telnet and router question

[Adam Maloney]

<rant>

Commercial routers do one thing and do it well - cisco's and Junipers are
not built from commodity PC hardware - they are built specifically to
route packets as fast as possible.  You could never get the kind of
throughput and latency on any Windows box that you could with a "real"
router.  Same goes for linux and freebsd (sorry) based routers - your off
the shelf PC hardware simply cannot compete on anything but price.

Now, if you're just talking about routing for a small network, maybe 2
interfaces, carry a default route to your ISP, then you could probably
make it work.  Lots of people do this because the entry point into "real"
gear is kind of high.  But it's pretty amazing what even little cisco's
can do.  A 2500 series has 2 T-1 interfaces, and is quite capable of
sustaining both at full speed.  Before the routing tables grew too large,
ISP's were running full BGP on these little guys.  I say little because a
2500 has a 20MHz 68030 processor, up to 16MB of flash, and up to 16MB of
memory.  Not a big box by any standard.

Probably the biggest performance gain on real routers is that the packet
switching can take place interface to interface, without generating an
interrupt for each packet and eating CPU.  This means that the processor
doesn't have to "do stuff" for each packet, which is why 7200's can
achieve 250,000+ packets per second.

Bigger routers add additional horsepower, but the CPU clock doesn't matter
as much as the special interfaces designed for switching packets, route
switch processors, etc.  A cisco 7200 has a 250MHz (give or take) R7000
MIPS processor (think SGI), up to 256MB RAM.  But by PC standards that's
not a very fast machine - but I would put my money on the 7200 being able
to handle a couple full DS-3's, some ATM (maybe IMA to make it
interesting), an 8-port T-1 card, a couple fast ether's, and full BGP.  A
windows box would just catch fire or whatever it is that they do these
days when things don't go their way :)

And throughput isn't everything - assuming you could build a PC that could
handle that kind of throughput, I would still have my money on the "real"
router providing less latency, fewer drops, etc.

But, if your application doesn't call for that kind of load, and you want
to save a few bucks, then a PC might do.

Cisco IOS has had SSH capability for awhile now, so telnet isn't
necessary.  You just need to make sure you have a copy of IOS that
supports it.

</rant>

Adam Maloney
Systems Administrator
Sihope Communications

On Wed, 30 Jul 2003, marlon corleone wrote:

> why is it router is invented, since in windows BOX it
> can act as a router which has ICS builtin, and 2nd why
> is it most routers configured through telnet services
> since it is being considered as "inseceure". can a
> router be configured through SSH, since it was being
> favored to be used for better security.
> 
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