~tore Tore Anderson's technology blog

IPv6 roaming in Sweden

I attended the Netnod Tech Meeting 2017 in Stockholm earlier this week. As I usually do when when going abroad, I spent some time testing to what extent IPv6 works while roaming in the various PLMNs I have access to.

The previous posts in this series are:

Test results

Telia - MCCMNC 24001

Home PLMN Tech IPV6 PDP context IPV4V6 PDP context
Telenor Norway 2G Fails IPv4-only connection
Telenor Norway 3G Fails IPv4-only connection
Telenor Norway 4G N/A (no service) N/A (no service)

It would appear that Telenor Norway does not have a 4G roaming agreement with Telia. My phone was unable to register in Telia’s 4G network, at least.

In 3G and 2G coverage, I could register, but IPv6 did not work. Requesting dual stack connectivity would only yield IPv4. This is of course a quite acceptable outcome for the vast majority of users, as the Internet will ostensibly work just fine..

In all likelihood the IPv6 failures observed on 2G and 3G is due to Telenor Norway’s HLR removing the IPv6 capabilities from my subscriber profile before transmitting it to Telia’s vSGSN. This is done to forestall the possible IPv6-related failures described in RFC 7445 sections 3 and 6.

Presumably Telenor Norway will, at some point in the future, remove this IPv6 capability blacklisting for Telia, after having ascertained that Telia’s 2G/3G network does not have any issues with supporting the IPv6 PDP types.

3 - MCCMNC 24002

Home PLMN Tech IPV6 PDP context IPV4V6 PDP context
Telenor Norway 3G Fails IPv4-only connection
Telenor Norway 4G Works perfectly Works perfectly

In 4G coverage, IPv6 works perfectly. In 3G coverage, it fails - presumably due to the same IPv6 capability blacklisting as described above for Telia.

I did however notice at one point that if I connected a dual stack IPV4V6 PDP context while in 3’s 4G network, and then moved into an area that had only 3G coverage, IPv6 kept working perfectly. Thus it would appear that 3’s 3G network has no issues supporting visiting subscribers using IPv6.

Note that 3 does not operate a 2G network.

Tele2 - MCCMNC 24007

Home PLMN Tech IPV6 PDP context IPV4V6 PDP context
Telenor Norway 3G Fails IPv4-only connection
Telenor Norway 4G Works perfectly Works perfectly

Same results as for 3.

I did not get to test physically moving from 4G to 3G coverage. That said, I know for a fact that Tele2 provides IPv6 to their own mobile subscribes, so it seems like a safe bet to assume that their 3G network would support IPv6 just fine, if it hadn’t been for Telenor’s IPv6 capability blacklisting.

Telenor Sweden - MCCMNC 24008

Home PLMN Tech IPV6 PDP context IPV4V6 PDP context
Telenor Norway 3G Works perfectly Works perfectly
Telenor Norway 4G Works perfectly Works perfectly

Perfect score. It is perhaps not surprising that if a single Swedish operator would be fully «IPv6-approved», and therefore exempt from Telenor Norway’s IPv6 capability blacklisting, it would be their Swedish sister company Telenor Sweden.

It might also be worth noting that Telenor Sweden is the vPLMN my phone prefers to register in if I leave it in the default automatic mode. Therefore, for Telenor Norway subscribers, IPv6 Just Works while visiting Sweden - unless one manually fiddles around with the network settings.

Net4Mobility - MCCMNC 24024

Home PLMN Tech IPV6 PDP context IPV4V6 PDP context
Telenor Norway 2G Works perfectly Works perfectly

Perfect score.

The Net4Mobility PLMN is, as far as I can understand, a joint venture between Tele2 and Telenor Sweden that provides shared 2G coverage for both of those providers. That is, if I lock my phone on to MCCMNC 24007 (Tele2) or 24008 (Telenor Sweden), it will nevertheless change to 24024 (Net4Mobility) if I also limit it to 2G only.

This means Net4Mobility is logically part of Telenor Sweden’s network, and thus it makes sense that it, like MCCMNC 24008, is exempt from Telenor Norway’s IPv6 capability blacklisting.