Internet Connectivity and Performance for the HEP Community. Presented at HEPNT-HEPiX, October 6, 1999 by Warren Matthews Funded by DOE/MICS Internet End-to-end Performance Monitoring (IEPM).

Goal. Why is our project important ? –Why am I here ? What do our studies mean to you ? –How does it affect HEP research ?

Overview. Brief review of the monitoring project. Performance measured by PingER. –Trends between Geographical regions. –A closer look at some “events”.

The Need for Monitoring Computing models for BaBar, RHIC, LHC have ambitious networking requirements. –Exabytes or petabytes of data –analyzed at collaborating Institutes Can the Internet perform ? –Data transfer –Analysis applications Where to allocate resources to make it better.

Effect on Applications –largely unaffected by poor performance File Transfer Web (HTML) telnet/SSH Video/Voice Conferencing –Even moderate losses can make it unusable More Interactive and More Sensitive to Problems

The PingER Project End-to-end –computers, routers, exchange points –utilization, routing Ping –ICMP echo request and reply –11x100 Byte Pings, 10x1000 Byte Pings

PingER Deployment 23 Monitoring Sites in 13 Countries. 536 Nodes at 381 sites in 55 Countries pairs. 53 Beacon Sites.

PingER Metrics Packet Loss –Queue is full Round Trip Time –Path Length –Speed of Link –Congestion / Delay at Router

PingER and Application Performance Same path Transit packets are treated the same by routers –Problems arise if protocols are treated differently Studies of HTTP show strong correlation Better than application performance –Loss and Response –Routes T TCP < (MSS / RTT TCP ) * (1 / sqrt(p))

Interconnected Networks Many of the DOE- Funded Labs are connected to the Energy Sciences Network (ESnet). Many other networks in the U.S. –vBNS, Abilene I2, THEnet European National Research Networks –GARR, JAnet, Renater, TEN-155

Performance on ESnet Utilization is currently low –SLAC upgrade due to anticipated demands of BaBar. Packet Loss is negligible. –Typically <0.1% Round Trip Times are good. –Dominated by path length –probably the most direct route As good as it gets.

Probably heavy traffic caused queuing.

Bulk transfer - Performance Trends Bandwidth TCP < 1460/(RTT * sqrt(loss))

Performance Between Networks Utilization on vBNS and Abilene is low –Packet Loss is low Utilization at Exchange points is also low. –ESnet Abilene, vBNS –Not the commercial Internet No longer one NOC –Routing Policies

CSU change routing to send SLAC packets via Sacramento.

Transatlantic Performance Traditional, and well-known, bottleneck. Packet Loss can be high. Large RTT is unavoidable.

Improving Performance Managed Bandwidth Quality of Service

December

Ten-155 became operational on December 11. murf Filters Smurf Filters installed on NORDUnet’s US connection. To North America To Western Europe

Regional Performance Performance within a NRN is usually good. –Packet Loss in Italy (GARR) is Good –Packet Loss in U.K. (JAnet) is Good/Acceptable Compare to U.S. –No exchange point between Laboratories and Universities. –But possibly debate on allocation of resources.

General Summary. Between Labs, –Good/Acceptable. University + Overseas Lab, –Very Variable (particularly U.S. Universities not on ESnet or vBNS). –Many Connections perform at less than good level, particularly “remote regions”. Between Universities, –Very Variable.

Recommendations (Observations) Connect to a Research Network. Bandwidth with low average utilization. Reserved Bandwidth and QoS.

Further Information CHEP’98, TechPub 8178, IEEE Any Questions ?