Messages in this thread | | | Date | Thu, 16 Sep 2004 07:37:16 -0400 | From | Neil Horman <> | Subject | Re: The ultimate TOE design |
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Wes Felter wrote: > Neil Horman wrote: > >> Paul Jakma wrote: >> >>> On Wed, 15 Sep 2004, Jeff Garzik wrote: >>> >>>> Put simply, the "ultimate TOE card" would be a card with network >>>> ports, a generic CPU (arm, mips, whatever.), some RAM, and some >>>> flash. This card's "firmware" is the Linux kernel, configured to >>>> run as a _totally indepenent network node_, with IP address(es) all >>>> its own. >>>> >>>> Then, your host system OS will communicate with the Linux kernel >>>> running on the card across the PCI bus, using IP packets (64K fixed >>>> MTU). > > >>> The intel IXP's are like the above, XScale+extra-bits host-on-a-PCI >>> card running Linux. Or is that what you were referring to with >>> "<cards exist> but they are all fairly expensive."? > > >> IBM's PowerNP chip was also very simmilar (a powerpc core with lots of >> hardware assists for DMA and packet inspection in the extended >> register area). Don't know if they still sell it, but at one time I >> had heard they had booted linux on it. > > > An IXP or PowerNP wouldn't work for Jeff's idea. The IXP's XScale core > and PowerNP's PowerPC core are way too slow to do any significant > processing; they are intended for control tasks like updating the > routing tables. All the work in the IXP or PowerNP is done by the > microengines, which have weird, non-Linux-compatible architectures. > I didn't say the assist hardware wouldn't need an extra driver. Its not 100% free, as Jeff proposes, but the CPU portion of these designs is _sufficient_ to run linux, and a driver can be written to drive the remainder of these chips. Its the combination that network device manufacturers design to today: A specialized chip to do L3/L2 forwarding at line rate over a large number of ports, and just enough general purpose CPU to manage the user interface, the forwarding hardware and any overflow forwarding that the forwarding hardware can't deal with quickly. > To do 10 Gbps Ethernet with Jeff's approach, wouldn't you need a 5-10 > GHz processor on the card? Sounds expensive. > To handle port densities that are competing in the market today? Yes, which as I mentioned earlier would price designs like this out of the market. Jeffs idea is a nice one, but it doesn't really fit well with the hardware that networking equipment manufacturers are building today. Take a look at Broadcoms StrataSwitch/StrataXGS lines, or Switchcores Xpeedium processors. These are the sorts of things we have to work with . They provide network stack offload in competitive port densities, but they aren't also general purpose processors. They need a driver to massage their behavior into something more linux friendly. If we could develop an infrastrucutre that made these chips easy to integrate into a platform running linux, linux could quickly come to dominate a large portion of the network device space.
Neil
> Wes Felter - wesley@felter.org - http://felter.org/wesley/ > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
-- /*************************************************** *Neil Horman *Software Engineer *Red Hat, Inc. *nhorman@redhat.com *gpg keyid: 1024D / 0x92A74FA1 *http://pgp.mit.edu ***************************************************/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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