Re: [Softwires] Thoughts on new I-D?: Gateway Initiated Dual-stack lite Deployment

[Sri Gundavelli <sgundave at cisco.com>]

Hi Christian,

Thanks for the review. We can surely add some text on the placement of the
CGN. Based on the topology and network design considerations, operators may
choose to place the CGN in the PDN gateway, or at the edge of the IPv4
network with the fixed and mobile networks within the CGN scope. As you
pointed out, the collocation of the both the functions on the PDN, do
require management of the shared address space. However, the spec does not
mandate the placement of the CGN function, as that is a typical deployment
and network topology consideration and its up to the operator. We can surely
add some text on this aspect.

Regards
Sri


On 11/4/09 8:16 PM, "Christian Vogt" <christian.vogt at ericsson.com> wrote:

> Frank and Sri -
> 
> I think you should add a motivation for your proposal to the document.
> This motivation should answer the questions:  Why does the NAT need to
> be de-coupled from the gateway that terminates the existing tunnel?  Why
> not co-locate the NAT with the gateway?  This would explain why you want
> to extend the existing tunnel towards the NAT using your proposal.
> 
> I see one motivation, which applies to networks with multiple gateways:
> In those networks, by de-coupling the NAT from the gateways, the global
> IPv4 addresses on the external side of the NAT can be shared more
> efficiently compared to co-locating a separate NAT with every gateway.
> 
> Are there other motivations for your proposal?
> 
> - Christian
> 
> 
> 
> On Oct 15, 2009, Frank Brockners wrote:
> 
>> FYI. We just wanted to draw your attention to a new draft "Gateway
>> Initiated Dual-stack lite" - which outlines a modified deployment
>> approach of the  original dual-stack lite. The approach applies to
>> those
>> network architectures which already employ some form of tunneling
>> technology in the access network. The key idea is to leverage the
>> existing access tunnel (which means that architectural changes within
>> the access network are limited to the gateway terminating access
>> tunnel)
>> and stitch it together with a softwire connecting to the CGN. While
>> largely targeted at mobility architectures, the solution could be
>> applied to broadband environments as well.
>> 
>> A copy of the draft is available at:
>> http://www.ietf.org/id/draft-gundavelli-softwire-gateway-init-ds-lite-00
>> .txt
>> 
>> 
>> We appreciate your thoughts and comments.
>> 
>> Thanks & regards, Sri & Frank
> 
> 
>