Nanxi Kang will present her Pre-FPO on Monday, June 29 at 12pm in CS 401. The members of her committee are: Jennifer Rexford (adviser), David Walker, Sanjay Rao (Purdue), Nick Feamster, Mike Freedman. Everyone is invited to attend her talk. The the abstract follow below: Managing large enterprise networks is challenging. Operators need diverse policies such as routing, access control, QoS and load balancing, for performance, security and reliability. The best practice to enforce these policies today is to configure rules on network switches individually. This forces operators to reason about many low-level details, all at the same time, including the choice of path, the rule-table space limits on each switch, and the hop-by-hop interaction of rules for forwarding, dropping, modifying, and monitoring packets. The rule-table space, in particular, is a scarce commodity on switches. While the rule-tables (e.g., TCAM) are optimized for high-speed arbitrary packet-header matching and widely used for ACL, QoS and forwarding, they have small capacities on the order of a few thousand entries. In this talk, we propose a series of abstractions that enable operators to specify high-level goals without worry about the configurations of underlying switches, and algorithms that realize these abstractions within the constrained rule-table sizes. We first present the "One-Big-Switch" abstraction, which virtualizes the network topology as a single switch and allows operators to specify network policies as if configuring a single switch. The rule placement algorithm is responsible for distributing the rules for this single switch to the underlying physical switches. With this abstraction, we also develop a traffic monitoring system, PacketSeer, which acts as "Wireshark" running on top of the "One-Big-Switch" to aid measurement and troubleshooting. The second abstraction is "One-Big-Server", which consists of a set of equivalent servers offering the same services (e.g., websites). Given the desired distribution of server loads, Niagara algorithms compute forwarding rules on a switch to split incoming traffic accurately. Finally, we propose "Attribute-Carrying IPs". ACIP allows operators to define policies for groups of hosts with the same attributes (e.g., owner role or department). Our ACIP allocation algorithms effectively compact these policies defined on host attributes (e.g., faculty or students, CS or EE) into a small number of switch rules. Together, these abstractions -- coupled with efficient algorithms for realizing the abstractions -- enables flexible enterprise network management on commodity switches.