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Hi experts,
Pls consent, how to prevent call drop due to T200 timer expiry.(network having 42% call drop error indication———- due
to T200*(N200+1)times expire-abnormal release]BR//
on the whole network ? 48% call drop ! that’s impossible…
T200 expiry usually refers to Abis failure, or equipment failure on one end (BTS or BSC). But if it affects the whole network, maybe you should check out your transcoder or your Ater/A interface links.
Are those interfaces “over satellite” ?Do you have any alarm in your OMC-R ?
Hi Pix,
modification is drop call reason percentage due to T200 expiry is 42% of the whole call drop.
Interfaces are not over satellite.
There are no alarm regarding it in OMCR.I have checked those sites having drop reason due to T200 expiry,
having slips & no such event of abis failure(according to log).BR//
Indranil.
T200 expiry means that the LAPD frame is sent from point A to point B on Abis, but without acknowledgment from point B.
If the frame is not acknowledged, it means it has not be received. Therefore the point A will retransmit the frame up to N200 times.
At N200+1 times, the point A will stop trying –> drop.
Now, how many reasons do you for not having an ACK from point B ?
A/ either the link is broken, and point B never received the initial data
B/ point B is down (or in a faulty state) and doesn’t receive/ack the frames.restart your processes on each end, investigate your Abis links, swap your control boards… there is not much you can do.
It’s either software pb or hardware pb.Dear Mr. Pix,
I have the same problem as Mr. Andranil,
Data link failure due to N200 time out which cause call drop.
This data link failure is abserving in most of the area.
Do you have any more comment regarding this issue?
BR,
Zia
Indranil said having slips,I guess there were clocking issues so a transmission configuration problem.
what t200 timer?
maximum of call drops in my network cause of t200.
help me for solusion.
thankshow to prevent call drop due to T200 timer expiry
As said earlier (just read older posts in this thread), it’s probably because of :
1/ Abis link failure
2/ Clock/Transmission BTS board failure
3/ Transmission BSC board failurePick your choice.
Can any one tell me that how can we know the number of drop call due to T200 exipry in nokia system ???
Hi,
Plz let me know about the LAPD Call drop.Can you explain,what is LAPD.
LapD is the signaling ‘link’ on the Abis.
Basically, it just means that there was a failure on the Abis, causing drops on the Air interface (as soon as the Abis is down, all calls handled by this abis are dropped)
T200 Timer.
what is a T200?
Plz let me know about the LAPD Call drop.Can you explain,what is LAPD.
