- This topic has 14 replies, 1 voice, and was last updated 10 years, 5 months ago by Antony B Jouh.
12th March 2010 at 20:34 #61432SHAFARGuest
as i see there are lots of profis here so please help me if you can, I will be very much grateful
during 2 days i’m facing huge dropped call rate of remote transcoder failure in one my BSC, it’s more than 3% for yesterday. it increased six times.
completely all cell are affected. it was more than 2000-2500 of drops per every cell yesterday.
I have no alarms in omc and drive-test didn’t help me also.
Where should i start my investigation? One hint, please help me anybody if you can
Thanks in advance
BR, Shafar12th March 2010 at 21:49 #61433SHAFARGuest
I work on A9130 B9
Thanx in advance12th March 2010 at 21:58 #61434lilyGuest
Good evening, Shafar!
This very morning I has been working on the same problem for one of our MX BSCs. – enormous MC739 (Number of dropped calls due to remote transcoder failure) counter.
(as I see you also have a problem with MX BSC they must be twins I think :)))
From my experience – in 99,9% of cases the cause is faulty MT120 board. The question is how to find it (and the sooner the better :)) especially if you have a lot of Aterm (> 20).
You can get from NPO or RNO statistic for Aint-channels (in NPO this option is available only if you have working zone with less than 2000 cells) – particularly for that BSC for several hours. There are only 2 counters: C750 and C751.
C750 – TIME_A_CHANNEL_BUSY
C751 – NB_A_CHANNEL_ALLOC if my memory doesn’t trick me
C750/C751 is average duration of Aint channel occupation.
Normally it ought to be around 30 – 40 sec. Of course you see much grater range in your values, but be very careful – if you see some channels where during some hour successively this value is around 3-3,5 sec – you are lucky and you’ve found faulty link.
Than – define an Ater link and reset MT120. It’s not bad to shutdown traffic on it before of course :))
Sometimes it doesn’t help and you should to change MT120 but it happens – as I see in our network – seldom.
Good luck!12th March 2010 at 22:01 #61435SergioGuest
What am i seeing?
Lilu you should be in bed many hours ago it’s midnight there as i remember
now you musn’t worry, should sleep well, eat well and behave yourself well too :0))13th March 2010 at 09:30 #61436SHAFARGuest
Lily thanx alot
your explanation is very clear
but i have no rno or npo
can i get necessary data anywhere else?
many thanxes13th March 2010 at 13:11 #61437lilyGuest
You can use raw data – it’s PM type 18. Files stores on OMC-R server, you can find them there:
something like that, i’m writing by memory 🙂
they are easy to read and understand.
write if you have questions
Thank you very much for your care, but you know instant messengers aren’t difficult in use 🙂
you have my skype contact 🙂14th March 2010 at 08:49 #61438PixGuest
in which country are you working ? we’ll push your boss to buy NPO !! That is a perfect example why you should buy it. Look how many calls you lost because of that… how much money it represents 🙂
Lily : call drops due to RTC could be due to anything, from TRX failure, to Abis, BSC, Ater or MT120 failures. Not only MT120… But I gueess, you meant when there are so many rtc drops all over the place, it is then probabl due to mt120… then agreed !
pix14th March 2010 at 10:51 #61439SHAFARGuest
sorry, guys, i must disturb you again with questions
at last i found that channels with very short time of occupancy it’s really always less then 4 sec
here they are
i am confused to which A-TERmux they belong?
please help me again
thank you for help but i doubt that anything can convent our owner to invest money in equipment now
we supposed to buy rno last year14th March 2010 at 11:56 #61440FRGuest
It is your 20th AterMux.14th March 2010 at 16:21 #61441lilyGuest
FR, are you sure?
As for me, it looks like 12th…
Dear Pix, your word?14th March 2010 at 19:26 #61442RexGuest
it’s 45, 46, 47 and 48 PCM, which is 12th AterMux.
Rex15th March 2010 at 06:03 #61443FRGuest
oops Sorry guyz.. Yes, its “12th”15th March 2010 at 12:48 #61444PixGuest
Yes, it seems to be the 12th atermux 🙂 TS29 is bad on all 4 interfaces, but i’m not sure what it means… MT120 faulty or misconfig of TS at MSC side ?
For info the excel formulas go like this (with # being the number you have listed below)
Atermux = INT(#/32) + 1
A PCM = INT(Atermux/4) + 1
TS = MOD(#,32)
Ater Mux = 12, A PCM = 45 TS 3
Ater Mux = 12, A PCM = 45 TS 16
Ater Mux = 12, A PCM = 45 TS 29
Ater Mux = 12, A PCM = 46 TS 4
Ater Mux = 12, A PCM = 46 TS 19
Ater Mux = 12, A PCM = 46 TS 29
Ater Mux = 12, A PCM = 47 TS 2
Ater Mux = 12, A PCM = 47 TS 11
Ater Mux = 12, A PCM = 47 TS 19
Ater Mux = 12, A PCM = 47 TS 29
Ater Mux = 13, A PCM = 48 TS 9
Ater Mux = 13, A PCM = 48 TS 17
Ater Mux = 13, A PCM = 48 TS 24
Ater Mux = 13, A PCM = 48 TS 2915th March 2010 at 13:42 #61445SHAFARGuest
Thank you guys very much
You’re very kind and helped me so much
actually i did not see any alarms on 12th MT120 but after its reseting everything is OK
during last time no drops MC739 on all BSC
thanx for formulas it’s clear how to calculate
thankx to all of you5th April 2010 at 19:07 #61446Antony B JouhGuest
very usefull thread
it was just in time for me and helped to fix my trouble
thank you all, guys