[Cake] [Bloat] Fwd: [Galene] Dave on bufferbloat and jitter at 8pm CET Tuesday 23

Taraldsen Erik erik.taraldsen at telenor.no
Fri Feb 26 02:26:45 EST 2021

Fra: Nils Andreas Svee <me at lochnair.net>

I am indeed running them on Ethernet. I don't actually use the B818 for anything else than as a LTE modem, so I wouldn't know, if I could get the thing to bridge I would. Or replace it with something else entirely that I can control, but that doesn't seem to be an option on FWA. That said the Zyxel looks like a better option since I assume it acts like a bridge by default.
The Zyxel device indeed acts as a bridge, or at least as close approximation as we can get it.  The PDP addressing protocol in mobile networks requres the address termination to happen where the SIM card resides.  So the device does some trickery with brctl, routing and iptables to simulate a bridge setup.

I dumped the raw signal stats the web interface grabs in an XML file together with the Flent tests. Also did some upload only tests tonight at different speeds (no VPN in play this time).
rsrp is good and rsrq is great at your location.  However you have ended up on the 800MHz band.  That is intended for coverage, not capacity.  It uses only 10MHz bandwitdh and is shared with a lot more customers.  You probably should be able to get an 1800MHz frequency which has 20MHz and is shared among fewer customers.

Most likely yes. That's been my observation as well, that it generally acts up the worst when somethings using the upstream. Not entirely sure what I can do about that, seeing as I had to shape at 5Mbit to get rid of the worst spikes (but not all).

This is tricky.  You don't have a static set of resources.  You request resources "as needed".  The "as needed" amongst other things reads the buffer back pressure.  So if you shape to far down the LTE device will not request enough resources.  Shape to high and there will not be enough resources available to share.  And available resources vary with number of subscribers on that cell, weather, the subscribers usage and interference from other cell towers.  To get a proper solution to this I don't see a way around getting the chipset manufacturers on board.

On that point, I would've liked to collect signal stats over time, but the B818 seems to insist on chucking me out after being idle for a few minutes, better known as scraping the stats with cURL

Have you tried to use the telnet service port (20249) on the B818?  Not all variants have that open but you could give it a shot.  You also may need to acquire an datalock code for the "at^datalock=" command.

telnet LAN_IP 20249

This is getting LTE/5G spesific.  Not sure if it belongs on the list.  Let us know if we are generating noise.

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