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Telenor Sweden using Subtonomy NocMap during successful HLR 2 SIM migration

Updated: Oct 30, 2023

Headphones laying on desk in front of monitor.

Telenor Sweden did an HLR (Home Location Register) migration as part of modernizing their core network. The two existing HLR:s were to be consolidated to a new one, with minimum customer impact. Subtonomy NocMap was used during the migration to monitor the service performance of the network in real-time.

6M SIM cards moved in HLR migration

14h to successfully migrate one HLR

Real-time monitoring of service performance during migration

About Telenor Sweden

Telenor Sweden is a telecommunications service provider with a network covering 99% of the Swedish population and more than 2.5 million mobile subscribers. Telenor Sweden is part of Telenor Group, one of the world’s major mobile carriers with operations in Scandinavia, Central Eastern Europe and Asia.


As part of a big Circuit Switch core modernization project, Telenor Sweden needed to migrate their two HLR:s. The two registers were to be moved into a single new HLR. The migration was also required to enable new services to be launched, e.g. VoLTE and Voice over Wi-Fi. Over six million SIM cards were to be moved in a live network during the migration, with minimal impact on the customers. Such project requires much preparation and is described as doing open-heart surgery on the network.


During the actual HLR migration it is extremely important to be able to see the network’s service performance live. This way, if something happens that affects traffic, issues can be captured and solved immediately and migration can be rolled back instantly should something severe occur. With Subtonomy NocMap, Telenor Sweden were able to see service performance in real-time with KPI:s such as success/failure rates, and also unique number of users and location updates to make sure devices were not lost during migration. The latter was also monitored to make sure no signaling storms occurred to e.g. roaming networks when all devices were being moved to a new location. These NocMap graphs were presented on big screens during the migration for the involved Telenor team to see current status of the network.

Magnus Johansson – Mobile Core at Telenor, says:

“We are very happy with the outcome of this HLR migration which did take lots of preparation. For a big project like this you always expect some minor glitches which in our case turned out to be some old IoT devices that didn’t understand they needed to do a location update, but other than that it was done very seamless without impacting our customers. Using NocMap for monitoring during the migration was of great help for us. For a critical project like this, you cannot afford to wait several minutes to see if something goes wrong and NocMap let us see all graphs in real-time and had something happened we would have been able to just click in the graph to immediately get directed to the source of the issue.”


The migration of the two legacy HLR:s to the new one was divided into two phases where each HLR was migrated with 14 days apart. Migrating one HLR took 14h and was done between Saturday-Sunday when traffic was at its lowest. The whole project was a success with the new HLR now fully operational.

Fredrik Edwall -EVP Sales & Marketing at Subtonomy, says:

“It was impressive to see Telenor in action on this HLR migration and all the work they put into it. This is the kind of project where failure is not an option and it was exciting to have NocMap serve as the EKG of the network, monitoring what was going on in real-time during the whole migration.”

Subtonomy provides intuitive machine learning software for Communications Service Providers for increased customer experience. The company is headquartered in Stockholm with sales office in Dubai and is working with telecom customers globally. More information about Subtonomy and its offerings can be found at or by contacting


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