “Communication Based Systems” and ICSI, Berkeley. More details can be foundunder http://www-tkn.ee.tuberlin.de. 1

is the case for the majority of solutions deployed or considered today, like GSM, GPRS or the emerging UMTS. 2.1 Wireless Access Design Issues Using the same technology, homogenous systems consist of access points with similar range/coverage and bit-rates. Such technology might be developed with the general design goal to support bit/rates as high as...