TDD or ePTP

Should i go for 20 Mhz band for ePTP though link is quite fine with 10 Mhz band with TDD mood considering latency period?? Basically i use it on high interference/ latency (sometimes power level/BW) issue.

Is there any other issue where i should go for ePTP option ?
When should i check TDD-PTP(AP) option?
Advantages?

Thanks

Asif Hasan

Hi Asif Hasan,

Its better to go with ePTP mode, since you are using this link on a high interference/latency. But the only downside is  QoS (MIR and traffic priority) capability and Link Quality/Capacity indicators are not available in this mode.

1.The  ePTP mode doesn't support GPS synchronizartion where as the TDD mode does.

2.TDD mode is used in a point-to-multipoint scenario only.

3.You should check ePTP when you need a PTP link without GPS sync, and select PTP mode when you want to use GPS sync.

4.Its better to go for ePTP over PTP when your requirement is lower latency.

If you need any further assitance please feel free to contact us at support @cambiumnetworks.com

Regards,

Sharath

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Thank you for your kind info. That was very helpful for me. Just one thing, since ePTP is only avaiable in 20/40 Mhz. So if we have to go for 5/10 Mhz band, how can i select ePTP mood in 5/10 Mhz??


@Asif Hasan wrote:

Thank you for your kind info. That was very helpful for me. Just one thing, since ePTP is only avaiable in 20/40 Mhz. So if we have to go for 5/10 Mhz band, how can i select ePTP mood in 5/10 Mhz??


Asif,

Unfortunately, we don't have 5/10MHz support just yet but we will add it to our roadmap.

Sakid

1 Like

Dear Sir,

In all your version

Thank you.

I have an ePMP 2000 AP radio that I am setup up with TDD setting, I 've noticed that the cnMaestro is showing Smart Antenna being powered but disconnected. I read a  post in the forum  saying that if I used TDD  the communication between my SmartAntenna and ePMP 2000 AP will be down. I want to be able to use it for multipe sm. What can I do, I want to deployed the radio in a area where high interferance is experienced. I want to take advantade of the SmartAntenna purspose. What can I do?  HELP!!!!!!!!!!!

Hi,

Smart Antenna can operate only in TDD mode.

Please check whether you've connected your Smart Antenna to ePMP2000 properly.

Please follow lnk below:

http://community.cambiumnetworks.com/t5/ePMP-2000-and-1000/ePMP2000-smart-antenna-connection/m-p/58522/highlight/true#M7488

Thank you.

Well I discover the Sector antennas  and the Smart Antennas Horizontal and Vertical lables don't match. I am sending you pictures. Anyways I fixed them but still getting the disconnected error, here are the pictures 

Hello,

From the pictures, the Sector antenna ports are correctly wired but the Smart Antenna ports should be connected left-to-left and right-to-right. Once you re-cable them, you will need to reboot the ePMP2000 for it to recognized the Smart antenna.

http://community.cambiumnetworks.com/t5/ePMP-Installation/ePMP2000-How-do-I-know-if-the-Smart-Antenna-is-turned-on-and/m-p/56469#U56469

Regards

2 Likes

I had them like that before and reboot the antenna got the same error  being disconnected

Hello,

Which of the errors in the Knowledge Base link I provided are you getting? Sorry, for some reason I cannot see the image you uploaded for the antenna error you are seeing.

Regards

This is the error I am getting, attached another picture. 

Thanks KDRAMA.

If you get this same error, independently on how you are making the connections to the Smart Antenna, it means the ePMP2000 is just not been able to talk to the antenna. It could be

- an issue with the cables connecting the ePMP2000 to the Smart Antenna

- an internal issue with the ePMP2000 Smart Antenna connectors

- an issue with the Smart Antenna

Please contact our support team so they can further help you troubleshoot this issue.

Regards

2 Likes

Hello everyone,
I’m about to deploy a PTP using ePMP200 Force and ePMP 300-25 force. Should i use ePTP Master & Slave or TDD mode. Note that i wanna carry 50Mbps on this link.

Thanks

Hi,

ePTP mode will provide you lower wireless latency , say 5ms and suitable for moderate noisy conditions.
TDD-PTP mode provides better throughput performance in high noisy condition with a wireless latency of say 10 ms

1 Like

Hi. Two different answers, depending on the gear.
If you are using ePMP1000 or 2000 series gear (such as your ePMP Force200) then the ePTP mode is significantly better. I’ve called it magic before – lower latency, faster speeds, and interference mitigation.

But, if you’re using ePMP3000 series gear (such as the ePMP Force300) then we’ve found that ePTP mode just doesn’t perform anywhere near the same. For latency and throughput, the ePTP mode is barely any different for us than TDD mode – and is usually actually worse for me. Less overall aggregate throughput than TDD mode, and higher latency as the link fills up.

Additionally – if I’m understanding your questions (PTP using ePMP200 Force and ePMP 300-15 force) then you’re only viable option will be TDD, since there isn’t ePTP Mode compatibility between Force 200 and Force 300 generations in ePTP mode.

For us - we have all our 1000/2000 generation gear PTP links (including Force200) in ePTP mode, and we have all our 3000 generation PTP links (including Force300) in TDD 75%/25% mode.

3 Likes

Just to expand ninedd’s thoughts:

ePTP is a variable latency mode which as the link gets busier the link latency increases. This is more pronounced as the number of small packets increases despite the throughput staying the same.

PTP-TDD is more linear in the latency as it generally does not increase by much as the link gets busier. Instead the additional processing causes the radios to show higher cpu % and increased frame usage.

The answer is really based on your needs:
Do you need to share the same channel in a back to back usage? Then a e3kL and a f300-25 in PTP-TDD mode is best.
Just need a stub link to a tower? either mode will work but at the cost of RF bandwidth usage.

If you are running VOIP or Vid-chat systems then the cost of higher latency is worth the stability in packet rate of PTP-TDD.

We have moved all but one of our links to e3kL and F300 radios and because of a couple network requirements everything is 50/50 TDD mode. That one link is still a e1k-LITE and a force100-csm (for the f110 dish) and its still capable of over 100mbps each way! But that link is scheduled to be swapped out this coming spring as that tower is getting too busy.