The IP over ATM Mailing List Archive by date

[manfredi@engr05.comsys.rockwell.com (Albert E. Manfredi)]

> From:	fred@cisco.com    29-MAR-1996 18:41

> The fact is that IP has been moved to any number of different link layers,
> and whenever a new link layer comes in (1822, X.25, bridged ethernets,
> switched ethernets, frame relay, SMDS, and now ATM) there has been a
> perception on the part of some that the users of the link layer were going
> to somehow change to meet the link layer's self-centric view of the world.

You could be right, but the fact is that ATM is radically different from 
all the other "link layer" nets you mentioned. None of those others 
pretends to have global coverage and "integrated services" applicability
as their raison d'etre. Not without some sort of external assistance,
assistance often provided by the telephone network.

> Surprise, surprise, every single time we have this silly debate, and every
> single time we find that the link layer network, whatever it's nifties may
> be, is not going to replace the network layer any time soon.

I'm not convinced that any rational definition of ATM with AALs would 
constrain it, functionally, to Layer 2. Which is different from any fancy 
implementation of iso-Ethernet or FDDI-II, or SSAP/DSAP use. There is a 
significant difference here. It's the semantics that generate the mindset.

> The global
> internet is not 1822, it is not X.25, it is not bridged Ethernets, it is
> not Frame Relay, it is not SMDS, and it's not going to be ATM.
> 
> But IP, wherever you want to go, can get you there and will continue to do
> so for the foreseeable future. That is not IP bigotry, that is a fact that
> is demonstrable with a phone call to any service vendor you want to call.

Exactly! With a phone call. If IP is everywhere, it's still that phone 
call you can rely on. IP is "everywhere" for datacomm, perhaps, but that 
phone, and by extension ATM, is there for all other types of data 
transfers. Even if now it might take two or three or more circuits to
carry one "conversation" in certain cases.

> Call me obnoxious, call me pig-headed, call anything but late to dinner.
> And if you want wide marketplace acceptance, smell the coffee.

As Pete pointed out, that could change overnight. If things like VoD take 
off and IP can't support them effectively, ...

Bert
manfredi@engr05.comsys.rockwell.com