The thing is, my iPads use AA/AQL/Three SIMs exactly the same as in the SXT and I can see the basestation three miles away across the glen, straight line of sight and the SXT is right in the upstairs office window pointing at that basestation. I currently have a 3G USB NIC with a SIM of the exact same type and that is on AA/Three; this works fine with the same view eastwards. My iPad has been on 4G with AA/Three this afternoon (so I could still access the internet via 4G while wifi was stuffed because I’d set my iPad’s WLAN i/f to 192.168.88.xx) and works fine even though it’s not near the east facing window, but in the back (west end) of the bedroom. My iPad gets 3 bars out of 4 even though it’s not near the good east-facing window.
I notice it refuses to do an LTE scan (? channel scan?) with an error message that sounds as if this model doesn’t support that feature, or current particular hardware doesn’t support it. (Well they should have just displayed it as unavailable in the ui, with a very brief keyword to serve as an explanation, rather than letting you click it and then telling you you did a bad thing.)
I’ve just locked myself out again foolishly and Janet, my chief button presser, is asleep, so no more exploring until the morning. Will read manual instead.
Janet uses AA/Three in her iPad and EE in her iPhone. She has unlimited data, whereas AA SIMs are mind-bogglingly expensive per byte but since I’m using it for backup it’s fantastic, because there’s no huge standing charge every month, it’s only couple of pounds plus the cost of traffic, so it’s ideal.
I see this ‘bridge’ object, and happily following a random webpage of instructions, I deleted it and that was how I locked myself out just now. I thought I needed to find out exactly what this thing is; I assumed I’d be able to connect more interfaces to it (somehow, in the UI) and thus bridge the LTE interface to the ethernet. I realise now that that’s all nonsense; I need to create a PPP object and then associate that with LTE and then bridge-connect the PPP object to the ethernet i/f.
I noticed that it mentions a 1450 byte (L3 PDU ?) MTU for LTE, iirc. This is roughly the same unwelcome nonsense that I get from my current 3G USB ‘dongle’ NIC -1450 or 1440 bytes, I forget which. I think the mobile network as presented by AA/AQL has an IP PDU of 1500, perhaps no more, but that seems uncertain. It has to be larger than that at L2 because there is the 2 byte overhead of PPP, so that makes it 1502 PPP MTU, or if it’s PPP+PPPoE that would be a 1500+2+6=1508 byte PPP MTU. Am I correct, does the L2 MTU have to be at least 1502 bytes? If it’s greater than 1500, won’t it perhaps be L2 MTU=1600, or could it just be a (mere) 1508?
The reason that I’m thinking about this is that I wonder if I could keep the IP MTU at 1500 even though I’m using PPP? Another thought occurs to me; what about the overhead of ethernet MAC framing if you’re doing IP+ethernet over the LTE i/f ? That’s way, way greater than 1508.