Hi Gang and all,
I think there are some points need to be considered between MAP series and
4rd-U.
4rd-U saids "IPv4 headers can be reversibly mapped into IPv6 headers so that
4rd tunnel packets can be designed to be valid IPv6 packets" in Section I. In
my understanding, the difference between 4rd-u and MAP-E is "IPv6 fragment
header vs IPv4 header". Both 4rd-U and MAP-E can keep the transparency, while
4rd-U reserves 12 bytes to improve the efficiency and MAT-E has some IPv4
redundancy octets but keep the original IP-IP encapsulation which is easy to be
operated.
Comparing with MAP-E, 4rd-U keeps the DF bit, TOS and so on with an additional
IPv6 fragment header, which incurs reusing IPv6 option 44.
If 4rd-U can be considered as a tunneling technique, the question is: does it
deserve adding the IPv6 fragment header in order to save 12 bytes efficiency
each packet?
If 4rd-U can be considered as a translation technique, the question is: does it
deserve adding the IPv6 fragment header in order to keep transparency?
Regards!
Jiang Dong
Tsinghua University
2012-03-27
From: GangChen
Date: 2012-03-27 15:53
To: Kevin Y
CC: Softwires WG
Subject: Re: [Softwires]Path to move forward with 4rdŠ
Hello Kevin and all,
I actually see current multiple solution proposal from different
angle. Regarding the changes you mentioned, MAP-T/E is also doing
that, e.g. added fragmentation header to survive DF bit; change ICMP
ID filed to carry the port information.
4rd-U doesn't beat MAP-series. I prefer to understand the situation is
4rd-U raised some points(e.g. CNP, Fully IPv4 transparency) which is
desirable heading to a perfect protocol design.
BRs
Gang
2012/3/27, Kevin Y <[email protected]>:
> Hi, Remi,
>
> This is beyond the charter of softwire WG, changing IPv6 address format
> needs much broad discussion in IETF community to understand its impact
> first, before we should even discuss if it is valid to design something
> like this in softwire. Have you done that ?
>
> Best Regards,
>
> Kevin Yin
>
> On Thu, Mar 22, 2012 at 10:04 PM, Guanghui Yu <[email protected]> wrote:
>
>> Hi Yiu
>>
>> 4rd-u changes the IPv6 header architecture (redefine
>> fragmentation header extension) and IPv6 address architecture (different
>> meaning of u-bit when g-bit=1). These are the fundamental changes. If
>> 4rd-u
>> becomes the standard, then there will be new defined 揑Pv6?packets on
>> the Internet, which are not compatible with existing IPv6 packets and
>> no existing devices can understand those packets.
>>
>>
>> Yu Guanghui <ygh at dlut.edu.cn>
>> Network and Information Center
>> Dalian University of Technology, China
>>
>>
>> On Fri, Mar 23, 2012 at 10:10 AM, Lee, Yiu
>> <[email protected]>wrote:
>>
>>> Hi Guanghui,
>>>
>>> I agree that both MAP and 4rd-u are similar technology and solving the
>>> same problem. From technical perspective, can you elaborate this a lithe
>>> bit?
>>>
>>> Thanks,
>>> Yiu
>>>
>>> From: Guanghui Yu <[email protected]>
>>> Date: Thu, 22 Mar 2012 20:26:40 +0800
>>> To: Softwires WG <[email protected]>
>>> Subject: Re: [Softwires] Path to move forward with 4rd?
>>>
>>> I read 4rd-u draft and found it is flawed.
>>>
>>
>>
>> _______________________________________________
>> Softwires mailing list
>> [email protected]
>> https://www.ietf.org/mailman/listinfo/softwires
>>
>>
>
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