Dear Ole,
Thanks for your quick and patient reply.I was just wondering why the IPv6
interface
is preferred to the others.
So the point is that as the access network is transitioning to DS-Lite, the
native IPv4
interface is becoming more and more unlikely to be used, and hence the IPv6
transport
should be prior to the IPv4 transport, in order to ensure a better IPv4
service. I hope
I have understood it correctly.
Best regards!
Yuchi Chen
From: Ole Trøan
Date: 2012-04-01 16:42
To: chenycmx
CC: sunjingwen; softwires WG
Subject: Re: [Softwires] [softwire]Basic Requirements for Customer Edge Routers
> It seems that you have missed some statements in the draft. In section 4.3,
> there are some lines clarifying 3 principles for IPv4 interface selection,
> just
> above the words you quoted:
> >1. IPv6 transport is preferred over any other.
>
> >2. Less address translation occurrences is preferred over more.
> [RFC5864][I-D.donley-nat444-impacts]
>
> >3. The closer the state is to the edge, the better.[RFC1958]
>
> According to the first principle, the IPv6 transport is prior to any other.
> That
> is the reason why the DS-Lite tunnel interface is preferred to native IPv4
> one.
>
> Actually, I have another question about this point. I think the question is
> not 'Why not use Native IPv4 interface for better performance', but 'Why
> prefer
> the IPv6 tunnel interface to the native IPv4 interface'. I didn't find the
> answer in
> the draft. Perhaps I've missed some words as well. IMHO, a clarification of
> the
> reason could be provided in the draft, and thus the principles about might
> seem
> to be more convictive.
the idea was to allow for a controlled move from a native IPv4 connection (that
is being sunet for an IPv6 only access) to IPv4 over DS-lite. the policy table
proposed is all about IPv4 exit, not trying to optimize what IPv4 link-layer
may give the best IPv4 service.
cheers,
Ole
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