Thank you very much, Jifl. The links is reliable using network switch. I can transfer data the whole day without data loss. Ethernet driver is set to Multicast Reception mode.
When tcp_sndbuf become lowering, the data are not going out anymore. It might be retries like you said. Is there any advise how would I debug those retries? Regards, On Mon, Nov 3, 2008 at 4:42 PM, Jonathan Larmour <[EMAIL PROTECTED]>wrote: > bandu wrote: > > Hi, > > > > I'm a bit new to lwip. > > > > When I transfer data both side with network switch, it work fine. > > > > When I'm using hub, I can see avialable tcp_sndbuf going down to zero and > > never coming back up to TCP_SND_BUF size. > > > > I'm checking tcp_sndbuf before tcp_write and I called tcp_output() > > > > When both TX and RX, I can see it happened more quickly than RX only. > > > > What would cause that tcp_sndbuf draining? i'm using lwip 1.3.0. > > Using a hub will make no difference to lwIP itself. If there's any problem, > it's at a lower layer. Are you sure the link is actually reliable? Are > packets getting through? Are there retries? That's the most likely reason > the send buffer is getting smaller. > > The only way a hub might affect what lwip sees at all is if your low-level > ethernet driver is setting the ethernet MAC to promiscuous mode. It > shouldn't be. Although even then, lwIP should happily be dropping the > packets - I wouldn't expect it to cause the problem you see. If your driver > was using promiscuous mode, all I would expect is that your software has to > do more processing before discarding the packet. > > Jifl > -- > eCosCentric Limited > http://www.eCosCentric.com/<http://www.ecoscentric.com/> The eCos experts > Barnwell House, Barnwell Drive, Cambridge, UK. Tel: +44 1223 245571 > Registered in England and Wales: Reg No 4422071. > ------["Si fractum non sit, noli id reficere"]------ Opinions==mine > > > _______________________________________________ > lwip-users mailing list > [email protected] > http://lists.nongnu.org/mailman/listinfo/lwip-users > -- Bandu [EMAIL PROTECTED]
_______________________________________________ lwip-users mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/lwip-users
