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RE: remember the "diameter of the internet"?

  • From: Martin, Christian
  • Date: Wed Jun 19 13:46:46 2002

>> When ANY router becomes as reliable as a dumb TDM device, then maybe 
>> we can begin collapsing the POP topology.  However, the very 
>nature of 
>> the Internet almost prevents this reliability from being achieved 
>> (having a shared control and data plane seems to be the primary 
>> culprit).
>Uhm. Actually, control & data planes are rather separate 
>inside modern routers. What is flaky is router software.  
>That's what you get when your router vendor sells you 1001 way 
>of screwing up your routing :)

Router hardware can be pretty flaky as well... ;)

I was more referring to the nature of IP.  With the exception of IS-IS, all
IP control plane protocols are subject to abuse/attack by the same data
plane that they are intending to control.

>> There are routers out there today that can single-handedly replace 
>> entire POPs at a fraction of the rack, power, and operational cost.
>> Hasn't happened, tho.
>I know two boxes like that - one is broken-as-designed, with copper 
>distributed fabric; another (courtesy of VCs who managed to 
>lose nearly 
>entire engineering team mid-way but hired a bunch of marketers 
>long before 
>there was anything to ship) is still in beta.


>> I don't like wasting ports for redundant n^2 or log(n^2) 
>> either, but router and reliability mix like oil and water...
>Actually, not.  A router is a hell of a lot simpler than a 
>Class-5 switch, 
>particularly if you don't do ATM, FR, X.25, MPLS, QoS, 
>multicast, IPv6, 
>blah, blah, blah. 

There are opponents to this assertion.  I haven't seen enough of what's in
the sausage to make a firm statement either way.  What I do know is that the
class-5 switch is designed to save lives.  A router is designed to fill
vendor wallets.  That, coupled with experience in the field suggests,
coupled with dogma and the high-level of sensitivty to being burned
repeatedly, suggests that the trend for chassis redundancy requiring massive
amounts of wasted space, unnecessary hierarchy, and added complexity to
continue.  Ces't la Vie!

>Demonstrably (proof by existence), those switches can be made 
>reasonably reliable. So can be routers. It's the fabled 
>computer tech culture of "be crappy, ship fast, pile features 
>sky high, test after you ship" aka OFRV's Micro$oft envy, 
>which is the root evil.




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