2016年1月20日 · Basically need something like tcpprob (kprobe) to insert a hook and record the estimated RTT of the TCP connection on every incoming packet (or on every change). UPDATE: I found a solution. rtt, congestion window and more can be logged using tcpprobe. I …

2012年11月20日 · If you want to get the values of the RTT calculated by wireshark/tshark, the following did the trick for me to print them on stdout: tshark -r myfile.pcap -Y 'ip.addr == AA.BB.CC.DD' -T fields -e tcp.analysis.ack_rtt (where I used the display filter after -Y to restrict the analysis to only one remote host)

2013年6月7日 · When you graph RTT in an IO graph, latency times are depicted between a data packet and the subsequent acknowledgment packet. You can always do your own handshake analysis and filter on {tcp.flags.syn==1} to find the start of the conversation and then set time deltas to calculate individual session RTTs.

2012年10月18日 · Yes there is. After a certain number of retries, the host is considered to be "down" and the sender gives up and tears down the TCP connection. Is there functionality for the client to indicate to the server to forget about the whole TCP segment for which part went missing when the IP packet went missing? The whole point is reliable communication.

2011年9月26日 · This means that the RTT calculation will depend on where you are capturing the trace For example, if you are capturing packets on node A, you will see A's ACK almost immediately after you see the corresponding segment arriving from node B and thus see a very low value for RTT in the B->A segments.

2013年1月30日 · I am trying to getr the rtt value being used by the linux kernel. There I see two variable which are giving the rtt values: srtt -- (smoothed RTT) rcv_rtt_est, which is actually the Receiver side RTT estimation. Now, I actually dont see the units of these variable output.

2012年11月28日 · [mpenning@Bucksnort tcpperf]$ tcptrace -xtraffic willers.pcap mod_traffic: characterizing traffic 1 arg remaining, starting with 'willers.pcap' Ostermann's tcptrace -- version 6.6.1 -- Wed Nov 19, 2003 16522 packets seen, 16522 TCP packets traced elapsed wallclock time: 0:00:00.200709, 82318 pkts/sec analyzed trace file elapsed time: 0:03:21 ...

2021年12月20日 · With this, I am also trying to calculate application RTT, which is to identify HTTP req/res round trip time over the same TCP connection and the values I am able to calculate in microseconds are, 1811 869 1356 965 984 2312 841 822 680 1140 3140 789 859 844 1575 1883 964 2107 890 1034 856 1337 1182 969 855 821 1583 907 1427 705 813 1318 681 1181 ...

2014年3月3日 · i have a simple question here, how to calculate the round-trip time in a tcp connection. I got the communication packets using tcpdump. In tcp packet, there are timestamp options, including TSval & TSecr. RFC 1323 says it can be used to calculate RTT. However, it didn't say how, or I didn't find it. Anyway, I am confused about this.

2013年4月26日 · You can so this using tcpprobe (inserts a hook into the tcp_recv processing path using kprobe and records the state of a TCP connection in response to incoming packets). Explained here: Extract TCP round trip time (RTT) estimations on linux