I betcha a small cup of coffee that at 100MB you're either auto-negotiating, or something is forcing full duplex. Go to your switch and force half-duplex, or do it on the NICs. Poor performance at 100MB with good performance at 10MB is a dead giveaway of duplexing mismatches. If you're using a hub, *it* cannot accept full duplex by standard. Forcing the NIC to full duplex should be impossible to a hub. Rick On Fri, 1 Jun 2001, Walker Traylor wrote: > Guys, > I'm experiencing a routing performance problem in the following > scenario: > > I've got a linux firewall running ip masquerading between my PC and DSL > connection like so: > > eth eth > PC-------linux f/w----------dsl modem---Inet > > > Download throughput (FTP) maxes out the DSL connection when downloading > from the Internet to either the linux f/w or to the PC, which is good. > Uploading directly from the linux f/w to some box on the Internet occurs > at full throughput, which is good. The problem is that the PC only > uploads at about half the possible throughput if the ethernet segment > between the PC and the linux f/w is at 100Mbps. If it is forced down to > 10Mbs, downloads occur at full throughput! The speed of the ethernet > segment between the f/w and the dsl modem does not seem to affect > anything. > No frame drops are reported via ifconfig on the f/w, nor on the dsl > modem. This has been tested with multiple ethernet cards on the f/w and > PC, including 3com cards, Intel cards (using e100 and eepro100 drivers), a > card using tulip drivers, and a card using via-rhine drivers. The end PC > may be either a linux or Windows box (both exhibit the same behavior.) > This behavior is exhibited on a Redhat 7.0 box using several version of > 2.2.x kernel ( all were somewhere between 2.2.14 - 2.2.18.) This behavior > also is exhibited on a Redhat 7.1 box running the stock 2.4.2-2 kernel > using the ipchains compatibility module. > > What gives? I've seen a few old thread with similar problems (they can be > dug up if someone needs them) but nobody ever has a response. > > > Thanks, > --Walker > > > > - > : send the line "unsubscribe linux-net" in > the body of a message to majordomo@vger.kernel.org > - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org
