IPv6 roaming in Romania

I am currently in Romania, Corona-stranded and rather bored. To kill some time, I decided to hack together a script that performs automated testing of IPv6 capability in all available PLMNs and use it with SIM cards from three different IPv6-capable PLMNs (🇵🇱 Orange, 🇸🇪 Tele2 and 🇳🇴 Telenor).

tl;dr

🤷‍♂️ Digi
✅ Orange
✅ Telekom
❌ Vodafone

Requesting a dual-stack IPv4v6 bearer always succeeds, but the resulting connectivity is sometimes IPv4-only.

Test results

Click the links in the Tech column to be taken directly to the corresponding output from my test script, and make sure to check out the footnotes for more information and explanations.

Digi (MCCMNC 22605)

SIM card	Tech	IPv4v6	IPv6
🇵🇱 Orange	LTE	📵 1	📵 1
🇵🇱 Orange	UMTS	📵 1	📵 1
🇸🇪 Tele2	LTE	📵 1	📵 1
🇸🇪 Tele2	UMTS	📵 1 2	📵 1 2
🇳🇴 Telenor	LTE	📵 1	📵 1
🇳🇴 Telenor	UMTS	📵 1	📵 1

Orange (MCCMNC 22610)

SIM card	Tech	IPv4v6	IPv6
🇵🇱 Orange	LTE	✅ 3	✅
🇵🇱 Orange	UMTS	✅ 3	✅
🇵🇱 Orange	GSM	✅ 3	✅
🇸🇪 Tele2	LTE	✅	✅
🇸🇪 Tele2	UMTS	4️⃣ 4	❌ 5
🇸🇪 Tele2	GSM	4️⃣ 4	❌ 5
🇳🇴 Telenor	LTE	✅	✅
🇳🇴 Telenor	UMTS	✅	✅
🇳🇴 Telenor	GSM	✅	✅

Telekom (MCCMNCs 22603 and 22606)

SIM card	Tech	IPv4v6	IPv6
🇵🇱 Orange	LTE	📵 1	📵 1
🇵🇱 Orange	UMTS	✅ 3	✅
🇵🇱 Orange	GSM	✅ 3	✅
🇸🇪 Tele2	LTE	📵 1	📵 1
🇸🇪 Tele2	UMTS	📵 1	📵 1
🇸🇪 Tele2	GSM	📵 1	📵 1
🇳🇴 Telenor	LTE	✅ 3	✅
🇳🇴 Telenor	UMTS	4️⃣ 4	❌ 5
🇳🇴 Telenor	GSM	4️⃣ 4	❌ 5

Vodafone (MCCMNC 22601)

SIM card	Tech	IPv4v6	IPv6
🇵🇱 Orange	LTE	4️⃣ 4	❌ 6
🇵🇱 Orange	UMTS	4️⃣ 4	❌ 6
🇵🇱 Orange	GSM	4️⃣ 4	❌ 6
🇸🇪 Tele2	LTE	4️⃣ 4	❌ 6
🇸🇪 Tele2	UMTS	4️⃣ 4	❌ 5
🇸🇪 Tele2	GSM	4️⃣ 4	❌ 5
🇳🇴 Telenor	LTE	4️⃣ 4	❌ 6
🇳🇴 Telenor	UMTS	4️⃣ 4	❌ 6
🇳🇴 Telenor	GSM	4️⃣ 4	❌ 6

Footnotes

1. I was unable to register in this PLMN (probably because there is no roaming agreement with the SIM card operator), so it was impossible to test. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹ ↩²⁰

2. Trying to register in the UMTS Digi PLMN with my 🇸🇪 Tele2 SIM card apears to trigger a bug in my modem. After such an attempt (which timed out in any case), it would be unable to register in any LTE PLMN and be unable to attach packet service in any UMTS or GSM PLMN (even though registration went fine). The modem had to be rebooted with AT+MSO=0 in order to start working again. I therefore had to manually make my script skip the Digi PLMN while testing with 🇸🇪 Tele2. ↩ ↩²

3. Automatic fallback from a single dual-stack IPv4v6 bearer to dual single-stack IP(v4)+IPv6 bearers appears to take place. I can spot this happening because the modem only reports IP config for a single stack even though both actually work. 🇵🇱 Orange is known to not support the dual-stack IPv4v6 bearer, so this is the expected behaviour. As for 🇳🇴 Telenor, I do not know if they perform IPv4v6 subscriber capability filtering or if Telekom do not support/block IPv4v6 bearers. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

4. Successful automatic fallback from IPv4v6 to IPv4, likely due to IPv4v6 and IPv6 not working. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³

5. Failed with 3GPP cause code 33: service not activated. Likely due to IPv6 subscriber capability filtering performed by the SIM card . ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

6. Failed with 3GPP cause code 32: service option not supported. Likely an intentional block by Vodafone. 😠 ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷