BU/NSF Workshop on I nternet M easurement I nstrumentation C haracterization Boston University, August 30,

IMIC Workshop: Panel IMIC Workshop: Panel 17:00 PM - 18:20 PM IMIC Challenges, Opportunities & Initiatives Coordinator: Azer Bestavros  Panelists  Sugih Jamin, University of Michigan  Walter Willinger, AT&T Research  Mostafa Ammar, Georgia Tech  Henning Schulzrinne, Columbia University  Karen Sollins, NSF/CISE ANIR Program Director

IMIC Workshop Themes IMIC Challenges  Common pitfalls in IMIC research  Dealing with issues of Internet Scale and Heterogeneity IMIC Opportunities  Uncharted research questions/issues  Inter/Intra-disciplinary collaborations to be fostered IMIC Initiatives  Needed Infrastructure? Funding Initiatives?  What is next? Future IMIC meetings

IMIC Workshop: Panel IMIC Workshop: Panel Recap and Questions Session I: “What is steady-state in the Internet?”  How important are topological measurements (e.g. hop distances)? How correlated are dynamic metrics and Internet topology? What are good metrics (e2e application-oriented vs network-oriented)?  What is the impact of measurement infrastructure on network behavior (e.g. stability)?  Is Network measurement enough? What about server measurement? What are the impacts of server performance over the network (and vice versa)?  Experience from Surveyor suggests that variability can be as high as 5-fold in short periods of time! How susceptible are IDMaps to variability? Could variability be a metric of IDMaps? How do we compose various metrics and measurements (e.g. additive vs min/max)?  What initiatives could facilitate the collection of Internet data and deployment instrumentation infrastructure?

IMIC Workshop: Panel IMIC Workshop: Panel Recap and Questions Session II: “The Good, the Bad, and the Ugly”  Characterization techniques dealing with heterogeneity and large scale. Success stories w.r.t. self-similarity, heavy-tailed distributions, multi-fractals. Spacio-temporal characterization is eminent due to trend in Internet topology characterization.  Modeling: Reduced to a data fitting exercise! No need for new “black boxes”. Cure is in focussing on “invariants” across large data sets. Turn Internet modeling into a physical science.  Performance Evaluation: Abstracting away the interesting. Variability is prevalent. Where is feedback?  Unique Opportunities: High quality measurements; first-rate experimental environment; exciting mathematics that ties measurement to underlying. Need “qualitative insights”!

IMIC Workshop: Panel IMIC Workshop: Panel Recap and Questions Session II: “The Good, the Bad, and the Ugly”  E2E views for getting accurate picture of Internet assuming NO help from the network (Infrastructure, Cross sections & Composition of cross sections).  Lack of correlation forces the use of multicast (vs unicast). Can we infer network characteristics with weaker correlations (than what multicast provides)?  Validation through simulations versus Validation through deployment and measurement. How important is the “controlled environment” requirement? Does a “controlled environment” make sense in the context of the Internet?  Opportunities: relating multicast to unicast; composing views; topology compression; integrating e2e techniques with network support.  Web versus Internet: Adding the “human factor” into an already complex system. Need for more datasets to validate models. Emerging trends at application layer may invalidate state-of-art results/conclusions.

IMIC Workshop: Panel IMIC Workshop: Panel Recap and Questions Session III: “The Application knows better”  The Anycast architecture as an E2E service that enables server performance to be taken into consideration. Interesting questions include effect on stability; positive impact of anycasting clients on non-anycasting clients. Challenges: How do we take the network characteristics into account? How does anycasting scale?  Leveraging network mechanisms to improve E2E performance (e.g. using Enhanced ECN to coordinate multiple streams to same client sharing network bottleneck and using DiffServ to prioritize packets based on context).  Need for parametric E2E transports that allow application to pick-and- choose their QoS along reliability, priority, deadlines, and dependencies (e.g. HPF).  Need to differentiate between policy (algorithmic) and transport protocols.

IMIC Workshop: Panel IMIC Workshop: Panel Recap and Questions Session IV: “The Network World Order”  Need to provide few service classes that match common applications (e.g. multimedia, etc.) What it my application is a “misfit”?  For multimedia traffic TCP friendliness is not good enough; RSVP is too complex, unscalable, and not incremental (as opposed to YESSIR).  Reservation techniques for QoS require resource allocation; SLAs are insufficient. Need mapping of SLAs to traffic provisioning mechanisms.  Network solutions require “economic incentive to throttle”---longer commitment implies expensive price (e.g. RNAP pricing).  Tradeoffs are possible once resource awareness is known---but it need not be hard. Can we capture such awareness in a middleware to make application development a snap :)  Bottlenecks are a moving target (Storage and CPU are moving to clients, B/W bottenecks are not in the backbone).

IMIC Workshop: Panel IMIC Workshop: Panel Issues Teasers:  Is measurement of network performance enough? What is the impact of server performance over the network (and vice versa)?  Validation through simulations versus validation through deployment and measurement. How important is the “controlled environment” requirement? Do network testbeds make sense in the context of IMIC?  What network mechanisms are “right” to support E2E application requirements (e.g. E-ECN, AnyCasting, DiffServ, …)?  Is pricing an option to impose a network world order? How does one reconcile pricing and variability (pricing requires consistency)?  What does it take to get “neat” solutions adopted?

BU/NSF Workshop on I nternet M easurement I nstrumentation C haracterization Boston University, August 30,