Jon Crowcroft wrote:
In message <v04220802b77bde136984(_at_)[10(_dot_)83(_dot_)97(_dot_)216]>,
Steve Deering typed:
>>We used to use "gateway" instead of "router" (and a few still do), and
i lik the fact that if you type getaway by mistake you get what people
are trying to do when they are routed ...
i also like the fact that MOST fancy things we do in traffic treatment
(firewall, diff/int serv, header compression, checksum) ignore this
layering rubbish idea and look at the whole packet and the whole state
of the systems where you need to......
I always thought peeking into other layer headers to make better decisions
doesn't always destroy layering. It's when the implementation gets tied to a
specific other-layer technology, or it *writes* into other layer headers, or
performs 'designated' other-layer functions, that layering is destroyed.
Say, a diff serv implementation that tries to figure out what kind of lower
layer protocol is present and if it succeeds in doing so, uses the lower layer
information to make forwarding decisions, is not really destroying layering,
is it.
I can still deploy this diff serv implementation readily over all kinds of
lower layer 'technologies' or standards, because it is not tied to any
specific such technology. If it can recognise the lower layer technology, it
uses that extra lower layer information to try improve performance, otherwise
it just performs default operations. So for example, I can still easily
transfer such an implementation from a wired-ethernet to some wireless
standard without any rework. Now, isn't *that* kind of layering good? Or am I
missing something.