On Wed, 2007-06-20 at 11:52 +0200, Matthias Weisser wrote: > Hi > > Today I found some time to do some deeper testing of my lwIP port. I > used wireshark and tested around a bit. > > The first thing I saw that there are TCP retransmissions from time to > time. These retransmissions happens about 5-10ms after the original > packet was transmitted but not for every packet. That seems a little > to early to me.
Were there any ACKs from the other side between the sending of the packet and its retransmission? If so, it could be fast retransmission and not a problem. If not, it does seem a bit early. Perhaps you could send a wireshark/ethereal capture file to illustrate the problem? > Another question is about the TCP window size. Which value makes sense > together with all the other options in the lwipopts.h? Maybe its worth > to write a little bit more about these options and how they depend on > each other. You're right that this the links between many options are not obvious, and it's been a frequently asked question/problem on the mailing list. I agree that more documentation would be good. Any volunteers? There was a useful post on the mailing list a few months ago documenting some "good" settings for everything, but I don't have a link to hand at the moment. As for the window size, apart from making sure it's at least twice the MSS, and that you have sufficient buffer space to accept a window worth of data in one go, there's not a lot more to it. Of course, bigger is better in terms of performance, but will require more memory for buffers. > Another point is about mailboxes. I implemented them as FIFOs but how > deep should this FIFOs be? I use 32 entries now but is this enough? Not sure. Kieran _______________________________________________ lwip-users mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/lwip-users
