Tuesday, August 13, 2013

SIGCOMM2013: B4 Experience with a Globally-Deployed Software Defined WAN

This is a report of the presentation done by Amin Vahdat  on 2013-08-13. Paper co-authors are Sushant Jain, Alok Kumar, Subhasree Mandal, Joon Ong, Leon Poutievski, Arjun Singh, Subbaiah Venkata, Jim Wanderer, Junlan Zhou, Min Zhu, Jonathan Zolla, Urs H√∂lzle, and Stephen Stuart(Google).

Wide Area Networks (WANs) that connects data centres are critical to Internet performance and expensive resource. Amin started his presentation with a few questions: Why adopt a new WAN architecture?  How can we build a network that built from merchant silicon, run network links at ~ 100% utilization, and differentiate between hi/low priority traffic?

In his talk, Amin presented his team experience in design, implementation, and evaluation of B4. B4 is a private Wide Area Network (WAN) connecting Google’s data centres across the planet. Amin described the special characteristics of Google’s data centres WAN that led to adopt Software Defined Network (SDN) architecture and OpenFlow to control individual switches. In particular, he discussed how they support standard routing protocols and centralized Traffic Engineering at their first SDN application. Regard the performance, Amin showed that B4 links run at near 100% utilization.
Also B4 performance has exceed their expectations but it has one outage that highlighted a number of important areas for SDN and WAN deployment future works:
  • Scalability and latency of the packet IO path between OFC and OFA is crucial and important for evolving OpenFlow
  • OFA should be asynchronous and multithreaded for more parallelism. 
  • Additional performance profiling and reporting
  • TE server must be adaptive to failure OFC when modifying TG that depends on creating new tunnels.
  • Measuring system performance to its breaking point with published envelopes regarding system scale.

Here is the full paper: http://conferences.sigcomm.org/sigcomm/2013/papers/sigcomm/p3.pdf