Walter Cerroni

Man-in-the-Middle Attack to the HTTPS Protocol

Web-based applications rely on the HTTPS protocol to guarantee privacy and security in transactions ranging from home banking, e-commerce, and e-procurement to those that deal with sensitive data such as career and identity information. Users trust this protocol to prevent unauthorized viewing of their personal, financial, and confidential information over the Web.

Wavelength and time domain exploitation for QoS management in optical packet switches

This paper addresses the problem of congestion resolution and quality of service differentiation in optical packet switching. The paper shows that by designing congestion resolution algorithms that combine the use of the wavelength and the time domain it is possible to significantly reduce information loss phenomena and also to guarantee quality of service differentiation among traffic classes. In particular this is achieved by means of QoS algorithms specifically designed to exploit the characteristics of optical technology. The results are different from the QoS techniques typically implemented in electronic networks. Performance evaluation obtained by simulation shows the influence of the main system parameters on packet loss probability and delay for two service classes.

Performance of Network Virtualization in cloud computing infrastructures: The OpenStack case

Cloud computing infrastructures will likely be a key component of future Internet architectures, owing to the many advantages of server and network virtualization, especially considering the emerging Network Function Virtualization and Software Defined Networking technologies. The cloud infrastructure will then determine the performance of the networking environment. In this paper, such issue is investigated with reference to OpenStack, a widely adopted cloud infrastructure management platform. In particular, the paper provides an insight on how OpenStack deals with multi-tenant network virtualization and evaluates the performance of its main network components by measuring packet throughput in an experimental test-bed.

Wavelength allocation algorithms in optical buffers

This paper addresses the problem of buffering performance optimization for asynchronous, variable length packets in a DWDM optical network. In the case of a multiplexing scheme that shares the wavelength resource among all packets regardless the connection they belong to, the problem of defining a wavelength allocation algorithm arises. Wavelength allocation has to be merged with delay allocation in buffers realized by means of fiber delay lines (FDLs). This paper proposes several allocation algorithms and compares their performance. It shows that the buffering performance strongly depends on the choice of the delay unit of the FDLs and that the algorithm aiming at reducing the artificial increase in the load due to the discrete time scale of the buffer gives best performance.

SIP-enabled Optical Burst Switching architectures and protocols for application-aware optical networks

This paper presents a novel application-aware network architecture for emerging IT services and future Internet applications. It proposes and analyses network architectures that integrate Session Initiation Protocol (SIP) with Optical Burst Switched (OBS) network technology in a unified manner. It demonstrates that the proposed SIP-enabled OBS network can be used to manage application sessions and provide network and IT services according to the application requirements. Furthermore, various SIP over OBS layering architectures, utilizing a number of end-to-end resource discovery protocols (both for network and non-network (IT) resources) are presented and analyzed. Finally, this paper reports on the validation of functionalities, mechanisms and protocols for the proposed SIP-enabled OBS network, from the node level to the network level, through a test-bed demonstrator.

Scheduling Algorithms for a Slotted Packet Switch with either Fixed or Variable Length Packets

We address the problem of congestion resolution in optical packet switching (OPS). We consider a fairly generic all-optical packet switch architecture with a feedback optical buffer constituted of fiber delay lines (FDL). Two alternatives of switching granularity are addressed for a switch operating in a slotted transfer mode: switching at the slot level (i.e., fixed length packets of a single slot) or at the burst level (variable length packets that are integer multiples of the slot length). For both cases, we show that in spite of the limited queuing resources, acceptable performance in terms of packet loss can be achieved for reasonable hardware resources with an appropriate design of the time/wavelength scheduling algorithms. Depending on the switching units (slots or bursts), an adapted scheduling algorithm needs to be deployed to exploit the bandwidth and buffer resources most efficiently.

Dynamic chaining of Virtual Network Functions in cloud-based edge networks

This manuscript investigates the issue of implementing chains of network functions in a “softwarized” environment where edge network middle-boxes are replaced by software appliances running in virtual machines within a data center. The primary goal is to show that this approach allows space and time diversity in service chaining, with a higher degree of dynamism and flexibility with respect to conventional hardware-based architectures. The manuscript describes implementation alternatives of the virtual function chaining in a SDN scenario, showing that both layer 2 and layer 3 approaches are functionally viable. A proof-of-concept implementation with the Mininet emulation platform is then presented to provide a practical example of the feasibility and degree of complexity of such approaches.

Key parameters for contention resolution in multi-fiber Optical Burst/Packet Switching nodes

Optical networking paradigms based on statistical multiplexing, such as Optical Burst Switching or Optical Packet Switching, require the adoption of suitable contention resolution mechanisms at the optical nodes due to packets/bursts attempting to get access to the shared output channel at the same time. In the most general case of multi-fiber output links, contentions are tried to be solved by exploiting different domains — namely space, wavelength and time — and by applying an optimal scheduling policy. This paper focuses on the key parameters that can be used to design and optimize an optical packet/burst contention resolution scheme and shows how such parameters should be correlated for a correct performance assessment, taking into account feasibility trade-offs due to limited optical buffering and wavelength conversion capability.

OPN06-6: Congestion Resolution in Optical Burst/Packet Switching with Limited Wavelength Conversion

This paper proposes a methodology to compare scheduling algorithms for congestion resolution in optical burst switching or optical packet switching networks, focusing on the issue of wavelength conversion capabilities. The performance of such algorithms when full wavelength conversion is available at the switching nodes are compared with the case of conversion capabilities over a limited range of wavelengths. The results presented show that limited range wavelength conversion is not necessarily performing worse than full wavelength conversion, as long as the correct terms of comparison are considered.

Standard-based approach to programmable hybrid networks

Programmable hybrid networks are considered in this article as a challenge to deploy flexible solutions for next-generation networks. A modular programmable router architecture, which takes advantage of emerging standards, is proposed to support dynamic management and configuration capabilities of network resources and services. The new node design concepts allow vendor-independent development of hybrid router functionalities and possible investigation of new standard interfaces. Validation of the proposed approach is proven in an open source software router context, emulating a hybrid circuit/packet service based on optical switching technology. The software emulator obtained allows programmable hybrid router functionalities to be tested at different levels of abstraction and with different modeling granularities, and is able to represent both logical and physical aspects.