Re: TCP window size issues

2003-10-18 Thread Carl Mascott
Ahhh, that may explain why, during FTP receive of a large file over a 5 KB/s link with a 56 KB recv window, I get one or two dropped packets at the same point every time, and then no further dropped packets for the rest of the transfer. Barney Wolff wrote: > On Fri, Oct 17, 2003 at 08:16:32PM -040

Re: TCP window size issues

2003-10-18 Thread Carl Mascott
> Andre Oppermann wrote: > Carl Mascott wrote: > > > > Here's a case that your logic does not handle correctly. > > > > 1. Kernel default buffer size = 32 KB > > > > 2. Routing table buffer size = 48 KB > > > > 3. Application sets buffer size to 32 KB > > > > 4. tcp_mss() selects 48 KB buffer

Re: TCP window size issues

2003-10-18 Thread Carl Mascott
te is established, as long as the kernel default recv window size is > 4096 (slight simplification here). Lev Walkin wrote: > Carl Mascott wrote: > > I have a few TCP window size issues. > [skip] > > 3. RFC 793 (TCP) says that shrinking the receive window after > >connec

Re: TCP window size issues

2003-10-17 Thread Barney Wolff
On Fri, Oct 17, 2003 at 08:16:32PM -0400, Carl Mascott wrote: > > NOTE: AFAIK, 4.4BSD through FreeBSD 4.6-R seem to have done > alright without the PR 11966 patch, but if someone knows > different, please speak up. I'm not really surprised. I would have thought that a well-behaved sender would b

Re: TCP window size issues

2003-10-17 Thread Andre Oppermann
Carl Mascott wrote: > > Here's a case that your logic does not handle correctly. > > 1. Kernel default buffer size = 32 KB > > 2. Routing table buffer size = 48 KB > > 3. Application sets buffer size to 32 KB > > 4. tcp_mss() selects 48 KB buffer size, giving the routing >table precedence

Re: TCP window size issues

2003-10-17 Thread Carl Mascott
Here's a case that your logic does not handle correctly. 1. Kernel default buffer size = 32 KB 2. Routing table buffer size = 48 KB 3. Application sets buffer size to 32 KB 4. tcp_mss() selects 48 KB buffer size, giving the routing table precedence over the application. I found it necessary

Re: TCP window size issues

2003-10-17 Thread Lev Walkin
Carl Mascott wrote: I have a few TCP window size issues. [skip] 3. RFC 793 (TCP) says that shrinking the receive window after connection is established is "strongly discouraged". I'm currently shrinking the receive window on my default route (PPP link) from 32 KB to 4 KB w

Re: TCP window size issues

2003-10-17 Thread Andre Oppermann
Andre Oppermann wrote: > > Carl Mascott wrote: > > > > Actually I have just fixed it in my copy of 4.8-R. I have a document > > that describes the problem and my solution. I could send you that > > and/or a set of patches. You might want to sketch out your own > > solution before you look at mi

Re: TCP window size issues

2003-10-17 Thread Andre Oppermann
Carl Mascott wrote: > > Actually I have just fixed it in my copy of 4.8-R. I have a document > that describes the problem and my solution. I could send you that > and/or a set of patches. You might want to sketch out your own > solution before you look at mine, though. Also, I'm not done > tes

Re: TCP window size issues

2003-10-17 Thread Carl Mascott
Actually I have just fixed it in my copy of 4.8-R. I have a document that describes the problem and my solution. I could send you that and/or a set of patches. You might want to sketch out your own solution before you look at mine, though. Also, I'm not done testing mine yet. > Carl Mascott wr

Re: TCP window size issues

2003-10-17 Thread Andre Oppermann
Carl Mascott wrote: > > I have a few TCP window size issues. > > 1. In FreeBSD 4.8-R the kernel default recv window is 56 KB. This >is so large that it causes dropped packets due to queue overflow >with my V.90 link (BW 5 KB/s on compressed data). > > 2. The 4

TCP window size issues

2003-10-17 Thread Carl Mascott
I have a few TCP window size issues. 1. In FreeBSD 4.8-R the kernel default recv window is 56 KB. This is so large that it causes dropped packets due to queue overflow with my V.90 link (BW 5 KB/s on compressed data). 2. The 4.4BSD TCP implementation has never had the correct precedence