Rafael Mompó Gómez

Integrated Multi-purposed Testbed to Characterize the Performance of Internet Access over Hybrid Fiber Coaxial Access Networks

This paper presents an experimental testbed to study the noise effect on the performance of the transport layer over Hybrid Fiber Coaxial (HFC) networks. We have successfully designed and implemented an integrated complex testbed, which is suitable not only for laboratory environments but also reusable for real-world networks. The main purpose of the testbed is modeling the residential broadband data network using hardware simulation under several noise conditions and observing the effects on the performance of popular Internet applications as well as native TCP/UDP performances. A large number of public domain Internet measurement tools have been evaluated, from which several selective software tools have been used. In addition, new software has been developed to combine all software and hardware devices. Based on the testbed, we were able to study several issues of TCP/UDP over HFC networks by making a large number of automatic measurements and analysis. The testbed infrastructure would be very useful for cable operator and end users for monitoring and troubleshooting HFC networks, and can be effectively reused for related studies in similar environments such as wireless and DSL.

Flexible COM-based Software Solution for HFC Network Performance Monitoring

Emerging HFC (hybrid fiber coaxial) networks with activated return path for data communications requires careful performance monitoring and preventative maintenance over the entire network. Return path is especially problematic due to the noise funneling effects that can strongly affect digital services. Besides, the HFC networks which base on existing CATV infrastructures require many considerations. The special characteristics of HFC network lead to the needs of taking into account many issues related to software, hardware, measurements, etc. This article focuses on the designing issues of HFC network monitoring software to deal with the noise problem in the physical layer, in respect to the trends of measurement software, and describes a performance monitoring software framework, which applies the Component Object Model (COM) approach. The software has been developed in the CEDETEL Lab — ESTI, University of Valladolid, in collaboration with RETECAL — Spain. The article is organized as follows: the first section addresses the general problems of HFC performances. The second section presents the typical issues of monitoring the performance of HFC physical layer. In the third section, the key issues of designing software for HFC network monitoring, and the COM approach will be discussed. In the fourth section, an HFC performance monitoring application, which has been developed in respect to the issues mentioned on the previous sections will be described. Finally, the last section presents conclusions and future works.