Heterogeneous networking

In this article, security challenges related to a mobile heterogeneous networking environment, and the general access patterns are discussed. A novel, unified networking architecture that enables secure heterogeneous networking, both in terms of networks and user devices is discussed. A comprehensive security framework providing a generalized authentication scheme using the Extensible Authentication Protocol (EAP) is then presented, by taking into account existing methods for secure network and device access.     

Measurement and Analysis of the VoIP Capacity in IEEE 802.11 WLAN

We measured the capacity for VoIP traffic in an IEEE 802.11b wireless testbed and compared it with the theoretical capacity and our simulation results. We identified factors that have been commonly overlooked in past studies but affect experiments and simulations. We found that in many papers, the capacity for VoIP traffic has been measured via simulations or experiments without considering these factors, showing different capacity in each paper. After these corrections, simulations and experiments yielded a capacity estimate of 15 calls for 64 kb/s CBR VoIP traffic with 20 ms packetization interval and 38 calls for VBR VoIP traffic with a 0.39 activity ratio. Furthermore, we measured the capacity for VoIP traffic using each access category introduced in the 802.11e standard and the effect of the TCP traffic on VoIP traffic. We found that while the 802.11e standard can protect the QoS of VoIP against TCP traffic, it does not improve the capacity due to the significant retransmissions during TXOP.     

A multilayered mobility management scheme for auto-configured wireless IP networks

The convergence of wireless and IP has led to the need for IP to handle mobility. The Mobile IP protocol was developed to facilitate IP mobility. However, it has a number of shortcomings for dynamically auto-configured networks. Mobility protocols like Mobile IP with Location Registers (MIP-LR) and Session Initiation Protocol (SIP) have been developed to address some of its shortcomings. Micromobility protocols like Cellular IP have been developed to address other shortcomings of Mobile IP. We present a new integrated mobility management scheme that advantageously combines the strengths of SIP and MIP-LR with the benefits of a micromobility management protocol similar to Cellular IP. A prototype implementation of our scheme is explained, and lessons learned in the prototyping process are presented.     

VoIP-based air traffic controller training

Extending VoIP beyond Internet telephony, we propose a case study of applying the technology outside of its intended domain to solve a real-world problem. This work is an attempt to understand an analog hardwired communication system of the U.S. Federal Aviation Administration, and effectively translate it into a generic standards-based VoIP system that runs on their existing data network. We develop insights into the air traffic training and weigh in on the design choices for building a soft real-time data communication system. We also share our real world deployment and maintenance experiences, as the FAA Academy has been successfully using this VoIP system in six training rooms since early 2006 to train the future air traffic controllers of the U.S. and the world.     

Media-independent pre-authentication supporting secure interdomain handover optimization [architectures and protocols for mobility management in all-IP mobile networks]

Handovers may cause delays and packet losses that affect real-time communication performance. Mobility protocols at several layers are designed to support handover, but they need to be optimized to ensure high-quality application performance. Existing optimization techniques are not sufficient to take care of interdomain and intertechnology handovers involving different access technologies, such as Wi-Fi, GSM, CDMA, and WiMAX. We categorize several types of handover, describe handover delay components, and propose a handover optimization framework called media independent pre-authentication that can provide optimizations for interdomain and intertechnology handover in a manner that is transparent to mobility management protocols. In addition, we also present experimental results demonstrating that this framework can achieve a significant reduction in handover delays for both network-layer and application-layer mobility management protocols.     

Programming Internet telephony services

The Internet offers an opportunity to enhance traditional telephony services, such as call forwarding, through interaction with e-mail, the Web, and directory services, as well as traditional media types. How do you effectively program these services? The authors propose a CGI (common gateway interface) solution for trusted user/developers (such as administrators) and the Call Processing Language (CPL)-a simple, robust, safe, call processing language-for untrusted user/developers     

Simultaneous mobility: analytical framework,theorems and solutions

The original Mobile IP (MIP) protocol does not perform Route Optimisation but uses Home Agents to forward traffic. Thus, it does not have problems with simultaneous mobility, that is, the special case when both end hosts are mobile and move at about the same time. However, MIP for IPv6 (MIPv6) uses binding updates that are sent directly to a correspondent node. Session Initiation Protocol based mobility management (SIPMM) and MIP with location registers (MIP‐LR) also use direct binding updates between a mobile host and a correspondent node. Thus, MIPv6, MIP‐LR and SIPMM are vulnerable to the simultaneous mobility problem. In this paper, we analyse the simultaneous mobility problem and solution mechanisms, and propose new ways for MIPv6, MIP‐LR and SIPMM to handle simultaneous mobility. Copyright © 2006 John Wiley & Sons, Ltd.     

Building open programmable multimedia networks

Recent advances in distributed systems and transportable software and increasing demand for better quality of service (QoS) control in multiservice networks are driving a reexamination of network software architectures. We established the Comet (Control, Management, and Telemedia) Group at Columbia University's Center for Telecommunications Research to provide comprehensive understanding of network software architecture for the 1990s and beyond. This research focuses on developing new network architectures that support service creation, QoS control, and the joint allocation of computing and communications resources. This provides an opportunity to reconcile the perspectives of the computing and communication communities. Future multiservice (multimedia) networks will carry traffic such as video, audio, and computer data with diverse QoS requirements. Such networks will thus require that we develop ways to manage many physical and logical entities, services, and users     

Report and discussion on the IEEE ComSoc TCGN Gigabit NetworkingWorkshop 1995

Presents a summary of the second Gigabit Networking Workshop. The focus of the workshop is on end-to-end (level 4) and higher issues. Topics discussed include: ATM and B-ISDN, TCP/IP over ATM, ATM role in the future Internet-based Global Information Infrastructure, traffic monitoring and middleware