Mallik Tatipamula

StEERING: A software-defined networking for inline service chaining

Network operators are faced with the challenge of deploying and managing middleboxes (also called inline services) such as firewalls within their broadband access, datacenter or enterprise networks. Due to the lack of available protocols to route traffic through middleboxes, operators still rely on error-prone and complex low-level configurations to coerce traffic through the desired set of middleboxes. Built upon the recent software-defined networking (SDN) architecture and OpenFlow protocol, this paper proposes StEERING, short for SDN inlinE sERvices and forwardlNG. It is a scalable framework for dynamically routing traffic through any sequence of middleboxes. With simple centralized configuration, StEERING can explicitly steer different types of flows through the desired set of middleboxes, scaling at the level of per-subscriber and per-application policies. With its capability to support flexible routing, we further propose an algorithm to select the best locations for placing services, such that the performance is optimized. Overall, StEERING allows network operators to monetize their middlebox deployment in new ways by allowing subscribers flexibly to select available network services.

On Resilience of Split-Architecture Networks

The split architecture network assumes a logically centralized controller, which is physically separated from a large set of data plane forwarding switches. When the control plane becomes decoupled from the data plane, the requirement to the failure resilience and recovery mechanisms changes. In this work we investigate one of the most important practical issues in split architecture deployment, the placement of controllers in a given network. We first demonstrate that the location of controllers have high impact on the network resilience using a real network topology. Motivated by such observation, we propose a min-cut based controller placement algorithm and compare it with greedy based approach. Our simulation results show significant reliability improvements with an intelligent placement strategy. Our work is the first attempt on the resilience properties of a split architecture network.

Realizing packet-optical integration with SDN and OpenFlow 1.1 extensions

This paper discusses the benefits of applying software defined networking (SDN) to circuit based transport networks. It first establishes the need for SDN in the context of transport networks. This paper argues that the use of SDN in the transport layers could be the enabler for both packet-optical integration and improved transport network applications. Then, this paper proposes extensions to OpenFlow 1.1 to achieve control of switches in multi-technology transport layers. The approach presented in this paper is simple, yet it distinguishes itself from similar work by its friendliness with respect to the current transport layer control plane based on generalized multiprotocol label switching (GMPLS). This is important as it will enable an easier and gradual injection of SDN into existing transport networks. This paper is completed with a few use case applications of SDN in transport networks.

Next-Generation Applications on Cellular Networks: Trends, Challenges, and Solutions

Applications over cellular networks now range from operator-consumer applications (e.g., mobile television, voice-over-ip, video conferencing), peer-to-peer applications (e.g., instant messaging), machine-to-machine applications (e.g., data telemetry and automotive applications), mobile web services (e.g., music and video streaming), and social networking applications. The current approach for developing mobile applications appears to focus on utilizing template-based application-development kits provided by platform developers (e.g., Googles Android, Apples iOS, or Nokias Symbian) to capture application designs and install them on the runtime platforms through use of code generators tied to particular versions of the platform. It is still unclear as to how an application developer (or network operator) conceptualizes the features of a mobile application in a platform-independent way, identifies its utility and explores its impact on the user, or further refines the choice of technology, platform, and mobility/interactivity requirements. This paper attempts to offer some guidelines, based on recent research in the industry and academia in these areas, toward the design and development of successful mobile applications that can utilize the capabilities of the next generation of cellular networks. We provide an overview of the growing trends of the rich multimedia and real-time mobile applications, including the diversity of application types, their impact on the enterprise and consumer, their traffic volumes, and their load and communication patterns. In addition to the overall trend analysis, we also study the design choices that are to be made, and how they are realized, and also describe how the platforms (client and server) may be implemented. Additionally, we focus on mobile video applications according to their communication characteristics and their distinct demands on the cellular network. We also present an analysis of device and network application programming interfaces (API) that form the basic building blocks for efficient and secure mobile application development of the future.

OpenFlow and Multi-layer Extensions: Overview and Next Steps

Even though software-defined networking (SDN) and the OpenFlow protocol have demonstrated great practicality in the packet domain, there has been some hesitance in extending the OpenFlow specification to circuit and optical switched domains that constitute wide area multi-layer transport networks. This paper presents an overview of various proposals with regards to extending OpenFlow to support circuit switched multi-layer networks. The goal is to shed light on these ideas and propose a way forward. This paper favors a top-down approach, which relies on transport networks main SDN use case: packet-optical integration, to help identify the sufficient extensions for OpenFlow to support circuit/optical switching.

On the Flexibility of MPLS Applications over an OpenFlow-Enabled Network

In todays networks, a node usually has a static role that cannot be easily changed without an expensive upgrade. In MPLS architecture, despite the flexible forwarding data plane not tied to a single forwarding technology, each MPLS node has to be dedicated for a specific role depending on its position in the edge or the core of the MPLS network domain. This paper proposes an approach to address the flexibility of an MPLS node to play multiple roles for different MPLS domains built on top of an underlying OpenFlow-enabled physical network. The pipelined approach through tables introduced in the version 1.1 and later of the OpenFlow specification allows the change of the packet processing behavior by just updating the memory structures -- such as the TCAM and hash tables. It exploits the power of the OpenFlow rules-based paradigm to demonstrate the high level programmability to achieve the deossification of an MPLS infrastructure. In order to validate our proposal, we have implemented our approach over a 100Gbps switch box built on network processors and tested it with three applications to evaluate its flexibility. The results show that the local software to hardware update of a Label Switched Path (LSP) can be made in 2.2ms, in average, and the deployment of a Label Switched Router (LSR) application with 400 labels takes only 392.5ms.

The freshman handbook: a hint for the server placement of social networks

There has been a recent unprecedented increase in the use of Online Social Networks (OSNs) to expand our social life, exchange information and share common interests. Many popular OSNs today attract hundreds of millions of users who share tremendous amount of data on it such as Facebook, Twitter, and Buzz. Given the huge business opportunities OSNs may bring, more and more new social applications has emerged on the Internet. For these newcomers in the social network business, one of the first key decisions to make is to where to deploy the computational resources to best accommodate future client requests. In this work, we aim at providing useful suggests to the new born social network providers (freshman) on the intelligent server placement, by exploring available public information from existing social network communities. In this work, we first propose three scalable server placement strategies for OSNs. Our solution can scalably select server locations among all the possible locations, at the same time reducing the cost for inter-user data sharing.

Characterization and design of effective BGP AS-path prepending

The AS path prepending approach in BGP is commonly used to perform inter-domain traffic engineering, such as inbound traffic load-balancing for multi-homed ASes. It artificially increases the length of the AS level path in BGP announcements by inserting its local AS number multiple times into outgoing EBGP announcement messages. In this work, we first present a comprehensive study on the characterization of Internet routing AS path prepending. We further propose an algorithm for computing the optimal padding strategies given multiple neighboring links. Our method considers the impact of AS relationship based local policies on ASPPs effectiveness. The algorithm can be used for three objectives, i.e., traffic load balancing, backup route provisioning, and bypassing a specific AS for security purposes, e.g., avoiding information censorship. We demonstrate the accuracy and effectiveness of our approach using real BGP data and traffic data from Abilene networks.

A Comprehensive Long-Term Evaluation on BGP Performance

The Border Gateway Protocol (BGP) is the de facto interdomain routing protocol on the Internet which controls the packet forwarding behavior on the data plane. It has significant impact on the well-being of the global Internet. Over the past ten years, there has been a large body of studies conducted on evaluating and improving the BGP performance. These studies develop tools using BGP data for identifying the Internet topology, AS relationships, and AS-level paths. More importantly BGP is the main data source for evaluating the Inter-domain routing performance and discovering routing anomalies such as prefix hijacking attacks. However, most of these studies focus on one or a few aspects of BGP in a short time period. Till today, the route monitoring system has been deployed for ten years and there has been a significant amount of criticisms on the bad performance of BGP. Our work is the first to critically examine and summarize BGP performance and its changes through time. We evaluate BGP from a diverse set of aspects ranging from routing diversity to convergence performance. We design a set of systematic statistical analysis to cope with the noise in data collection process. Due to the huge volume of data required for the analysis, we implement our evaluation system on top of the cloud computing platform from Amazon EC2. Our results provide a few insights on how to improve BGP and the Internet routing system in the future.