Wes Felter wrote:

Neil Horman wrote:

quoted

Paul Jakma wrote:

quoted

On Wed, 15 Sep 2004, Jeff Garzik wrote:

quoted

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).

quoted

quoted

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."?

quoted

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/

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-- 
/***************************************************
  *Neil Horman
  *Software Engineer
  *Red Hat, Inc.
  *nhorman@redhat.com
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  *http://pgp.mit.edu
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