[lwip-users] Re: [lwip] MSS and config generally

[Kieran Mansley]

On 6 Jun 2002, Dirk Koopman wrote:

> Can you get me some pointers as to how to alter the MSS segment size
> successfully?
>
> I have recently ported lwip to an embedded platform and am having the
> following two symptoms:-
>
> 1. I have an *incoming* segment size of 128, ie I connect to an external
> site using TCP (native interface) and get back data in 128 byte gobs,
> one per datagram.
>
> 2. It is EXCEEDING slow, this may well be a timing error of some kind on
> my (ie even though I think I am; I am not calling the timer routines as
> often as I think I am).
>
> Does this sound familiar to anyone and what are the issues (and
> parameter settings) in lwipopt.h to get larger MSS sizes (or to switch
> it off).

Alter TCP_MSS (in lwipopts.h) to your requirements?

Also, make sure that the config options related to this are set to
sensible amounts.  Your poor performance could be due to insufficiently
sized TCP_SND_BUF, TCP_SND_QUEUELEN or TCP_WND

Kieran

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