Subject: New I-D on Carrier Grade NAT

From: "Tomohiro Nishitani" <[email-masked]>
Date: Fri, 04 Jul 2008 11:40:15 +0900

Hi,

I submitted new draft on Carrier Grade NAT.

"Carrier Grade Network Address Translator (NAT) Behavioral Requirements
for Unicast UDP, TCP and ICMP"

http://www.ietf.org/internet-drafts/draft-nishitani-cgn-00.txt

Abstract of our draft is as follows:

---
This document defines basic terminology for describing different
types of carrier-grade Network Address Translation (NAT) behavior
when handling Unicast UDP, TCP and ICMP. Developing carrier-grade
NATs that meet this set of requirements increase transparency of data
between carrier networks.
---

Comments welcome.

Thanks.

Tomohiro Nishitani

-- 

Tomohiro Nishitani
Chief, Network Systems and Technologies,
Innovative IP Architecture Center
NTT Communications Corporation
[email-masked]
TEL: +81-3-6800-3214

---

From: [email-masked]
Date: Fri, 04 Jul 2008 04:17:00 -0600

> between carrier networks.

As much as I am all for killing NAT as soon as we can, I understand the 
potential need for such a device as currently carriers are doing just this 
using multiple devices (and frequently nesting NATs). 

I would prefer that the Abstract was changed to the following: 

This document defines basic terminology for describing different\types of 
carrier-grade IPv4 Network Address Translation (NAT) behavior when handling 
Unicast UDP, TCP and ICMP. Developing carrier-grade NATs that meet this set 
of requirements increase transparency of data between carrier networks. 

Where there is an emphasis on the fact that this is IPv4 only, not a 
backdoor for bringing NAT into v6. 

I also think you need to consider the requirements for non-stationary 
devices as these are starting to be more common and will complicate CGN to 
no end as they move from one cell site to another or into a new carrier 
while trying to maintain their IP session (most critical if it is UDP 
based). 

Eric 

Eric

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From: "Tomohiro Nishitani" <[email-masked]>
Date: Tue, 08 Jul 2008 11:26:39 +0900

Hi, Eric.
> As much as I am all for killing NAT as soon as we can, I understand
> the potential need for such a device as currently carriers are doing
> just this using multiple devices (and frequently nesting NATs).
> This document defines basic terminology for describing different\types
> of carrier-grade IPv4 Network Address Translation (NAT) behavior when
> handling Unicast UDP, TCP and ICMP. Developing carrier-grade NATs that
> meet this set of requirements increase transparency of data between
> carrier networks.
> devices as these are starting to be more common and will complicate
> CGN to no end as they move from one cell site to another or into a new
> carrier while trying to maintain their IP session (most critical if it
> is UDP based).
> Eric
> Eric
>
I appreciate the decirption that developing carrier-grade NATs that meet
this set of
requirements increase transparency of data between carrier networks.

As you indicated, I don't consider movable devices. If a carrier
supplies wireless access
services, it may be need to consider your indication. I think trying to
maintain their IP session
may not be behavior of CGN but CPE or teminal.

Best Regard,

Tomohiro Nishitani

-- 

Tomohiro Nishitani

---

From: [email-masked]
Date: Tue, 08 Jul 2008 03:57:50 -0600

Hi Tomohiro,

> may not be behavior of CGN but CPE or teminal.

I am not sure how it works in 3GPP or other cellular data networks, but in 
802.16e WiMAX there is an ASN (Access Service Network ), this is a device 
that is responsible for maintaining the session as the device crosses 
between cell sites, and carriers. (The Access Service Network in WiMAX: The 
Role of ASN-GW" http://www.mustafaergen.com/asn-gw.pdf)) This device may 
also be the one responsible for DHCP(v4 and v6). 

I am not sure how a CPE would be capable of telling the network where to 
pass an UDP session on to the next base station (cell site) without loosing 
the session, thus it is a feature of the CGN (as represented by the ASN 
gateway). 

Eric