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M. Nord

Bio: M. Nord is an academic researcher from Telenor. The author has contributed to research in topics: Transmission delay & Packet switching. The author has an hindex of 5, co-authored 7 publications receiving 51 citations.

Papers
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Proceedings ArticleDOI
11 Jun 2003
TL;DR: In this paper, a joint comparative performance evaluation of contention resolution in OBS and OPS is presented, as well as methods of quality of service (QoS) differentiation in optical burst switching (OBS) and optical packet switching (OPS).
Abstract: Future network should be able to efficiently serve packet-based networks, such as the Internet. In this paper, based on results from COST 266, we explore characteristics of optical burst switching (OBS) and optical packet switching (OPS). Both node design and metropolitan area network (MAN) are discussed. A unique joint comparative performance evaluation of contention resolution in OBS and OPS are presented, as well as methods of quality of service (QoS) differentiation in OBS/OPS networks, and their performance.

20 citations

Journal ArticleDOI
TL;DR: Experimental characterization of a three-node OpMiGua network test-bed with ingress, core, and egress nodes confirms zero packet loss and jitter of the circuit-switched guaranteed service transport class of service (CoS) and shows how adding a packet- Switched statistical multiplexed CoS increases lightpath utilization.
Abstract: Hybrid optical network architectures that combine beneficial properties of circuit- and packet-switching are attractive for multimedia networks. We have already proposed and reported the experimental demonstration of elements of a hybrid optical network architecture, the OpMiGua network. We now report experimental characterization of a three-node OpMiGua network test-bed with ingress, core, and egress nodes. The experiment confirms zero packet loss and jitter of the circuit-switched guaranteed service transport class of service (CoS) and shows how adding a packet-switched statistical multiplexed CoS increases lightpath utilization

9 citations

Proceedings ArticleDOI
17 Mar 2002
TL;DR: In this paper, a novel transparent optical protection-switching scheme capable of switching with minimum, and even without, loss of data is demonstrated, which will be attractive for networks where optical transparency or high level of protection security, like protection against security attacks, tampering or earthquakes, are desired.
Abstract: We have demonstrated a novel transparent optical protection-switching scheme capable of switching with minimum, and even without, loss of data. The detection circuit has proven to trigger the optical switch when failure situations, like the unplugging of a fibre-connector or the fibre being exposed to abnormal environmental conditions, occurs. We believe this protection scheme will be attractive for networks where optical transparency or high level of protection security, like protection against security attacks, tampering or earthquakes, are desired.

7 citations

Book Chapter
01 Jan 2003
TL;DR: Optical Packet Switching and Optical Burst Switching come into play, with the goal of reducing delays and improving the utilisation of the network's resources through statistical multiplexing.
Abstract: Most existing wide area telecommunication networks (WAN) have an SDH based, electronically circuit switched transport core. Connection setup or tear down may require days or weeks and multiplexing/demultiplexing always require complex optical/electro/optical (O/E/O) conversions. Nowadays, the operators and vendors are working on an optical control plane, which should control setup and tear down of connections. Work on automatically switched optical network (ASON) and generalised multi-protocol label switching (GMPLS) takes place within ITU and IETF, respectively. Resulting optically circuit switched (OCS) networks can offer explicit transfer guarantees, since circuit establishments are confirmed. However, this generates a delay equal at least to the round-trip time, typically several ms. Even though OCS networks will offer more flexibility than today's solution, the access to the optical bandwidth will still be provided with fibre/wavelength granularity. Future networks should be able to serve a client layer that includes packet-based networks, such as the Internet, which may have a highly dynamic connection pattern with a significant portion of bursty traffic between the communicating pairs. In this case, OCS transport may not be flexible enough. It would require over-dimensioning of the number of connections and of the bandwidth reservation of each connection, to avoid excessive delay and extensive buffering at the ingress router. Here is when Optical Packet Switching (OPS) and Optical Burst Switching (OBS) come into play, with the goal of reducing delays and improving the utilisation of the network's resources through statistical multiplexing. This comes at the expense of not being able to offer explicit transfer guarantees. However, suitable node design and proper dimensioning of network resources may enable support of most services over the same network. OPS and OBS logical performance in relation to contention resolution and quality of service (QoS) differentiation will be discussed in 4.3 and 4.4. Moreover, hybrid schemes are possible where OPS and OBS share the WDM layer with an OCS scheme, serving applications with the need for explicit transfer guarantees. Europe has been very active in OPS research, especially through projects like RACE ATMOS [1], ACTS KEOPS [2], IST DAVID [3], IST STOLAS [4] and COST 266. OBS was proposed very recently [5], but different research groups in Europe have already made significant contributions to this field, as later sections in this chapter show. Inevitably, there are some differences in terminology within the research community; we here explicitly describe some concepts and terms used in this chapter. Both optical packet …

6 citations

Proceedings ArticleDOI
01 Sep 2006
TL;DR: Separation of two QoS classes in a hybrid time-interleaved circuit/packet node is demonstrated and guaranteed packets follow circuit switched paths with absolute priority, while statistical multiplexed packets are packet switched and are subject to packet loss.
Abstract: Separation of two QoS classes in a hybrid time-interleaved circuit/packet node is demonstrated. Guaranteed packets follow circuit switched paths with absolute priority, while statistical multiplexed packets are packet switched and are subject to packet loss.

5 citations


Cited by
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Journal ArticleDOI
TL;DR: The contention resolution and avoidance schemes proposed for bufferless OPS networks are surveyed and the Quality of Service (QoS) issue in a QoS-capable bufferlessOPS network is reviewed.
Abstract: Optical Packet Switching (OPS) is the promising switching technique to utilize the huge bandwidth offered by all-optical networks using the DWDM (Dense Wavelength Division Multiplexing) technology. However, optical packet contention is the major problem in an OPS network. Resolution and avoidance are two schemes to deal with the contention problem. A resolution scheme resolves collisions, while an avoidance scheme tries to reduce the number of potential collision events. Many OPS architectures rely on optical buffers to resolve contention. Unfortunately, optical buffering technology is still immature as it relies on bulky optical fiber delay lines. Furthermore, it requires a complex control. Therefore, a bufferless OPS network could still be the most straightforward implementation in the near future. In this article, we survey the contention resolution and avoidance schemes proposed for bufferless OPS networks. We also review the resolution and avoidance schemes that can handle the Quality of Service (QoS) issue in a QoS-capable bufferless OPS network.

95 citations

Journal ArticleDOI
TL;DR: In this paper, an integrated hybrid optical network field-trial is described to demonstrate the ability to both aggregate and transport sub-wavelength circuits, and offer high throughput efficiency by statistically multiplexing traffic on transport wavelengths.
Abstract: Carriers are under constant pressure to meet the ever-increasing bandwidth demand while reducing cost per bit, enhancing network throughput, and offering a large variety of services. Hybrid packet and circuit network technologies are being widely investigated and considered as a solution for offering both the high network throughput of the packet domain and wavelength services, i.e., a low fixed latency and zero packet loss. To enable carriers to serve a higher number of customers requiring wavelength services, optical transport network (OTN)-based sub-wavelength switching is adopted to support finer granularity with similar performance to full wavelength services. However, OTN is not able to perform statistical multiplexing and achieve the throughput efficiency of packet networks. In this work an integrated hybrid optical network field-trial is described to demonstrate the ability to both aggregate and transport sub-wavelength circuits, and offer high throughput efficiency by statistically multiplexing traffic on transport wavelengths. Results show the transport of sub-wavelength services with packet-delay variation limited to only 15 ns and 82.4% wavelength utilization using statistical multiplexing.

30 citations

Journal ArticleDOI
TL;DR: The architecture is suitable for optical packet and optical burst switching and provides appropriate contention resolution schemes and QoS guarantees and a concept, called virtual memory, is developed to allow controllable and reasonable periods for delaying optical traffics.
Abstract: This paper presents an architecture for an all optical switching node. The architecture is suitable for optical packet and optical burst switching and provides appropriate contention resolution schemes and QoS guarantees. A concept, called virtual memory, is developed to allow controllable and reasonable periods for delaying optical traffics. Related to its implementation, several engineering issues are discussed, including the use of loopbased optical delay lines, fiber Bragg gratings, and limited number of signal amplifications. In particular, two implementations using optical flip-flop and laser neuron network based control units are analyzed. This paper also discusses the implementation and performance of an alloptical synchronizer that is able to synchronize arriving data units to be aligned on the clock signal associated with the beginning time of slots, in the node, with an acceptable error.

27 citations

Journal ArticleDOI
TL;DR: This paper proposes a node architecture suitable for optical packet and burst switching that allows a prioritized buffering mechanism for contention resolution and QoS support and develops a theoretical model for evaluating its performance based on a new conservation law and a queuing network model.

20 citations

Dissertation
01 Jan 2007
TL;DR: This doctoral thesis summarizes research in quantum cryptography done at the Department of Electronics and Telecommunications at the Norwegian University of Science and Technology (NTNU) from 1998 to 2002.
Abstract: This doctoral thesis summarizes research in quantum cryptography done at the Department of Electronics and Telecommunications at the Norwegian University of Science and Technology (NTNU) from 1998 ...

18 citations