Re: [DNA] Considerations for DNA Schemes with multiple Interface andLayer 2 Technologies

[Erik Nordmark <erik.nordmark@sun.com>]

JinHyeock Choi wrote:
> Dear Yong-Geun
> 
> I think that the case 3.2, 'Single interface with Make before Break'
> will affect DNA solution design. I agree that we are not familiar with 
> this case, so it would be of much help, if you elaborate the below
> with more detail. 
> 
>      We think that we are not familiar with this case. But in CDMA[7], a
>      mobile station can access two or more different base stations
>      simultaneously. In this case, a host can make a new link-layer
>      connection before an old link-layer connection is torn down.
> 
> Especially I wonder whether it's possible for a host to distinguish 
> the IP packets from the old link-layer connection FROM the ones
> from the new link-layer connection.  

I hope that L2 can actually tell the packets apart.
If this is possible, then the implementation could present the packets 
from the different links are arriving on different interfaces to IP.

If this isn't possible, then I fear that the question "am I attached to 
the same link as before" can no longer be answered with "yes" or "no"; 
there will be cases when the interface is attached to the same link but 
also attached to a new link.

I don't understand the CDMA constraints, but for instance with 802.11,
if somebody builds a radio which can talk to two APs at the same time,
it wouldn't be hard to have the software present those to IP as "wlan0" 
and "wlan1". If this is done, then DNA would work just fine.

     Erik