Duplicate MCC MNC pairs

[mstan]

It is my understanding that an MNC and MCC combination should be considered unique. Upon inspecting the data, I have found 41 instances where an MCC and MNC pair share more than one entry. Attached is a CSV that denotes the identified MCC and MNC and how many times the pair occurs within the JSON file.

duplicate_mcc_mnc.csv

[barrettoTNI]

I haven't checked your full list of duplicates but I'm familiar with the top three entries. They are not duplicates. 234-50 covers the Channel Islands (Jersey is the biggest island and Guernsey is the second biggest) both of which are self-governing dependency of the British Crown. Both serviced by the Jersey Telecom (well JT Group Ltd which is the parent company of JT and Wave Telecom). So what you're seeing is 3 listings all under the umbrella of the United Kingdom MCC of 234:

234-50 for Guernsey (GG)
234-50 for Jersey (JE)
234-50 for United Kingdom (GB)

They are all the same network so they share the same MCC-MNC. Note, that's just for JT, there are other networks serving Channel Islands as well, Airtel is 234-03 so you'll see that three times as well.

The second and third on your list are in the same situation. 234-18 is the Isle of Man network serviced by Cloud 9, while 234-58 is also the Isle of Man but service by Manx Telecom. Since the Isle of Man is also a self-governing dependency of the British Crown, you'll see them twice:

234-18 for Isle of Man (IM)
234-18 for United Kingdom (GB)

Manx Telecom for the Isle of Man will be represented twice as well.

BTW, it looks like you created your CSV from an app (spreadsheet or database), that is treating the MNC's as integers, as such you're losing information. The MNC digit length is either 2 or 3 digits for any given country. For the United Kingdom (GB) and all it's dependencies of the British Crown will have two digit MNCs. So the the MNC entry for Airtel in the Channel Islands is 03 not 3. That will most likely matter, depending on how you are using the information (for example if you're going to be building 4G DIAMETER routing rules realms, those MNCs will be padded to 3 digits so Airtel would be epc.mnc003.mcc234.3gppnetwork.org

I'm familiar with the JT and Manx off the top of my head because my company has direct roaming agreements with those two MNOs. The repeated entries you're seeing for US MCCs (310, 311, 313) are going to be similar but for US Territories (i.e., not part of the 50 States). In any event, those repeated entries are going to be for the same network operator so they can be considered one and the same even if it listed in multiple self-governed regions or countries.

Hope that makes sense.

Cheers,
//Robert

• editted - missed a word