I’ve looked over the user’s guide and find the distinction between Sessions, Registrations, and Re-Registrations fairly clear. But I’d like more information if it is available and someone could point me at it.
Sessions are defined as the number of times an LUID has been “in session”. Registrations are the number of registration requests received from an SM, and reregistrations are the number of registration requests received from an SM which is already in session.
Clearly in an ideal world sessions will equal registrations and reregistrations will always be zero. My questions:
What causes an SM to decide that it has dropped session and to send a registration request while the AP still believes the SM is in session? Rewording that, what criteria is evaluated by the SM to cause it to make that decision? If this is proprietary just tell me that and I’ll drop the subject.
From the definition of a session/registration can we presume that a session count larger than 1 indicates a drop and resync of the TDM stream?
If we are dropping link, and everything else seems to be working it is reasonable to accept the idea that the link budget does not provide enough fade margin. What is Motorola’s recommended fade margin for the 900 MHz platform? Does Moto use the noise floor as the reference for fade margin?
Thanks in advance.
The AP’s Session count for an SM also increments when the SM is rebooted or power cycled. The AP’s other two counters apparently depend on whether the AP has given the SM up for dead; I presume this is when the AP’s Sessions page shows the SM as IDLE.
If the AP considers the SM idle, then the new session is considered a Registration. If the AP’s timer has not yet expired for the SM, and the Sessions page still shows the SM as IN SESSION, then the new session is considered a Re-Registration.
I’ve never timed the AP to learn how long it takes for the SM’s session to go IDLE. I also don’t know if this timer can be changed. One possiblity is the Bridge Entry Timeout – with a default value of 25 minutes, which the minimum – on the AP’s Configuration page. I suspect, however, that the time is shorter than that.
Teknix wrote:
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I've never timed the AP to learn how long it takes for the SM's session to go IDLE. I also don't know if this timer can be changed. One possiblity is the Bridge Entry Timeout -- with a default value of 25 minutes, which the minimum -- on the AP's Configuration page. I suspect, however, that the time is shorter than that.
Aye, my observations as well. I believe I am seeing some "spurious" reregistrations. Not huge numbers but enough to make things look anomalous.
We are running 7.1.4 with software scheduling on 900 Advandate hardware. On sites which have noise issues at the client end of the link I sometimes see a high reregistration rate. Those make sense, when I see several reregs during a night with little jitter, I find myself wondering what might be causing it.