Date: Sun, 20 Jan 2013 20:12:09 -0600 From: Adam Vande More <amvandemore@gmail.com> To: Karthik Reddy <22karthikreddy@gmail.com> Cc: freebsd-questions@freebsd.org Subject: Re: What is the timeout of TCP in freeBSD? Message-ID: <CA%2BtpaK3mP06wt=3G5GYN8EV1pvYsn2Eq070Fuo-eHq_4UJExjw@mail.gmail.com> In-Reply-To: <CALK7g0h82SJSObmVo08z6=UAgB-ykc3QS4ApCAnkcvxbCdy5UA@mail.gmail.com> References: <CALK7g0h82SJSObmVo08z6=UAgB-ykc3QS4ApCAnkcvxbCdy5UA@mail.gmail.com>
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On Sun, Jan 20, 2013 at 8:50 AM, Karthik Reddy <22karthikreddy@gmail.com>wrote: > I was doing a experiment on FreeBSD for testing TCP timeout and RTO. OS is > being run from two different VMware versions 4.0 and 5.0. > > Present Scenario: VMware Player 4.0 > I'll start a telnet session to a non-existing system in the network. When I > look at the tcpdump the RTO starts at every 3 seconds and after some > exponential backoff starts. In this scenario after 75 seconds the TCP gives > up and tells me that there is no system existing with the IP and telnet > session terminates. > > Next Scenario: VMware Player 5.0 > In this scenario, I did the same but the RTO starts at 5 sec and then > varies. In this scenario, it takes more than 120 seconds for telnet session > to tell me that there is no system is available in the network. > > I have seen sysctl in both VM's. net.inet.tcp.keepinit = 75000 > > Is this problem something related to timing of the VM's or any other issue? > What's the wallclock delta during such a test? Have you tried setting 'kern.hz="50"' or fiddling other TC options? UP VM's tend to keep time better than other multicore configs. -- Adam Vande More
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