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Re: I-D Action:draft-ietf-v6ops-nat64-pb-statement-req-00.txt

Some comments on this draft, from the perspective of someone familiar with the various BEHAVE documents.
* R6 lists TCP, UDP, ICMP, and TLS as protocols to be supported. I am surprised that TLS is listed in addition to TCP, since full TCP support would imply TLS. I am also surprised that DTLS is not listed, if listing TLS is seen as necessary. Any explanation for this?
* R7 lists the BEHAVE requirement documents for TCP and UDP. Is there some reason for not listing the BEHAVE requirement document for ICMP?
* R8 talks about fragmented packets. Is there some reason to include this specifically, given that the BEHAVE requirements cover fragmentation in some detail? The BEHAVE requirements do not mention the 5 second stuff, but they talk about out-of-order fragments which R8 does not mention.
* I6 and I7 talk about SCTP and DCCP support. Is it acceptable to support these by transporting them over UDP?
* I8 talks about multicast. Should multicast support comply with the BEHAVE requirement document for multicast? 

* A (long) comment on R2.
There is a class of applications that work today through NAT44s. As a general rule, these are applications that do not carry addresses embedded inside protocol messages, and have communication initiated by the host behind the NAT. Is this the same class of applications that should be supported by the proposed translation mechanism?
Code in a NAT that recognizes packets of a specific application protocol and does special processing of that packet is known as an ALG (Application Level Gateway). The BEHAVE group considers an FTP ALG to be acceptable, because FTP was there before NATs, but other ALGs are discouraged (= default off). Is this rule consistent with the proposed transition mechanism? This rule is given in RFC 4787, which R7 says the mechanism must comply with. 

If so, is R2 an attempt to formalize all this in different words?

- Philip



On Tue, 13-May-08, at 19:30 , Internet-Drafts@ietf.org wrote:
A New Internet-Draft is available from the on-line Internet-Drafts directories. This draft is a work item of the IPv6 Operations Working Group of the IETF.
Title : IPv4/IPv6 Coexistence and Transition: Requirements for solutions 
	Author(s)       : M. Bagnulo, et al.
	Filename        : draft-ietf-v6ops-nat64-pb-statement-req-00.txt
	Pages           : 17
	Date            : 2008-05-13

This note presents the problem statement, analysis and requirements
for solutions to IPv4/IPv6 coexistence and eventual transition in a
scenario in which dual stack operation is not the norm.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-v6ops-nat64-pb-statement-req-00.txt

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

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Internet-Draft.
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