Subject: RE: Question:draft-ietf-mpls-atm-03.txt

From: Levi Daphna <[email-masked]>
Date: Sun, 21 May 2000 15:01:00 +0300

Eric,

Let me see if I understand, connecting LC-ATM interfaces via an ATM VP is
just like IP over ATM,
but instead of using ATM interfaces to connect Routers we use LC-ATM
interfaces to connect LSRs.
The LSRs are logically adjacent to one another while they are physically
connected via ATM VP connection. 
I am not quite sure what is the logic to do that , after all this is the
infamous overlay model.
(unless you use the ATM cloud as a multiservice cloud and then you can avoid
ships in the night) .

Daphna

> -----Original Message-----
> From:	Eric Gray [SMTP:[email-masked]]
> Sent:	ה מאי 18 2000 23:25
> To:	[email-masked]'
> Cc:	Eric Gray; Eric W Gray (E-mail)
> Subject:	Re: Question:draft-ietf-mpls-atm-03.txt
> 
> Daphna,
>  
>     When using a Virtual Path to connect LSRs across
> multiple intervening VP switches, VP values are set at
> each intervening switch - usually via configuration or
> provisioning.
>  
>     For the ATM switches at each end of the virtual
> path, the VPI is set in the same way. 
>  
>     The actual VPI need not be the same at any two
> ATM physical links since the VP switch may change 
> the VPI value in switching cells from input interface
> to output interface.  However, VP switches do not
> change VCI values, so MPLS needs the two LSRs at
> either end of a VP to act as if they are adjacent in
> assigning VCI values.
>  
>     Does this help?
>  
> --
> Eric Gray << File: TechTool.gif >>