Despite the importance of real-world experiments, nearly all ongoing research activities addressing video streaming over MANETs are based on simulation studies. Earlier research shows that the limited resources of mobile handhelds, which are not modeled in most network simulators, can be a severe bottleneck. We study the capability of a modern handheld to perform one core task, which is the forwarding of video streams. We present end-to-end video quality and network measurements, along with an analysis of resource consumption. Our studies of the recent handheld Nokia N900 show that it can forward up to 3.70 Mbps. However, subjective video quality is compromised already at 3.35 Mbps, due to excessive delay. Our analysis unveils that direct memory access (DMA) relieves the CPU of forwarding overhead and that, due to the digital signal processor (DSP) support, additional coding overhead does not decrease the forwarding capacity. Finally, we find that power management impacts results considerably. It is possible to increase the forwarding capacity up to 27.4% by increasing the frequency of internal buses. Hence, our results demonstrate that the forwarding capacity is highly dependent on the internal state and activity of the device.

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© 2 0 1 2 I E E E . P e r s o n a l u s e o f t h i s m a t e r i a l i s p e rm i t t e d . P e rm i s s i o n f r om I E E E m u s t b e o b t a i n e d f o r a l l o t h e r u s e s , i n a n y c u r r e n t o r f u t u r e m e d i a , i n c l u d i n g r e p r i n t i n g / r e p u b l i s h i n g t h i s m a t e r i a l f o r a d v e r t i s i n g o r p r om o t i o n a l p u r p o s e s , c r e a t i n g n ew c o l l e c t i v e w o r k s , f o r r e s a l e o r r e d i s t r i b u t i o n t o s e r v e r s o r l i s t s , o r r e u s e o f a n y c o p y r i g h t e d c om p o n e n t o f t h i s w o r k i n o t h e r w o r k s .

Abstract. Wireless networks enable mobility, multihoming, and Delay Tolerant Networks. In such networking environments, the principles of the Internet, i.e., the end-to-end principle and the combination of location and identification in IP addresses, cannot be applied. In this paper, we propose a scalable application centric approach for mobility and multihoming that is able to interconnect highly heterogeneous networks where the networks may belong to different networking paradigms, e.g., IP based and Delay Tolerant Networks. Applications and users that aim to communicate, form communities. Community members might together have several network technologies available, and the community layer manages internetworking information for the members to seamlessly integrate these. Networking adaptation layers are used to provide a common interface for the different networks to the community layer. Addressing is based on names, cryptographic identifiers, and network locators and such that identifiers can also be created in infrastructure-less and disconnected situations.

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