> Here is the senario I was thinking about
> Case 1
> R1 --- R2 --- R3
> Case 2
> R1 --- SW --- R3
> Assume that the wide area segments are the same in both cases and that SW and
> R2 are collocated. In case 1 there are 2 router hops between R1 and R3. In case
> 2, given a full mesh of PVCs, R1 and R2 are only one hop apart. This does not
> imply that the traffic flows any differently relative to the physical paths
> taken, but if I do a traceroute I think it will look different. Am I missing
> the point here?
No, you're not missing the point. My point is just that you can do the
same things as well with routers, assuming the routers can push the
amount of traffic you need to push. (And I think a 7507 or so can push
2-3 OC3s, though I could be wrong).
My point is just basically a "so what if the IP-level path is shorter"?
I fail to see why that's a Good Thing, especially since it hides information
that I want to see...
Acceptable arguments are:
o Switches can handle more throughput
o Switched networks are easier for humans (or at least, humans without
huge brians && many internal registers) to design/debug/maintain.
o Switches are requied because without going to a smaller decision space
(re: how much work per unit the switch/router has to do to decide where
to forward the data unit off to), existing routed technology can't
support moving IP packets at the desired speed while having to evaluate
the 40-60k routes we'll have soon.
But not "my traceroutes are shorter".
Anyway, you (Jim) run a very good, reliable network using ATM technology.
I suppose I shouldn't prickle quite so easily, but I feel there are
a lot of misconceptions out there...
I don't disagree with anything you have said. I don't think "too many hops"
is an interesting criticism of an NSPs network. All I was saying is that it is
possible, using switches, to reduce your hop count. I am not arguing the
merits of doing so. Today, regardless of how fast switches can push cells, if
your network is IP based you need to traverse routers. When the routers get
overloaded you must either install more routers or faster routers.
Ps. I don't take it personally Avi. I only argue with you because when I do
I often learn something.