C5x latency-time slot


#1

Hi, Im planing to make an ptp over 3.2 km. using C5x with 20-25 dBi.Mimosa´s dish,
My question is ¿ wich latency or time slot have that antennas ? 2-4 ms. will be nice, more than that for ptp is too high for me.

Thanks,


#2

Out of curiosity what are you trying to run over the link that wants such low latency?

I have not gotten any of the C5xs to play with myself, but I know they do not have GPS, so there won’t be the normal time slotted TDMA that you see on other GPS synced devices. You probably will be using normal Time Slotting which will distribute slots according to how much utilization is going in each direction. I have not seen anywhere in Mimosa’s documentation on how large those time slots are. (My shot in the dark guess would be 10 ms, but I would differ to anyone who says differently)

If you want 2-4 ms time slots you probably will want to look at the Mimosa B5 or B5c for that level of control.


#3

Online games, I know that is not best thing, but not any possibility to have fiber optic connection out side the city. Before to have A5c with C5,( 16-20 ms. ) i had 2-3 ms ping from the PC to the remote router,( Ubiquiti M5-400 gear ) same distance, etc.

If I remember well, on the B5 lite is 2-4 ms so 4-8 ms isn´t bad anyway.


#4

You probably would get similar latency as the old M5 gear with a C5x PTP link.

The reason you are seeing higher latency with the A5 and the C5 is that you are probably in SRS. This sets the TDMA to 10 ms and also is a PTMP framework that needs to save time for multiple people to talk.

You can lower the latency on the C5-A5 link by switching to WiFi-Interop. But if you have lots of customers on the A5 and you have other A5s in the area it can get hairy keeping the self-interferance down…


#5

Hi all,

I would suggest using Auto TDMA mode (located on the Link page) so you have the best latency and higher throughput. The only real reason to use actual timing windows is for fixed frames.

If you changed to auto, you should see 1-2ms instead of your 4-8ms. Let us know what you see after the change.


#6

Hi Dustin, are you talking on the C5x or A5c? Because on the A5c is on SRS, right now I change on to WiFi op to see if the latency is less, anyway on the A5c there is only two C5 connected.

Thx.


#7

@J.Enrique

@DustinS is talking about the B5 line, and the C5x as well, but there is no reason to use anything but Auto with the C5x. when you have them set in Auto TDMA you get lower latency, but no GPS Sync, which often is not a problem for most people.

BTW, where did you get your C5xs? my distributors are giving me runarounds about when they will be getting in and I want to play with them. (By “play” I really should say “use the heck out of them”)

The A5 and A5c only have Fixed frame mode enabled for SRS, by going to WiFi Interop you leave fixed frame world and are using standard (with improvements) WiFi.


#8

For the moment is out of stock.

So I need to wait a little bit more :slight_smile: