During the last years, the interest in Delay/Disruption Tolerant Networks has been significantly increased, mainly because DTN covers a vast spectrum of applications, such as deep-space, satellite, sensor and vehicular networks. Even though the Bundle Protocol seems to be the prevalent candidate architecture for delay-tolerant applications, some practical issues hinder its wide deployment. One of the functionalities that require further research and implementation is DTN queue management. Indeed, queue management in DTN networks is a complex issue: loss of connectivity or extended delays, render occasionally meaningless any pre-scheduled priority for packet forwarding. Our Queue-management approach integrates connectivity status into buffering and forwarding policy, eliminating the possibility of stored data to expire and promoting applications that show potential to run smoothly. Therefore, our approach does not rely solely on marked priorities but rather on active networking conditions. We present our model analytically and compare it with standard solutions. We then develop an evaluation tool by extending ns-2 modules and, based on selective scenarios primarily from Space Communications, we demonstrate the suitability of our model for use in lowconnectivity/high-delay environments.
The increase of real-time applications as well as the vast usage of portable wireless devices has led to a corresponding increase of real-time traffic with strict bandwidth and delay requirements. In order to satisfy the requirements of various applications we typically use Service Differentiation. However, as new real-time applications are created, their portion of the total traffic increases, thus making more and more difficult to satisfy completely their requirements. In this paper we propose a new scheme, which is based on the axiom that 'different types of applications typically utilize different packet sizes'. With Size Based Treatment (SBT) different packet sizes are dropped with different probability by the queue. Small sized packets can benefit and transmit on higher rates, increasing the total system fairness.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.