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RE: [802.21] Link indications thread within DNA



Hi Eric,
I followed that thread but, I think that the definition of the "link up" and
"link down" in that discussion is related with the definition of **IETF's
LINK**. 
Anyway, I agree with you that we, IEEE 802.21 needs to define the term of
"link going down" in our IEEE terms.

Related with this, let me share my 2 cents. 
Regarding, the IEEE 802.16e networks, I think that we can use the the HO_IND
message from the MSS to the serving BS as "link going down" trigger.

Regards,
Junghoon Jee


________________________________

	From: owner-stds-802-21@ieee.org [mailto:owner-stds-802-21@ieee.org]
On Behalf Of NJEDJOU Eric RD-RESA-REN
	Sent: Monday, June 20, 2005 4:29 PM
	To: STDS-802-21@listserv.ieee.org
	Subject: [802.21] Link indications thread within DNA
	
	

	Hi all, 
	I wonder if some of you have followed the past discussions within
DNA around how to define link up and link down. Defining "link up", "link
going down" and "link down"  are of the biggest importance to 802.21 because
it will be our ability to precisely to give the most meaningful definition
to those terms that will render possible the work of media specific groups
in the attempt to specify the exact states of link layer protocols when the
event should be fired.  For example 802.21 identifies the need for a "link
going-down" indication to be sent to the MIH in order to prepare handoff in
make before break scenarios. The group has to move into the work of
specifying exactly what link going down means. The 802.11 RSSI is an
indication which variation within any time window can not be relied upon to
ascertain that the 802.11 link is going down (simply because the RSSI itsef
is everything but reliable). 802.11k is trying to define a signal power
level that is more reliable than the RSSI. It might still be time for .21 to
help shape the specification of that parameter 11k is trying to come up in
the way that its variation in time be more reliable thant RSSI's.

	If there is any 802.11k working group member on this list they may
want to give more developments than i can. 

	Eric Njedjou