Transcript Pchar: Child of pathchar

pchar: Child of pathchar
(from notes on presentation
by Bruce Mah)
Alan Verlo, EVL
pathchar
• Developed by Van Jacobsen, LBL (1997)
• Determine per-hop network path characteristics:
– Bandwidth, propagation delay, queue time, drop rate
– Sends series of packets with random payload sizes over time to
each hop in a path to determine bandwidth
• Attempts to assess real-world network conditions
• Alpha version (1997) is most current release
• Slides of algorithms used:
ftp.ee.lbl.gov/pathchar/msri-talk.tar.gz
pchar
• Developed by Bruce Mah (Sandia, CA)
<[email protected]>
• Independent implementation
• Varies IP ttl to control how far into network the
packets go, gives links traversed
• Vary packet sizes (bandwidth & latency)
• Many repetitions (loss & queuing)
– 32 packets for each packet size, about 40 sizes
– 1400 packets total for each hop
pchar
• Minimums of each packet size for each hop may
give characteristics of each hop w/o queuing delay
• Space between min and max curves may show
characteristics between hops
pchar
• To get:
www.ca.sandia.gov/~bmah/Software/pchar
• FreeBSD, Solaris, Linux, Irix