Computer Communications and Networks

Nian-Feng Tzeng
Center for Advanced Computer Studies
University of Louisiana at Lafayette

Different research topics have been pursued in this area, including high-performance routers, switching fabrics, wireless and sensor networks, and scalable multicasting. They are outlined in sequence.

• High-Performance Routers
  High-speed routers are necessary to handle rapidly growing traffic in the Internet at the aggregated packet forwarding rates expected to reach terabits per second. Existing or earlier proposed routers often lacks scalability because they utilize a shared backplane bus or crossbar to interconnect line cards (LC's) and forwarding engines (FE's). Their packet classification mechanisms could easily become performance bottlenecks, as the router's speed increases or the routing/filter table sizes grow. This project investigates router architecture with good scalability and capable of forwarding hundreds of millions of packets per second, in order to keep up with future transmission technologies. It aims to help advance the state-of-the-art of router design and to enable large networking configurations.

  Current routers rely on enhanced software search algorithms or specific hardware support to meet the IP address lookup rate (of up to 5 million lookups per second per lookup unit), but a future high-speed network calls for routers with aggregate lookup rates of some two orders of magnitude higher than a lookup unit presently can offer. Hardware-assisted mechanisms for fast packet forwarding appear promising. In particular, the use of caches to hold lookup results can fulfill subsequent lookup requests for identical destinations immediately without resorting to FE's for lookups, reducing the mean lookup latency tremendously. Unlike other software- or hardware-based forwarding improvement approaches, our hardware-assisted mechanisms can be effectively applicable to both IPv6 and IPv4, ideally suitable for scalable high-performance routers.
  
  

• Switching Fabrics
  A switching fabric connects line cards (LC's) of a router to provide paths for packets to travel from arrival LC's to their respective departure LC's. It dictates the scalability and the overall performance of the router. We have pursued scalable switching fabrics with distributed packet routing and low hardware complexity, realized via the multistage structure whose adjacent stages are interconnected according to the indirect n-cube connection style. The proposed fabrics compare favorably with known multistage-based counterparts.
  
  
• Wireless and Sensor Networks
  Click this work to find out details on the topic.
  
  
• Scalable Multicasting
  Multicast has evolved into one of the most interesting Internet service but is yet to receive widespread deployment by service providers. This project investigates into a highly scalable multicast structure and several critical issues related to multicast scalability, in an attempt to help advance the state-of-the-art of multicast technologies and to enable large multicast applications that otherwise cannot be realized in the Internet. The considered scalable multicast framework achieves high scalability by means of a two-tier approach, where a component in the lower tier consists of group members within an Autonomous System (AS) and is constructed according to any known shared-tree-based multicast protocol (like CBT, bi-directional PIM-SM, or SM). It includes protocol development and implementation, design and evaluation of hardware multicast support, technology demonstration, and preparation of Internet RFC's.
  

Publications

• N.-F. Tzeng, STRESS: Efficient Multicast Shared Trees via Restricted Search, accepted for presentation at 2005 IEEE Int'l Conference on Communications (ICC 2005), May 2005.

• N.-F. Tzeng, SPAL: Speedy Packet Lookups under Distributed Router Architecture, Proc. 33rd Int'l Conference on Parallel Processing, Aug. 2004, pp. 284-291. Abstract, PDF (965K).

• M. Mandviwalla and N.-F. Tzeng, DRA: A Dependable Architecture for High-Performance Routers, Proc. Int'l Workshop on Network Design and Architecture (IWNDA 2004, held in conjunction with 33rd Int'l Conference on Parallel Processing), Aug. 2004, pp. 265-272. Abstract, PDF (350K).

• N.-F. Tzeng, Multistage-Based Switching Fabrics for Scalable Routers, IEEE Transactions on Parallel and Distributed Systems, vol. 15, pp. 304-318, April 2004. Abstract, PDF (1250K).

• N.-F. Tzeng, Hardware-Assisted Design for Fast Packet Forwarding in Parallel Routers, Proc. 32nd Int'l Conference on Parallel Processing, Oct. 2003, pp. 11-18. Abstract, PDF (387K).

• N.-F. Tzeng and P. Alla, Guided Shared Trees for Efficient Multicast in Large Networks, Proc. 2003 IEEE Int'l Conference on Communications (ICC 2003), May 2003. Abstract, PDF (238K).

• N.-F. Tzeng and M. Mandviwalla, Performance Evaluation of Router Switching Fabrics, Proc. 9th IEEE Int'l Conference on Parallel and Distributed Systems, December 2002, pp. 542-547. Abstract, PDF (282K).

• N.-F. Tzeng and R. Batchu, Design and Evaluation of Scalable Switching Fabrics for High-Performance Routers, Proc. 31st Int'l Conference on Parallel Processing, August 2002, pp. 167-174. Abstract, PDF (521K).

• N.-F. Tzeng and M. Mandviwalla, Cost-Effective Switching Fabrics with Distributed Control for Scalable Routers, Proc. 22nd IEEE Int'l Conference on Distributed Computing Systems, July 2002, pp. 65-73. Abstract, PDF (513K).

• K. Vibhatavanij, N.-F. Tzeng, and A. Kongmunvattana, Simultaneous Multithreading-Based Routers, Proc. 29th Int'l Conference on Parallel Processing (ICPP '00), Aug. 2000, pp. 362-369. Abstract, PDF (738K).

• N.-F. Tzeng, K. Ponnuru, and K. Vibhatavanij, A Cost-Effective Design for ATM Switching Fabrics, Proc. 1999 IEEE Int'l Conference on Communications (ICC '99), June 1999, pp. S37.4.1-5. Abstract, Compressed PDF (81K).

Funding

• National Science Foundation under Grants EIA-9871315 and CCR-0105529.
• U.S. Army Research Office via Grant/Cooperative Agreement No. DAAG55-98-1-0240.
• Board of Regents, State of Louisiana under Contracts No. DOD/LEQSF(1997-01)-06, No. LEQSF(1998-99)-ENH-TR-101, and No. LEQSF(2000-01)-ENH-TR90.