Introduction
LineA is a Brazilian National laboratory in Rio de Janiero. It was created to support the Brazilian participation in scientific experiments using data from large astronomical surveys - the Dark Energy Survey projects and Sloan Digital Sky Survey III. There is a requirement to download 2 Tbytes/year until 2017 from SLAC to LineA. This is ~ 500kbits/sec averaged over a year. The physicist customer at SLAC appears to be Wechsler, Risa H. <risa@slac.stanford.edu.
At first glimpse the throughput required to SLAC seems pretty minimal. However from our monitoring of the connection from SLAC to LineA the performance does not look good. There is a lot of congestion at times as exhibited by massively elongated RTTs (factor of two going from 200ms to 400ms).
Assuming they are using TCP (Reno) with no large windows then with 400ms RTT throughput is limited to 1.3MBits/sec. Also the link from SLAC to LIneA (see below) is sometimes experiencing losses of over 5% (yellow background, black means no connectivity) which can dramatically degrade performance, e.g. at 5% the max throughput is about 76kbits/sec (see http://wand.net.nz/~perry/max_download.php).
Thus if the dedicated circuit can be provisioned to not get congested then the RTT will stay close to ~ 200msec so increasing throughput by a factor of 2. You can further improve by opening up your Unix TCP windows (see http://en.wikipedia.org/wiki/TCP_tuning) assuming you have not already done this. I would hope also that the dedicated circuit would not experience the large losses. Thus a dedicated may make sense in this case.
Possible solution
The current plan is to leverage OSCARS to create an end-to-end layer 2 (ethernet VLAN) service between LIneA and FNAL/SLAC. We will need
to coordinate VLAN IDs for these circuits, but more importantly, you guys will have to coordinate the last mile connectivity (i.e. routing) between the site/ESnet DMZ and the host.
Host
NODENAME: ms01.linea.gov.br
IPADDRESS: 186.232.60.129
SITENAME: linea.gov.br
NICKNAME: BR.LINEA.GOV.N3
FULLNAME: Laboratorio Interinstitucional de e-Astronomia
LOCATION: Rua General Jose Cristino, 77 St. Kitts, Rio de Janeiro, RJ
COUNTRY: Brazil
CONTINENT: Latin America
LATANDLONG: -22.9035 -43.2096
PROJECTTYPE: NOT-SET
PINGSERVER: NOT-SET
TRACESERVER: NOT-SET
DATASERVER: NOT-SET
URL: http://www.linea.gov.br
CONTACTS: Ciuffo
COMMENTS: Dark matter Search collaborator, add by Cottrell 6/19/2012.
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