Apparently the 2G thing varies greatly depending on the country you are traveling to.
Swisscom has published a list showing the possible roaming partners and the supported network standard:
Just wondering how current this list is. But you can see that apparently all providers in Germany (Telekom, Vodafone and Telefonica O2) have switched off the 3G network, but that 2G is still in operation. In Germany, calls can be made via both 2G and 4G and apparently even via 5G. So you will hardly make calls over 2G unless you are in an area where the provider whose network you are logged into only offers 2G (EDGE).
In France, on the other hand, all providers still offer 3G, but all of them still have 2G, with the exception of Free.
However, according to this list, calls cannot be transferred via LTE (i.e. 4G). In this case, the mobile phone chooses 3G for calls or, in the worst case, even 2G. The new 2G lockdown mode could prevent this in the future.
This list has existed at Swisscom for ages and is, as far as I know, relatively up to date. Unfortunately, Sunrise and Salt no longer have such a list of roaming partners. The fact that you can also make calls via 4G (VoLTE) with Vodafone and O2 has apparently only recently become the case. At least I only had VoLTE roaming in Germany with Telekom. This didn’t work for the others, so calls were made over 2G.
@MagicMax wrote:
Swisscom has published a list showing the possible roaming partners and the supported network standard:
I didn’t know the list yet - it’s interesting. 2G or EDGE still seems to be the minimum standard everywhere. I found on the internet: Only the coverage via the older and slower 2G (GSM, GPRS and Edge) is retained, otherwise cell phones without internet functionality would no longer work at all.
This probably means that 2G or EDGE will be retained for a longer period of time. As a result, security on the Internet does not seem to be guaranteed under 2G (which is one reason for blocking it in lockdown mode) and nothing happens when the EDGE network is selected (you can make phone calls and surf very slowly). The search and automatic switching would only have to happen if you are surfing and something from 4G is available. Maybe that’s too complicated.
The first generation of mobile communications was known in Switzerland as “Natel C”. Natel C was based on NMT technology and therefore on analog radio (1G/NMT).
https://en.wikipedia.org/wiki/Nordic_Mobile_Telephone
https://de.wikipedia.org/wiki/Natel
Second generation mobile communications (2G/GSM) is based on time slot procedures. Second generation mobile communications uses the advantages of digital radio.
[https://de.wikipedia.org/wiki/B%C3%BCndelfunk#Digitaler\_B%C3%BCndelfunk](https://de.wikipedia.org/wiki/B%C3%BCndelfunk#Digitaler_B%C3% BCndelfunk)
Important cornerstones of 2G/GSM are:
- Time-division multiplexing => https://de.wikipedia.org/wiki/Multiplexverfahren#Time-division multiplexing_(TDMA)
- ISDN (B channel) => https://de.wikipedia.org/wiki/Integrated_Services_Digital_Network
- Primary multiplex connection => [https://de.wikipedia.org/wiki/Prim%C3%A4r multiplex connection](https://de.wikipedia.org/wiki/Prim%C3%A4r multiplex connection)
- SDH => https://de.wikipedia.org/wiki/Synchrone_Digitale_Hierarchie
- SS7 => https://de.wikipedia.org/wiki/Signalling_System_7
The basic element of these technologies is the time slot.
https://de.wikipedia.org/wiki/Zeitschlitz
With third-generation mobile communications (3G/UMTS), the shift away from time slot methods towards pure IP networks began.
https://de.wikipedia.org/wiki/Internet_Protocol
The basic element in the IP network is the data packet.
https://de.wikipedia.org/wiki/Datenpaket
Up to and including 3G/UMTS, voice telephony was implemented exclusively using circuit switching (circuit switching=> CS).
https://www.elektronik-kompendium.de/sites/kom/0211191.htm
https://de.wikipedia.org/wiki/Leitungsvmietung
Mobile communications from the fourth generation (4G/LTE, 5G and 6G) are pure IP networks. Mobile communications from the fourth generation (4G/LTE, 5G and 6G) only support voice telephony via packet switching (packet switching => PS).
[https://de.wikipedia.org/wiki/Packet brokerage](https://de.wikipedia.org/wiki/Packet brokerage)
Packet-switched voice telephony in the 4G/LTE mobile network is called VoLTE (Voice over LTE).
https://de.wikipedia.org/wiki/VoLTE
Packet-switched voice telephony in the fifth generation (5G) mobile network is called VoNR.
[https://community.swisscom.ch/t5/Mobile/5G-in-Liechtenstein/m-p/772675#M12457](https://community.swisscom.ch/t5/Mobile/5G-in-Liechtenstein/m-p/ 772675#M12457)
IMS is a very important part of the core network of modern mobile networks that work with packet switching.
[https://community.swisscom.ch/t5/Archiv-telefonie/Handy-Empfang-im-Minergiehaus-besser/m-p/656772#M61190](https://community.swisscom.ch/t5/Archiv-telefonie/ Cell phone reception-poor-in-the-minergie-house/m-p/656772#M61190)
[https://community.swisscom.ch/t5/Archiv-telefonie/Advanced-Calling-VoLTE-und-WiFi-Calling/m-p/658091#M56525] (https://community.swisscom.ch/t5/Archiv-telefonie/Advanced-Calling-VoLTE-und-WiFi-Calling/m-p/658091#M56525)
https://en.wikipedia.org/wiki/IP_Multimedia_Subsystem
The switch from circuit-switched voice telephony (CS) to packet-switched voice telephony (PS) is anything but trivial, especially in the area of roaming, and is therefore subject to many problems and restrictions for all mobile phone providers worldwide.
https://community.swisscom.ch/t5/Mobile/VoLTE-Roaming/m-p/657972
If the mobile phone does not support packet-switched voice telephony or the mobile phone provider has not enabled the use of packet-switched voice telephony, voice telephony will fall back to circuit-switched voice telephony (circuit switch fallback => CSFB). See:
https://community.sunrise.ch/d/23412-telefonat-willkuerlich-ruf-beendet/15
https://community.sunrise.ch/d/24019-auto-telefonieren/4
[https://community.sunrise.ch/d/28020-voip-empfang-mit-5g-besser/29](https://community.sunrise.ch/d/28020-voip-empfang-mit-5g- bad/29)
Anyone traveling to a country in which there is no nationwide public 2G/GSM or 3G/UMTS mobile network, for example the USA, should take satellite communication equipment with them for emergency communication. See the multi-page comments at:
https://community.swisscom.ch/t5/Mobile/VoLTE-Roaming/m-p/657972
https://de.wikipedia.org/wiki/Notruf#Notruf_per_Satellitenkommunikation
[https://community.swisscom.ch/t5/Mobile/Umleitung-von-Anrufen/m-p/763315#M12065](https://community.swisscom.ch/t5/Mobile/Umleitung-von-Anrufen/m-p/ 763315#M12065)
In Germany, the switch from UMTS2100 to UMTS900 was missed. Details:
[https://community.swisscom.ch/t5/telefonie-Wissensbox/2025-ist-Schluss-3G-macht-Platz-f%C3%BCr-mehr-leistung/tac-p/703050/highlight/true#M533 ] (https://community.swisscom.ch/t5/telefonie-Wissensbox/2025-ist-Schluss-3G-macht-Platz-f%C3%BCr-mehr-leistung/tac-p/703050/highlight/true#M533 )
@Koniferski wrote:
Also interesting in the article are the security concerns about 2G - they apply to everyone. Maybe you have to wait until the providers only offer 4G and above.
As long as the latest mobile communications standard (currently: 5G) provides insufficient protection against IMSI catchers due to inadequate authentication of the mobile network by the mobile phone, I do not consider a single mobile network on this planet to be sufficiently secure.
https://www.dr-datenschutz.de/authentisierung-authentification-und-autorisierung/
[https://www.heise.de/news/IMSI-Catcher-Ueberwachung-auch-in-5G-Netzen-moeglich-9190322.html](https://www.heise.de/news/IMSI-Catcher- Monitoring-also-possible-in-5G-networks-9190322.html)
[https://www.eff.org/files/2019/07/09/whitepaper\_imsicatchers\_eff\_0.pdf](https://www.eff.org/files/2019/07/09/whitepaper_imsicatchers_eff_0. pdf)
[https://www.heise.de/news/IMSI-Catcher-Why-Ueberwacher-es-so-einfach-haben-4646749.html](https://www.heise.de/news/IMSI-Catcher- Why-supervisor-makes-it-so-easy-4646749.html)
As long as standards bodies such as 3GPP and ETSI are receptive to lobbying by secret services, the security of mobile networks will not improve significantly. Today, any WLAN that is properly secured with WPA2-Enterprise, EAP-TLS, AES-128, SHA-256 and IEEE 802.11w (Protected Management Frames => PMF) is more secure than the most modern (5G) mobile network!
https://www.securew2.com/solutions/wpa2-enterprise-and-802-1x-simplified
[https://www.heise.de/ratgeber/WLAN-und-LAN-securen-mit-IEEE-802-1X-und-Radius-979513.html](https://www.heise.de/ratgeber/ Secure WLAN-and-LAN-with-IEEE-802-1X-and-Radius-979513.html)
How secure standards for radio networks from ETSI are can currently be seen in the TETRA trunked radio standard. TETRA is often used across Europe for police radio.
[https://www.heise.de/news/Digitaler-Behoerdenfunk-Massive-Schwachstellen-bei-TETRA-entdeckt-9226620.html](https://www.heise.de/news/Digitaler-Behoerdenfunk-Massive- Vulnerabilities-discovered-in-TETRA-9226620.html)
[https://www.rtl-sdr.com/encryption-on-the-tetra-protocol-has-been-broken/](https://www.rtl-sdr.com/encryption-on-the-tetra -protocol-has-been-broken/)
https://de.wikipedia.org/wiki/Terrestrial_Trunked_Radio
https://de.wikipedia.org/wiki/B%C3%BCndelfunk
It also annoys me when the optimal network is not selected in terms of reception. Especially if roaming with 5G is possible and the provider that Swisscom always uses always has an overloaded 4G network. You can quickly switch to manual.
I wouldn’t say that the control over the provider specified by Swisscom doesn’t play a role for 99% of customers, but rather that 99% simply don’t care about it because many no longer even know that you could change it manually. But the cursing because of the overloaded network still happens.
And why don’t 99% of customers know it? Because they don’t care at all. The main thing is that the cell phone works abroad and that is what it does. Correct settings provided. I have only very rarely experienced overloaded networks, especially via 5G. The speed is often slower if you surf the Internet as a “foreigner” because you certainly have a lower priority than your own “domestic” customers. The devices change provider if there is no reception and a different network is available. But this takes a few seconds. Especially when you’re traveling, it hardly makes sense for cell phones to automatically always select the strongest network, since one is actually always slightly better than the other. This would also have an impact on the battery life.
I also didn’t talk about overloaded 5G networks, but rather overloaded 4G networks. In the UK it was annoying that the cell phone always switched to the Swisscom preferred network. And for this one they didn’t have a 5G roaming agreement (although they do have a 5G network). This means you were constantly being redirected from a 5G network with strong reception and very good bandwidth to a network with completely overloaded 4G because it was prioritized that way by Swisscom. And that’s annoying. And you can fix it yourself as an expert. And yes, the customers are not interested in being able to select manually, but they are interested in the network moving smoothly and with these prioritizations it doesn’t always do that and that’s where the swearing I mentioned occurs.
The cell phones don’t always have to choose the strongest network, but they switch very quickly to the one prioritized by Swisscom, which is often counterproductive for the customer. They also remain on this network. This is my experience confirming the original statement of this thread.
Because of these prioritizations, depending on the situation, you have no choice but to manually switch to a “sliding” network (which many people are no longer able to do these days).
I just have the feeling that this prioritization is constantly being changed by Swisscom.
In France, Orange F might have been the priority until a month ago, but today it might be Bouygues.
In Germany you should not choose the O2 network if you want the caller ID to work correctly. Unfortunately, due to the technical complexity, there are apparently cases where this no longer works properly (due to the prevention of number misuse, e.g. by means of spoofing): [See e.g. here](https://www.teltarif.de/amp/tkg-rufnummernanzeige- hide/news/90282.html)
I’ve never had any problems in France, I haven’t been to Germany for a long time, it’s been over 1.5 years.
In France all the networks were good and delivered good performance. Orange-F felt a little better, but it probably depends on the region.
a month later
I was traveling in Spain this week.
My cell phone was practically always logged into the “Movistar” network ( Telefonica ), which worked great.
However, my colleague who traveled with me is not at Swisscom, but at Yallo (Sunrise sub-brand). His cell phone registered on Orange when the network was automatically selected. The Orange network was much worse, sometimes showing good signal strength (even 5G), but it was almost impossible to access the internet, or the data loaded much slower than my Movistar network. Manual network selection on Movistar helped him.
But it is very obvious that there are different priorities between Swiss providers when choosing networks during roaming.
@MagicMax wrote:
But it is very obvious that there are different priorities between Swiss providers when choosing networks during roaming.
That was always my suspicion too. You should get to this list - that would be nice. I feel like that happened way back in the day
I still remember times when there were different prices for roaming between different providers in the same country, so for example it might have been cheaper to make calls in France via Bouygues than via France Telecom (now Orange-F).
Back then (before the smartphone era) you could save network coded in the menu and thus set your own prioritization (information was saved on the SIM card). Today the tariffs per country or group of countries are the same for the end customer everywhere, but I can imagine that the network providers have different purchase prices and then try to steer the customer to the network that is cheapest for them.
7 days later
Interesting that it chose Moviestar in Spain? I was also in Spain and Fuerteventura last week and the network was always on Vodafone ES on all devices. It was like that in the past too. Should be the preferred partner in Spain. But I switched manually to Moviestar because I had a much better network with this provider including 5G and VoLTE. A colleague with a Sunrise cell phone also had Orange there. Network coverage and speed was atrocious with Orange.
However, many providers also have such network prioritizations abroad, it is common practice in the industry and is certainly also related to the purchasing conditions. What is interesting is that Swisscom or Sunrise usually have other preferred partners abroad.
3 months later
I’m going to France for a few hours today.
I’m excited to see which net I’ll land on.
The route may also play a role, i.e. where you go in France and where the network transition from the Swisscom network into roaming takes place.
As a rule, the Swisscom network continues a little way into France from the border, then it switches as soon as the Swisscom signal can no longer be received. And this location could perhaps play a role; my device might then simply choose the network whose signal is strongest there. I can therefore imagine that if I drive from Basel in the direction of Mullhouse, I might end up on a different network than if I set foot on French soil in the Vaud Jura or in the Portes du Soleil ski area.
At the Portes du Soleil my cell phone dialed Orange-F last time.
Today we’re heading towards Mullhouse-Colmar, maybe SFR or Bouygues will come there, I’m curious.
A magic that would be logical but probably doesn’t always work that way.
We are in Germany 5-6 times a week and have a Pixel 6 Pro and a Pixel 7, both with Wingo International subscription, both eSim.
The devices are usually in the same bag.
But while my girlfriend’s Pixel 6 pro is almost always on the Telekom or Vodafone network, my Pixel 7 almost always connects to the annoying O2 network.
If I switch manually to Telekom and then activate the automatic network selection again, I will soon be back on the O2 network, while my girlfriend’s device very rarely switches to the O2 network.
In France we both have a different network every time, although here in the Basel region we practically always go out to the same place and are then in the same places in F.
In F we manually select the “FREE” network, which almost always has 5G and the highest speed for measurements in the St. Louis and Euroairport area.