Shihabur Rahman Chowdhury

A survey of naming and routing in information-centric networks

The concept of information-centric networking (ICN) defines a new communication model that focuses on what is being exchanged rather than which network entities are exchanging information. From the ICN perspective, contents are first class network citizens instead of hosts. ICNs primary objective is to shift the current host-oriented communication model toward a content-centric model for effective distribution of content over the network. In recent years this paradigm shift has generated much interest in the research community and sprung several research projects around the globe to investigate and advance this stream of thought. Content naming and content-based routing are core research challenges in this research community. In this survey, we analyze, compare, and contrast the naming and routing mechanisms proposed by some of the most prominent ICN research projects.

PayLess: A low cost network monitoring framework for Software Defined Networks

Software Defined Networking promises to simplify network management tasks by separating the control plane (a central controller) from the data plane (switches). OpenFlow has emerged as the de facto standard for communication between the controller and switches. Apart from providing flow control and communication interfaces, OpenFlow provides a flow level statistics collection mechanism from the data plane. It exposes a high level interface for per flow and aggregate statistics collection. Network applications can use this high level interface to monitor network status without being concerned about the low level details. In order to keep the switch design simple, this statistics collection mechanism is implemented as a pull-based service, i.e. network applications and in turn the controller has to periodically query the switches about flow statistics. The frequency of polling the switches determines monitoring accuracy and network overhead. In this paper, we focus on this trade-off between monitoring accuracy, timeliness and network overhead. We propose PayLess - a monitoring framework for SDN. PayLess provides a flexible RESTful API for flow statistics collection at different aggregation levels. It uses an adaptive statistics collection algorithm that delivers highly accurate information in real-time without incurring significant network overhead. We utilize the Floodlight controllers API to implement the proposed monitoring framework. The effectiveness of our solution is demonstrated through emulations in Mininet.

Dynamic Controller Provisioning in Software Defined Networks

Software Defined Networking (SDN) has emerged as a new paradigm that offers the programmability required to dynamically configure and control a network. A traditional SDN implementation relies on a logically centralized controller that runs the control plane. However, in a large-scale WAN deployment, this rudimentary centralized approach has several limitations related to performance and scalability. To address these issues, recent proposals have advocated deploying multiple controllers that work cooperatively to control a network. Nonetheless, this approach drags in an interesting problem, which we call the Dynamic Controller Provisioning Problem (DCPP). DCPP dynamically adapts the number of controllers and their locations with changing network conditions, in order to minimize flow setup time and communication overhead. In this paper, we propose a framework for deploying multiple controllers within an WAN. Our framework dynamically adjusts the number of active controllers and delegates each controller with a subset of Openflow switches according to network dynamics while ensuring minimal flow setup time and communication overhead. To this end, we formulate the optimal controller provisioning problem as an Integer Linear Program (ILP) and propose two heuristics to solve it. Simulation results show that our solution minimizes flow setup time while incurring very low communication overhead.

PolicyCop: An Autonomic QoS Policy Enforcement Framework for Software Defined Networks

Network management is becoming increasingly challenging with the relentless growth in network size, traffic volume, and the diversity in QoS requirements. Traditionally, the concept of predefined Service Level Agreements (SLAs) has been utilized to establish QoS parameters. However, most state-of-the-art technologies in this area are both proprietary and inflexible. To this end, Software Defined Networking (SDN) has the potential to make network management tasks flexible, scalable, and an open platform to encourage innovation. In this paper, we present the design of PolicyCop, an open, flexible, and vendor agnostic QoS policy management framework targeted towards OpenFlow based SDN. PolicyCop provides an interface for specifying QoS SLAs and then exploits the control planes API to enforce them. PolicyCop also monitors the network and autonomically readjusts network parameters to meet customer SLAs. We present experimental results to demonstrate PolicyCops effectiveness in ensuring throughput, latency, and reliability guarantees.

On orchestrating virtual network functions

Middleboxes or network appliances like firewalls, proxies, and WAN optimizers have become an integral part of todays ISP and enterprise networks. Middlebox functionalities are usually deployed on expensive and proprietary hardware that require trained personnel for deployment and maintenance. Middleboxes contribute significantly to a networks capital and operational costs. In addition, organizations often require their traffic to pass through a specific sequence of middleboxes for compliance with security and performance policies. This makes the middlebox deployment and maintenance tasks even more complicated. Network Function Virtualization (NFV) is an emerging and promising technology that is envisioned to overcome these challenges. It proposes to move packet processing from dedicated hardware middleboxes to software running on commodity servers. In NFV terminology, software middleboxes are referred to as Virtual Network Functions (VNFs). It is a challenging problem to determine the required number and placement of VNFs that optimize network operational costs and utilization, without violating service level agreements. We call this the VNF Orchestration Problem (VNF-OP) and provide an Integer Linear Programming (ILP) formulation with implementation in CPLEX. We also provide a dynamic programming based heuristic to solve larger instances of VNF-OP. Trace driven simulations on real-world network topologies demonstrate that the heuristic can provide solutions that are within 1.3 times of the optimal solution. Our experiments suggest that a VNF based approach can provide more than 4 χ reduction in the operational cost of a network.

Orchestrating Virtualized Network Functions

Middleboxes or network appliances like firewalls, proxies, and WAN optimizers have become an integral part of todays ISP and enterprise networks. Middlebox functionalities are usually deployed on expensive and proprietary hardware that require trained personnel for deployment and maintenance. Middleboxes contribute significantly to a networks capital and operation costs. In addition, organizations often require their traffic to pass through a specific sequence of middleboxes for compliance with security and performance policies. This makes the middlebox deployment and maintenance tasks even more complicated. Network function virtualization (NFV) is an emerging and promising technology that is envisioned to overcome these challenges. It proposes to move packet processing from dedicated hardware middleboxes to software running on commodity servers. In NFV terminology, software middleboxes are referred to as virtualized network functions (VNFs). It is a challenging problem to determine the required number and placement of VNFs that optimizes network operational costs and utilization, without violating service level agreements. We call this the VNF orchestration problem (VNF-OP) and provide an integer linear programming formulation with implementation in CPLEX. We also provide a dynamic programming-based heuristic to solve larger instances of VNF-OP. Trace driven simulations on realworld network topologies demonstrate that the heuristic can provide solutions that are within 1.3 times of the optimal solution. Our experiments suggest that a VNF-based approach can provide more than 4× reduction in the operational cost of a network.

A taxonomy of decentralized online social networks

Despite their tremendous success, centrally controlled cloud-based Online Social Networks (OSNs) have inherent issues related to user privacy and control. These issues have motivated researchers to make a paradigm shift in the OSN architecture by proposing to replace centrally controlled OSNs with Decentralized OSNs (DOSNs) in a peer-to-peer setting. DOSNs give users more autonomy and the chance to participate in social networks without loosing control over their data. The various DOSN proposals have significant differences in their proposed services, architecture and extent of decentralization. In this survey, we study a number of proposals for peer-to-peer DOSNs, distil a set of criteria to compare them, and provide a taxonomy for their comparison.

αRoute: A name based routing scheme for Information Centric Networks

One of the crucial building blocks for Information Centric Networking (ICN) is a name based routing scheme that can route directly on content names instead of IP addresses. However, moving the address space from IP addresses to content names brings scalability issues to a whole new level, due to two reasons. First, name aggregation is not as trivial a task as the IP address aggregation in BGP routing. Second, the number of addressable contents in the Internet is several orders of magnitude higher than the number of IP addresses. With the current size of the Internet, name based, anycast routing is very challenging specially when routing efficiency is of prime importance. We propose a novel name-based routing scheme (αRoute) for ICN that offers efficient bandwidth usage, guaranteed content lookup and scalable routing table size.

Vehicular communication: protocol design, testbed implementation and performance analysis

Vehicular Communication Networks and Systems (VCNS) and Intelligent Transportation Systems (ITS) are one of the most attractive and challenging topics in recent days since a well efficient protocol for vehicular communication can facilitate the reduction of traffic congestion and can provide us with many more promising applications. In this paper, we propose a protocol for vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) communication. As one of the challenging parts of this paper, we present an experimental testbed in which two major applications of V2I & V2V communication (i.e. traffic congestion detection and emergency warning) is implemented. Based on careful analysis, we also calculate some key system parameters which reflect the efficiency of the protocol in different applications.

Generalized Recovery From Node Failure in Virtual Network Embedding

Network virtualization has evolved as a key enabling technology for offering the next generation network services. Recently, it is being rolled out in data center networks as a means to provide bandwidth guarantees to cloud applications. With increasing deployments of virtual networks (VNs) in commercial-grade networks with commodity hardware, VNs need to tackle failures in the underlying substrate network. In this paper, we study the problem of recovering a batch of VNs affected by a substrate node failure. The combinatorial possibilities of alternate embeddings of the failed virtual nodes and links of the VNs make the task of finding the most efficient recovery both non-trivial and intractable. Furthermore, any recovery approach ideally should not cause any service disruption for the unaffected parts of the VNs. We take into account these issues to design a generalized recovery approach that can achieve customized objectives such as fair treatment on the failed VNs, partial treatment based on priority, and so on. We provide integer linear programming (ILP) formulations for two variants of our recovery scheme, namely, fair recovery model and priority-based recovery model. We also propose a fast and scalable heuristic algorithm to tackle the computational complexity of the ILP solution. Evaluation results demonstrate that our heuristic performs close to the optimal solution and outperforms the state-of-the-art algorithm.