Somaya Arianfar

LIPSIN: line speed publish/subscribe inter-networking

A large fraction of todays Internet applications are internally publish/subscribe in nature; the current architecture makes it cumbersome and inept to support them. In essence, supporting efficient publish/subscribe requires data-oriented naming, efficient multicast, and in-network caching. Deployment of native IP-based multicast has failed, and overlay-based multicast systems are inherently inefficient. We surmise that scalable and efficient publish/subscribe will require substantial architectural changes, such as moving from endpoint-oriented systems to information-centric architectures. In this paper, we propose a novel multicast forwarding fabric, suitable for large-scale topic-based publish/subscribe. Due to very simple forwarding decisions and small forwarding tables, the fabric may be more energy efficient than the currently used ones. To understand the limitations and potential, we provide efficiency and scalability analysis via simulations and early measurements from our two implementations. We show that the system scales up to metropolitan WAN sizes, and we discuss how to interconnect separate networks.

On content-centric router design and implications

In this paper, we investigate a sample line-speed content-centric routers design, its resources and its usage scenarios. We specifically take a closer look at one of the suggested functionalities for these routers, the content store. The design is targeted at pull-based environments, where content can be pulled from the network by any interested entity. We discuss the interaction between the pull-based protocols and the content-centric router. We also provide some basic feasibility metrics, discussing some applicability aspects for such routers.

On preserving privacy in content-oriented networks

The recent literature has hailed the benefits of content-oriented network architectures. However, such designs pose a threat to privacy by revealing a users content requests. In this paper, we study how to ameliorate privacy in such designs. We present an approach that does not require any special infrastructure or shared secrets between the publishers and consumers of content. In lieu of any informational asymmetry, the approach leverages computational asymmetry by forcing the adversary to perform sizable computations to reconstruct each request. This approach does not provide ideal privacy, but makes it hard for an adversary to effectively monitor the content requests of a large number of users.

Deadline-based resource management for information-centric networks

Unlike in traditional IP-based end-to-end network sessions, in information-centric networks the data source may change during a communication session. Therefore the response time to subsequent data requests may vary significantly depending on whether data comes from nearby cache, or a distant source. This is a complication for designing resource management, reliability and other algorithms, that traditionally use RTT measurements for determining when data is considered lost and should be retransmitted (along with related congestion control adjustments). This paper discusses a different approach for designing resource management in information-centric networks: data packets are assigned with a lifetime, that is used as a basis for scheduling and resource management in the network, and for congestion control and retransmission logic at the end hosts. We demonstrate an initial evaluation of this approach based on ns-3 simulations on CCN framework.

A Framework for Privacy Analysis of ICN Architectures

Information-Centric Networking (ICN) has recently received increasing attention from the research community. Its intriguing properties, including identity/location split, in-network caching and multicast, have turned it into the primary paradigm for many recent inter-networking proposals. Most of these are mainly concerned with core architectural issues of ICN including naming, routing, and scalability, giving little or no attention to privacy. Privacy issues however, are together with security, an integral part of any contemporary communication technology and play a crucial role for its adoption. Since the core functions of an ICN architecture are content name based, many opportunities for privacy related attacks–such as user profiling–are created; being aware of these privacy threats, users might completely dismiss the idea of using an ICN-based network infrastructure. Therefore, it is important to investigate privacy as an integral part of any ICN proposal. To this end, in this paper, we develop a privacy framework for analyzing privacy issues in different ICN architectures. Our framework defines a generic ICN model as well as various design choices that can be used in order to implement the functions of this model. Moreover it considers a comprehensive list of privacy attack categories, as well as various types of adversaries.

Fast reroute for stateless multicast

Multicast applications such as real-time streaming and video/teleconferencing tolerate delay and packet loss poorly. As a consequence, multicast routing and forwarding should offer flexibility and resiliency for them. In this paper, we introduce fast reroute methods for LIPSIN, a novel Bloom filter based multicast forwarding fabric. We propose two different algorithms, both capable of rerouting traffic immediately after the failure is detected, keeping service disruption at minimum. The two solutions give flexibility to operators by allowing trade-offs between bandwidth and configuration complexity. Finally, we give guidelines about the applicability of our methods by conducting simulations.

Reducing server and network load with shared buffering

Today, content replication methods are common ways of reducing the network and servers load. Present content replication solutions have different problems, including the need for pre-planning and management, and they are ineffective in case of sudden traffic spikes. In spite of these problems, content replication methods are more popular today than ever, simply because of an increasing need for load reduction. In this paper, we propose a shared buffering model that, unlike current proxy-based content replication methods, is native to the network and can be used to alleviate the stress of sudden traffic spikes on servers and the network. We outline the characteristics of a new transport protocol that uses the shared buffers to offload the server work to the network or reduce the pressure on the overloaded links.

Marooned magic numbers - An adaptive congestion control architecture

TCP and other Internet transport protocols rely on series of hard-coded initial values for their connection state, particularly for the congestion control parameters. For example, recently the initial value of congestion window has been under much debate, as there is a desire to make TCP more efficient for common use cases, while not endangering its performance on scenarios with limited network bandwidth. Our take on this discussion is that there is no clear single set of initial values that would work for all cases. Earlier research has proposed sharing connection and congestion control state among multiple connections over time, but that approach is limited to sharing connections to a particular host, which is not sufficient, because services are often distributed across multiple hosts, and opening multiple connections to the same host is a rather rare use case. We aim to solve this problem by proposing the Pathlet Transport Architecture that models the network paths as a series of pathlets, and uses those as the basis of initializing and maintaining the various transport parameters, particularly those related to congestion control. We analyze our initial instantiation of the PTA architecture using ns-3 simulations for TCP congestion control parameters, and show how it improves the communication performance in various different network scenarios, where single common set of magic values would fail.