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The First Columbia-Goettingen Workshop on Internet Research, June 30, 2008

We are excited to announce the First Columbia-Goettingen Workshop on Internet Research, to be held on June 30, 2008, 9:00-13:00, Institut fuer Informatik, Sternwarte-Nebengebaeude, Geismarlandstr. 11, 37083 Goettingen. Interested researchers and students are welcome to join this event!

The Computer Networks Group (NET) in the Institute of Computer Science at the University of Göttingen and the Internet Real-Time Lab (IRT) in the Computer Science Department at Columbia University are pleased to co-organize the First Columbia-Göttingen Workshop on Internet Research.

Preliminary Program

9:00-10:00 Session 1
Welcome and introduction
Prof. Xiaoming Fu and Prof. Dieter Hogrefe, Inst. f. Informatik, Univ Göttingen

Keynote "Voice over IP: Beyond Replicating the Analog Phone"
Prof. Henning Schulzrinne, Dept. of Computer Science, Columbia Univ, IEEE Fellow
Abstract: VoIP has become a core Internet service, slowly replacing traditional circuit-switched telephony for both residential and enterprise use. However, most of the commercial systems focus on replicating century-old models and services, rather than leveraging the opportunities offered by an Internet-based service. In this talk, I will describe the core principles of VoIP and how VoIP can be enhanced to provide more user control over reachability, more flexible services and transparent mobility.
Short biography: Prof. Henning Schulzrinne received his Ph.D. from the University of Massachusetts in Amherst, Massachusetts. He was a member of technical staff at AT&T Bell Laboratories, Murray Hill and an associate department head at GMD-Fokus (Berlin), before joining the Computer Science and Electrical Engineering departments at Columbia University, New York. He is currently chair of the Department of Computer Science.
Protocols co-developed by him, such as RTP, RTSP and SIP, are now Internet standards, used by almost all Internet telephony and multimedia applications. His research interests include Internet multimedia systems, ubiquitous computing, mobile systems, quality of service, and performance evaluation. He is a Fellow of the IEEE and currently serves as ACM SIGCOMM vice chair.

10:00-10:10 Coffee break
10:10-11:30 Session 2
One Server Per City: Using TCP for Very Large SIP Servers
Kumiko Ono, Dept. of Computer Science, Columbia Univ
Abstract: The transport protocol for SIP can be chosen based on the requirements of services and network conditions. How does the choice of TCP affect the scalability and performance compared to UDP? We experimentally analyze the impact of using TCP as a transport protocol for a SIP server, and suggest how to reduce the impact of TCP for a scalable SIP server especially under overload control.
Short bio: Kumiko Ono is a Ph.D student in Computer Science at Columbia University working with Prof. Henning Schulzrinne. She previously worked at NTT laboratories on VoIP services and its network architecture. Her research interests center around real-time communication and security. She received her M.S in Computer Science from Columbia University and her B.S in Mathematics from Ochanomizu University in Tokyo, Japan.

Parametric traffic modeling of aggregated application level traffic
Ralf Lübben, Inst. f. Informatik, Univ Göttingen
Abstract: Parametric traffic models help researchers for realistic traffic simulation, a deep understanding of the traffic and mathematical analysis of protocols. Several previous models of individual applications do not represent today's reality anymore and also describe only one application at one time. This work in progress attempts to build a parametric model for the whole mixture of applications which are running of the network.
Short bio: Ralf Lübben received his MSEE degree from the University of Hanover in November 2007 and joined the Computer Networks Group at the University of Göttingen in January 2008 as a research assistant and PhD student. His current research interest is on traffic modeling, network topology, multi-path routing and congestion control.

Decoupling Congestion Control using Traffic Aggregates
and Middleboxes
Niklas Neumann, Inst. f. Informatik, Univ Göttingen
Short bio: Niklas Neumann received his MSc. in Computer Science from the University of Göttingen in November 2007 and since then works as research assistant and PhD student in the Computer Networks Group. His research interests are mobile networks, security and economic issues for the Internet and congestion control.

Multi-Path Routing and Pre-Congestion Notification
Mayutan Arumaithurai, Inst. f. Informatik, Univ Göttingen / Nokia Siemens Networks
Abstract: Pre-Congestion Notification is currently being investigated for admission control and flow termination in a Diffserv network. However it is currently limited to non-elastic traffic. We study the effect of such a marking based AC/FT algorithm for IP traffic and plan to extend it to investigate this in a multi-path scenario(probably ECMP too). Moreover we would like to extend this work to study the feasibility of using a marking based algorithm for choosing between available multipaths, and using the multipaths effectively to transfer traffic.
Short bio: Mayutan Arumaithurai received his MSc. in Computer Science from Technical University of Hamburg in December 2006 and since then works at Nokia Siemens Networks (previously Siemens Corporate Technology). From April 2007 he is a PhD student at the Computer Networks Group, working on congestion control, mobility, SIP, QoS and AAA.

11:30-11:40 Coffee break
11:40-13:00 Session 3
Template-based Signaling Compression for Push-to-talk over Cellular (PoC)
Andrea Forte, Dept. of Computer Science, Columbia Univ
Abstract: The Session Initiation Protocol (SIP) has been chosen as the standard signaling protocol for the IP Multimedia Subsystem (IMS). SIP is a text-based protocol with messages often exceeding 1000 bytes in size, thus causing high call set-up delays on low bit-rate links.
Signaling Compression (SigComp) is currently the only option cellular operators have for the compression of signaling messages. We study the performance of SigComp, showing that SigComp cannot achieve the level of compression required by Push-To-Talk over Cellular (PoC) services in the IMS. Furthermore, we propose an alternative compression mechanism, namely Template Based Compression (TBC), and show through measurements how we can achieve higher compression ratios than SigComp, satisfying the requirements for PoC on low bit-rate links.
Short bio: Andrea Forte received his master's Degree in Telecommunication Engineering at the University of Rome "La Sapienza", Italy. Currently he is a research scientist at Columbia University and a member of Prof. Henning Schulzrinne's Internet Real-Time laboratory. His research interest is in real-time networking, in particular on IEEE 802.11 networks and VoIP issues. In these research fields he has published a number of papers in peer-reviewed journals and international conferences, including IEEE International Conference on Network Protocols (ICNP), IEEE Wireless Communications, IEEE GLOBECOM, among the others.

Dynamic Mesh based Overlay Multicast Protocol Framework
Jun Lei, Inst. f. Informatik, Univ Göttingen
Abstract: Multicast has emerged as an efficient mechanism for supporting group communications, however, IP multicast for worldwide media distribution remain limited due to its technical and deployment issues. Motivated by the studies on network layer multicast and application level multicast, we propose a dynamic mesh based overlay multicast protocol (DMMP) framework to efficiently serve a large number of cocurrent clients with relatively high inbound bandwidth and low start-up delay. Particularly, the DMMP framework only involves participating end hosts without relying on delicately deployed infrastructure nodes, while providing certain efficiency, reliability and resilience.
Short Bio: Jun Lei received her Master of Engineering from Zhejiang University, China in April 2004. She is currently a research assistant and PhD candidate at the Computer Networks Group, University of Göttingen. She has published several referred papers in international conference proceedings and journals including Computer & Security, ACM WSWiM and IWCMC, in the field of peer-to-peer streaming, overlay multicast, wireless and mobility in the Internet. She is visiting Internet Real-Time Lab of Columbia University for 2 months in August and September 2008.

Opportunistic Fair Scheduling in Lossy Wireless Networks with Network Coding
Fang-Chun Kuo, Inst. f. Informatik, Univ Göttingen
Abstract: Recently, network coding (NC) schemes are designed to improve capacity and energy efficiency in wireless networks by exploiting the broadcast nature of wireless medium. However, those works have an implicit assumption that the "links" are reliable. Therefore, utilizing network coding in lossy wireless network is considered in our work. A probabilistic framework is used to estimate reception of native frames of each client, without explicit feedback or additional signaling overhead. Our NC-aware scheduling algorithm considers both data rate and fairness in frame selection and it maximizes the expected goodput of the network under the temporal fairness constraint.
Short bio: Fang-Chun Kuo received her M.Phil. from the Department of Electrical Engineering, University of Southampton, UK in 2005. She is currently a research assistant and PhD candidate at the Computer Networks Group, University of Göttingen. She is interested in network security, overlay networks, and wireless network coding, and has published several referred papers, including in ACM SIGCOMM Computer Communications Review, IEEE INFOCOM Global Internet Symposium, IEEE VTC and IEEE WCNC.

Security Analysis, Prototype Implementation and Performance Evaluation of a New IPSec Session Resumption Method
Florian Tegeler, Inst. f. Informatik, Univ Göttingen
Abstract: The talk gives a short overview on IPSec session resumption which is especially important in mobility scenarios. Usually key negotiation during session establishment generates a high computational load leading to session establishment times of up to one second, which is worse when a high number of nodes is trying to (re)connect to a gateway simultaniously as it is the case after a gateway failure. A solution is presented utilizing the previous connection state stored in a so called ticket. This approach is security analyzed, theoretically evaluated and later implemented to directly demonstrate the advantages and impact of the new ticket based session resumption approach.
Short bio: Florian Tegeler received his MSc degree in Computer Science and Dipl.-Physics degree from the University of Göttingen, both in 2008. He is a research assistant and PhD student at the Computer Networks Group from July 2008, working on network security, wireless networks and delay tolerant networks.

Contact:
Prof. Dr. Xiaoming Fu
Computer Networks Group
Institute of Computer Science
Lotzestr. 16-18
37083 Göttingen
fu@informatik.uni-goettingen.de

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