NETWORK TESTING SERIES

(1)

152

SERIES

EDITORIAL

he last call for this series received seven submissions. We accepted two of them, with one from academia and another from a joint team of academia and industry. At the time of writing this editorial for these two articles, we are also closing the process of reviewing the next batch of submissions. The number of submissions remains stable, and we should be able to pick and publish at least one from the product ven-dors, test laboratories, or test equipment venven-dors, which gives enough industrial favor to this series. We are seeking the pos-sibilities of increasing the number of submissions to exceed 10 in the future calls, and publishing three articles per issue with possibly one from invited authors and two from the open call. The due dates remain June 1 and December 1 each year.

The article on packet dispersion (“Packet Dispersion Tech-niques over WiMAX Links: Challenges and Problems”) exam-ines the problems in applying bandwidth estimation techniques such as CapProbe for a path of all wired links to a path with at least one wireless link such as WiMAX. Since the packet dis-persion techniques for bandwidth estimation of a path rely on measuring the change in the time interval between consecutive packets through the path, the error would be high if some links in the path do tricky things other than the simple in first-out (FIFO). Unfortunately, in order to maximize the bandwidth usage and reduce the transmission and signaling overheads, WiMAX, as an example wireless link standard, exercises the packing and concatenation functions to pack small packets into one and concatenate several packets into a burst, respectively. These destroy the nature of the work-conservative FIFO links and distort the time interval between consecutive packets, which is relied on by the packet dispersion techniques. To cir-cumvent such problems, the authors suggest enlarging the size of measuring packets to over half that maximum frame size, and the time interval between the first and last measuring pack-ets to over the maximum burst duration defined in the stan-dard. There is further work needed in that direction. In general, this is an interesting article on testing and measuring a path.

The article on the wrap-around testing methodology (“A Sys-tematic and Flexible Approach for Testing Future Mobile Net-works by Exploiting a Wrap-Around Testing Methodology”) presents a testing framework that wraps around the testing target with its inbound and outbound both connected to the test envi-ronment. As the testing target grows in size from a module to a system without a physical platform to a system with the physical platform, the testing environment also grows in size, but without having to be rebuilt or relocated. When the testing tools utilized are selected properly, the testing environment can combine the flexibility of simulations and the high performance of hardware solutions. As the same testing tools can be used in all the testing phases, the maintenance problems stemming from large and

het-erogeneous testing toolkits can be alleviated. The article demon-strates the application of this approach to testing a Long Term Evolution (LTE) evolved node B (eNB), where the performance of LTE air interfaces is tested under various channel conditions.

BIOGRAPHIES

YING-DARLIN[F] ([email protected]) is a professor of computer science at National Chiao Tung University (NCTU) in Taiwan. He received his Ph.D. in com-puter science from the University of California in Los Angeles (UCLA) in 1993. He served as the CEO of the Telecom Technology Center during 2010–2011 and a visiting scholar at Cisco Systems in San Jose, California during 2007–2008. Since 2002, he has been the founder and director of Network Benchmarking Lab (NBL, www.nbl.org.tw), which reviews network products with real traffic. He also cofounded L7 Networks Inc. in 2002, which was later acquired by D-Link Corp. He recently, in May 2011, founded Embedded Bench-marking Lab (www.ebl.org.tw) to extend into the review of handheld devices. His research interests include design, analysis, implementation, and benchmark-ing of network protocols and algorithms, quality of service, network security, deep packet inspection, P2P networking, and embedded hardware/software co-design. His work on multihop cellular was the first along this line, and has been cited over 500 times and standardized into IEEE 802.11s, WiMAX IEEE 802.16j, and 3GPP LTE-Advanced. He is currently on the editorial boards of IEEE

Transactions on Computers, IEEE Computer, IEEE Network, the IEEE Communi-cations Magazine Network Testing Series, IEEE Wireless CommuniCommuni-cations, IEEE Communications Surveys and Tutorials, IEEE Communications Letters, Computer Communications, Computer Networks, and IEICE Transactions on Information and Systems. He recently published a textbook, Computer Networks: An Open Source Approach (www.mhhe.com/lin) with Ren-Hung Hwang and Fred Baker

(McGraw-Hill, 2011). It is the first textbook that interleaves open source imple-mentation examples with protocol design descriptions to bridge the gap between design and implementation.

ERICAJOHNSON([email protected]) is the director of the University of New Hampshire InterOperability Laboratory. In this role, she manages and over-sees over 20 different data networking and storage technologies providing all aspects of administration, including coordination of high-profile testing events, coordination with different consortia, and working with various industry fora. She is also a prominent member of organizations both internally and external-ly. She enjoys a powerful mix of technology and business related activities. At the University of New Hampshire she participates in the UNH Steering Commit-tee for Information Technology, the Senior Vice Provost for Research Working Group, and Computer Science Advisory Board. In the industry, she was appointed the technical representative of North America for the IPv6 Ready Logo Committee and was also chosen to be an IPv6 Forum Fellow. Passionate about the laboratory and its possibilities, she continues to work with many industry fora, commercial service providers, network equipment vendors, and other universities in order to further the InterOperability Laboratory’s mission. EDUARDOJOO([email protected]) is a software project leader at Empirix, Inc., in Bedford, Massachusetts. He received his M.S. in computer system engineering, computer communications and networks, from Boston Univer-sity in 2006. He joined Empirix, Inc., in 2001 and has led the successful development of network testing and emulation systems, including Packet-Sphere Network Emulator, PacketPacket-Sphere RealStreamer, Hammer NxT, and Hammer G5. He is currently leading the development of next generation mobile broadband data network monitoring and testing tools. His areas of interest include voice and data protocols and wired, wireless, and mobile network communications.