Rupa Krishnan

Rupa Krishnan

Research Areas

Authored Publications
Google Publications
Other Publications
Sort By
  • Title
  • Title, descending
  • Year
  • Year, descending
    Moving Beyond End-to-End Path Information to Optimize CDN Performance
    Harsha V. Madhyastha
    Sushant Jain
    Arvind Krishnamurthy
    Thomas Anderson
    Jie Gao
    Internet Measurement Conference (IMC), ACM, Chicago, IL(2009), pp. 190-201
    Preview abstract Replicating content across a geographically distributed set of servers and redirecting clients to the closest server in terms of latency has emerged as a common paradigm for improving client performance. In this paper, we analyze latencies measured from servers in Google’s content distribution network (CDN) to clients all across the Internet to study the effectiveness of latency-based server selection. Our main result is that redirecting every client to the server with least latency does not suffice to optimize client latencies. First, even though most clients are served by a geographically nearby CDN node, a sizeable fraction of clients experience latencies several tens of milliseconds higher than other clients in the same region. Second, we find that queueing delays often override the benefits of a client interacting with a nearby server. To help the administrators of Google’s CDN cope with these problems, we have built a system called WhyHigh. First, WhyHigh measures client latencies across all nodes in the CDN and correlates measurements to identify the prefixes affected by inflated latencies. Second, since clients in several thousand prefixes have poor latencies, WhyHigh prioritizes problems based on the impact that solving them would have, e.g., by identifying either an AS path common to several inflated prefixes or a CDN node where path inflation is widespread. Finally, WhyHigh diagnoses the causes for inflated latencies using active measurements such as traceroutes and pings, in combination with datasets such as BGP paths and flow records. Typical causes discovered include lack of peering, routing misconfigurations, and side-effects of traffic engineering. We have used WhyHigh to diagnose several instances of inflated latencies, and our efforts over the course of a year have significantly helped improve the performance offered to clients by Google’s CDN. An anonymized data set is available for download. View details
    Globally Fair Resource Allocation for Wireless Mesh Networks
    Ashish Raniwala
    Pradipta De
    Srikant Sharma
    Tzi-cker Chiueh
    17th Intl Symposium on Modelling, Analysis and Simulation of Computer and Telecommunication Systems (MASCOTS)(2009)
    An Empirical Comparison of Throughput-Maximizing Wireless Mesh Routing Protocols
    Ashish Raniwala
    Tzi-cker Chiueh
    Fourth Intl Wireless Internet Conference (WICON)(2008)
    Design of a Channel Characteristics-Aware Routing Protocol
    Ashish Raniwala
    Tzi-cker Chiueh
    IEEE Infocom Mini-Symposium on QoS and Performance Evaluation(2008)
    Evaluation of a Stateful Transport Protocol for Multi-channel Wireless Mesh Networks
    Ashish Raniwala
    Srikant Sharma
    Pradipta De
    Tzi-cker Chiueh
    International Workshop on Quality of Service (IWQoS),(2007)
    End-to-End Flow Fairness over IEEE 802.11-based Wireless Mesh Networks
    Ashish Raniwala
    Pradipta De
    Srikant Sharma
    Tzi-cker Chiueh
    IEEE Infocom Mini-Symposium on 802.11 Wireless LANs(2007)
    MiNT-m: an autonomous mobile wireless experimentation platform
    Pradipta De
    Ashish Raniwala
    Krishna Tatavarthi
    Jatan Modi
    Nadeem Ahmed Syed
    Srikant Sharma
    Tzi-cker Chiueh
    USENIX MobiSys(2006), pp. 124-137