On Sun, Mar 2, 2008 at 5:11 PM, Ingo Flaschberger <[EMAIL PROTECTED]> wrote: > Dear Bareney, > > >> And back to 1x is not fast enough: > >> There are no 1gbit single port network cards that > >> support more than 1 > >> lane, even if you plug it into a 16 lane slot. > >> (and I'm not talking about 10gbit cards; if you have > >> 10gbit upstream you > >> have enough $$ to buy good gear) > > > > Ok, well I've never seen a router with 1 port. I > > thought we were talking about building a router? > > Have you ever read the link? > Have you noticed that the axiomtek appliance has 7 gigabit ports? > Each one connected with 1 lane pci-e? > > > The lack of PCIe cards is a good reason to consider a > > PCIX machine. On the systems that we have, the 1x PCIe > > ports are a lot slower than a PCI-X card in the slot. > > Perhaps, but: pci-x: 4gbit for the whole bus system. > pci-e: 2gbit/lane > > > You need 4Gb/s of throughput to handle a gigablt > > router. (1 GB/s full duplex times 2). 1x is 4Gb/s > > maximum. In my view, you always need twice the > > bandwidth on the bus to avoid contention issues. > > sample1: > 3 pci-cards: > card 1: 1x = 2gbit (dedicated) > card 2: 1x = 2gbit (dedicated) > card 3: 1x = 2gbit (dedicated) > -------------------- > sum: 6gbit > (but the use only 3) > > sample2: > 2 pci-x cards > card 1: 4gbit (shared) > card 2: 4gbit (shared) > card 3: 4gbit (shared) > --------------------- > sum: 4gbit > > homework: > calculate with 7 ports. > > Kind regards, > Ingo Flaschberger > >
André Oppermann's excellent paper has even more info to why PCIe is better than PCI-X for networking : http://people.freebsd.org/~andre/Optimizing%20the%20FreeBSD%20IP%20and%20TCP%20Stack.pdf --Niki _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[EMAIL PROTECTED]"
