I just tried data-only e-Sim from one of the prepaid providers (data plan was dedicated for US). Here in US it roams on T-Mobile. While it works and speeds are OK (10/2 MBit/sec) the ping time is 620ms and jitter is 326 ms which is atrocious (I don’t have any other T-Mobile plan but on my AT&T prepaid ping is 23ms and jitter is 31 ms).
I tried Skyping on this e-Sim and it was unusable. Picture was low quality and the other side couldn’t hear me most of the time. Not really surprising with latency this high.
Upon closer inspection I found that my IP is from Amazon AWS data center is Singapore which where provider is located. So it seems all my data packets are making a round trip halfway across the world.
I understand why this may be necessary – they need to track my data usage and traffic has to travel through their servers. But does it mean latency ALWAYS has to be this high? Can this be implemented in a different way so that packets don’t have to travel across the world? I mean in this case since plan was geared towards USA they could’ve had servers in Amazon US data centers?
I never used international roaming on any major brands (i.e. AT&T or T-Mobile) and don’t know if it also as bad. If someone tried that – can you report what you experienced? Does it suffer from the same high latency? Or do they have some kind of more advanced carrier-level roaming implementation?