Path: utzoo!utgpu!watserv1!watmath!att!linac!pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!uupsi!sunic!fuug!tuura!jel From: jel@tuura.UUCP (Jerry Lahti) Newsgroups: comp.protocols.tcp-ip Subject: Re: SCO <-> Sun == molasses Message-ID: <1000@tuura.UUCP> Date: 8 Feb 91 12:27:32 GMT References: Organization: Nokia Data Systems Oy Lines: 28 jsparkes@bwdls49.bnr.ca (Jeff Sparkes) writes: > I've set up a PC running SCO Unix 3.2.1. It mostly runs fine, but >FTP and NFS traffic between it and a SparcStation 1+ running SunOS 4.1.1 is >um, pathetic. FTP transfers of 0.5 K/s. NFS reads that (almost) never >complete. > I suspect the window size negotiation breaks down, since telnet >works fine. Anybody know any workarounds/bugfixes? >-- I have had similar problems and there is a workaround. In my case the problem was that the default SCO TCP window and NFS request size are 4 KB. Unfortunately when the SparcStation behaves accordingly and pumps out three or four Ethernet frames in rapid succession the poor PC Ethernet adapter can not keep up and drops all but the first frame. The workaround with TCP is to give the -onepacket flag to ifconfig (see manual for details). With NFS you have to give mount options which make the read and write sizes small enough so that the request will fit into a single Ethernet frame. An alternative is buying a better Ethernet adapter. I saw the problem with Etherlink II but the Western Digital cards do quite a bit better. At least our 486 machine with WD8013EBT seems to keep up quite well with our SPARCserver 330 without any parameter tweaking. Jerry Lahti Nokia Data Systems Oy Domains: jel@xerver.data.nokia.fi