Matt Mathis

Email: mathis@psc.edu
Work phone: 412.268.3319
or other contact information.

Point of view: The glass is neither half full nor half empty, it is the wrong size.

For very quick conversations, MathisTCP (on AIM), mathis_15206 (YIM) or mathis@psc.edu (jabber) might be best, but please introduce yourself.

I am dedicated to the idea that an ordinary user running an ordinary network application on an ordinary workstation should either saturate some workstation bottleneck or completely fill some network link.

Research Projects

NPAD Network Path and Application Diagnosis is focused on developing diagnostics that mitigate the effects of "symptom scaling". The "end-to-end network performance debugging" problem is difficult because the only symptom of nearly all flaws is reduced performance. Furthermore that one symptom is scaled by RTT, such that conventional diagnostics typically yield false pass results for local tests. Under the NPAD project we assembled tools and resources to enable people to quickly diagnose and correct the majority flaws that affect users connected to high speed networks. [NOT CURRENTLY FUNDED]

A white paper on our approach to the symptom scaling problem.
Tutorial and recipes for manually tuning older TCP implementations.
A one-click automatic NPAD/pathdiag diagnostic service for last mile and system problems.
Resources for checking for application bottlenecks.

Web100 is focused on providing sufficient instrumentation within TCP (e.g. a MIB) to support the broad diagnosis of all parts of the application and network. At the minimum it can provide basic information about application performance (does TCP stall waiting for the app?), and detailed information about TCP itself (e.g. buffer utilization) and the network (e.g. RTT, reorder and loss statistics). The final MIB, RFC 4898, is now on the standards track. Furthermore some end-system bottlenecks (e.g. buffer space) can be autotuned [Semke] as a side effect of the improved instrumentation. Web100 autotuning is in Linux and a similar algorithm is present in VISTA. [DONE]

Net100 is focused on applying Web100 to DoE applications. While Web100 must take a purest stance on appropriate TCP enhancements, Net100 can afford to embrace a number of workarounds.[DONE]

MTU is the next biggest bottleneck.

My current and past papers and presentations are archived here.

Other research interests, parallel projects and collaborations

Networking research at PSC.
VH (Visual Human) is an NIH application that requires high performance interactive network services.
NLANR -- a National Laboratory for Applied Network Research
I founded and chaired the IP Provider Metrics WG under the IETF until about 1996.

How Fast is Fast?

This chart shows the transfer time vs file data size for various data rates. For example at 100 megabits/second (which I consider to be the "baseline" for high speed transfers) it takes slightly less than 2 minutes to transfer a gigabyte and about a day to transfer a terabyte. At 10 gigabits/s, which is now the standard for Internet "trunks", it takes about 1 second for a gigabyte and about 20 minutes for a terabyte. At 1 megabit/s, which is close to DSL or cable rates, it takes several hours for a gigabyte and several months for a terabyte.

Other Interests

I am in the process of moving my personel pages elsewhere. My family is more than slightly complicated. My daughter Emma has made us all very proud

I am President of the East Suburban Unitarian Universalist Church (ESUUC), in Murrysville PA (a suburb of Pittsburgh, adjacent to Monroeville and Plum).

I am the treasurer of CDN/CDSS which runs weekly contra dances in Pittsburgh.

Evil is defined by mortals who think they know "The Truth" and use force to apply it to others.
-me.

This page is http://www.psc.edu/~mathis/index.html.

For additional information check out these pages: Pittsburgh Supercomputing Center, Network research at PSC, or Matt Mathis. Please send comments and suggestions to mathis@psc.edu.