organized by
May 19-24 2002, Pisa - ITALY

workshop 3

sponsored by
Cassa di Risparmio di PISA



WORKSHOP 3 - International Workshop on IP over WDM

A workshop co-located with Networking 2002
May 24, 2002 - CNR Research Area, Pisa, Italy

A workshop sponsored by CNIT
Consorzio Nazionale Interuniversitario per le Telecomunicazioni


Giancarlo Prati
Scuola Superiore di Studi Universitari e Perfezionamento Sant'Anna & CNIT
Piazza Martiri della Libertà, 33
56127 Pisa ITALY
Tel: +39-050-970719
Fax +39-050-9711208


Piero Castoldi
Scuola Superiore di Studi Universitari e Perfezionamento Sant'Anna & CNIT
Piazza Martiri della Libertà, 33
56127 Pisa ITALY
Tel: +39-050-970719
Fax +39-050-9711208


The increasing demand for broadband services over the Internet poses two main challenges regarding the deployment of an efficient protocol stack for the transmission and a reliable bandwidth provisioning over the links. On the one hand, IP has become the standard routing protocol for all applications over the Internet. On the other hand, in satisfying the increasing demand for bandwidth, optical network technologies represent a unique opportunity because of their almost unlimited potential bandwidth. Recent developments in wavelength-division multiplexing (WDM) technology have dramatically increased the traffic capacity of optical networks. IP over WDM is being envisioned as one of the most attractive architectures for the new Internet. Statistical multiplexing of traffic remains thus a task for the upper layers, e.g., IP. The straightforward advantages of interfacing IP directly over WDM, as opposed to existing solutions that rely on intermediate layers such as SONET/SDH and ATM, include overall reduction of equipment cost and management complexity, as well as improved bandwidth efficiency. However in order to grant Quality of Service by directly interfacing IP over WDM we need to couple a control plan to the IP data plane. The network designer is facing two technical challenges: reducing the complexity of multi-layer architectures and, where possible, providing all-optical packet switching making use of the most advanced devices.

The technical program will be built on the basis of invited talks given by recognized leading experts in the field. Organiser and speakers work together during the organisation phase in order to tune the presentations to generate a non-overlapping natural workflow of the workshop.

The invited contributions are relevant to any research issue specific to IP-over-WDM integration, covering theoretical aspects, system implementation and experimental test-bed. Hence, topics include, but are not limited to:

* Migration scenarios towards ip-over-wdm integration
* Network "delayering"
* Protocol stacks for ip-over-wdm integration
* Network architectures
* Intelligence in the optical layer
* Peer model vs overlay model
* Routine, signaling, control and survivability
* Experimental setup

Invited Speakers

Koichi Asatani, Kogakuin University, Japan 
Dominique Chiaroni, Alcatel CIT, France
Andrea Fumagalli, University of Texas at Dallas, U.S.
Ranjan Gangopadhyay, Indian Institute of Technology, India
David K Hunter, Marconi Labs, U.K.
Adam Kapovits, Eurescom, Germany
Francesco Matera, Fondazione U. Bordoni, Italy
Sudhir Dixit, Nokia, U.S. 

Program and forum for thinking and discussion

Registration and coffee
Welcome from the Organizer
Koichi Asatani,
Trends in technologies and standards for IP over Optical
Francesco Matera,
The role of the 40 Gbit/s in the future optical WDM IP transport network
Coffee break
David K. Hunter,
An IP-over-OPS network
Ranjan Gangopadhyay,
Routing and Wavelength Assignment in IP over WDM Networks
Adam Kapovits,
IP over WDM - important issues for carriers
Dominique Chiaroni,
Place of optics in next generation of IP networks
Sudhir Dixit,
The Challenge of Traffic Grooming and Subwavelength Lightpath Routing in the Optical Internet
Andrea Fumagalli,
Differentiated Reliability (DiR) in IP over WDM networks
Coffee break
15:45-16:45 Discussion

The workshop will be conducted in an informal and highly interactive format, so as to stimulate discussion and exchange of opinions among the speakers and the attendees. The workshop is meant to give point of views, research trends, and authorative answers regarding fundamental questions that researchers, network designers and network operators are facing today. The technical program will be concluded by a plenary discussion allowing for the comparison of different perspectives on the network evolution. In this session, the speakers are invited to give the flavour of "vision and business" to their interventions.

The workshop is strictly related to the general conference technical program which includes an invited talk by Imrich Chlamtac on "IP over WDM" and a tutorial on "Optical Networks" given by H. Perros and G. Rouskas.

Abstract of presentation

  • Trends in technologies and standards for IP over Optical, Koichi Asatani, Kogakuin University,Japan
    The presentation will introduce the recent trends in R&D on IP over Optical in Japan and also present current status of standards on optical transport networks in ITU-T and other related standardization organizations.
  • Place of optics in next generation of IP networks, Dominique Chiaroni, Alcatel CIT, France
    The rapid needs in new high capacity networks for the metro and the backbone based on the Internet Protocol push constructors to propose concrete solutions in a best term. It has been demonstrated that optics has a strong potential in terms of performance and cost, and many new optical functions are currently studied in the laboratory of diverse companies to identify a real potential in terms of product. However, the optical technology has no real existing market, except for transmission systems, and an intermediate introduction is urgently required to let the possibility to this advanced optical technology to be developed for a product target. In addition many efforts are currently required in terms of integration, packaging and costs to have a chance to be competitive with respect to an existent electronic technology. If for transmission systems the market is quite preserved since there is no other technology alternative in terms of capacity transported over long distances, for any other function : switching or processing it is urgent to propose different approaches :
    - an intermediate opto-electronic approach to try to introduce some basic function and contribute to promote the benefit of optics for potential shot term systems
    - highlight where the advantages of optics with respect to electronics can be found for different system alternatives exploiting not only the arguments of cost but also the arguments in terms of functionality like : robustness, power consumption, simplicity, performance, stability, ....
    - try to find solutions to reduce the cost of basic components to don't restrict the market to only point-to-point transmission systems
    - propose optical concepts argued on the different advantages we could have and exhibiting feasibility issues at the lab level but also in the objective of a long term product introduction
    - start to think standardisation issues
    So in the presentation, some arguments to position optics as a serious candidate for a next generation of networks will be given. Some system concepts will be presented for a first introduction of optics in the network. Finally, a network approach will be proposed and described focusing not only on feasibility issues (physical and performance) but also in terms of cost benefits for the future IP network.
  • Differentiated Reliability (DiR) in IP over WDM networks, Andrea Fumagalli, Marco Tacca, Ferenc Unghvary, The University of Texas at Dallas,USA, Monica de Lacerda Rocha, Alberto Paradisi, Sandro Marcelo Rossi, CPqD Foundation, Brazil
    Current WDM networks typically offer only two degrees of service reliability: full protection in the presence of a single fault in the network, and no protection at all. This situation reflects the historical duality that has its roots in the once divided telephone and data environment. The circuit oriented service requires protection, i.e., provisioning of readily available spare resources toreplace working resources in case of a fault. The datagram oriented service relies upon restoration, i.e., dynamic search for and reallocation of affected resources via actions as routing table updates. The current development trend, however, is gradually driving the design of networks towards a unified solution that will jointly support traditional voice and data services, as well as a variety of novel multimedia applications. The growing importance of concepts, such Quality of Service (QoS) and Differentiated Services --- that provide multiple levels of service performance in the same network --- evidences this trend.. Consistently with this pattern, the concept of Differentiated Reliability (DiR) will be formally introduced to provide multiple reliability degrees (or classes) in a single network layer using the desired protection mechanism. According to the DiR concept, each connection in the layer under consideration is guaranteed a minimum acceptable reliability degree, or equivalently a maximum acceptable failure probability, allowed for that connection. The reliability degree chosen for a given connection is thus determined by the application requirements, and not by the actual network topology, design constraints, robustness of the network components, and span of the connection. The DiR concept will be illustrated using three well established protection schemes, i.e., Dedicated Path Protection (DPP) in WDM ring, DPP in WDM mesh network, and Shared Path Protection (SPP) in WDM mesh network. Experimental results measured on the IP over WDM test-bed OMEGA (Optical Metro network for Emerging Gigabit Applications) will be presented to prove the technical feasibility of the DiR concept.
  • Routing and Wavelength Assignment in IP over WDM Networks, Ranjan Gangopadhyay, Indian Institute of Technology, Kharagpur, India
    In this presentation we first provide the routing and wavelength assignment policies in wavelength-routed optical network.We then introduce various emerging architectural alternatives for IP over optical networks.Various RWA algorithms for dynamic provisioning of optical channels on IP-over-WDM networks are then presented. Finally, we give the exposition of integrated routing and waveband routing and discuss the scopes of further activities in this area.
  • An IP-over-OPS network, David K. Hunter, Derek R. McAuley, Marconi Labs, Cambridge, UK
    This talk shows how to use optical devices to construct all-optical data-paths, using packet oriented switching. Asynchronous Time Division (ATD) Multiplexing transports IP, permitting the small buffers in optical packet switches to be used in the core. We do not attempt to replicate the functionality of today's optically interfaced IP routers; indeed this transition may never happen.
    IP is interfaced to the optical core by electronic edge routers implementing traffic smoothing and congestion control. In the core, each packet remains entirely in optical format, reducing the cost of e/o and o/e conversion. The core switches employ optical switching and a small amount of optical delay-line buffering, all under electronic control. Routing table lookup is carried out electronically.
    The core network uses fixed-length slots, facilitating control logic pipelining. Capacity within slots is treated much as in SDH/SONET frames, as a byte stream. There are two classes of service - CBR (Constant Bit Rate) and RCBR (Renegotiated Constant Bit Rate, as proposed by Grossglauser), which carry different applications according to some classification scheme.
  • IP over WDM - important issues for carriers, Adam Kapovits, Eurescom, Germany
    * Interoperability
    * Advantages of ASTN compared to conventional OTN
    * Carrier requirements for providing optical transport services to IP clients
  • The role of the 40 Gbit/s in the future optical WDM IP transport network,Francesco Matera, Fondazione Ugo Bordoni, ITALY
    Future optical transport network will be based on the WDM transmission and on the process of the wavelength conversion. In order to be compatible with the dynamical characteristic of the internet traffic, a suitable management is required for future networks and in particular such a management has to be able to assign in a fast way the lightpaths following the traffic peaks distribution. Furthermore particular transmission techniques are already available to carry the IP packet directly on the wavelengths using lighter format with respect to the SDH/SONET.
    It is now questionable if the future networks, especially in the transport environment, will use the channel bit rate either at 10 Gbit/s or at 40 Gbit/s. At the moment systems based on hundreds of wavelengths at 10 Gbit/s are already commercially available, but it is our opinion that in few months the technology on the 40 Gbit/s will become very reliable and as a consequence the cost of a 40 Gbit/s channel could be comparable with the one of the 10 Gbit/s. Furthermore a network based on the nx40 Gbit/s shows an important characteristics from the point of view of the IP traffic: it is suitable to support the traffic peaks by allocating the excess information in the circuits that are generally free. This way we can investigate on transmission techniques based on the concept of optical burst switching used in the TDM environment instead of the WDM with high number of wavelengths at lower bit rate.
    In this talk we report on the status of the transmission nx40 Gbit/s by including also the all optical wavelength conversion process. We report the results obtained in the framework of the IST ATLAS project that show how to implement a network based on 40 Gbit/s lightpath with distance up to 2000 km, including also the wavelength conversion process, supporting a traffic of dime of Tbit/s.
    The topics reported in this presentation regards:
    - The RZ format for the 40 Gbit/s;
    - The transmission in G.652 and G.655 fibres with dispersion management;
    - The hybrid Raman/EDFA amplification;
    - Devices for all optical wavelength conversion at 40 Gbit/s (SOA, PPLN)
    - Optical 3R regeneration;
    - 4x40 Gbit/s experiments in links 500 km long with wavelength conversion.
  • The Challenge of Traffic Grooming and Subwavelength Lightpath Routing in the Optical Internet, Sudhir Dixit, Nokia, U.S.A.
    The explosion in the demand for bandwidth implies that the Internet infrastructure will increasingly become optical, and needs for traffic grooming and aggregation will become critical at the edge of the network. The criticality comes due to the decreasing size of the IP packet and the duration of the flows. This talk will focus on two important aspects of the optical Internet: traffic aggregation at the edge and subwavelength path setup in the optical core. We propose integrated lightpath and IP over WDM agent-based approaches to groom and transport the client traffic onto a dynamic logical topology established over the optical network. The integrated approach has been studied against the single hop and multi-hop approaches to demonstrate its benefit on improving the performance. The agent-based approach effectively manages the aggregation of traffic across the optical core between the IP client networks. It offers the benefit of effective resource utilization and addresses the scalability problem. Finally, we touch upon the issues of provisioning end-to-end sub-wavelength connections, and present some constraint-based routing solutions to route sub-wavelength connection requests using G-MPLS.

Supporting material

Copy of the slides presented at the workshop will be collected in a booklet and distributed to the attendees in advance. Slides will also be made available on the Web.

last updated 09-May-2002