The 5G Core Network (5GC) – Part 3 – Local Breakout

Ever since GPRS came around the corner one and a half decades ago there’s been this concept of international roaming with ‘local breakout’ in which IP packets of roaming subscribers are sent directly to the Internet from the visited network. Sounds nice but in practice, it’s not really used. Instead, the current approach is referred to as ‘home routing’ in which IP packets of roaming subscribers are tunneled back to the home network and only from there to the Internet. So will this change with 5G core networks?

Those familiar with the matter will point out that while local breakout sounds nice in theory, the problem in practice today is that the home network is bypassed and hence billing mechanisms would have to be redesigned. So from that point of view it is rather unlikely that we will see 5G local breakout any more than we see 2G/3G/4G local breakout today.

However, when you look at the 5G Roaming Architecture in 3GPP TS 23.501 Chapter 4.2.4 you will notice that the local breakout solution is described BEFORE the home routing option. This is also the case when looking at 5G signaling procedures in 3GPP TS 23.503! This is different from the order in the 4G roaming architecture described in 3GPP TS 23.401 Chapter 4.2.2, where home routing comes first!

So is this an indication that people have realized that from a purely technical point of view it makes no sense to tunnel back all those IP data packets of roamers!? It might be worth to find out more about if there are new 5G billing models specified somewhere in 3GPP that could better accommodate ‘local breakout’ while roaming in a 5G world.

P.S.: To be fair, in some in some cases, home routing makes quite sense, especially if you roam to countries with a lot of restrictions and firewalls that separates their country’s Internet from the rest of the world. In such countries, home routing through a GTP tunnel usually shields roamers from this. Also, getting an IP address from the home country usually also helps against geo-blocking and geo-detection of some web services and ensures ‘service continuation’ while traveling abroad.