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- See Towards Analysis of ICMP vs TCP Ping Latencies
IPv6 results gathered using ping-vs-tcp.pl script. They are yet to be analyzed
Tests complete in less than a day; not many IPv6 addresses
About 56 nodes with IPv6 addresses, 14 of which responded with Npings
- We essentially have a 14-point data set
- IPv4 results gathered from SLAC. (Repeating Virginia Tech experiments.)
- Complete batch may be downloaded here (approx. 24 MB)
- Skimmed results; findings are pretty much the same as before
- Identified relevant events in the network stack that highlight timing (_RECVFROM, _RECVMSG, _IP_RECV, _NETIF_RX etc.). Looking for instrumentation that enables us to measure timestamps. We also need to figure out how to determine whether ICMP & TCP traffic are treated differently? and then how to measure the difference?
- perf-tools allows us to measure transport events
- If we could assume that the path for ICMP & TCP through the network is the same, then the only difference between two (controlled) tests would be the time spent in the transport layers. This can be measured using perftools.
- However, such measurements must be made in a controlled environment where ICMP and TCP are treated the same. (I say so because some results — e.g., in East Asia and South Asia — clearly show that ICMP performs much worse than TCP.)
- We would also need to cater for cross traffic and queuing delays. Given how small the differences are, one may argue that the variations in measurements are due to cross traffic. Perhaps we should start with controlled tests and then see if real world measurements reflect similar behavior.
- We need to setup a test environment. We can either setup a bare-metal box or use a VM.
- I will see if I can arrange for a bare-metal box.
- Want MAs at:Want MAs at:Umar is concentrating on understanding why there are some significant differences. He will look at the impact of the stacks (by setting up a control environment wit the latest Linux tools, and see if the difference in the stack traversals times is significant when compared to the overall RTT differences. He is also thinking of seeing if there are common elements (e.g. hops) that can be tied to significant differences in RTT time.
- SLAC and Virginia tech (Les, Umar) measurements for ping vs nping completed,
- China (Saqib has agreed to join in),
- Thailand (Charnsak has agreed to join in),
- If others wish to join the paper (i.e. make the measurements - takes just over a week elapsed time, help analyze the data and put together the paper), we need to know soon.
- Pakistan (Wajahat)?
- Malaysia-Sarawak (Johari)?
- Malaysia mainland (Adib)?
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