Subject: Re: [v4tov6transition] a few quick reviews of the documents for today

From: Jason Lin <[email-masked]>
Date: Sat, 25 Sep 2010 17:10:45 +0800

>>5. IPv6 Transition Guide For A Large ISP Providing Broadband Access
draft-yang-v4v6tran-ipv6-transition-guide
>>
>>This is a very interesting document, I like reading about specific
networks and natives and pros/cons
>>in your specific case. A couple of questions/comments:
>>
>>Section 1: What's "the existing single transition technology" referred
from the text?
======================================
Thank you, it should be explained more in details.

I think its idea is that "a suitable completely solution" is needed besides
the specific technology
like 6rd, DS-Lite, ect.

There are many options for different specific scenarios, but due to the
features of each technology,
some technologies may not compatible with others, some may be not needed
when some one is deployed,
and some will interoperating with others in good performance.

So, it is possible that some combinations of a group of solutions or
technologies could be the
"completely solutions". For example, when we are building a completed new
dual-stack metro network
and access network, 6rd may not be considered as the the subscribers' access
method.

Another example is while we upgrade the BRAS to IPv6-only, and the CR to
Dual-stack, what relative
technologies should be deployed as the best practice?

It may be a combination of
[ds-lite_cpe]+[v6_bras]+[ds_metro_cr]+[ds-lite]+[ds_backbone]. And the
pros and cons over here should be considering together.

=========================================
>>I like the contrasting of various deployment options in Section 2.1. (Does
Section 2.1.1 assume
>>that dual stack == simultaneous roll-out of IPv6 in all routers in the
network? Many networks
>>employ a gradual approach to deployment, converting a small number of
routers at a time and/or
>>acquiring new devices for pure IPv6-only service on a case-by-case basis.
The pros/cons may be
>>different if you do this instead of a one-time rollout.)
============================================
Yes, I agree that it is possible to conduct a incremental deployment on the
existing IP backbone
in some cases. And the pros and cons may be different. For the solution of
6PE over MPLS backbone,
it is more reasonable to conduct a incremental deployment rather than a
simultaneously deployment.

For incremental deployment:
Pros:
   o  Helpful for the smooth transition, less influence to existing services
on other POPs which
   do not upgrade.

   o  The v6 traffic will not increase rapidly in a short term, which could
be good for performance
   and stability of the IP backbone.

For the upgrading of existing IP backbone, the most possible fact is it will
be done before
the metro network, access network and providing IPv6 services. The optimal
situation is v6 traffic
will increase gradually along with the metro networks providing v6 services
one by one.

However, the reason for a Large scale broadband network transitioning to v6
is mainly the fast
increasing rate of the subscribers who are accessing to different metro
network. Therefore, it
is possible that the ipv6/dual-stack services are highly demanded for many
metro networks nearly
at the same time when the IPv4 addresses are exhausted. So, the related POPs
of backbone are required
to support dual-stack focus on a small period of time.

===============================================

Best Regards,

Jason Lin
jasonlin.gz (at) gmail.com

China Telecom