Re: [HOKEY] ERX-12 -- Please review changes

[Yoshihiro Ohba <[e-mail]>]

On Mon, Feb 25, 2008 at 08:32:17PM -0800, Lakshminath Dondeti wrote:
> On 2/25/2008 7:26 PM, Yoshihiro Ohba wrote:
>> Roundtrips between EAP peer and EAP authenticator on the access link
>> are not major part of signaling latency compared to AAA roundtrips.  I
>> have not heard a complaint on 802.11i 4-way handshake latency.
>
> Consider that not to be the case any more.  I am complaining. :)  More  
> seriously, handover latency of 10-20ms is a target in some networks.

I have not heard of 10-20ms handover latency requirement.  If we
assume there is such a requirement, then none of ERX and EAP-KDE will
satisfy the requirement because one AAA roundtrip can be even more
than 20ms even with local AAA servers.  Note that pre-authentication
can eliminate such a post-handover AAA roundtrip.

Yoshihiro Ohba


>
> If there is a sufficient budget for handover, we probably need to do  
> nothing for reauthentication.
>
> regards,
> Lakshminath
>
>>
>> Although it would be a nice thing to reduce any kind of roundtrips as
>> much as possible, I am not sure, after reading the IETF Last Call
>> comments, people outside the HOKEY WG seem to wonder if the expected
>> benefit for more optimization with ERX pays to its deployment cost
>> especially for existing lower-layers.  This is my main motivation to
>> come up with EAP-KDE method.
>>
>> Yoshihiro Ohba
>>
>> On Mon, Feb 25, 2008 at 05:31:08PM -0800, Lakshminath Dondeti wrote:
>>> Hi Bernard,
>>>
>>> I have reviewed draft-ohba-eap-kde-01 before and it does not meet 
>>> fast reauthentication goals.  Please see below:
>>>
>>> On 2/25/2008 3:24 PM, Bernard Aboba wrote:
>>>> [BA] I've recently seen a draft (from Yoshi, submitted today) that  seems
>>>> to provide similar functionality with no changes to RFC 3748.  Although
>>>> I haven't reviewed the document in depth, it did seem to provide
>>>> method-independent re-authentication without multiple round-trips
>>>> (at least for case of a local ERX server, which is the most important
>>>> one from a performance point of view). 
>>> The number of roundtrips on the access link is 3, if we take 
>>> connection open or an equivalent into account.  With ERP, the peer 
>>> can start sending authenticated data after 1 RT.
>>>
>>>> This document will probably be discussed in IEEE 802, which could adopt
>>>> it as their approach to EAP re-authentication going forward.
>>> In other access technologies, the handover latency requirements are 
>>> more stringent and they have already adopted ERP and waiting for 
>>> publication of the ERP RFC.  Without further optimizations, 802.11 
>>> with 3 RTs or more for connection setup and EAP-KDE and 2 more for 
>>> the 4-way exchange has little to no hope of really achieving low 
>>> handover latency.
>>>
>>> That model does not fit for voice call continuity.
>>>
>>> regards,
>>> Lakshminath
>>>
>>>> If possible, it would be good to have a single standard for this, as opposed
>>>> to multiple competing ones.
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>>>
>>
>
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