PTP450 radio unable to deliver 100Mbps speed on the internet WHY?

[KOwopetu123]

Dear Team

I have a challenge with the Cambium PTP450 (3.6GHz) radio link on a point to point platform over a 6km distance range between my POP and a customers location.

After installing the radio link i got this RSSI levels

And when i did Link capacity test this is the result of what i got

But with this Link capacity test result I was not able to get upto 80Mbps on both download and upload when I did an internet speedtest.

Please why is this so?

My thinking was that with above result i got on the Link capacity test from this radio I thought I will be able to get upto at least 100Mbps on this radio link.

Pls I need your help.

[Charlie]

First off, I recommend 450i or 450b, not 450.

The PMP/PTP 450 has only 100BaseT link, so of course you’ll never get over 100 Mbps and has a less powerful CPU.

Yes, the RF here can handle 105 Mbps down and 100.67 Mbps up. But note that is using “Link Test without Bridging” and max packet size of 1714. It is also using all 4 Data Channels (Ultra High, High, Medium and Low).

To most closely simulate a Internet Speed Test you should cap the packet size to the average packet size of the test. Also should probably use only one Data Channel (depends on the test but generally this is the case). Also use “Link Test with Bridging and MIR” to more closely simulate the CPU load.

But note this still doesn’t include any Ethernet on either side, which will slightly increase the CPU load for real traffic.

Hope that helps.

[KOwopetu123]

Dear Charlie

Thanks for your prompt response I was able to use iperf and WAN Killer to carry out a radio capacity test in which I was able to push upto 97Mbps both download and upload on the radio link.

[Neil_Capell]

The CPU on a PTP450 basically hits 100% when traffic reaches 65-70Mbps. It’ll never do more than that.

Get yourself a pair of 450b’s, they are super cheap, and you’ll see speedtests that will match your link capacity tests.