Marvin A. Sirbu

SPV: secure path vector routing for securing BGP

As our economy and critical infrastructure increasingly relies on the Internet, the insecurity of the underlying border gateway routing protocol (BGP) stands out as the Achilles heel. Recent misconfigurations and attacks have demonstrated the brittleness of BGP. Securing BGP has become a priority.In this paper, we focus on a viable deployment path to secure BGP. We analyze security requirements, and consider tradeoffs of mechanisms that achieve the requirements. In particular, we study how to secure BGP update messages against attacks. We design an efficient cryptographic mechanism that relies only on symmetric cryptographic primitives to guard an ASPATH from alteration, and propose the Secure Path Vector (SPV) protocol. In contrast to the previously proposed S-BGP protocol, SPV is around 22 times faster. With the current effort to secure BGP, we anticipate that SPV will contribute several alternative mechanisms to secure BGP, especially for the case of incremental deployments.

Pricing Multicast Communication: A Cost-Based Approach

Multicast and unicast traffic share and compete for network resources. A cost-based approach to multicast pricing, based on accurate characterization of multicast scalability, will facilitate the efficient and equitable resource allocation between traffic types. Through the quantification of link usage, this paper establishes a multicast scaling relationship: the cost of a multicast distribution tree varies at the 0.8 power of the multicast group size. This result is validated with both real and generated networks, and is robust across topological styles and network sizes. Since multicast cost can be accurately predicted given the membership size, there is strong motivation to price multicast according to membership size. Furthermore, a price ceiling should be set to account for the effect of tree saturation. This tariff structure is superior to either a purely membership-based or a flat-rate pricing scheme, since it reflects the actual tree cost at all group membership levels.

Distributed authentication in Kerberos using public key cryptography

The authors describe a method for fully distributed authentication using public key cryptography within the Kerberos ticket framework. By distributing most of the authentication workload away from the trusted intermediary and to the communicating parties, significant enhancements to security and scalability can be achieved as compared to Kerberos V5. Privacy of Kerberos clients is also enhanced. A working implementation of this extended protocol has been developed, and a migration plan is proposed for a transition from traditional to public key based Kerberos.

The process of innovation in five industries in Europe and Japan

The study examines the relationship between outside influences and the firms innovation process. A sample of commercially successful and unsuccessful R&D projects of a number of firms is discussed in terms of diverse market, resource, technical and organizational factors. The stimulus for a project, the sources of ideas used and the influences of competition and regulatory constraints were expected to vary among industries, and these differences are described. The authors suggest that their findings might be understood based on the evolution of a business from one having initially fluid and independent product and process technologies to one having a highly automated process technology designed for a specific standard product. Consequently, the relationship between product and process will shape and constrain the firms ability to innovate in response to a changing environment.

Technological choice in voluntary standards committees : an empirical analysis

Vendors frequently compete to have their technology adopted as part of a voluntary consensus standard. In this paper we report the results of an empirical study of the factors that influence the choice of technologies in voluntary technical standards committees. Participation in standards committees is viewed as an aspect of the product development process of corporations involved in markets where network externalities are present. The factors hypothesized to affect the technology decision are: the market power of the coalition sponsoring the technology, the installed base of the products containing the technology, the size of the firms that make up the coalition, the promotional activities of the sponsors (such as technical contributions submitted), the perceived superiority of the technology, and the political skills of the coalition. These hypotheses were tested by collecting data concerning specific technical decisions that were made in several standards committees in the area of computer communicatio...

Credits and debits on the Internet

Since the advent of banking in the Middle Ages, bank customers have used paper based instruments to move money between accounts. In the past 25 years (1972-97), electronic messages moving through private networks have replaced paper for most of the value exchanged among banks each day. With the arrival of the Internet as a mass market data network, new technologies and business models are being developed to facilitate electronic credit and debit transfers by ordinary consumers. These new systems include CyberCash (which is a gateway between the Internet and the authorization networks of the major credit cards) and the Secure Electronic Transactions protocol (a standard for presenting credit card transactions on the Internet), as well as First Virtual (a way of using e-mail to secure approval for credit card purchases of information), GC Tech (a payment system that can use credit or debit via an intermediation server), and NetBill (a public private key encryption system for purchasing information).

Optimal bundling strategy for digital information goods: network delivery of articles and subscriptions

Abstract The digitization and networking of information goods necessitate a rethinking of their production and distribution economics. An N -good bundling model with multi-dimensional consumer preferences is developed to study the key factors that determine the optimal bundling strategy. Using analytical and empirical methods, mixed bundling is established as the dominant (i.e. profit maximizing) strategy. Pure unbundling is also shown to outperform pure bundling, even in the presence of some degree of economies of scale, if consumers positively value only a subset of the bundle components, which is the predominant case in the academic journal context. These results provide strong incentives for academic journal publishers to engage in mixed bundling, i.e. offer both individual articles and journal subscriptions, when selling and delivering over the Internet.

A narrowband approach to efficient PCS spectrum sharing through decentralized DCA access policies

This article addresses spectrum sharing and open access for personal communications services (PCS). Traditional regulation has allocated electromagnetic spectrum through fragmentation into mutually exclusive frequency blocks. Block allocation schemes produce trunking inefficiencies in the use of multiple narrowband RF channels. Broadband allocation schemes such as code division multiple access (CDMA) can accommodate multiple users on a single RF channel. Due to the near-far problem, the only way competing CDMA operators could share common spectrum is through collocation of cell sites, which hinders market mechanisms. An alternative approach is narrowband spectrum sharing through a decentralized dynamic channel assignment (DCA) approach, such as autonomous reuse partitioning (ARP). Multiple-operator DCA allocation schemes for low-tier PCS systems have been proposed in some countries. Under such an approach, competing operators use a common air interface to share the available spectrum. Open access can improve opportunities for competition in the provision of PCS. Other things being equal, a multi-operator DCA system outperforms that achievable by multiple carriers under a traditional fragmented spectrum, even for overlapping networks and unequal traffic loads. In this article we use a discrete event simulation to explore the spectrum efficiency implications of adopting a narrowband decentralized DCA/ARP spectrum-sharing policy. We explore as well regulatory measures so operators will deploy infrastructure instead of appropriating channels from competitors.

Spectrum sharing through dynamic channel assignment for open access to personal communications services

This paper focuses on a narrow band technical solution that uses decentralized spectrum sharing to facilitate open access among competing personal communications services (PCS) operators. Existing policies that apportion spectrum by fixed channel assignment (FCA) involve inefficiencies resulting from fragmentation of the available resource into mutually exclusive frequency blocks. Dynamic channel assignment (DCA) has been previously demonstrated to be flexible in handling traffic variability and to simplify frequency planning for a single network operator. We use a discrete event simulation to demonstrate that DCA with autonomous reuse partitioning (ARP) provides more capacity than standard DCA; this property still holds when channels are shared among multiple operators, with partially overlapping networks and unequal traffic shares. We explore the impact of limiting the maximum number of channels that can be assigned to one cell site as an incentive for operators to build more cells, rather than simply appropriating channels from competitors.

Wireless is changing the policy calculus for municipal broadband

Historically, the justification for municipal provisioning of “last-mile” communications infrastructure has focused on the natural monopoly aspect of wireline infrastructure. Growing interest in wireless ISPs, municipal hot spots, and access to public space for siting wireless infrastructure suggests new and expanded opportunities for local government participation in telecommunication services. This paper examines the implications of emerging wireless technologies for the policy debate over whether municipalities should be playing an active role in providing last-mile broadband services and, if so, what the nature of that role should be.