Re: [OPSAWG] Fwd: New Version Notification for draft-nishizuka-cgn-deployment-considerations-00.txt

[GangChen <[e-mail]>]

Kaname-san,

2013/4/11, kaname nishizuka <[e-mail]>:
> Thank you for your comments.
>
> (2013/04/11 12:49), GangChen wrote:
>> Hello authors,
>>
>> Thanks for sharing your tests.
>> Some comments are below.
>>
>> Section 5.2 provides two formulas to estimate the address multiplexing.
>> If the formula of static assigment is intended to align with
>> I-D.donley-behave-deterministic-cgn, it may be amended by adding
>> active subscriber's coefficient. CGN may only assign static port block
>> to active users.Meanwhile, log just needs to add one record for each
>> user.
> It is dynamic assignment of port block.

That is correct. In some senses, a bulk of port is *statically*
reserved to a particular user. It's worth to be noted several
implementations are doing deterministic NAT behavior just following
those rules.

> We are describing the static assignment case.
> In that case, the same active subscriber's coefficient can not be used.
>
> There are potential users who have been assigned an internal IP address
> (and thus external address and port range) but are not generating any
> packet.
> In the dynamic assignment of port block, they don't consume external
> ports so they are not active subscribers.
> On the other hand, in the static assignment, they are reserving the
> external address and port range resources.
> If there is a mapping rule, that is the static assignment.
>
>> Section 6.1 states the MCS is highly dependent with retention time of
>> NAT table. It would be intereted to add some discussions if CGN could
>> interact with PCP.
>>
>> BTW, the table shown CGN sets retention time for DNS. would you do DNS
>> filter on CGN to identify DNS package?  I saw you also described DNS
>> bypass CGN. Are those related?
> Thanks for your suggestion.
> Yes, those are related.
> The point is that DNS query almost does not affect the performance of
> the CGN because
> retention time for DNS is sufficiently short (3 sec.).
> I think we need not to bypass DNS queries.

When I read the section at first time, I thought bypass DNS queries is
recommended since there is additional load(e.g. translation and logs)
to CGN. I guess the statement may be more clear if you could add
discussions what is the loss of bypass DNS queires.

Best Regards

Gang


> regards,
> kaname
>
>> Many thanks
>>
>> Gang
>>
>> 2013/4/2, kaname nishizuka <[e-mail]>:
>>> Dear all,
>>>
>>> As I mentioned before, we are testing CGN under the support of Japanese
>>> Government.
>>> Now, we've uploaded a new draft based on the result of our verification.
>>> The useful information about the average consumption of the ports are
>>> available on the document.
>>> Please look through it and all kind of feedback are welcome.
>>> We mentioned Victor's draft "CGN Deployment with BGP/MPLS IP VPNs Draft"
>>> in
>>> introduction
>>> because part of our research shares the same motivations with it.
>>>
>>> The document is *NOT* intended to be Standards Track. It's for
>>> Informational.
>>> The wrong description is just mere mistake, so we'll soon correct it in
>>> the
>>> next revision.
>>>
>>> The full report of our work will be available soon on the Web.
>>> We've just finished writing.
>>>
>>> Best regards,
>>>
>>> kaname
>>>
>>> -------- Original Message --------
>>> Subject: 	New Version Notification for
>>> draft-nishizuka-cgn-deployment-considerations-00.txt
>>> Date: 	Thu, 28 Mar 2013 07:12:25 -0700
>>> From: 	[e-mail]
>>> To: 	[e-mail]
>>>
>>>
>>>
>>> A new version of I-D,
>>> draft-nishizuka-cgn-deployment-considerations-00.txt
>>> has been successfully submitted by Kaname Nishizuka and posted to the
>>> IETF repository.
>>>
>>> Filename:	 draft-nishizuka-cgn-deployment-considerations
>>> Revision:	 00
>>> Title:		 Carrier-Grade-NAT (CGN) Deployment Considerations.
>>> Creation date:	 2013-03-29
>>> Group:		 Individual Submission
>>> Number of pages: 16
>>> URL:
>>> http://www.ietf.org/internet-drafts/draft-nishizuka-cgn-deployment-considerations-00.txt
>>> Status:
>>> http://datatracker.ietf.org/doc/draft-nishizuka-cgn-deployment-considerations
>>> Htmlized:
>>> http://tools.ietf.org/html/draft-nishizuka-cgn-deployment-considerations-00
>>>
>>>
>>> Abstract:
>>>      This document provides deployment considerations for Carrier-Grade-
>>>      NAT (CGN) based on the verification result include the
>>> investigation
>>>      of the number of sessions of applications.  The verification was
>>>      conducted in StarBED which is one of the largest scale network
>>>      experiment environment in Japan.  A million of subscribers was
>>>      emulated and it revealed the realistic behavior of CGN.
>>>
>>>
>>>
>>>
>>> The IETF Secretariat
>>>
>>>
>>>
>>>
>
>
> --
> ----
> Kaname Nishizuka
> Innovative Architecture Center
> NTT Communications Corporation
> [phone]
>
>