Nachi/Welchia Aftermath

Wed Jan 21 18:17:16 UTC 2004

> > more generally... "if you want routing, buy a router."
> 
> 	amen.
> 	imho there can't be a better routing equipment than a real router :)

i guess i need to explain in more detail.  keep in mind that i'm technophobic
and that when VLANs first appeared i was convinced that the end of the world
was upon us... 

that having been said, "ip switching" isn't a bad thing.  if you've got more
than one vlan'd subnet in a switch or switch-cluster, then it's not good to
scoot packets up and down a trunk to a router just to let folks on one vlan
talk to folks on another.

that's the way i use my switer at home and i'm an ideal target audience for
it since my kids can't invoke an SLA when they aren't able to play netgames.

at work, though (for all values of "at" and "work"), there's a router trunk
and the packets between vlans go through real routers.  in addition to what
might be a router-centric superstition, it's MUCH easier to find problems
when you can point to each powered box and say "this one's a switch" and
"this one's a router".

and when it comes to wide area links, it turns out that the reputation of
switches was wrecked in its earliest years, both with poor diagnostics and
unreasonably low buffer sizes and a serious lag in implementation of things
like RED.  the DEC GigaSwitch, and various Vitalink products, were the poster
children for "why wide area bridging is bad".  i won't list the poster
children for "why switches that try to do point-to-point routing is bad"
since unlike DEC and Vitalink, the companies in question are still in
business.

watching nanog discussions over the years of how to make switches be routers
without bloodshed or lost weekends is a lot like, to paraphrase tom lehrer,
watching a christian scientist cope with appendicitis.

so with the possible exception of inter-vlan "ip switching" in a lan context,
if you want routing, buy a router.