We study the performance of Selective Acknowledgments with TCP over the ATM-UBR service category. We examine various UBR drop policies, TCP mechanisms and network con gurations to recommend optimal parameters for TCP over UBR. We discuss various TCP congestion control mechanisms compare their performance for LAN and WAN networks. We describe the e ect of satellite delays on TCP performance over...

This paper describes a gigabit LAN/WAN gateway being developed for the MAGIC gigabit testbed. The gateway interfaces a gigabit LAN developed by DEC Systems Research Center and the MAGIC SONET/ATM wide area network. The UNI provides 622 Mb/s throughput between the LAN and WAN environments, and supports either a single OC-12c or four OC-3c tributaries. The architecture will initially support IP r...

Der vorliegende Beitrag führt in das Thema Netzwerkvirtualisierung ein, beleuchtet die unterschiedlichen Methoden in LAN, WLAN und WAN und zeigt anhand konkreter Praxisbeispiele, inwieweit die konsequente Virtualisierung von Netzen – wir sprechen von „Total Network Virtualization“ – Unternehmen helfen kann, sowohl bei den Investitionen als auch bei Betriebskosten massiv Kosten zu reduzieren. 1 ...

Due to the high bandwidth requirement and rate variability of compressed video, delivering video across wide area networks (WANs) is a challenging issue. Proxy servers have been used to reduce network congestion and improve client access time on the Internet by caching passing data. In this paper, we investigate ways to store or stage partial video in proxy servers to reduce the network bandwid...

Workgroup multimedia applications such as videoconference, teleteaching or CSCW demand multipoint service from Telecommunication Networks. This is not just a broadcast service but it is a service where N sites transmit traffic to N sites. This service requires that the network support a large number of workgroups with few (5-20) participants together with low delay, low delay jitter, high throu...

To allow a seamless integration between wireless LANs and Wireless WANs, we developed a full stack adaptation model and a simple subnet architecture that superimposes Mobile-IP on cellular-type wireless LANs. The idea is to use Mobile IP as an integrative layer atop different LAN/WAN networks. While Mobile-IP is widely used in wireless WANs, it is not known how well it performs under a wireless...

Integrating dedicated applications with a wireless LAN and WAN infrastructure, the COSMOS system provides "Construction Site Mobile Operations Support". In this paper, we focus on the approach taken in COSMOS for bandwidth management across the bottleneck satellite WAN link, particularly for supporting video conferencing between company headquarters and construction sites. We discuss the IETF Q...

Recent proposals have shown that database replication providing 1copy-serializability can have excellent performance in LAN environments by using powerful multicast primitives. In this paper, we evaluate whether a similar approach is feasible in WAN environments. We identify the most crucial bottlenecks of the existing protocols, and propose optimizations that alleviate the identified problems....