Subject: RE: Multiple Levels of LMM agents (was: RE: [mobile-ip] Revised L ocalized Mobility Management Requirement s)

From: James Kempf <[email-masked]>
Date: Wed, 9 May 2001 15:24:58 -0700 (PDT)

Hi Hesham,

>	=> To avoid multiple single point of failiures and keeping unnecessary 
>	state within the network. The solution is not so trivial IMO. 
>	There are several downfalls to consider. Robustness is only one, 
>	Security is another, network availability is another one. All that 
>	amounts to cost. 
>

This is an interesting comment. Normally in network design,  one tries
to avoid *single* points of failure. Multiple points of failure 
provide redundency, which helps improve reliability

Are you proposing that a design based on a single point of failure
is better?

		jak

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From: "Hesham Soliman (ERA)" <[email-masked]>
Date: Thu, 10 May 2001 01:49:02 +0200

> Are you proposing that a design based on a single point of failure
	=> No of course not, I said multiple  single points of failure. 
	You can make one redundant for a cost, you can make three
	redundant for a much higher cost. 
	So the goal is obviously to minimise the number of single points 
	of failure. More clearly one is better than two and two is better
	than 3.

	Hesham

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From: James Kempf <[email-masked]>
Date: Thu, 10 May 2001 06:07:56 -0700 (PDT)

>	of failure. More clearly one is better than two and two is better

Maybe I'm missing something but I still don't see the difference. 
What is the difference between multiple single points of failure
and multiple points of failure? 

As for cost, it is true that redundency comes at a cost, but that is
a network engineering issue. If a deployment wants  to pay the cost,
it is up to them. If they don't, then they don't.

But if the design does not have redundency in it,  then even if
a network operator wants to have redundency, they can't, no matter
how much they pay.

		jak