Support for high performance UDP/TCP applications Xing Li 2007-08-25
Background More and more demonstration and trials on high-performance applications Application-specific stream or data Consume large network bandwidth Heavily rely on network support What can NOC do to support for it? If there is a lambda path lucky! RTT is still an issue Otherwise Measurement and monitoring Network performance measurement tool Application-specific measurement tools End to end performance guarantee Inter-AS routing adjustment Agreement on enabling application-related ACLs
Where are the bottlenecks? AS2 AS3 AS1 access Bad cabling Wrong speed Wrong duplex mode firewall Bandwidth bottleneck Host parameters
Possible Paths
Case study In KR It is not via the CERNET – KR path It is not via the CERNET– APAN – KR path It is not via the CERNET – TEIN2 – KR path It is not via the CERNET – TEIN2 – JP – KR path It is via the CERNET – APAN – Abilene – KR path And the return path may be totally different
The Ideas Use measurement tools to Help users to do self-service Separate the network problems from the end system problems Find the network segments which cause the problem
SASM Framework
The operation modes of basic tools
Server discovery and registration
From Arlington to TEIN2 Beijing server using WALN Not good using RJ45 Good
TCP transfer speed Formula Theory SUN §WINDOWS
The TCP measurement Tool
The testing steps Default test Window size test Parallel session test The default TCP transfer speed for the e2e peer Window size test Check the client window Parallel session test Check the server window Physical speed limit Comparison with ping and UDP (dvping) tests Check packet loss (ping and dvping) Check RTT (ping and dvping) Check throughput (dvping)
Comparison with UDP (dvping) Compare with UDP (dvping) Check RTT, packet loss and the physical speed limit
Summary of the TEIN2 NOC measurement servers clinet ICMP U/UDP M/UDP U/TCP ping ssmping dvping iperf –c smjoin iperf –s smclock dvmcast ssmpingd Socket stack U – Unicast M - Multicast
TEIN2 Measurement Server Locations 202.179.252.102 202.179.244.105 202.179.242.102 202.112.35.200 CERNET TEIN2
SASM Framework
A Document http://noc.tein2.net:8036/support-for-hp/hp-mc-20070507.html Login: tein2 passwd: tein2
eVLBI example
Summary Application specific tools Distributed servers alone the path dvping (UDP) iperf (TCP/UDP) Distributed servers alone the path Scalable Application Specific Measurement (SASM) Open traffic monitoring SNMP Netflow Applications TCP vs. UDP International collaboration