Hi,
I am planning PTP backhaul links to connect between mine sites and camps. I was initially planning ot use the PTP670 but it does not support 2+0 configuration so now I am thinking of PTP550.
What are the key benefits of the PTP670 that would be compromised if a PTP550 is used?
Thanks in advance!
Hi @Maissa, the ptp 670 is better suited for difficult spectrum conditions. How much bandwidth do you need to pass?
Hi Tommaso,
thanks for your reply.
I need between 400 and 450Mpbs,s o the PTP670 would be suitable. My only consideration is that there is no redundancy.
Regards,
Maissa
Hi Maissa, I'd like to point out some considerations when selecting between the two products. Also, keep in mind that the headline rates are in ideal conditions and, with unlicensed microwave, this is not aways possible. I would encourage you to use our free design tool, LINKPlanner, (with interference added) to predict performance.
At a high level, the PTP670 is a FPGA based chipset with a proprietary protocol. This means that we have more flexibility to make changes and add features into the chipset. For example, the PTP670 has excellent nLOS and NLOS performance due to the high number of sub-carriers within the OFDM modultion (up to 1024 vs 256 in Wi-Fi), as well as, high spectral efficiency (10bit/sec/Hz). Also, as Tommaso, points out, the PTP670 is very robust when dealing with high interference and challenging environments. While there isn't redundancy built in, see the attached application note for doing this via network equipment. Also see the white paper on some innovative features (any reference to PTP650 also applies to PTP670).
The PTP550 is an 802.11acWave2 based chipset using the standard 802.11 protocol. There are actually 2 radios transmitting data (3 if you count the always on spectrum analyzer), up to 80MHz wide channels each, across the 5GHz frequency band. The headline rate of 1.36Gbps requires 2x80MHz wide channels being used with low interference (which is really hard to do). This is what we refer to as a 2+0 setup. The real benefit of the PTP550 is the asymmetrical, non-contiguous channel bonding. This allows flexible channel configuration across multiple frequency bands (e.g. 20MHz wide channel in 5.8GHz bonded with a 40MHz wide channel in 5.1GHz). While the two radio configuration can be seen as some form of redundancy, that was not the initial intention with the product.
In summary, the PTP550 is a very cost effective solution for small to medium distance links with medium to high throughput (environment dependent). The PTP670 is a very robust solution for medium to long distance links with small to medium throughput (environment dependent). If throughput is the main driver, then PTP550 would be a good option; if stability is the main driver, then PTP670 would be a better option. With either option, it is going to be difficult to achieve the spec sheet data rates with any moderate interference.
Hi Chris,
Thank you very much for the insights, that's very helpful.
I have been using Linkplanner, however without adding interference. There is no other network in the area that uses the 5GHz spectrum. Is general moderate interference not automatically included in the link perfromance?
Thanks,
Maissa
I find LINKPlanner to be conservative in general. However, with unlicensed PTP links, interference isn't calculated unless you 'check' the interference boxes within the link configuration. LINKPlanner will default to some interference values based on the frequency band and channel size. The values can be changed and the more accurate numbers you can provide, the more accurate the prediction will be. Even something like -85dBm or -90dBm can affect performance, depending on the link.
I find that LINKPlanner is very conservative for PMP links and I actually don't add interference unless there is a very high noise floor at the AP level.