Jennifer Rexford

Central Control Over Distributed Routing

By: 
Stefano Vissicchio, Olivier Tilmans, Laurent Vanbever, Jennifer Rexford
Appears in: 
CCR August 2015

Centralizing routing decisions offers tremendous flexibility, but sacrifices the robustness of distributed protocols. In this paper, we present Fibbing, an architecture that achieves both flexibility and robustness through central control over distributed routing. Fibbing introduces fake nodes and links into an underlying linkstate routing protocol, so that routers compute their own forwarding tables based on the augmented topology. Fibbing is expressive, and readily supports flexible load balancing, traffic engineering, and backup routes.

Dynamic scheduling of network updates

By: 
Xin Jin, Hongqiang Harry Liu, Rohan Gandhi, Srikanth Kandula, Ratul Mahajan, Ming Zhang, Jennifer Rexford, Roger Wattenhofer
Appears in: 
CCR August 2014

We present Dionysus, a system for fast, consistent network updates in software-defined networks. Dionysus encodes as a graph the consistency-related dependencies among updates at individual switches, and it then dynamically schedules these updates based on runtime differences in the update speeds of different switches. This dynamic scheduling is the key to its speed; prior update methods are slow because they pre-determine a schedule, which does not adapt to runtime conditions.

SDX: a software defined internet exchange

By: 
Arpit Gupta, Laurent Vanbever, Muhammad Shahbaz, Sean P. Donovan, Brandon Schlinker, Nick Feamster, Jennifer Rexford, Scott Shenker, Russ Clark, Ethan Katz-Bassett
Appears in: 
CCR August 2014

BGP severely constrains how networks can deliver traffic over the Internet. Today’s networks can only forward traffic based on the destination IP prefix, by selecting among routes offered by their immediate neighbors. We believe Software Defined Networking (SDN) could revolutionize wide-area traffic delivery, by offering direct control over packet-processing rules that match on multiple header fields and perform a variety of actions.

A network-state management service

By: 
Peng Sun, Ratul Mahajan, Jennifer Rexford, Lihua Yuan, Ming Zhang, Ahsan Arefin
Appears in: 
CCR August 2014

We present Statesman, a network-state management service that allows multiple network management applications to operate independently, while maintaining network-wide safety and performance invariants. Network state captures various aspects of the network such as which links are alive and how switches are forwarding traffic. Statesman uses three views of the network state. In observed state, it maintains an up-to-date view of the actual network state. Applications read this state and propose state changes based on their individual goals.

SDX: a software defined internet exchange

By: 
Arpit Gupta, Laurent Vanbever, Muhammad Shahbaz, Sean Patrick Donovan, Brandon Schlinker, Nick Feamster, Jennifer Rexford, Scott Shenker, Russ Clark, Ethan Katz-Bassett
Appears in: 
CCR August 2014

BGP severely constrains how networks can deliver traffic over the Internet. Today’s networks can only forward traffic based on the destination IP prefix, by selecting among routes offered by their immediate neighbors. We believe Software Defined Networking (SDN) could revolutionize wide-area traffic delivery, by offering direct control over packet-processing rules that match on multiple header fields and perform a variety of actions.

Report of the DIMACS working group on abstractions for network services, architecture, and implementation

By: 
Jennifer Rexford, Pamela Zave
Appears in: 
CCR January 2013

A workshop on Abstractions for Network Services, Architecture, and Implementation brought together researchers interested in creating better abstractions for creating and analyzing networked services and network architectures. The workshop took place at DIMACS on May 21-23, 2012. This report summarizes the presentations and discussions that took place at the workshop, organized by areas of abstractions such as layers, domains, and graph properties.

Rehoming edge links for better traffic engineering

By: 
Eric Keller, Michael Schapira, Jennifer Rexford
Appears in: 
CCR April 2012

Traditional traffic engineering adapts the routing of traffic within the network to maximize performance. We propose a new approach that also adaptively changes where traffic enters and leaves the network—changing the “traffic matrix”, and not just the intradomain routing configuration. Our approach does not affect traffic patterns and BGP routes seen in neighboring networks, unlike conventional inter-domain traffic engineering where changes in BGP policies shift traf-

Public Review By: 
Telefonica Research

Router grafting is a recently proposed technology (Keller et al., NSDI’10) that permits migrating one local endpoint of a session between two routers without having to inform the remote one. By doing so, it permits reconfiguring several aspects of an IP network without imposing downtimes or inflicting severe and potentially dangerous changes to BGP. In this paper the authors looks at the potential of putting router grafting to work for the benefit of traffic engineering. The main idea is that an optimal traffic engineering depends among others on the characteristic of the traffic matrix to be served. Router grafting allows reshaping a traffic matrix by selecting the ingress and egress points at which traffic is received and handed over to other networks. Therefore, it has the potential to improve traffic engineering by applying it on an easier to handle, reshaped traffic matrix. The authors formulate a generalized traffic engineering problem that includes the extra degree of freedom, propose two heuristics for solving it, and present evaluation results based on Internet2 traffic. These results point to a potential improvement of around 20% due to router grafting. An interesting paper making the case for router grafting more concrete by putting it into the context of traffic engineering and evaluating using real traffic data. The reviewers criticized almost consistently the assumption that traffic is handed over between networks over a single link, pointing to the fact that peering or customerprovider relationships typically require two networks to meet at multiple points. A second suggestion for improvement was to consider in the evaluation more realistic data regarding the availability of alternative points to which an existing link can be migrated (eg, factoring practical aspects like the existence of ports and circuits for moving the traffic to the new end-point). One could look, for example, at some Internet Exchange Points (IXP) and provide a more concrete quantification of benefits based and their actual tenants and the costs for moving to alternative sites. Finally, a more in-depth look at the source behind the demonstrated 20% performance gain would benefit this paper. Where does it come from? Is it connected to diurnal traffic patterns or is it a one-shot improvement that once performed requires no further alternation of inter-connection points? Overall, a solid performance evaluation work that leaves some interesting questions open for future study.

The Networking Philosopher's Problem

By: 
Jennifer Rexford
Appears in: 
CCR July 2011

While computer networking is an exciting research field, we are far from having a clear understanding of the core concepts and questions that define our discipline. This position paper, a summary of a talk I gave at the CoNext’10 Student Workshop, captures my current frustrations and hopes about the field.

Architecting for Innovation

By: 
Teemu Koponen, Scott Shenker, Hari Balakrishnan, Nick Feamster, Igor Ganichev, Ali Ghodsi, P. Brighten Godfrey, Nick McKeown, Guru Parulkar, Barath Raghavan, Jennifer Rexford, Somaya Arianfar, and Dmitriy Kuptsov
Appears in: 
CCR July 2011

We argue that the biggest problem with the current Internet architecture is not a particular functional deficiency, but its inability to accommodate innovation. To address this problem we propose a minimal architectural “framework” in which comprehensive architectures can reside. The proposed Framework for Internet Innovation (FII) — which is derived from the simple observation that network interfaces should be extensible and abstract — allows for a diversity of architectures to coexist, communicate, and evolve.

How secure are secure interdomain routing protocols

By: 
Sharon Goldberg, Michael Schapira, Peter Hummon, and Jennifer Rexford
Appears in: 
CCR October 2010

In response to high-profile Internet outages, BGP security variants have been proposed to prevent the propagation of bogus routing information. To inform discussions of which variant should be deployed in the Internet, we quantify the ability of the main protocols (origin authentication, soBGP, S-BGP, and data-plane verification) to blunt traffic-attraction attacks; i.e., an attacker that deliberately attracts traffic to drop, tamper, or eavesdrop on packets.

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