Re: [MEXT] GRE support in DSMIPv6 - AD review

[Basavaraj Patil <[e-mail]>]

Sri,

For the resolution of the IESG comments regarding the TLV header, I have
said that this spec should get rid of it and if someone feels the need for
it to be specified, they can do so (potential docs suggested being the IPv4
support I-D or the GRE Keys I-D in Netlmm WG).

My comment was based on the reopening of the discussion regarding the need
for GRE encapsulation in the context of DSMIP6. I agree that nothing has
changed since we had this discussion a while ago and as you can tell neither
has my opinion regarding the need for GRE for host based mobility.
But I am fine with whatever is deemed as the consensus regarding the TLV
header and/or GRE encapsulation support in the DSMIP6 I-D.

-Raj


On 1/19/09 1:01 PM, "Sri Gundavelli" <[e-mail]> wrote:

> Raj,
> 
> We went over all this list year back. You asked the same question,
> you got the same answers. There are no new arguments. If you want
> to ignore the use of GRE key in NEMO use, for marking different MNP
> flows for differential treatment on the HA, or the point of carrying
> legacy payload traffic, or about a single integrated HA/LMA serving
> mobile nodes and leveraging a common encap mode, you may so, but the
> fact reamins. Its useful in PMIP, it may be useful in NEMO, or may not
> be so useful in client-MIP, fine, lets not apply restrictions.  If we
> have a home agent that can perform GRE switching in the hardware, its
> a good reason for me to leverage for all mobile flows and not build one
> more mode.
> 
> We really should not be re-opening converged cases. There is a AD
> comment on lack of specification on the tunneling mode, we can
> easily fix that, rather dug open the whole mountain. Hesham spent
> lots of time on adding all the TLV and the related support, we
> dont have to waste all that, if there is some thing minor missing.
> 
> Regards
> Sri
> 
> 
> On Mon, 19 Jan 2009, Basavaraj Patil wrote:
> 
>> 
>> I still fail to really understand why GRE encapsulation is needed for host
>> based mobility (DSMIP6).
>> The only argument below is that it provides "richer semantics than
>> IPv6-in-IPv6". Can you provide an explicit example of how the richer
>> semantics are useful vs the IP-in-IP encapsulation for DSMIP6?
>> 
>> Cheers,
>> -Raj
>> 
>> 
>> On 1/19/09 12:09 PM, "Sri Gundavelli" <[e-mail]> wrote:
>> 
>>> 
>>> 
>>> On Fri, 16 Jan 2009, Behcet Sarikaya wrote:
>>> 
>>>> [behcet] I couldn't understand why MN would need to support GRE. Can
>>>> someone
>>>> explain the use case?
>>>>  
>>> 
>>> This issue was discussed at length. Many reasons were cited as why the
>>> GRE encapsulation mode may be needed in client-based mobility and why
>>> it should not be restricted to network elements alone.
>>> 
>>> The LMA element in Proxy Mobile IPv6 is a feature extension to the
>>> Mobile IPv6 home agent. They have a strong relation. If some one
>>> implements home agent function, implements the data plane with all
>>> the hardware support for GRE and it cant be leveraged when supporting
>>> client-based mobile nodes ? Its the same home agent that serves both
>>> types of nodes.
>>> 
>>> The options that we are standardizing NETLMM or MEXT, each should not
>>> take a different path. Its not that we have one revocation option for
>>> PMIP, one for NEMO and the other for MIP6. Keeping them together will
>>> save implementors to leverage all these features and resources across.
>>> 
>>> GRE is another enapsulation mode, it exists with much richer semantics
>>> than IPv6-in-IPv6. The ability to carry non IP traffic, I'm not saying
>>> I support this for carrying IPX/AT traffic, but the point that its a
>>> useful encapsation mode that exists in MIP4 and cant be ignored for
>>> good reasons.
>>> 
>>> Sri
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>>> Thanks,
>>>>  
>>>> Behcet
>>>> 
>>>> 
>>>>> Hi Pasi, Hesham,
>>>>> 
>>>>> The TLV header was specified in the DS-MIPv6 document after rather a
>>>>> long and acrimonious debate on the former MIP6 mailing list. There were
>>>>> atleast two consensus calls that were run at that time.
>>>> 
>>>> => I don't realy want to get into that, we all know there was no concensus
>>>> and we had to teleconference to come up with the existing method
>>>> 
>>>> Anytime you have
>>>>> a UDP header with IPv4/IPv6/GRE header following it, you need the TLV
>>>>> header.
>>>> 
>>>> 
>>>> 
>>> _______________________________________________
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>> 
>> 

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