20M BackHaul, Actual Measured Throughput

I have several 20MBH, but one particular is becoming loaded with traffic. I need help understanding the actual amount of throughput that one of these units have. I have the downlink set to 75% and monitor it with mrtg. The traffic on the unit today hit 4.5M (DOWN) and I started losing packets for the first time ever on this link, not serious packet loss. The ping times went from avg 2 to 10ms to 30ms and above. So my quesiton is are these BH’s getting overloaded with traffic. If 14M is available and I have a 75% downlink ration shouldn’t that ~10.5M for down and ~3.5M for up? Should I look at upgrading to 45M units? Suggestions needed.


What did your uplink look like? Also, what is considered not serious packet loss <1%, <5%? Also, in the configuration page does it show that you are set for 20 Mbps or could it be set to 10 Mbps?

Uplink was 900K to 1M. I ran a ping count for 200 times and lost 18 of them and ping times were as high as 100ms. It is set for 20M on the configuration.

What is the amount of throughput we should see out of these units?


Not sure if this helps or not…

I have seen my backhauls (20s and 60s) not return pings or SNMP data but still pass data normally. It almost seems like they are too busy to processing normal traffic to deal with traffic addressed for them - this has shown up only under heavy loads though. Perhaps a built in priority for bridging data instead over answering it?


I have also seem some strange activity when troubleshooting backhaul links. With my laptop plugged into a CMM-Micro, I had two seperate command prompt screens open and was running continuous pings to the IP address of the BHM and the BHS. Obviously I couldn’t start the pings at the ‘exact’ same time, but I tried to get them as close together as possible. There were some times where the BHS would respond but the BHM wouldn’t. One would wonder how the far end of the link is responding to pings when the near end is not.

Perhaps this goes along with acherman’s findings. The BHM is passing the ICMP data, just not responding to ICMP echo requests directly to itself.

So what type of Bandwidth should I expect to see with a 75% downlink ratio set?

10.5M Down and 3.5 Up? I am trying to see if I need to upgrade my BH to 45M or greater?

I don’t set my at 75% I run at 50% set at 20M I normally get 6.5 up and down. The numbers you are showing seem way off what is your uplink and downlink efficiency % on the link test? What does your link test show for up and down speed? do these match mrtg? What version software? You could also have switch or cable problem. need more info.