Cloud Core Router Throttling Traffic

We have a Cloud Core Router CCR1009-8G-1S-1S+ as the primary connection between our network and the external internet.
Clients on our network are given addresses over PPPoE. Each has a bandwidth limit of 100M/100M (our backbone is 300M/300M).
The firewall is not extensive.
Each customer has a fixed external IP, with src-nat rules set on outgoing traffic to assign the external IP address.

We are struggling with complaints from customers who are complaining that they are getting slow speeds - perhaps as low as 1 Mbps download.
No obvious reason. Upload generally OK.
Rebooted the CCR at 13.00 today and everyone was happy again.

Tonight the whole network went slow and could only be fixed by a reboot of the CCR.

Any ideas?
Thanks

Should have added that uploads seem to fine.
Gradually turning things off with no joy

  • Moved one client from PPPoE to Fixed IP
  • Then disabled the src-nat rule for that client so they no longer have a fixed IP address

Anyone?
We’ve put a huge amount of effort in reconfiguring our network so that it is routed instead of flat so we can rule out broadcast traffic
Also found a mention of spanning tree protocol causing routers to hang, so we’ve disabled RSTP across the network.

Any ideas how we can identify if this is
a) a problem in our network
b) a problem with the CCR
c) a problem with our backhaul provider

Thanks

Could you do an export and post config hiding external ips and names etc.
What is the CPU usage like when this happens.
How many queues are you running?
How are you providing connectivity to your customers. Through fibre, wireless?