Woj,

I am confused. You said "given that EA=0 is already covered (eg embedding of
full IPv4 address, no address sharing, if not the other case)". If I read
the spec right, this is my understanding: If I want to embed full v4 address
in the CE v6 address, the v4 address will be embedded in the EA. If so, how
would EA=0? 

"The EA bits encode the CE specific IPv4
   address and port information.  The EA bits can contain a full or part
   of an IPv4 prefix or address, and in the shared IPv4 address case
   contains a Port-Set Identifier (PSID)."

I prefer one solution vs. N solutions given that the one solution can
logically solve all problems and doesn't cause confusion. Consider we agreed
on including 1:1 MAP. When an operator deployed it, he had to ask if I want
to share v4 addresses, should I put the v4 info in the EA or set EA=0 and
provision PSID? It will create unnecessary confusion. Simply put I am not
"calling out for a "remove that part of the spec & complicate it" case". My
position is quite an opposite. I am calling out for "not adding confusion to
complicate a spec".

In the end, it is up to WG to decide.

Thanks,
Yiu

From:  Wojciech Dec <[email protected]>
Date:  Friday, July 27, 2012 8:06 AM
To:  "Yiu L. LEE" <[email protected]>
Cc:  Ole Trøan <[email protected]>, Softwires-wg <[email protected]>
Subject:  Re: [Softwires] map-00: review on the mode 1:1



On 26 July 2012 16:59, Lee, Yiu <[email protected]> wrote:
> Ole,
> 
> IMHO the WG will need to decide whether EA=0 should be covered at all. If
> not, then the draft could explicitly mention EA must be > 0 and must
> contain v4 information in the CE address. If the WG decided this needed to
> be cover, I would recommend to have a new draft to cover it and leave EA=0
> undefined in the base draft.

What are the technical arguments for making such a decision?
Furthermore, given that EA=0 is already covered (eg embedding of full IPv4
address, no address sharing, if not the other case) you appear to be calling
out for a "remove that part of the spec & complicate it" case, even though
not disputing the use-fullness of the use-case.  Seems a sure way to get us
from 1 solution to N solutions just for the sake of it.

Thanks,
Woj.
> 
> Thanks,
> Yiu
> 
> On 7/26/12 6:22 AM, "Ole Trøan" <[email protected]> wrote:
> 
>> >Yiu,
>> >
>>> >> Set EA bits=0 only saves bits in v6 address and decouples v4/v6 address
>>> >> dependency. It doesn't bring any new function compared to embedding full
>>> >> v4 address in the EA-bit. However, the operation models of EA-bit>0 or
>>> >>=0
>>> >> are very different. By the way, this works only for MAP-E. I fail to see
>>> >> why we want to include this in the base spec.
>> >
>> >what do you say in the spec if EA=0 and provisioned IPv4 prefix length =
>> >32.
>> >the spec has to say something about this to be complete.
>> >
>> >cheers,
>> >Ole
>> >
>> >
>>> >>
>>> >> Thanks,
>>> >> Yiu
>>> >>
>>> >>
>>> >> On 7/25/12 9:45 PM, "Satoru Matsushima" <[email protected]>
>>> >> wrote:
>>> >>
>>>> >>> Hi Yiu,
>>>> >>>
>>>> >>> On 2012/07/26, at 4:08, Lee, Yiu wrote:
>>>> >>>
>>>>> >>>> Ole,
>>>>> >>>>
>>>>> >>>> Where can I get the formal definition of 1:1 mode? My understanding
of
>>>>> >>>> 1:1
>>>>> >>>> refers to one public IPv4 address per subscriber but you refer very
>>>>> >>>> specific to decoupling IPv4 and IPv6 addresses.
>>>>> >>>>
>>>> >>>
>>>> >>> It doesn't 1:1 in MAP and 4rd context, because embedding full ipv4
>>>> >>> address in ea-bits is as a result of prefix allocation operation.
>>>> >>>
>>>>> >>>> Before MAP was accepted as WG item, MAP was proposed to embed IPv4
>>>>> >>>> address
>>>>> >>>> information (EA bits > 0) in the CE IPv6 address to achieve
>>>>> stateless.
>>>> >>>
>>>> >>> No, there was no such definition for EA-bits length restriction.
>>>> >>>
>>>>> >>>> Now there is a new proposal to add a new feature to have the IPv4
>>>>> >>>> information
>>>>> >>>> in the BR only. This change requires to provision individual
>>>>> >>>>subscriber
>>>>> >>>> information to the BR (instead of aggregated information). Benefit
are
>>>>> >>>> saving bits and breaking v4 and v6 address dependency.
>>>> >>>
>>>> >>> There's no change from previous spec, to just clarify MAP, as a
>>>> >>>stateless
>>>> >>> solution, could naturally support most granular mapping rule in its
>>>> >>> nature.
>>>> >>>
>>>>> >>>>
>>>>> >>>> Questions to WG:
>>>>> >>>> Is it useful feature to be included in MAP? If not, why and
>>>>> >>>>alternative?
>>>>> >>>>
>>>> >>>
>>>> >>> I believe that it does not make sense to restrict EA-len > 0 for both
>>>> >>>MAP
>>>> >>> and 4rd. It does make sense that you see MAP as framework of solutions
>>>> >>> which covers specific 1:1 solution by the mapping algorithm.
>>>> >>>
>>>> >>> cheers,
>>>> >>> --satoru
>>>> >>>
>>>> >>>
>>>>> >>>> Thanks,
>>>>> >>>> Yiu
>>>>> >>>>
>>>>> >>>> On 7/25/12 2:40 PM, "Ole Trøan" <[email protected]> wrote:
>>>>> >>>>
>>>>>> >>>>> Yiu,
>>>>>> >>>>>
>>>>>>> >>>>>> I am not asking whether MAP supports 1:1 mode with no EA bits or
>>>>>>> >>>>>>not.
>>>>>>> >>>>>> I
>>>>>>> >>>>>> am
>>>>>>> >>>>>> asking MAP allows to embed the 32-bit address in the EA bits to
>>>>>>> >>>>>> achieve
>>>>>>> >>>>>> 1:1 mode:
>>>>>>> >>>>>>
>>>>>>> >>>>>> "The EA bits can contain a full or part
>>>>>>> >>>>>> of an IPv4 prefix or address, and in the shared IPv4 address case
>>>>>>> >>>>>> contains a Port-Set Identifier (PSID)."
>>>>>>> >>>>>>
>>>>>>> >>>>>> Why not use this instead?
>>>>>> >>>>>
>>>>>> >>>>> you can do either.
>>>>>> >>>>> embedding a complete IPv4 address and PSID does require a lot of
IPv6
>>>>>> >>>>> space though.
>>>>>> >>>>> e.g. /56 - 32 - 6 = /18
>>>>>> >>>>>
>>>>>> >>>>> 1:1 mode is typically referred to a model where IPv4 and IPv6
>>>>>> >>>>> addressing
>>>>>> >>>>> are independent.
>>>>>> >>>>>
>>>>>> >>>>> cheers,
>>>>>> >>>>> Ole
>>>>>> >>>>>
>>>>> >>>> _______________________________________________
>>>>> >>>> Softwires mailing list
>>>>> >>>> [email protected]
>>>>> >>>> https://www.ietf.org/mailman/listinfo/softwires
>>>> >>>
>> >
> 
> _______________________________________________
> Softwires mailing list
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