Solving routing and spectrum allocation related optimization problems

We provide a comprehensible introduction to RSA-related problems in flexgrid networks. Starting from its formulation, we analyze network live cycle and indicate different solving methods for the kind of problems that arise at each network phase: from the initial network planning to network re-optimization, going through network operation.Peer ReviewedPostprint (author’s final draft

Insights on the Internet routing scalability issues

In recent years, the size and dynamics of the global routing table have increased rapidly along with an increase in the number of edge networks. The relation between edge network quantity and routing table size/dynamics reveals a major limitation in the current architecture. In this paper we introduce the two problematics target as the main cause for the Internet scalability issue. Subsequently, we describe the different proposals that address the scalability problem. We group them in three categories: Separation, Elimination and GeographicPostprint (published version

Managing Interdomain Traffic in Latin America: A New Perspective based on LISP

The characteristics of Latin American network infrastructures have global consequences, particularly in the area of interdomain traffic engineering. As an example, Latin America shows the largest de-aggregation factor of IP prefixes among all regional Internet registries, being proportionally the largest contributor to the growth and dynamics of the global BGP routing table. In this article we analyze the peculiarities of LA interdomain routing architecture, and provide up-to-date data about the combined effects of the multihoming and TE practices in the region. We observe that the Internet Research Task Force initiative on the separation of the address space into locators and identifiers can not only alleviate the growth and dynamics of the global routing table, but can also offer appealing TE opportunities for LA. We outline one of the solutions under discussion at the IRTF, the Locator/Identifier Separation Protocol, and examine its potential in terms of interdomain traffic management in the context of LA. The key advantage of LISP is its nondisruptive nature, but the existing proposals for its control plane have some problems that may hinder its possible deployment. In light of this, we introduce a promising control plane for LISP that can solve these issues, and at the same time has the potential to bridge the gap between intradomain and interdomain traffic management.Peer ReviewedPostprint (published version

Advantages of a PCE-based control plane for LISP

The Locator/Identifier Separation Protocol (LISP) is one of the candidate solutions to address the scalability issues in inter-domain routing. The current proposals for its control plane (e.g., ALT, CONS, NERD) have various shortcomings, including the potential dropping of packets at LISP routers during the resolution of the EID-to-RLOC mapping. In this paper, we introduce a new Control Plane (CP) for LISP supported by an architecture that borrows concepts from both the Path Computation Element (PCE) and Intelligent Route Control (IRC). Our CP is able to tackle three different problems simultaneously: (i) packets sourced from end-hosts are neither dropped nor queued during the mapping resolution; (ii) the EID-to-RLOC mapping can be obtained and configured approximately within the DNS resolution time needed to fetch the destination EID address; and (iii) our approach can blend IRC with the PCE capabilities, to perform upstream/ downstream Traffic Engineering (TE) through the dynamic management of the mappings. In particular, our CP supports the utilization of different LISP ingress and egress local routers for the same flow sourced from a domain.Peer ReviewedPostprint (author’s final draft

End-to-end KPI analysis in converged fixed-mobile networks

©2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The independent operation of mobile and fixed network segments is one of the main barriers that prevents improving network performance while reducing capital expenditures coming from overprovisioning. In particular, a coordinated dynamic network operation of both network segments is essential to guarantee end-to-end Key Performance Indicators (KPI), on which new network services rely on. To achieve such dynamic operation, accurate estimation of end-to-end KPIs is needed to trigger network reconfiguration before performance degrades. In this paper, we present a methodology to achieve an accurate, scalable, and predictive estimation of end-to-end KPIs with sub-second granularity near real-time in converged fixed-mobile networks. Specifically, we extend our CURSA-SQ methodology for mobile network traffic analysis, to enable converged fixed-mobile network operation. CURSA-SQ combines simulation and machine learning fueled with real network monitoring data. Numerical results validate the accuracy, robustness, and usability of the proposed CURSA-SQ methodology for converged fixed-mobile network scenarios.The research leading to these results has received funding from the Spanish MINECO TWINS project (TEC2017-90097-R), and from the Catalan Institution for Research and Advanced Studies (ICREA).Peer ReviewedPostprint (author's final draft

Near real-time estimation of end-to-end performance in converged fixed-mobile networks

© Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/The independent operation of mobile and fixed network segments is one of the main barriers that prevents improving network performance while reducing capital expenditures coming from overprovisioning. In particular, a coordinated dynamic network operation of both network segments is essential to guarantee end-to-end Key Performance Indicators (KPI), on which new network services rely on. To achieve such dynamic operation, accurate estimation of end-to-end KPIs is needed to trigger network reconfiguration before performance degrades. In this paper, we present a methodology to achieve an accurate, scalable, and predictive estimation of end-to-end KPIs with sub-second granularity near real-time in converged fixed-mobile networks. Specifically, we extend our CURSA-SQ methodology for mobile network traffic analysis, to enable converged fixed-mobile network operation. CURSA-SQ combines simulation and machine learning fueled with real network monitoring data. Numerical results validate the accuracy, robustness, and usability of the proposed CURSA-SQ methodology for converged fixed-mobile network scenarios.Peer ReviewedPostprint (author's final draft

Coordination of radio access and optical transport

New 5G and beyond applications demand strict delay requirements. In this paper, we propose coordination between radio access and optical transport to guarantee such delay while optimizing optical capacity allocation. Illustrative results show near real-time autonomous capacity adaptation benefits based on radio access delay requirements.The research leading to these results has received funding from the HORIZON SEASON (G.A. 101096120), the UNICO5G TIMING (TSI-063000-2021-145), and the MICINN IBON (PID2020-114135RB-I00) projects and from the ICREA institution.Peer ReviewedPostprint (author's final draft

Experimental evaluation of a dynamic PCE-based regenerator-efficient IA-RWA algorithm in translucent WSON

We devise a novel dynamic PCE-based impairment-aware RWA algorithm in translucent GMPLS WSON that minimizes regenerator usage. Experimental evaluation carried out on the Open GMPLS/PCE control plane of CTTC ADRENALINE test-bed shows that significant improvements (>340%) are attained in terms of the offered traffic load.Peer ReviewedPostprint (published version

Meeting the requirements to deploy cloud RAN over optical networks

Radio access network (RAN) cost savings are expected in future cloud RAN (C-RAN). In contrast to traditional distributed RAN architectures, in C-RAN, remote radio heads (RRHs) from different sites can share baseband processing resources from virtualized baseband unit pools placed in a few central locations (COs). Due to the stringent requirements of the several interfaces needed in C-RAN, optical networks have been proposed to support C-RAN. One of the key elements that needs to be considered are optical transponders. Specifically, sliceable bandwidth-variable transponders (SBVTs) have recently shown many advantages for core optical transport networks. In this paper, we study the connectivity requirements of C-RAN applications and conclude that dynamicity, fine granularity, and elasticity are needed. However, there is no SBVT implementation that supports those requirements, and thus, we propose and assess an SBVT architecture based on dynamic optical arbitrary generation/measurement. We consider different long-term evolution-advanced configurations and study the impact of the centralization level in terms of the capital expense and operating expense. An optimization problem is modeled to decide which COs should be equipped and which equipment, including transponders, needs to be installed. The results show noticeable cost savings from installing the proposed SBVTs compared to installing fixed transponders. Finally, compared to the maximum centralization level, remarkable cost savings are shown when a lower level of centralization is considered.Peer ReviewedPostprint (author's final draft

Experimental demonstration of cognitive provisioning and alien wavelength monitoring in multi-domain EON

This paper proposes a cognitive multi-domain EON architecture with machine-learning aided RMSA and alien wavelength monitoring. Testbed experiments show modulation format recognition, QoT monitoring and cognitive routing for a 160 GBd alien multi-wavelength lightpath.Peer ReviewedPostprint (published version