, Telecom Tigers: MNP Call Flow Normal Mobile to Mobile Call

Sunday, June 13, 2010

MNP Call Flow Normal Mobile to Mobile Call

Hi All,
Writing this to throw some light on call flows when MNP(Mobile Number Portability) will be implemented in India.
There is one very interesting a full form of MNP floating in industry "Mujhe Nahi Pata", hope after reading this we will be able to say goodbye to that :)

Before coming to the point i would like to elaborate some terms which will used later in explaination.

1) MNPDB--> Mobile Number Portability Database, where in all details of subscriber is stored.
2) Ported In/Out--> Ported In/Out subscriber are those which have changed there Service provider
Exp: A was originally Airtel Subscriber and availed MNP and changed to
Vodafone so A will be Ported in number for Vodafone and Ported out Number for Airtel.
These terms are enough to get a feel of normal mobile to mobile in MNP.

Here i have taken example to Vodafone Delhi where Subscriber A in MSC1 and Subscriber B in Coverage of MSC2.
Let us now go through signaling flow in steps:
1) Subscriber A dials Subscriber B
2) MSC1 receives B number and SRI is sent to MNP server instead of HLR as in case of traditional call flow.
3) MNP checks its database and founds that this is own subscriber and relays that SRI to HLR.
4) HLR on receiving SRI check the VLR address of subscriber and send PRN to MSC2.
5) In response to PRN MSC2 returns with MSRN.
6) HLR forward that MSRN number to MSC1 in SRI Response Message
7) MSRN is now dialled out from MSC1 to MSC2 to establish the voice path between two MSCs
After this call flow remains same as in case of traditional call flow which is already posted in this blog.
**There may be some changes in call flow as Implementing MNP is operator specific, they implement the way which is best feasible for them.
But Implementing Concept remains the same.
Hope it had been informative for you.
More call flows to come in case of MNP as this was normal scenario, till then happy reading.
Remember sharing knowledge is best way to gain knowledge, expecting inputs/comments from readers as well :)

Thanks & Regards
telecomtigers@gmail.com
http://homepageforu.webs.com/

15 comments:

  1. Shohit - that's very insightful - thx.

    I would have another question, to which I can't find an answer:

    Does an SRI include on any signal layer the A number of the calling party?

    I think it is not included on MAP level, but is there any chance to get this information at this stage of the call setup process?

    Thx

    André

    ReplyDelete
  2. Thank you all for your precious comments... keep them coming..as they keep us motivated!!!

    ReplyDelete
  3. nice info.. but how dinamically MNP DB changes ?

    ReplyDelete
  4. @Anonymous: Thankx..... Its same as HLR whenever there is new MNP subscriber it has to be updated in MNP database also at the same time.

    ReplyDelete
  5. Hi, Im Naren, When do we give All Call Query??

    ReplyDelete
  6. Hi,
    Any one have an idea about non served party MNP call flow...Hope the above scenario is for served party(Originating)i am expecting terminating scenario that too for non served party(Calling party)call flow.
    ex Airtel customer activated MNP for Vodafone.So his MNP in/out has been created for both Airtel as well Vodafone only.In that case if any one calls Reliance to that MNP activated customer how the call will be routed,If it route as like normal i.e. Reliance MSC will contact Airtel MSC after that Airtel MNP replies as the number you have called is ported out to Vodafone(NID),then again the call will be back to reliance and then routed to Vodafone...

    If this is the type of call flow then unnecessary resource are wasted also if MNP database of Airtel fails then the never be routed to vodafone right.

    If i am wrong please guide me proper reply.

    Thanks and Regards,
    Mothilal Amarnath
    mothilal.amarnath@ericsson.com

    ReplyDelete
  7. @Naren: All call query means you have to query MNPDB for each and every mobile call. Regarding when it is done, if you have gone through normal mobile to mobile call in same PLMN SRI to HLR is replaced by SRI to MNPDB.

    Feel free to revert in case of doubt...

    CHeerS!!~

    ReplyDelete
  8. @Mothilal: There is one more Node which will keep all MNPDB of different operators in Sync.
    Central Database Base (CDB/ Central MNPDB.

    Taking your example i.e
    Airtel subscriber has moved to Vodafone.
    In this case all MNPDB server including Reliance MNPDB will be updated by CDB that this particular number is now moved to Vodafone.

    Once call is originated from Reliance subscriber to that particular number, in response to SRI to MNPDB Reliance MSC will get LRN+B Number here LRN will of Vodafone not Airtel.
    So call will be routed to Vodafone, Airtel will not come in picture.

    Hope i am clear
    Feel free to revert.....

    Regards
    Shobhit
    leostroika@gmail.com

    ReplyDelete
  9. very good info on MNPDB& CDB thanks

    ReplyDelete
  10. If there are multiple HLRs , how STP know to which HLR it should route the SRI . Based on number analysis ???

    ReplyDelete
  11. Hi,
    GT analysis will be more appropriate answer.

    ReplyDelete

 
Template design by Amanda @ Blogger Buster