Gabriele Corliano

Gabriele holds an MSc in Computer Science from the Polytechnic of Turin, awarded in October 2000. In July 2000 he also gained a diploma in Telecommunication Engineering from the Eurecom Institute (Sophia Antipolis, France). He first worked for Motorola in the domain of Personal Communications. As a software designer, he first participated to the design of end-to-end IP over EDGE communication systems; and then, in the design of GSM - UMTS dual mode cell reselection. He joined BT Research in June 2001. Working in the Networks Research Centre (formerly Edge Lab) as a research scientist, he currently leads the IP Networking Research Group.

Projects

IP Networking Research Group

Part-time PhD^? (Lancaster University): "Contractual mobility for user roaming". Arguing the reasons why current roaming across different providers is deficient, this paper suggests a new definition of roaming based on the concept of explicit contractual mobility. This enables users to establish explicit business relationships with visited providers in an ad hoc fashion. The functions required to enable this are described in the context of a business plane where no specific roaming model is enforced ? users are not wedded to a particular tariff, but only to what they choose and what they pay for. The plane represents a playing field for economic tussles, where current and future commercial roaming models will be realized, and the fittest will survive. This study explores the architectural issues surrounding the provision of flexible, efficient, highly dynamic user mobility in both fixed and wireless environments and in both technical and contractual aspects.

Recent past projects

Data and control planes separation (2005 - 06). IP networks have been originally designed according to principles that today do not allow them any more to absorb the requirements emerging from the current economic and societal scene. The dramatic shift from circuit-switched to IP-based networks, undertaken by most network operators and service providers, have created new business and technical requirements that are now constantly putting under stress IP networks? ability to represent a suitable alternative to circuit-switched networks as a carrier-grade network infrastructure. One outstanding open question for operators and providers today is guaranteeing service availability. It is well known that IP networks are still easily subject to many kinds of denial of service (DoS) attacks, which can sensibly reduce service availability, as well as create losses and introduce costs (e.g. protection costs). One approach to solving these problems is implementing a certain degree of separation between the data and control planes, in order to introduce a sufficient level of protection to ensure (nearly) constant service availability. The objectives of this task are therefore threefold: first to compile a registry of vulnerabilities and deficiencies created today by the current design of IP data and control planes (and possibly some foreseeable in the near future); then, to assess existing technologies that implement any degree of separation of the two planes; and finally, to compile a registry of solutions to the problems identified, partly designed by us and partly as a particular arrangement of existing technologies. With its registries of problems and solutions, as well as with its technology assessment, this work aims primarily to contribute to the 21C roadmapping activities, by providing thoughtful advice on the future evolution of the IP control plane.

End-to-end QoS (2003 - 06). End-to-end Quality of Service (QoS) requires that every involved element along the network path delivers its part of quality. Hence, signalling is required to allow applications to request a specific QoS from the network, and to allow the network to allocate resources on the involved network elements, coordinate their responses (i.e. resources allocated or not), and present to applications an end-to-end response (i.e. QoS request accepted or not).

Computational networking - Application task (2005 - 06). The project's fundamental approach is to take some of the tools and techniques that are being gathered together and developed by the Computational Networking theoretical task and to apply them to a specific problem domain. Our objective is to develop novel results which are interesting to some or all of our target audience i.e. BT lines of business, equipment vendors, CII partners, and the wider academic routing community. In doing so we will demonstrate the value of the general approach advocated by the Computational Networking theoretical task and also, we hope, the specific novel tools developed there.

Inter-domain routing (2004 - 05). We discuss the problem of routing control, and its ownership, in the Internet. We consider the ownership of routing control an economic tussle and we suggest that a routing architecture should cope with any outcome of it and, accordingly, support a whole spectrum of control approaches, including host-, operator- and shared-controlled ones.

Addressing, naming and routing (2002 - 05). As it is hard to predict accurately what tomorrow's Internet traffic may look like, flexibility comes as a very important requirement for the design of the services networks should offer. With that in mind, we address three main points for a good evolvable network architecture: shared control (e.g. QoS mechanisms), identity and structure.

Guaranteed QoS Synthesis (GQS) overall system design (2003 - 06). The core idea of the GQS technology is given by the GQS gateway, which mediates between a signalling-based service negotiation and a packet-based marking mechanism, namely ECN. ECN marks are interpreted as load signals, such that by analysing the packet marking rate, a GQS gateway can determine whether to accept further service requests and what price to charge for ongoing and new service invocations. Currently, RSVP is the signalling protocol used to establish the end-to-end service.

Guaranteed QoS Synthesis (GQS) signalling system design (2003 - 06). Internal control path mechanisms include all mechanisms that enable gateways, upon external request, to configure and query data path mechanisms. They allow gateways to gain views of the congestion state from other peer gateways, decide whether to admit a flow or not, and provide a response to the external requester.

End-to-end QoS coordination (2004 - 06). End-to-end Quality of Service (QoS) requires that every involved element along the network path delivers its part of quality. Hence, signalling is required to allow applications to request a specific QoS from the network, and to allow the network to allocate resources on the involved network elements, coordinate their responses (i.e. resources allocated or not), and present to applications an end-to-end response (i.e. QoS request accepted or not).

Naming, numbering and addressing in converged networks and services (2004 - 05). Naming, numbering and addressing in converged networks and services (2004 - 05). Identification systems, such as numbering, naming, addressing and identity management systems are considered key enablers for most current and future BT communications services. They have to be able to support the range of services to be delivered, the platforms, systems and processes through which these services will be delivered, and the business models under which BT will be expected to operate. However, the convergence of different wireless and fixed network technologies into a common seamless platform has substantially complicated both the design of identification systems for converged services and the allocation and management of the corresponding identifiers. In addition, the current model where customers have a number of different terminals, with different names from different naming schemes is neither appropriate for BT?s seamless mobility vision, nor user friendly (users have to remember, and keep up to date, a many different identities). This work looks at the short and medium term implications of the convergence of wireless and fixed networks for both the design of identification systems for converged services, and allocation and management of the corresponding identifiers.

Seamless Mobility - Networks Evolution (2003 - 04). This task investigates the impacts of networks evolution to providers and operators of seamless mobile services. We look at the essence of seamless mobility, discussing the trade-off between creating simplicity and completeness for users, and introducing complexity and intelligence for networks. We review and study different network technologies (fixed and wireless), both in terms of technical capabilities (such as performance, supported services, roaming/handover, quality of service, addressing, identity), and in terms of commercial status (degree of maturity, deployment, business opportunities). We compare and evaluate different technologies and their evolution rates and make projections about their time-to-maturity and business impacts. Outcomes of the work include technology timelines, future technology projections and strategic recommendations.

Rustling Project (2001 - 03). The Rustling project moves a critique to the current roaming definition. The forced service homogenization across providers and the obligatory use of roaming agreements represent two serious limiting factors for the evolvability of services and the communications market. We therefore suggest a new definition of roaming based on the concept of explicit contractual mobility. This enables users to establish explicit business relationships with visited providers in an ad hoc fashion, i.e. on a per session basis, independently of roaming agreements, and in an automated fashion.

Selected Publications

Internet Quality of Service

Guaranteed QoS synthesis - an example of a scalable core IP quality of service solution Peter Hovell, Bob Briscoe and Gabriele Corliano, in BTTJ Special Edition on IP Quality of Service, Volume 23 Issue 2, (Apr 2005). Abstract: With the transition of services like IP telephony to be carried over IP networks there is the potential for catastrophic numbers of calls to fail whenever sufficient demand is focused on unpredictable points in the core IP network. This is well-known; Service differentiation helps but does not alleviate the problem - call admission control is required but seems expensive for the few occasions it is required. This paper describes a BT-developed experimental mechanism called guaranteed QoS synthesis (GQS) that performs call admission control for core IP networks for constant bit-rate streams (voice and video). The mechanism is primarily aimed at Internet services but it may be possible to extend it for VPN applications. The GQS mechanisms is economic to deploy and operate , and scales without any increase in complexity. It achieves these properties by keeping no flow state in the network and basing call admission decisions on the measured congestion across the network. The paper describes the high-level GQS architecture as well as some of the deployment issues and potential savings in the operational support area. How GQS enables the separation of the interconnect QoS and retail business models is also explained.

An architecture for edge-to-edge controlled load service using distributed measurement-based admission control, B. Briscoe, G. Corliano. Eardley, P. Hovell, A. Jacquet, D. Songhurst, Internet Engineering Task Force (IETF) Transport Services working group Internet Draft, Jul 2005 (Obsoleted). Abstract: This document describes an architecture to achieve a Controlled Load (CL) service edge-to-edge, i.e. within a particular region of the Internet, by using distributed measurement-based admission control. The measurement made is of CL packets that have their Congestion Experienced (CE) codepoint set as they travel across the edge-to-edge region. Setting the CE codepoint, which is under the control of a new Per Hop Behaviour (CL-ramp-PHB, defined in draft-briscoe-tsvwg-cl-phb- 00.txt), provides an "early warning" of potential congestion. This information is used by the ingress node of the edge-to-edge region to decide whether to admit a new CL microflow. A use case is described which shows how the PHB is a fundamental building block in the edge-to-edge architecture, and in turn how this is a building block within a broader QoS architecture achieving an end- to-end CL service.

Network Availability & Denial of Service

Securing Network Availability,, L. Burness, G. Corliano, B. Harman, A. Murgu, F. El-Moussa, L. He, IBT Technology Journal, Jan 2006. Abstract: We live in a world that relies increasingly on its communications infrastructure. Any availability problem with our network or network services will impact not only on our immediate revenue, but also on our customers trust in our network. The objective of this paper is twofold: first to describe the vulnerabilities and deficiencies that exist within current networks; then to describe some potential solutions to these problems. A key theme throughout this discussion is the separation of the data and control planes. Within the PSTN, the control network is physically separate from the data circuits. This, along with tightly controlled and limited network interfaces, makes certain types of attack impossible. Unfortunately, with a connectionless packet network, this type of separation will never be completely possible. Further, the nature of network inter-working is changing as we move towards a world of increasing service diversity and dynamic, ad hoc networks.

Seamless Access & contractual mobility

Explicit contractual mobility for user roaming, G. Corliano, K. Khan, J. Mitchener, Fifth annual postgraduate symposium (PGNet) 2004, June 2004. Abstract: Arguing the reasons why current roaming across different providers is deficient, this paper suggests a new definition of roaming based on the concept of explicit contractual mobility. This enables users to establish explicit business relationships with visited providers in an ad hoc fashion. The functions required to enable this are described in the context of a business plane where no specific roaming model is enforced users are not wedded to a particular tariff, but only to what they choose and what they pay for. The plane represents a playing field for economic tussles, where current and future commercial roaming models will be realized, and the fittest will survive.

Economic tussles in the market for public mobile access market, G. Corliano, K. Khan, BT Technology Journal, Jul 2003. Abstract: The convergence of different wireless and fixed access systems into a common seamless access platform has accelerated the conflict of economic interests between players in traditionally separate market sectors. Whereas technology systems have predictable and desirable behaviour ? and therefore evolution ? the players in the converging market sectors have not. This paper argues that, in its original vision, the systems specifying the business interactions between mobile users and access providers (the business interface) have not been designed considering the unpredictability of the outcome of economic tussles. The mobile industry encoded in its designs the result of past contentions, not allowing for their variation. Because the market currently does not capture the business opportunities created by the convergence of heterogeneous access networks, the designs of the business interface should now be re-considered to accommodate such convergence and allow for evolution. We have therefore formulated a set of principles for the design of the business interface. The application of these principles highlighted specific limitations of the current interface. On the basis of this study, we conclude that the future business interface should allow providers to disseminate their offers to customers (possibly not end users) in an automated way; and customers to select offers in an automated and intelligent way, and then dynamically establish ad hoc business relationships with providers. In addition, end users should be able to hold, at the same time, more than one business relationship with different providers, without experiencing any switching barriers. Finally, providers should be able to dynamically re-configure their metering capabilities on visited networks? systems without having adjacent providers to necessarily support their charging capabilities.