The IP over ATM Mailing List Archive by date

[Masataka Ohta <mohta@necom830.cc.titech.ac.jp>]

> Ohta-san, 
> 
>   cv > For IP multicast over ATM, you forward between LIS using routers.
>  ohta>>  No, it is multicast but not multicast over ATM, unless the routers
>  ohta>>  relay cells, that is, unless the conventional model is used.
> 
> No, I do not think so, 
> multicast is the multicast of IP level, not of ATM level. 

Esaki-san, we are talking about multicast over IP over ATM.

> So that, even routers of LIS relay multicast packets, it is fine for IP
> multicast over ATM. 

With the same logic, you can say, even routers of LIS relay unicast
packets, it is fine for IP unicast over ATM.

Of course, it's fine if routers relay cells.

> If my understanding on the classical IP model is not wrong, the classical 
> IP model does not preclude cell-by-cell relaying at the router. 

It's not a issue of correctness.

The problem is that, classical model is unfriendly to a lot of existing and
future Internet protocols and that, with cell-by-cell relaying routers,
we don't need the classical model.

So, the classical model is not wrong but is undesirable and unnecessary.

> Both classical model and conventional model can relay the packets 
> of multicast packet through cell-by-cell.   
> It is just the implementation decision of each routers. 

A IP over ATM router MAY relay data packet-by-packet.

But, if a router CAN NOT relay data cell-by-cell, it is NOT a router
for IP over ATM.

> When we only focus on the scalable IP multicast over ATM, classical 
> IP model can scale, IF the LIS is not huge scale and the ATM cloud 
> (the domain LIS can be defined) is not huge. 

I'm afraid you don't understand what we are discussing.

LISes are, from the begininng, considered to be unscalable.

That is, everyone agreed from the day one that the number of hosts
in a LIS can not be arbitrary large.

The problem we are discussing these days are that, LISes can't be
geographically large. The size of LISes are physically constrained.

The point of LIS model that the size of LISes can be arbitrary large,
is denied.

> LIS will be fine.  But, LIS will have some issues (e.g. "complete" 
> autoconfiguration). 

You had better call your geographically crippled version of LIS
PLIS (Physical Logical IP Subnet) or, more simply, just subnet.

							Masataka Ohta