[Techtalk] DHCPD Question

Raven, corporate courtesan raven at oneeyedcrow.net
Thu Oct 11 18:15:56 EST 2001

Heya --

Quoth Kath (Thu, Oct 11, 2001 at 05:38:00PM -0400):
> Yeah.  A few of us did the thinking on switching vs routing last year and
> noticed that all major vendors are pushing switches over routers and also
> beefing up the features on switches, such that a switch is more and more
> becoming a Layer-3 (and sometimes in higher) device, than just a Layer-2
> device.
	Yeah, the distinction between them is becoming more and more
artificial.  Routers overwhelmingly switch now.  The first packet in any
data stream will actually have a layer-3 lookup performed on it, and be
"traditionally" routed, but then that information gets entered into a
forwarding table and all subsequent packets in the stream are switched
on the line care.  This is so much faster -- it saves a call to the
router's CPU (and the attendant waits to go from card to backplane to
CPU and then to the outbound card), and you get exponential performance

	At the same time, most modern routers are also capable of doing
port-filtering and layer 4 stuff, and I have heard rumors of stateful
firewalling coming soon.  Kinda makes it difficult to be a beginning
networking student -- they tell you routers are layer three devices, and
it's a big lie.  [grin]  1, 2, 3, and usually 4.  (And if you're routing
over a Linux box, odds are you're firewalling there too, and so it gets
even more complex.)

	At the same time, most modern switches now have "router cards"
or "switch-route processors", which is the same thing as the "route
switch processor" in the routers... aaaaaah!

	I think the reason that so many vendors are pushing switches is
the speed.  Switching is faster than routing, and so they can say their
product has gigabit capacity and look really good.  (And when you get
into things like ATM, adding all the multimedia capabilities makes it
even more attractive to the purchaser.)  I understand there is ATM
support for Linux, but haven't gotten to play with it at all yet.

Raven, slightly hyperventilating
"Well, which is the Muse of coding?"
"Raven.  Also known as the Bitchy."
 -- Tessa and RavenBlack, on inspired arts

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