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can anyone tell me about N7 – how many A channels can it handle at a time or how many subscribers at a time be accomodated with one N7
Hello Fahim,
In theory, one N7 channel can take care of 256 A=interface channels (256 subscribers).
In reality, you must use a big safety margin to avoid any type of congestion (can only use up to 40% of capacity). Therefore, the rule is :1 N7 for 100 A channels (100 calls)
Easy to remember, isn’t it ?
Rule of thumb : 4 PCM (max. 120 calls) for 1 N7
Thnx Pix,
your answer has been of great help to me
Hello Again,
I would like to put another question regarding N7 – that is SCCP – what is it’s role and how it works in the context of A channel ?
N7/SCCP carries all signalling messages that can be exchanged between BSC and MSC (CONNECTION REQUEST, HO REQUIRED, ASSIGNMENT REQUEST, RELEASED, AUTHENTICATION, CIPHERING, etc…). It also carries SMS (am I correct ?? i remember this…) 🙂
All other timeslots carry data or voice.
hi,
In normal cases N7 is defined in the 16th TS of the first Ater TP of one Ater Mux – that means SCCP should be available on those TPs only, right ? if so – then why the busy/available SCCP column of USD A-interface seems rather a bit indiscriminate in nature ?
i’m not familiar with the USD window, and the terms you use. But maybe what i’m going to tell you will answer your question :
when a comm is located on a certain AterMux, it doen’t mean the signalling will go through the SS7 which is n the same Ater Mux.
Even more complicated : Most of the time, for one communication, the signalling BSC-MSC is on one SS7 TS, and the signalling MSC-BSC is on another S7 TS 🙂It’s totally dynamic and “random”.
Can you explain what is th eactual meaning of 2*2-34+2 which we find ericsson MMU fron panel.
Dear Sohag,
I think you are talking about MW PDH links. think that is wirtten in product documents of MINILINK of Ericsson
Hi Pix,
But – does sccp works on a TS or A channels where N7 has not been defined ? say, ss7 has been defined in one A out of four in one ATR – so other As – will SCCP work in other As?
SCCP and SS7, it’s the “same” thing (one is the name of the protocol, the other the name of the pysical channel)
the SS7 of 1 TS out of 4 E1 will carry enough signalling for the 4 E1’s.
If you have 8 E1s, you’ll need two SS7. The signalling of one circuit channel will be carried on either SS7, not necessarily the one located on its “4-E1s” group.Is that answering your question ?
Hello Fahim,
I think the busy/available SCCP column of USD A-interface is showing “the function of DTC board”(You can see from the configuration table).
In USD, the one that has busy/available SCCP mean this DTC board has BSSAP/SCCP function.
For the others has N7/MTP and TCHRM function depend on the BSC configuration.Warmest regards,
Hi Rala,
Here lies the confusion – the DTCC board whose corresponding Ater TP contains the N7 – does not always carry SCCP rather it seems quite random in nature -if I am right !! can you please elaborate your answer regarding this ?
Ok.
The DTC (SBL) are identified according to the software provided and because of the different software loading in the DTCC (RIT) so there are three types of DTCC:
The BSSAP/SCCP DTC manages the user application layer messages and user connections(SCCP)–> In USD, we will see the SCCP available at this DTC type.
The N7/MTP DTC manages the MTP–> the DTC that contains the N7 on timeslot 16.
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