issue 3: nat traversal

hi all, 

let us try to close the nat traversal issue (issue 3) from 
http://www.vpnc.org/ietf-mobike/issue3.txt

here is what we currently have: 

- charter says that we should not modify the ikev2 nat traversal mechanism.
none of the proposal tries to todo that. 
- draft <draft-eronen-mobike-simple-00.txt> addresses nat traversal. 
- draft <draft-eronen-mobike-mopo-01.txt> and
<draft-dupont-ikev2-addrmgmt-06.txt> additionally add a mechanism to
indicate nat traversal prevention.

a number of people pointed to the need to support nat traversal. 

hence, i think that we could have support for
- nat traversal and
- a nat traversal prevention (if you think you don't need it)
without conflicting with the charter.  

to address the scenarios there also needs to support for an end host moving
from not-behind a nat to behind a nat.  

ciao
hannes