Force 300 questions

Ah, now I see.

There are no plans to do ePTP for Force 300, because it's unnecessary.  The latency is already about as good as it will get using 802.11ac Wave 2.  The software will continue to see improvements in performance, stability, etc.

"Flexible" mode of operation is being considered in the near future as well.


@Fedor wrote:
Hi all,

FCC DFS and Forward compatibility with ePMP2000 AP will be introduced in 4.2 Release in August.
PMP mode will be available once ePMP3000 will be delivered with 4.3 FW Release.

Thank you.

Need some clarification here, please. What I am reading is 4.2 will allow the F300 to be backwards compatible with the ePMP2000AP, but PMP mode will not be available until 4.3 is released. Does this mean the F300 will only work in PTP mode with an ePMP2000 using 4.2 FW?

I think ePTP mode is very necessary.  I understand this is a new product and it needs tweaking.  Now I know that ePTP mode isn't happening I can move on to something else that will work for that application. Thanks.

Now Force 300 ( and PTP550) with 5 ms frame has avg 6-7 ms latency  and more under heavy traffic load. It is too much in comparison with competitors.

To reduce latency in ptp operation  to 2-4 ms  ( under big trafiic load )  we need  to have 1) flexible frame 2) frame  size 2.5 ms. 

Flexible frame is also very important to increase Download throughput up to 95% of total channel capacity against 75% ( in TDD DL/UL =75/25 ) that we have now.

If ePTP mode is not applicable for 802.11 ac wave 2,  we should have  flexible frame,  frame size 2.5 ms  both for Force 300 and PTP550.


@CambiumMatt wrote:

There are no plans to do ePTP for Force 300


Was that what the Force300 and 3000 "a look forward webinar" said?  I understood that the TDD mode was the 1st out of the box, but I thought that all the other modes were all coming as the software matured.  Did I missunderstand?


@CWB wrote:

@Fedor wrote:
Hi all,

FCC DFS and Forward compatibility with ePMP2000 AP will be introduced in 4.2 Release in August.
PMP mode will be available once ePMP3000 will be delivered with 4.3 FW Release.

Thank you.

Need some clarification here, please. What I am reading is 4.2 will allow the F300 to be backwards compatible with the ePMP2000AP, but PMP mode will not be available until 4.3 is released. Does this mean the F300 will only work in PTP mode with an ePMP2000 using 4.2 FW?


With backwards compatibility F300 will support PMP mode. However, keep in mind that in this PMP mode the F300 is speaking to an ePMP1k/2k series so its really 11n. The conversation around 4.3 is that, this is where the F300 will speak the 11AC PMP language and communcate to the ePMP3K along with support MUMIMO. 


@Nathan Dothager wrote:

I think ePTP mode is very necessary.  I understand this is a new product and it needs tweaking.  Now I know that ePTP mode isn't happening I can move on to something else that will work for that application. Thanks.


Our original purpose for ePTP mode was to provide the lowest latency in PTP application where the PMP TDD mode did not. In F300 with fixed DL/UL ratio, you will notice that the latency is much lower. Around 5ms. We will continue to evaluate the need for ePTP so please keep the feedback coming. However, please try the TDD mode of operation. Beyond that Flexible mode makes the most sense even before ePTP as you can dynamically have the F300 allocated bandwidth depending on traffic profile. 

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@Vyacheslav wrote:

Now Force 300 ( and PTP550) with 5 ms frame has avg 6-7 ms latency  and more under heavy traffic load. It is too much in comparison with competitors.

To reduce latency in ptp operation  to 2-4 ms  ( under big trafiic load )  we need  to have 1) flexible frame 2) frame  size 2.5 ms. 

Flexible frame is also very important to increase Download throughput up to 95% of total channel capacity against 75% ( in TDD DL/UL =75/25 ) that we have now.

If ePTP mode is not applicable for 802.11 ac wave 2,  we should have  flexible frame,  frame size 2.5 ms  both for Force 300 and PTP550.


Vyachelav,

Are you looking at latency under load with ping? Please note that ping takes lower priority in both cases when there is traffic present. This is not the case in e1K/e2K.

Sakid

Sakid,
We are measuring throughput with ping . Max throughput is estimated as max TCP traffic with avg RTT <9ms without ping losses .Without traffic average RTT is 3-4ms. The same do our competitors.
If it is possible to give Ping high priority as default it will be good!

I think Flexible mode with 2.5ms frame size could help, but not reach as good results as ePTP.
Sure latency is way better than actual 802.11n-based TDD mode in ePMP 1000/2000, but I think you can do more.

We, as WISP, are continuously competing with fiber-based competitors with very low latency.
Having a link with 2-7ms latency instead of 1-2ms means a lot for some customers.

And what about when you have two hops? You're adding about 10ms of latency or more!

You say Force 300 is an upgrade, a "step forward", but you have to think about all situations. You have to admit ePTP mode was helpfull when it was launched on ePMP 1000 and it's even more usefull now the market is changed and every millisecond counts.

ePTP Mode is very, very helpfull when you need low-latency and low-budget links. We used and we're using it A LOT, and, as I can see from this thread, we're not alone.

You can see below the difference from Force 200 ePTP Mode in two very clean links.
Force 200 link is 95.5% traffic on MCS15 (64 QAM 5/6), Force 300 link is 95.6% traffic on DS MCS 9 (256 QAM 5/6), so very clean, both on 20MHz channel.

Both links were not under load.

As you can see ePTP is far more stable and the latency is very low. On Force 300 the latency is 4ms as avg, which is 4x times the latency on ePTP.


How can you say ePTP is "unnecessary"? That's a step backwards, not a step forward!

Force 200 ePTP Mode

Force 300 PTP Mode

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What he said. If I'm being honest, the latency I'm seeing on our production Force 300 is not backhaul worthy.  It's all over the place with or without traffic on it.  I'm trying to be patient.  Trying so hard...

D@mn it boys!!! Don't hold back....tell us how you really feel. 

  First our competitor  ( based on  802.11 ac wave 2) has 2 ms frame size,  adaptive ( flexible) UL/DL ratio, second one  FPGA  based radio-   fixed UL/DL ratio 25/75, frame  size 2 ms. Both  have stable average 2-3 ms ping RTT under almost  full channel load ( 95% of channel capacity). May be they have priority for ping packets, nobody  knows.

Force 300 and PTP550 should have not worse  latency result  under heavy traffic load. Good result  in ping delay    in empty channel does not make sence.

2 giuseppe4

Please show Ping in ePTP mode  with ping packet size 1470 bytes.  

When it comes to backhauls, the majority of links are not fixed frame or sync'ed.  I don't know why we wouldn't get ePTP mode for a product that's (currently) PTP only.

I'm not too concerned about the latency, but why not use all of the resources of the hardware to our advantage?

As Vuacheslav asked, here's ping with ePTP on Force 200 and PTP TDD on Force 300 using packet size 1470 bytes.

ePTP on Force 200 is still far better.

About ~20Mbps traffic is passing through both links, so a little bit load situation.

 

Please, Cambium, don't ignore our need of and ePTP Mode to have a low latency.

PTP TDD Force 300

ePTP Force 200

I suppose ePTP mode uses variable frame size, like wifi but with packet error rate control ( ePMP link adaptation).   It allow to see low RTT  ( two way delay/ latency) under not big traffic. Under heavy traffic there will  not be big difference in RTT  beetween 1) ePTP mode with flexible frame size and flexible UL/DL  ratio and 2) flexible UL/DL ratio  with fixed frame 2.5 ms.

So there are 3  ways to reduce RTT delay :

1) ePTP mode -flexible frame size and flexible UL/DL

2) fixed frame size 2.5 ms with flexible UL/DL

3) fixed frame size 2.5 ms with fixed UL/DL =15/85.

All of them will give almost equal RTT delay under high traffic load.

So at least one of these ways should be implemented in Force 300, PTP550 ptp link. It will allow to get  low 3-4 ms stable RTT delay in channel  under high traffic load.

Also 4) fixed frame size 5 ms with flexible UL/DL will allow to reduce  two way delay from current avg 6-7ms to  avg 4-5 ms.  Cambium promises to make this 4) mode soon at least for Force 300. But it will be efficient  and should be done  also for PTP550.

How to achive  stable delay  ( ping RTT) below  4-5 ms with high (95%  of channel capacity)  traffic  load  ( as competitors have)  is another separate  and very important  task, that also should be solved. Now we see delay and jitter growth when traffic load is increasing  espesially under impact of interference.

Any news from Cambium about Force 300 latency in PTP?

Seriously folks... can you wait just a bit longer for the dev's to figure out how to squeeze another few ms of latency reduction out of THE LOWEST priced bp/Hz Cambium PtP @ $340 total price!? Look at the big picture here... there's a lot of projects going on, ePMP 3000 is top priority, there's limited dev time... if you so desperately need a few ms better latency, limp along with F200's for a bit longer or shell out a bit more for PTP450 or 670 in the interim. This is THE least expensive introductory product being made in this category by Cambium. What do you guys expect!? How long did it take for UBNT to have the feature set they have today after first AC release!? HINT... It's been YEARS of development and a few generations of radio equipment! This is a diamond in the rough, give these guys some time and support, I know they need it!

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ok.. pero no deberian lanzar al mercado un producto como bueno.. y sin terminar de desarrollar. al menos un funcionamiento básico estable.