Re: [DNA] QUESTION: Remove Link Down information indraft-ietf-dna-link-information-03

[Greg Daley <gregd@research.panasonic.com>]

Hi,

I think that this is a good point.  There's a mix
of protocols which have different properties
regarding Link-Down indications.

802.21 is one of those which is potentially better behaved,
while PPP (LCP) and existing 802.11 are poorly behaved,
as anyone may forge a packet to tear down the connection.

In the PPP case it was because the protocol was designed
when people trusted the physical layer to be under the
MAC, in 802.11, I guess it was an oversight.

The better behaved protocols may potentially
be used to send indications up the stack to control
packet queuing and vertical handovers.

We haven't described 802.21 here though, because of
the simultaneous development of the specifications.

Greg

Yoshihiro Ohba wrote:
> FYI, IEEE 802.21 defines link down indication, but with more detailed
> information on why the indication has been generated.  Depending on
> the detailed information the receiver of the indication is allowed to
> take different actions including silent discarding the indication.  It
> may be possible to define more sophisticated indications in a future.
> My personal opinion is that it sounds premature to conclude that link
> down indication is harmful in general.
> 
> Yoshihiro Ohba
> 
> 
> On Tue, Jul 18, 2006 at 09:18:49AM -0700, James Kempf wrote:
>> I'm fine with this. The history of Link Down in IETF is that nobody has 
>> ever figured out a way to allow it to be done securely. I hope that we can 
>> record this somewhere (maybe an RFC "Link Down Considered Harmful"? from 
>> the IAB) so people stop wasting time on it.
>>
>>            jak
>>
>> ----- Original Message ----- 
>> From: "Suresh Krishnan" <suresh.krishnan@ericsson.ca>
>> To: "Dna" <dna@eng.monash.edu.au>
>> Cc: "greg Daley" <gregd@research.panasonic.com>; "Bernard Aboba" 
>> <aboba@internaut.com>; "Jari Arkko (JO/LMF)" <jari.arkko@ericsson.com>; 
>> "Alper Yegin" <alper.yegin@yegin.org>
>> Sent: Monday, July 17, 2006 3:57 PM
>> Subject: [DNA] QUESTION: Remove Link Down information in 
>> draft-ietf-dna-link-information-03
>>
>>
>>> Hi Folks,
>>>  In its current form draft-ietf-dna-link-information-03 provides 
>>> information about both link up and link down events. There were some 
>>> concerns raised about the presence of link down events in this document, 
>>> since DNA does not necessarily use the link down event. So instead of 
>>> spending time to understand how to treat this event in this WG, one 
>>> proposed solution was to remove link down related info from this document 
>>> and let other wgs(perhaps future ones) work on it. If you have any 
>>> opposition to this solution please respond to the mailing list by the 24th 
>>> of July 2006 stating your objection.
>>>
>>> Cheers
>>> Suresh and Greg
>>>
>>
>>