This document describes a framework for Virtual Private Networks (VPNs) running across IP backbones. It discusses the various different types of VPNs, their respective requirements, and proposes specific mechanisms that could be used to implement each type of VPN using existing or proposed specifications. The objective of this document is to serve as a framework for related protocol development in order to develop the full set of specifications required for widespread deployment of interoperable VPN solutions.

This paper presents the design and evaluation of a support service for mobile, wireless clients of a distributed publish/subscribe system. A distributed publish/subscribe system is a networked communication infrastructure where messages are published by senders and then delivered to the receivers whose subscriptions match the messages. Communication therefore does not involve the use of explicit addresses, but rather emerges from the dynamic arrangement of publishers and subscribers. Such a communication mechanism is an ideal platform for a variety of Internet applications, including multi-party messaging, personal information management, information sharing, on-line news distribution, service discovery, and electronic auctions. Our goal is to support such applications on mobile, wireless host devices in such a way that the applications can, if they chose, be oblivious to the mobility and intermittent connectivity of their hosts as they move from one publish/subscribe access point to another. In this

Emerging technologies such as Bluetooth are expected to become a ubiquitous solution for providing short range, low power, low cost, pico-cellular wireless connectivity. Bluetooth is a Master driven Time Division Duplex (TDD) system that supports an asynchronous channel for data traffic as well as synchronous channels for voice traffic. Data applications running over Bluetooth such as http, ftp and real audio will need transport layer protocols such as TCP and UDP to send packets over the wireless links. In this paper we study several schemes designed to improve the performance of asynchronous data traffic over a Bluetooth piconet that supports multiple active slaves. We propose and compare a number of SAR policies and MAC scheduling algorithms with a view towards enhancing the performance of transport layer sessions. We investigate the effect of different FEC and ARQ schemes at the baseband level, using a two-state Markov channel model for the Bluetooth RF link. We also study how the presence of circuit-switched voice impacts the performance of data traffic. Keywords--- Medium Access Control (MAC), Scheduling, Time Division Duplex (TDD), Segmentation and Reassembly (SAR), Forward Error Correction (FEC), Automatic Repeat Request (ARQ), TCP, UDP. I.

The volume and complexity of traffic on the Internet is increasing rapidly, making it both more difficult and more important to understand. To this end we have created the CoralReef passive traffic monitoring suite, which can be

The Internet architecture provides an unsequenced datagram delivery service. Nevertheless, many higher-layer protocols, such as TCP, assume that packets are usually delivered in sequence, and consequently suffer significant degradation when packets are reordered in flight. While there have been several recent proposals to create protocols that adapt to reordering, evaluating their effectiveness requires understanding the dynamics of the reordering processes prevalent in the Internet. Unfortunately, Internet packet sequencing is a poorly characterized and understudied behavior. This failing can be largely attributed to the lack of accurate and universally applicable methods for measuring packet reordering. In this paper, we describe a new set of active measurement techniques that can reliably estimate one-way end-to-end reordering rates to and from arbitrary TCP-based servers. We validate these tools in a controlled setting and show how they can be used to measure the time-domain distribution of the reordering process along a given path.

Behavior of current communication protocols as well as current and future networked applications is of fundamental importance for technical and commercial success of Mobile Internet. The forthcoming wireless Wide-Area Networks, such as GPRS and UMTS, are quite complex and network operators have a large set of parameters to tune the transfer performance of these networks. In this situation it is of great value to be able to execute practical experiments. The Seawind emulation software introduced in this paper enables measurements of protocol implementations in modeled networking environments. The Seawind software provides a rich set of ways to define transfer characteristics including delays and errors. The software has also means to conduct large sets of experiments in an automatic fashion. In addition, tools of analyzing measurement data has been integrated into the Seawind software.

... decade has led to an increasingly nomadic computing lifestyle. A computer is no longer an immobile, gargantuan machine that remains in one place for the lifetime of its operation. Today's personal computing devices are portable, and Internet access is becoming ubiquitous. A well-traveled laptop user might use half a dozen different networks throughout the course of a day: a cable modem from home, wide-area wireless on the commute, wired Ethernet at the office, a Bluetooth network in the car, and a wireless, local-area network at the airport or the neighborhood coffee shop. Mobile host

This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards " (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. The Extensible Authentication Protocol (EAP), defined in RFC 3748, enables extensible network access authentication. This document specifies the EAP key hierarchy and provides a framework for the transport and usage of keying material and parameters generated by EAP authentication algorithms, known as "methods". It also provides a detailed system-level security analysis, describing the conditions under which the key management guidelines described in RFC 4962 can be satisfied.

The Point-to-Point Protocol (PPP) [1] provides a standard method for transporting multi-protocol datagrams over point-to-point links. PPP defines an extensible Link Control Protocol (LCP) for establishing, configuring, and testing the data-link connection. This document defines several additional LCP features which have been suggested over the past few years.

To deploy real-time services to mobile Internet users, providing low latency handover is an important issue. If a handover is performed across IP subnets, the mobile node generally needs to acquire a new care-of IP address to avoid losing ongoing connections. This paper describes existing alternatives to acquire a care-of address on a visited subnet, and evaluates the related protocols with respect to their effect on the handover latency. We have found that these protocols involve random wait times that can lead to delays in the order of seconds, even when performing a handover between high speed wireless networks. To decrease these delays, we suggest that some of the current recommendations and requirements should be changed in order to support low latency handover.