XB7 cannot run Pods and MOCA

TL; DR

Comcast XB7 (Technicolor CGM4331COM 2.0) cannot simultaneously support xFi Pods (single gigE model) and MOCA (Actiontec ECB6200).  The MOCA link drops anywhere from a few seconds to a few minutes and the Pods frequently re-mesh.  Unplug either all the Pods or all the MOCA transceivers and all ethernet traffic stabilizes.  (MOCA:  300Mbps office throughput, 600Mbps living room.  Ditched all Pods).

Details:

I have nearly 3 decades of datacenter class networking and wifey has 2 decades network and wifi product management.  We are techies.  Yet, we spent weeks troubleshooting fully-meshed wifi Pods and fully-meshed coax MOCA.

The Comcast internet plan we have isn't relevant to the XB7 problem, but it's 150Mbps/10Mbps.  We upgraded it to 1Gbps/40Mbps.  Again, not relevant.

The XB7 wifi is okay for power and coverage, but we needed more backyard and frontyard coverage, so we bought 3 xFi Pods.  Those were easy to install (power and use app to add each one) and were highly reliable.  Downside was Pods only provided about 70Mbps throughout.  Not surprising since one Pod radio is backhaul mesh to each Pod and the XB7, and one radio for wifi clients.

70Mbps and 40ms latency wasn't enough for my upstairs workdesk (or Xbox One ;-).  I researched and bought 2 Actiontec ECB6200 MoCA 2.0 transceivers to take advantage of our house RG6 coax home runs to deliver hardwired throughputs.   The XB7 (Technicolor CGM4331COM 2.0) supports MOCA 2.0.

Remember, the XB7 and Pods were providing wifi with NO wired ethernet connections (just in case anyone thinks I had a spanning tree link).  The XB7 GUI Troubleshooting - MOCA showed each Actiontec transceiver at 1200Mbps raw link and about -42dB.

Adding the MOCA transceivers created two problems:  Pods were randomly re-meshing (slow flashing white LED) dropping all traffic, and MOCA link uptime was always less than 8 minutes, sometimes less than 30 seconds.

I spent days checking coax (all RG6), coax plates, connectors, and MOCA compliant splitters.  Nothing solved the low MOCA link uptimes until (wifi expert) wifey made an observation:  Pods and MOCA are fully meshed networks.

Think about that for a moment.  Both independent systems (wifi Pods, coax MOCA transceivers), were randomly re-meshing when Pods and MOCA transcievers were connected to the XB7.

Unplugging the Actiontec MOCA transceivers returned Pod mesh to the slow, but reliable state.  That led me to putting a MOCA POE (Point Of Entry) filter at the XB7, thus blocking the XB7 from becoming the MOCA Network Controller (or joining the MOCA mesh).

With the XB7 unable to join the two Actiontec MOCA mesh, I added the Pods and then EVERYTHING was reliable (70Mbps Pods, 300-600Mbps MOCA with hours of MOCA link uptime).

Root cause:  XB7 apparently cannot multiplex wifi Pod mesh and MOCA mesh.