A resource allocation framework for network slicing

International audienceTelecommunication networks are converging to a massively distributed cloud infrastructure interconnected with software defined networks. In the envisioned architecture, services will be deployed flexibly and quickly as network slices. Our paper addresses a major bottleneck in this context, namely the challenge of computing the best resource provisioning for network slices in a robust and efficient manner. With tractability in mind, we propose a novel optimization framework which allows fine-grained resource allocation for slices both in terms of network bandwidth and cloud processing. The slices can be further provisioned and auto-scaled optimally based on a large class of utility functions in real-time. Furthermore, by tuning a slice-specific parameter, system designers can trade off traffic-fairness with computing-fairness to provide a mixed fairness strategy. We also propose an iterative algorithm based on the alternating direction method of multipliers (ADMM) that provably converges to the optimal resource allocation and we demonstrate the method’s fast convergence in a wide range of quasi-stationary and dynamic settings

OKpi: All-KPI Network Slicing Through Efficient Resource Allocation

Networks can now process data as well as transporting it; it follows that they can support multiple services, each requiring different key performance indicators (KPIs). Because of the former, it is critical to efficiently allocate network and computing resources to provide the required services, and, because of the latter, such decisions must jointly consider all KPIs targeted by a service. Accounting for newly introduced KPIs (e.g., availability and reliability) requires tailored models and solution strategies, and has been conspicuously neglected by existing works, which are instead built around traditional metrics like throughput and latency. We fill this gap by presenting a novel methodology and resource allocation scheme, named OKpi, which enables high-quality selection of radio points of access as well as VNF (Virtual Network Function) placement and data routing, with polynomial computational complexity. OKpi accounts for all relevant KPIs required by each service, and for any available resource from the fog to the cloud. We prove several important properties of OKpi and evaluate its performance in two real-world scenarios, finding it to closely match the optimum

Approximation Algorithms for Virtual Service Functions Chain Placement

Η εικονικοποίηση λειτουργιών δικτύου (NFV) είναι μια αναδυόμενη τεχνολογία στην οποία η επεξεργασία των ροών του δικτύου δεν εκτελείται πλέον από εξειδικευμένο hardware, αλλά αντίθετα, μπορεί να επιτελείται σε απλούστερους servers που βρίσκονται σε κόμβους ενός κατανεμημένου υπολογιστικού νέφους (cloud). Αυτές οι λειτουργίες συνήθως εκτελούνται σύμφωνα με πολιτικές που έχουν σχεδιαστεί από τους μηχανικούς του δικτύου. Τέτοιες λειτουργίες μπορεί να είναι τείχη προστασίας, εξισορροπητές φορτίου, φίλτρα περιεχομένου και βαθιά επιθεώρηση πακέτων. Αυτή η τεχνολογία στοχεύει στην αντιμετώπιση των βασικών προκλήσεων της δικτυακής υποδομής (data centers) των παρόχων υπηρεσιών, όπως το χρηματικό κόστος, οι περιορισμοί χωρητικότητας, η πολυπλοκότητα της διαχείρισης του δικτύου, η κατανάλωση ενέργειας και οι αστοχίες λογισμικού. Ένα από τα κύρια πλεονεκτήματα αυτής της προσέγγισης είναι ότι οι λειτουργίες εικονικού δικτύου (VNF) μπορούν να δημιουργηθούν και να κλιμακωθούν κατ’ απαίτηση χωρίς την ανάγκη εγκατάστασης νέου εξοπλισμού. Οι ροές δικτύου συχνά απαιτείται να υποβάλλονται σε επεξεργασία από μια διατεταγμένη ακολουθία λειτουργιών δικτύου. Για παράδειγμα, ένα σύστημα ανίχνευσης εισβολής μπορεί να χρειαστεί να επιθεωρήσει τα πακέτα πριν από τη συμπίεση ή κρυπτογράφηση τους. Επιπλέον, διαφορετικοί πελάτες μπορούν να έχουν διαφορετικές απαιτήσεις λειτουργίας σχετικά με την ακολουθία των λειτουργιών δικτύου που πρέπει να εκτελεστούν. Η διατεταγμένη ακολουθία πολλαπλών VNFs που απαιτείται να εκτελεστεί σε ένα δίκτυο ονομάζεται αλυσίδα εικονικών λειτουργιών (Service Function Chain - SFC). Ένα θεμελιώδες πρόβλημα που προκύπτει όταν ασχολούμαστε με αλυσίδες λειτουργιών δικτύου είναι η ανάθεσή τους σε επιλεγμένους κόμβους του δικτύου με σκοπό την βελτιστοποίηση κάποιου κριτηρίου. Αυτό το πρόβλημα είναι γενικά πολύ δύσκολο να λυθεί και οι περισσότε-ροι υπάρχοντες αλγόριθμοι, κυρίως ευρετικοί, δεν έχουν εγγυημένη απόδοση. Για το λόγο αυτό, στην παρούσα διπλωματική εργασία μελετάμε κάποιους σημαντικούς προσεγγιστικούς αλγόριθμους για την τοποθέτηση SFCs/VNFs. Προσπαθούμε να δείξουμε πώς ορισμένες περιπτώσεις του προβλήματος τοποθέτησης SFC/VNF μεταπίπτουν σε γνωστά προβλήματα, όπως το Πρόβλημα Πολλαπλών Σακιδίων με Περιορισμούς Ανάθεσης και το Πρόβλημα Μεγιστικού Καλύμματος με Περιορισμό Πόρων. Προτείνουμε επίσης έναν ορισμό προβλήματος που προκύπτει σε περιβάλλοντα υπολογιστικού νέφους. Εκεί οι διαχειριστές αποσκοπούν στις πιο προσοδοφόρες, από πλευράς ρυθμού μετάδοσης δεδομένων, αλυσίδες υπηρεσιών υπό περιορισμούς πόρων και προτείνουμε μια πιθανή λύση για μια ειδική περίπτωση του προβλήματος.Network Function Virtualization (NFV) is an emerging techonology in which network functions are no longer executed by proprietary software appliances but instead, can run on commodity servers located in distributed cloud nodes. These functions typically perform packet flow operations according to policies designed by network engineers. Examples of network functions include firewalls, load balancers, content filters, and deep packet inspection. This technology aims at dealing with the major challenges of today’s enterprise middlebox infrastructure, such as monetary cost, capacity limitations, management complexity, energy consumption and failures. One of the main advantages of this approach is that Virtual Network Functions (VNFs) can be instantiated and scaled on demand without the need of installing new equipment. Network flows are often required to be processed by an ordered sequence of network functions. For instance, an Intrusion Detection System may need to inspect the packet before compression or encryption are performed. Moreover, different customers can have different requirements in terms of the sequence of network functions to be performed. The sequence of multiple VNFs required by network operators to perform traffic processing is called a Service Function Chain (SFC). A virtual function can be executed on one or several servers. A fundamental problem arising when dealing with chains of network functions is how to map these functions to nodes (servers) in the network while achieving a specific objective. This problem is in general very hard to solve and most existing algorithms, mainly heuristics, have no provable performance guarantees. For this reason, in this thesis we study notable approximation algorithms for SFC/VNF placement, targeting to highlight techniques of guaranteed approximation solutions. We aim to show how instances of the SFC/VNF placement problem reduce to known problems, like the Multiple Knapsack With Assignment Restrictions Problem and the Budgeted Maximum Coverage Problem. We also propose a problem definition that arises in cloud environments, where operators may need to route the most profitable service chains under resource constraints and we sketch a solution for a special instance of it

Network Function Virtualization Service Delivery In Future Internet

This dissertation investigates the Network Function Virtualization (NFV) service delivery problems in the future Internet. With the emerging Internet of everything, 5G communication and multi-access edge computing techniques, tremendous end-user devices are connected to the Internet. The massive quantity of end-user devices facilitates various services between the end-user devices and the cloud/edge servers. To improve the service quality and agility, NFV is applied. In NFV, the customer\u27s data from these services will go through multiple Service Functions (SFs) for processing or analysis. Unlike traditional point-to-point data transmission, a particular set of SFs and customized service requirements are needed to be applied to the customer\u27s traffic flow, which makes the traditional point-to-point data transmission methods not directly used. As the traditional point-to-point data transmission methods cannot be directly applied, there should be a body of novel mechanisms that effectively deliver the NFV services with customized~requirements. As a result, this dissertation proposes a series of mechanisms for delivering NFV services with diverse requirements. First, we study how to deliver the traditional NFV service with a provable boundary in unique function networks. Secondly, considering both forward and backward traffic, we investigate how to effectively deliver the NFV service when the SFs required in forward and backward traffic is not the same. Thirdly, we investigate how to efficiently deliver the NFV service when the required SFs have specific executing order constraints. We also provide detailed analysis and discussion for proposed mechanisms and validate their performance via extensive simulations. The results demonstrate that the proposed mechanisms can efficiently and effectively deliver the NFV services under different requirements and networking conditions. At last, we also propose two future research topics for further investigation. The first topic focuses on parallelism-aware service function chaining and embedding. The second topic investigates the survivability of NFV services

Optimal Network Service Chain Provisioning

International audienceService chains consist of a set of network services, such as firewalls or application delivery controllers, which are interconnected through a network to support various applications. While it is not a new concept, there has been an extremely important new trend with the rise of Software-Defined Network (SDN) and Network Function Virtualization (NFV). The combination of SDN and NFV can make the service chain and application provisioning process much shorter and simpler. In this paper, we study the provisioning of service chains jointly with the number/location of Virtual Network Functions (VNFs). While chains are often built to support multiple applications, the question arises as how to plan the provisioning of service chains in order to avoid data passing through unnecessary network devices or servers and consuming extra bandwidth and CPU cycles. It requires choosing carefully the number and the location of the VNFs. We propose an exact mathematical model using decomposition methods whose solution is scalable in order to conduct such an investigation. We conduct extensive numerical experiments, and show we can solve exactly the routing of service chain requests in a few minutes for networks with up to 50 nodes, and traffic requests between all pairs of nodes. Detailed analysis is then made on the best compromise between minimizing the bandwidth requirement and minimizing the number of VNFs and optimizing their locations using different data sets