Ross Teixeira will present his MSE thesis talk “SwitchScope: A View from the Inside” on Wednesday, May 8th, 2019 at 3pm in CS 402. The members of his committee are Jennifer Rexford (adviser) and David Walker. Everyone is invited to attend his talk. His abstract follows below. Title: “SwitchScope: A View from the Inside” Abstract: Running a modern network requires constant diligence to maintain efficiency and reliability for customers. This is made challenging by the fact that the life of a packet inside each switch is complex, and yet currently quite hard to observe and debug. Packets entering a switch may be dropped (by access control policy or a full queue), or delayed (by a long queue) or modified (by policy) before heading to the next hop. Prior telemetry systems allow network operators to analyze flows that a switch sees, but they do not grapple with the internals of the switch’s multiple pipelines. In this talk, I will discuss our contributions towards SwitchScope, a flexible telemetry system that utilizes programmable (PISA) switches, and which allows debugging switch configurations and determining the source of bottlenecks or lost packets. I will detail our work on an expressive query language that provides network operators insight into the life of packets in a switch, as well as our compilation strategies to support useful queries about lost packets while minimizing the use of switch resources.