VanLUG Email Archive
> You mean on a page-aligned or cache-aligned boundary? That
> kind of sucks becuse then your IP header is two bytes short
> of being aligned. :)
Word-aligned, or even half-word aligned. And yes, that does suck.
> So where's the problem? When these are added, the fragmented datagram
> reassembly code can be fixed to take advantage of the new representation.
Indeed, it can. However, this should have been fixed years ago, IMHO.
> You seem to be dwelling on transient technical issues.
Well, if you consider four years `transient,' yes. And it's only
transient popularity issues that make Linux more popular than
NetBSD. And so on.
> Optimizing IP datagram reassembly is only a small, insignificant
> subtask in comparison to the overall goal of world domination.
Indeed, any technical issue is a small, significant subtask in
comparison to the overall goal of world domination. Marketing is
the key here.
> Smart applications will have a tunable packet size, perhaps on a per-network
> basis.
This is utter rubbish. Smart applications will rely on the layers
below them to set up appropriate packet sizes. In some protocols,
such as IPv6, this means the application will be informed that it
must use smaller sizes. In others, such as IPv4, the lower layers
will fragment. Good applications don't try to second-guess their
lower layers.
> IPv4 datagrams are limited to 64 K
> in size, so if your network handles packets of that size or larger, you just
> aren't going to see fragmentation, so it won't matter one bit how well
> optimized the code is for doing reassembly.
Indeed. However, Linux is often running on Ethernets, where this
does make a difference. You may want to consider optimising this.
> > Are you saying that one should
> > use Linux for routers, but not for end systems?
>
> I am, but nobody seems to be listening.
I've not heard you once recommend against using Linux for an end
system. Just out of curiousity, what doyou recommend one use instead?
cjs
Curt Sampson
Info at http://www.portal.ca/
Internet Portal Services, Inc. Through infinite mist, software reverberates
Vancouver, BC (604) 257-9400 In code possess'd of invisible folly.