What is HLR Lookup or phone number lookup ?
HLR Lookup details
- IMSI
- MCC and MNC
- Visiting MSC,
- Number Portability
- Subscriber Status (Active , InActive, Unknown)
- Roaming Information.
In case of failure in hlr lookup, hlr may returns following codes:
- Absent Subscriber, means subscriber is not online.
- Call Barred, the SMS service is barred for this msisdn.
- No Response, means the request timeout.
- Provider Abort, means GSM MAP protocol error occurred.
- TeleService Not Provisioned, means subscriber is not allowed to use sms service.
The HLR lookup service providers, provides HTTP Apis to HLR lookup applications. The service providers receives the API over http from hlr lookup app and do SS7/Sigtran level messaging and sends the result back. The service provider provides SDKs in different programming languages. Sdk can be linked to the hlr lookup app.
HLR Lookup benefits:
- Any organization which uses to send bulk sms to the thousands of mobile users, can update their mobile number data base via hlr lookup or clean database for inactive numbers. So they can reduce the cost of sending sms in bulk.
- The Mobile operators or bulk sms providers can use this service for least cost routing. As bulk sms providers and mobile operators have multiple signaling providers for sending sms. By hlr lookup the roaming location can be know , this can be used to select routes for sending sms. As one route for a country may be low cost than other.
- Marketing people, can use this service to advertise the product at correct location.
- For sending billing CDRs to correct mobile operator. The roaming network might needs to bill the home network for a delivered sms. Now there is number portability , so just by looking at mobile number its not possible to find the home network. The home network can be find from IMSI received in hlr lookup.
- Provides real time information for the subscriber.
What is Mobile Number Portability:
In this a person can change mobile operator without changing the mobile number. A new sim is issued to the mobile number user, by the new mobile operator. New sim have new IMSI , which belongs to new mobile operator. So the mobile number is mapped to new IMSI. This information is updated on older mobile operator as well. Some places this is also achieved by having a central database.
From the older sim an sms is send for mobile number portability. Generally this takes few days to port a mobile number from one operator to other. When number is ported , the HLR of new mobile operator is updated.
When there is a MT call for the number which has been ported, the call goes to the previous mobile operators GSMC. Now as this number is ported , the signaling is initiated to new operator from older one.
When there is a MT call for the number which has been ported, the call goes to the previous mobile operators GSMC. Now as this number is ported , the signaling is initiated to new operator from older one.
Core HLR lookup or number lookup is done over SS7 network. In this HLR lookup provider , provides easy to use HTTP (xml or json) APIs to do the HLR lookup. HLR Lookup provider accepts the HTTP Api Request, convert HTTP Api in SS7 message for HLR Lookup or number lookup and response of SS7 message back to the HLR Lookup Api response.
What is HLR or Home Location Register:
HLR is the central database which maintains mobile subscriber's static as well as dynamic information. This is located in home network of a mobile user. HLR is used to authenticate calls and SMS. A sim card details are stored against an IMSI n the hlr. The IMSI is the primary key of the HLR record. The HLR is always contacted either sim in home network or its roaming. HLR is continuous updated by the SIM cards via roaming network, so that HLR have all location/roaming information of the mobile subscriber.
These days a SIM cards have multiple IMSI . A sim card is Uniquely identified in HLR by ICCID.
What is ICCID ?
An ICCID is the unique number given to the SIM card.
What is ICCID ?
An ICCID is the unique number given to the SIM card.
The HLR Lookup providers have connections to all mobile operators in world . Either they have own Global Title or they get on lease from a mobile operator.
HLR Lookup Network :
In SS7 network STP is like a router. The hlr lookup requesting server may not be directly connected to the HLR. This might be connected via many STPs in SS7 network.
Routing for HLR lookup:
In SS7 network every node is having a global address called global title. A mobile number is an example of global title. A mobile number is composed of CC (country code), MNC (mobile network code). A MNC identifies the mobile operator and the area where this number belongs.
When a request in initiated from HLR lookup server, the SCCP (SS7 layer ) level information is mentioned in the message. The source address is filled with global title of hlr lookup server and destination address is filled with msisdn of the subscriber.
This request is sent to the directly connected STP. The STP sends the request to the next hope based on the destination global title.
When request reaches to the desired HLR , for a msisdn ,the HLR sends back the response. Now the routing of response is done based on source global title ,which was present in request.
HLR lookup for mobile phone location:
Hlr lookup is used to get mobile phone location, as it gives the serving msc. So based on digits mobile country code and mobile network code approx location can be find.
There are options as well for getting cell id for a mobile device , which gives more accurate location information for location. This information can be used for cell broadcast.
HLR Lookup Message Flow :
HLR lookup network have wired and wireless components. It uses ss7 or sigtran network for wired connectivity. Nodes in ss7 network is used to transfer GSM level MAP request from source to destination.
In SS7 SCP, denotes the database , in case on HLR lookup , HLR is the database node which have mobile subscriber profile. The mobile subscriber is configured with static information (IMSI, Services , Grps etc.) , along with dynamic information (visiting VLR, visiting MSC/SGSN etc.).
In SS7 network STP is like a router. The hlr lookup requesting server may not be directly connected to the HLR. This might be connected via many STPs in SS7 network.
Routing for HLR lookup:
In SS7 network every node is having a global address called global title. A mobile number is an example of global title. A mobile number is composed of CC (country code), MNC (mobile network code). A MNC identifies the mobile operator and the area where this number belongs.
When a request in initiated from HLR lookup server, the SCCP (SS7 layer ) level information is mentioned in the message. The source address is filled with global title of hlr lookup server and destination address is filled with msisdn of the subscriber.
This request is sent to the directly connected STP. The STP sends the request to the next hope based on the destination global title.
When request reaches to the desired HLR , for a msisdn ,the HLR sends back the response. Now the routing of response is done based on source global title ,which was present in request.
HLR lookup for mobile phone location:
Hlr lookup is used to get mobile phone location, as it gives the serving msc. So based on digits mobile country code and mobile network code approx location can be find.
There are options as well for getting cell id for a mobile device , which gives more accurate location information for location. This information can be used for cell broadcast.
HLR Lookup Message Flow :
- HLR Lookup Platform Receives HTTP request with MSISDN.
- Lookup Platform, builds the SS7 MAP SRI-SM message and send this to HLR over SS7.
- Upon receiving response SS7-MAP SRI-SM RESP , HLR lookup platform build HTTP response and send to HTTP application.
HLR Lookup for cell id (location):
Some times it is required to get the very near location of mobile phone (e.g 100 meter ). I this the hlr lookup app can obtain the cell id of the serving cell where mobile is roaming. This is achieve by another GSM-MAP operation over ss7/Sigtran. In the ATI (Any Time Interrogation) message is sent to the HLR with location information requested with cell id, along with msc , imsi and vlr.
HLR sends PSI ( Provide Subscriber Info) message to the VLR with requested info received in ATI.
VLR sends the PSI response with requested (e.g cell id, msc, vlr , imsi ) information (if success else an error code is returned). Received information is sent back to the hlr lookup app with ATI response.
Hello,
ReplyDeleteI have heard that HLR lookup is also performed over SMPP? In that how the HLR is connected with ? Still it is on SS7 or Sigtran or SMPP directly?
Yes, there are vendors providing HLR Lookup service over SMPP. But again its replaces the HTTP part not SS7. The HLR Lookup over smpp is terminated to smpp server , then smpp server does lookup on ss7.
ReplyDelete