[openssl-users] OpenSSL Behaviour under low bandwidth

Kurt Roeckx kurt at roeckx.be
Fri May 15 20:21:41 UTC 2015

On Fri, May 15, 2015 at 12:44:03PM +0100, Martin Beynon wrote:
> That is right from 100Mbps down to 150 kpbs everything works as expected.
> As I continue tuning down the bandwidth below 150kbps openssl starts to
> stop sending data. It becomes very bursty and there are whole periods of
> seconds where no data is sent from openssl even though it's 17KB TLS buffer
> is full and pings, for example, can be sent and received normally.
> There appears to be some relation to the size of this buffer and the
> minimum achievable throughput we can get.. Unless my maths is off; 140 Kbps
> would give about 17KB/s throughput.. Coincidence?

Do you send packets to OpenSSL in blocks of 17 KB?  Is that
blocking or non-blocking?


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