Re: [lwip-users] TCP Buffer Size Increment

[Gaurav Jain]

Simon,
TCP has a mechanism to increase the buffer after every successful
transaction. So after receiving how does it increase it to 1460 bytes(
the upper limit)?

On Wed, Feb 3, 2016 at 11:38 AM, Simon Goldschmidt <address@hidden> wrote:
>
> Gaurav Jain wrote:
>> I have implemented a TCP server [..]
>> I have set the buffer limit size at the client to 512 bytes. However,
>> what I am observing is that the first packet the server receives is
>> 512 bytes, but there onwards the packet size is randomly changing and
>> most of the times being 1460 bytes.
>
> Since TCP is a streaming protocol, you can never ensure the remote side
> sends 512 byte segments. You need to handle the data as it comes in
> instead or use UDP, where you can control the datagram size.
>
> One thing you could do is put an upper limit to the segment size by
> changing TCP_MSS. However, 536 is the lower limit for this, so when setting
> it to 512, the remote side is still allowed to send 536 bytes. Plus it
> is allowed to send less...
>
>
> Simon
>
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