Re: [Softwires] [softwire]Basic Requirements for Customer Edge Routers

["Yuchi Chen" <[e-mail]>]

Dear Sun,

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.

Best Regards!



Yuchi Chen

From: sunjingwen
Date: 2012-04-01 11:05
To: mark; ot
CC: softwires WG
Subject: [Softwires] [softwire]Basic Requirements for Customer Edge Routers
Dear authors,
I've read the draft-townsley-troan-ipv6-ce-transitioning-02, and I have a question confused me very much.
 
In section 4.3, 
>In the case of DS-Lite and Native IPv4 configuration being present at the same time, 
>DS-Lite would be preferred as it uses IPv6 transport and Native IPv4 does not.
 
Do you mean if the CE receive user’s IPv4 packet, it will choose to use tunnel rather than IPv4?
But I think if use native IPv4 can also arrive the destination (IPv4 internet), the native IPv4 will more efficient than the tunnel, because it needn’t encapsulation and decapsulation.
 
Please correct me if there is any mistake~
 
     Thank you




Best regards!
sun jingwen