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

["Rajiv Asati (rajiva)" <[e-mail]>]

Hi Simon,

> An ISP is running out of addresses. It considers two options: static CGN
> vs dynamic CGN. Static allows, let's say, 32 users per public IPv4
> address. Given the 1:10 figure from the draft, it follows that dynamic
> allows 320 users per public IPv4 address.

1:32 (dynamic assignment) on top of 1:10 (static assignment)? Did you
intend to nest?

Could you please clarify?

Cheers,
Rajiv

-----Original Message-----
From: Simon Perreault <[e-mail]>
Date: Thursday, April 4, 2013 5:49 AM
To: Behave WG <[e-mail]>
Subject: Re: [BEHAVE] Fwd: New Version Notification
for	draft-nishizuka-cgn-deployment-considerations-00.txt

>Le 2013-04-03 20:57, Senthil Sivakumar (ssenthil) a écrit :
>> If it is not the address, what is the limiting factor? The reason ISP
>> is deploying CGN is the shortage of addresses and cant provide a
>> single address to each of his subscribers. Maybe you meant to say the
>> address is not the only limiting factor. I never said the text was
>> saying static isnt good enough :-), I deduced from the study that the
>> usage of ports is far more compellingly efficient with dynamic port
>> allocation and the cost of logging infra can be justified.
>
>I'll try to illustrate my point with an example with numbers.
>
>An ISP is running out of addresses. It considers two options: static CGN
>vs dynamic CGN. Static allows, let's say, 32 users per public IPv4
>address. Given the 1:10 figure from the draft, it follows that dynamic
>allows 320 users per public IPv4 address.
>
>If 32 is "enough", why suffer the trouble of logging (among others) just
>to get to 320? If 32 and 320 are both "enough", then considerations
>other than efficient use of public IPv4 addresses must take priority.
>
>"Enough" could mean something like "enough to support projected growth
>for X years".
>
>> Most of the studies in the past projected how bad the logging problem
>> is but didn¹t have any data on the other side of the equation on how
>> inefficient the static port allocation is. I wouldn¹t want this draft
>> to say one is better than the other, but let the operators choose, if
>> 10:1 static to dynamic port allocation is justified for their
>> deployment.
>
>The 10:1 figure is useful. However, the conclusion "therefore dynamic is
>better" is premature. There are tons of other criteria to consider. Even
>worse, it is very possible that the 10:1 figure does not even matter: if
>static is "good enough", you may not care that dynamic is 10 times better.
>
>Simon
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