Support for high performance UDP/TCP applications Xing Li 2007-08-25.
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Transcript of Support for high performance UDP/TCP applications Xing Li 2007-08-25.
Support for high performance UDP/TCP applications
Xing Li2007-08-25
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 AS2 AS3 AS3
AS1 AS1
access access
Bad cablingWrong speed
Wrong duplex mode
Bad cablingWrong speed
Wrong duplex mode
firewall firewallBandwidth bottleneck
Host parameter
s
Host parameter
s
Possible Paths
Case study
In KRIt is not via the CERNET – KR pathIt is not via the CERNET– APAN – KR pathIt is not via the CERNET – TEIN2 – KR pathIt is not via the CERNET – TEIN2 – JP – KR pathIt 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
max__ _
_ _throughput
receive window size
round trip time
max_,
.. / secthroughput bytes
65 535
056117 027
max_,
.. / secthroughput bytes
24 567
05643886
Formula
SUN §WINDOWS
Theory
The TCP measurement Tool
The testing steps
• Default 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
server clinet
ICMP
ICMP
U/UDP
U/UDPM/UDP
U/UDP
U/UDP
U/TCP
U/TCP
U/UDP
ping
ssmping
dvping
iperf –c
smjoin
iperf –s
smclock
dvmcast
ssmpingd
Socket stack
U – UnicastM - Multicast
202.179.252.102
202.179.244.105
202.179.242.102
202.112.35.200
CERNET
TEIN2
TEIN2 Measurement Server Locations
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– 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