24,975 research outputs found

    Joint Energy Efficient and QoS-aware Path Allocation and VNF Placement for Service Function Chaining

    Full text link
    Service Function Chaining (SFC) allows the forwarding of a traffic flow along a chain of Virtual Network Functions (VNFs, e.g., IDS, firewall, and NAT). Software Defined Networking (SDN) solutions can be used to support SFC reducing the management complexity and the operational costs. One of the most critical issues for the service and network providers is the reduction of energy consumption, which should be achieved without impact to the quality of services. In this paper, we propose a novel resource (re)allocation architecture which enables energy-aware SFC for SDN-based networks. To this end, we model the problems of VNF placement, allocation of VNFs to flows, and flow routing as optimization problems. Thereafter, heuristic algorithms are proposed for the different optimization problems, in order find near-optimal solutions in acceptable times. The performance of the proposed algorithms are numerically evaluated over a real-world topology and various network traffic patterns. The results confirm that the proposed heuristic algorithms provide near optimal solutions while their execution time is applicable for real-life networks.Comment: Extended version of submitted paper - v7 - July 201

    Implementation of Distributed Time Exchange Based Cooperative Forwarding

    Full text link
    In this paper, we design and implement time exchange (TE) based cooperative forwarding where nodes use transmission time slots as incentives for relaying. We focus on distributed joint time slot exchange and relay selection in the sum goodput maximization of the overall network. We formulate the design objective as a mixed integer nonlinear programming (MINLP) problem and provide a polynomial time distributed solution of the MINLP. We implement the designed algorithm in the software defined radio enabled USRP nodes of the ORBIT indoor wireless testbed. The ORBIT grid is used as a global control plane for exchange of control information between the USRP nodes. Experimental results suggest that TE can significantly increase the sum goodput of the network. We also demonstrate the performance of a goodput optimization algorithm that is proportionally fair.Comment: Accepted in 2012 Military Communications Conferenc

    Forwarding and optical indices of 4-regular circulant networks

    Get PDF
    An all-to-all routing in a graph GG is a set of oriented paths of GG, with exactly one path for each ordered pair of vertices. The load of an edge under an all-to-all routing RR is the number of times it is used (in either direction) by paths of RR, and the maximum load of an edge is denoted by π(G,R)\pi(G,R). The edge-forwarding index π(G)\pi(G) is the minimum of π(G,R)\pi(G,R) over all possible all-to-all routings RR, and the arc-forwarding index π→(G)\overrightarrow{\pi}(G) is defined similarly by taking direction into consideration, where an arc is an ordered pair of adjacent vertices. Denote by w(G,R)w(G,R) the minimum number of colours required to colour the paths of RR such that any two paths having an edge in common receive distinct colours. The optical index w(G)w(G) is defined to be the minimum of w(G,R)w(G,R) over all possible RR, and the directed optical index w→(G)\overrightarrow{w}(G) is defined similarly by requiring that any two paths having an arc in common receive distinct colours. In this paper we obtain lower and upper bounds on these four invariants for 44-regular circulant graphs with connection set {±1,±s}\{\pm 1,\pm s\}, 1<s<n/21<s<n/2. We give approximation algorithms with performance ratio a small constant for the corresponding forwarding index and routing and wavelength assignment problems for some families of 44-regular circulant graphs.Comment: 19 pages, no figure in Journal of Discrete Algorithms 201
    • …
    corecore