Second device not working on home MoCA network

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jmshapir

New Around Here
Hi,

I have Cox home internet service. I am using MoCA to run internet to a WiFi router and to a second device.

I've put a wiring diagram below.

The WiFi router is working fine but the second device is not getting internet. This is true regardless of which second device I use (PC, Roku, etc.). It is also true when I connect the second device using a shorter cable that runs right into the amp/splitter. And it's true even after I replaced the MoCA adapter.

The problem started when I upgraded my cable modem to a newer model.

Does anyone have thoughts on what might be the problem with my configuration?

I am out of ideas here and would really appreciate any suggestions.

Thanks.



wiring_diagram.PNG
 

degrub

Very Senior Member
Are you getting moca sync lights on all three Actiontecs ?

what happens if you plug the coax going to the device 2 Actiontec into the amp/splitter port used by the device 1 coax ?

post a clear picture of the label side of the amp/splitter showing the cables connected, please.

did you replace the modem or did a Cox technician replace it ?
 
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eibgrad

Very Senior Member
What if you bypass the amplifier/splitter completely and attach the non-working device directly to the MoCA adapter off the modem?

Are these non-working devices configured properly by DHCP but just not working wrt the internet (what about local access?), or are they NOT configured at all by DHCP?
 

krkaufman

Senior Member
Quick hits...
  • Good: having the modem direct-connected to the provider and isolated from any MoCA-infused coax is a good thing, providing the strongest possible signal to the modem, and future-proofed for DOCSIS 3.1, 4.0 and on -- given that the DOCSIS 3.1 and MoCA specs now have overlapping frequency ranges.

  • Problem: amplifiers severely attenuate MoCA signals passing between input and output ports, if MoCA can even pass. Given you’re using an amp with a built-in “PoE” MoCA filter, the PPC-9M-U/U, I’m a little surprised that you’re getting a connection at all. Solution: If you’re only doing MoCA over your coax (i.e. not cable TV), the amp is not needed at all: amps don’t boost MoCA signals, just frequencies 5-1002 MHz (typical); plus, MoCA has its own built-in automatic power adjustment, amplification and reduction. So the recommendation is to replace the amp with a right-sized MoCA-compatible splitter.

  • Problem: MoCA WAN not LAN. You've established a MoCA network to link the Ethernet WAN port of the modem near the cable point-of-entry to the Ethernet WAN port of your wireless router. The MoCA adapter at the router location is connected to the router's WAN port, right?

    The Ethernet equivalent of the diagrammed setup is connecting a network switch to the WAN port of the modem, then connecting both the router WAN port and the second device to the switch. As a result, the second device resides within your WAN segment, rather than where it needs to be ... on the router LAN.

    Solution[1]: MoCA LAN-only: The preferred, optimal solution is to move the router to the modem location, connecting their WAN ports using an Ethernet patch cable ... and then using MoCA to extend the router LAN where needed. The downside is that you'd need another device to function as a wireless access point -- or another router, allowing the current router to be reconfigured as an access point in its current location.

    Solution[2]: dual WAN/LAN MoCA networks: MoCA allows for operating two separate MoCA networks within the MoCA Extended Band D frequency range; so you could establish a second MoCA network extending the router LAN over your coax. Drawbacks: Lower speeds, extra MoCA adapter required, and much configuration. The segmentation of the Extended Band D range, combined with lost spectrum required for signal separation, results in the two MoCA 2.5 networks having maximum throughput of 400 and 1200 Mbps:
    * Network 1 (D-Low, 1125-1225 MHz): 400 Mbps max
    * Network 2 (D-High, 1350-1675 MHz): 1200 Mbps shared max

    So you'd need an additional MoCA "LAN" adapter at the router location, connected to the shared coax and a LAN port on the router, and then you'd need to manually configure all the MoCA adapters for their respective WAN or LAN MoCA network.

    The additional cost, configuration hassles and reduced throughput make this a less than ideal solution.
 
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krkaufman

Senior Member
Solution: If you’re only doing MoCA over your coax (i.e. not cable TV), the amp is not needed at all: amps don’t boost MoCA signals, just frequencies 5-1002 MHz (typical); plus, MoCA has its own built-in automatic power adjustment, amplification and reduction. So the recommendation is to replace the amp with a right-sized MoCA-compatible splitter.
...
Solution[1]: MoCA LAN-only: The preferred, optimal solution is to move the router to the modem location, connecting their WAN ports using an Ethernet patch cable ... and then using MoCA to extend the router LAN where needed. The downside is that you'd need another device to function as a wireless access point -- or another router, allowing the current router to be reconfigured as an access point in its current location.

The recommended changes would result in a setup like the following:

wiring_diagram - mod.png



edit: p.s. If curious, the dual MoCA WAN/LAN setup would echo this diagram, though adjusted for ISP type and your other specifics
 
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krkaufman

Senior Member

Just for completeness, is there just the one coax line available between the central amp location and where the router is located in your original diagram? (Or is there some creative way to effect the second line?)

If you had a second coax line available between the locations, you'd be able to keep the MoCA WAN and LAN networks of the "dual MoCA networks" solution isolated, eliminating the need for all the D-Low/D-High custom configuration.

Example 2nd coax line:
double-coax.png
Example "creative" 2nd line:
creative 2nd line.png
 

jmshapir

New Around Here
Are you getting moca sync lights on all three Actiontecs ?

Yes! Coax lights are blinking on all Actiontecs.

what happens if you plug the coax going to the device 2 Actiontec into the amp/splitter port used by the device 1 coax ?

Changing the configuration of amp/splitter ports doesn't seem to change the behavior.

post a clear picture of the label side of the amp/splitter showing the cables connected, please.

See below. Blue is the coax connected to the Actiontec that is connected to the modem. Red is the coax that runs to the device that is not working. The other three are not in use; Actiontecs on the other end are unplugged. Behavior is unchanged when I disconnect those entirely. I know that I should also cap unused ports and have ordered some caps so I can do that.

One specific question I have is whether the blue coax should be moved to the "input" port on the amplifier/splitter? I've read conflicting things about that but from the thread here it seems that maybe I should switch to the input port?

amp_splitter.PNG

did you replace the modem or did a Cox technician replace it ?

I replaced it myself.

Thanks very much for these helpful replies.
 

degrub

Very Senior Member
The MOCA sync led and the power led should on solid, not blinking. They are on the top edge. Do you mean the ethernet port leds (2) ? One of those will be blinking when data is being transferred.

If the moca light is blinking, then it is not able to sync but is still trying. Either there is an additional device on the coax running DOCCIS 3 .1 which will interfere or there is a cable fault, splitter fault, or other physical issue.

MOCA can pass on/between the output ports only on this amp/splitter. See this thread

Disconnect all cables except those being used for the moca network. See if that works. If it does, add the others back one at a time and check for issues. We have seen other devices that could use moca (like tv set top boxes, DVRs ) that are on the same coax cause issues. If the moca modems boot up and sync first and then the other moca devices, it would work. if the other devices booted up first, then the moca network would not work.

Did anything else change physically on the coax network when you changed out the modem ? Even relocation of a device ?
 
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krkaufman

Senior Member
One specific question I have is whether the blue coax should be moved to the "input" port on the amplifier/splitter?
Absolutely not, unless you’d like to test it. That you’re not using the input port explains why you have a connection between the modem-attached adapter and the others; the odds of that happening would drop significantly if you have adapters separated by the amp’s built-in “PoE” MoCA filter.

Further, per MoCA bullet 4 of PPC’s install notes for the amp, you should only be using ports 1-4 for your MoCA nodes. (Though I’d still recommend just switching to a right-sized MoCA 2.x-compatible passive splitter.)

So the remaining issue is then just that you only have a MoCA WAN, with the second device connecting on the wrong side of the router’s WAN port.
 
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degrub

Very Senior Member
i wonder if the previous "modem" was a modem router that was providing a LAN IP address to the secondary devices.
Yes, with the current setup, device 2 is directly exposed to the Internet. Maybe that is desired. i doubt the modem and the ISP upstream will accept providing two WAN IP addresses though unless that is the service he signed up for.

Although ports 5-8 are not the desired ports for MOCA ( probably for loss issues at the moca frequencies) the documents don't appear to prohibit their use. They do suggest those for the "shorter cable runs" , so it should just be a loss issue that he can get around by swapping cable locations.
 

krkaufman

Senior Member
Although ports 5-8 are not the desired ports for MOCA ( probably for loss issues at the moca frequencies) the documents don't appear to prohibit their use. They do suggest those for the "shorter cable runs" , so it should just be a loss issue that he can get around by swapping cable locations.
Yep, “should” vs “can” ... given the OP has only 3 nodes. (But MoCA connectivity isn’t the problem, it seems, though diagnostics info would be useful to confirm that.)

Further, per MoCA bullet 4 of PPC’s install notes for the amp, you should only be using ports 1-4 for your MoCA nodes.
233FB7A2-7E03-4D0E-A2B5-D905A7BED5E5.jpeg
 
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krkaufman

Senior Member
Yes, with the current setup, device 2 is directly exposed to the Internet. Maybe that is desired. i doubt the modem and the ISP upstream will accept providing two WAN IP addresses though unless that is the service he signed up for.
Fair point. If so, then, as you indicate, the issue would likely be with the ISP provisioning, requiring a call to their ISP customer support line.
 

krkaufman

Senior Member
i wonder if the previous "modem" was a modem router that was providing a LAN IP address to the secondary devices.
Solid speculation.
The problem started when I upgraded my cable modem to a newer model.

Did anything else change physically on the coax network when you changed out the modem ? Even relocation of a device ?
Switching from a combo cable modem/router (aka cable gateway) to the modem-only Motorola MB7621 would effectively constitute removal of a device from their setup.

Simple question... What was the model # of the "modem" that was replaced?

And it's possible they had a cascaded router setup that hadn't yet posed any usability issues. (i.e. their TP-Link AC4000 router should have been configured in AP mode, if their prior modem was actually a gateway).
 
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krkaufman

Senior Member
The MOCA sync led and the power led should on solid, not blinking.
I believe some of the later MoCA 2.5 adapters have blinking MoCA/coax status LEDs, to indicate activity. At least the goCoax adapters do, per their Quick Start Guide:

3. ... Step5: MoCA LED will be green/blinking if traffic is passing.​
 

jmshapir

New Around Here
Solid speculation.


Switching from a combo cable modem/router (aka cable gateway) to the modem-only Motorola MB7621 would effectively constitute removal of a device from their setup.

Simple question... What was the model # of the "modem" that was replaced?

It was a CISCO DPC3825.

And it's possible they had a cascaded router setup that hadn't yet posed any usability issues. (i.e. their TP-Link AC4000 router should have been configured in AP mode, if their prior modem was actually a gateway).
 

jmshapir

New Around Here
The MOCA sync led and the power led should on solid, not blinking. They are on the top edge. Do you mean the ethernet port leds (2) ? One of those will be blinking when data is being transferred.

My Actiontec adapters have three lights: Power (Solid green), Coax (blinking green), Ethernet (glowing green, can't tell for sure if it's blinking).

If the moca light is blinking, then it is not able to sync but is still trying. Either there is an additional device on the coax running DOCCIS 3 .1 which will interfere or there is a cable fault, splitter fault, or other physical issue.

MOCA can pass on/between the output ports only on this amp/splitter. See this thread

Disconnect all cables except those being used for the moca network. See if that works. If it does, add the others back one at a time and check for issues. We have seen other devices that could use moca (like tv set top boxes, DVRs ) that are on the same coax cause issues. If the moca modems boot up and sync first and then the other moca devices, it would work. if the other devices booted up first, then the moca network would not work.

I disconnected everything not in use. I powered down all devices on the network. I then powered up only the Second Device. It worked. I then powered up only the WiFi Router. It did not work.

I then powered everything down and went in the other order. Now WiFi Router works and Second Device does not.

I wonder if this is related to the issue that you and @krkaufman note above, that my previous modem was also a router, and my new modem is not?

Did anything else change physically on the coax network when you changed out the modem ? Even relocation of a device ?

See above, and thanks again.
 

krkaufman

Senior Member
It was a CISCO DPC3825.
Ok, so that confirms that it was a combo cable modem/router (aka gateway) device, per Cox's spec page, here -- though the next question would be whether it was left configured as a gateway or had been set to bridge mode (aka modem-only configuration). Given things used to work with this gateway device in place, odds are that it was in gateway mode, acting as both a modem and router ... and swapping it for a modem-only device eliminated the router that was establishing the OP's LAN.

I wonder if this is related to the issue that you and @krkaufman note above, that my previous modem was also a router, and my new modem is not?
Ya think?!? ;)

edit: I tried to explain the why above...
Problem: MoCA WAN not LAN. You've established a MoCA network to link the Ethernet WAN port of the modem near the cable point-of-entry to the Ethernet WAN port of your wireless router. The MoCA adapter at the router location is connected to the router's WAN port, right?

The Ethernet equivalent of the diagrammed setup is connecting a network switch to the WAN port of the modem, then connecting both the router WAN port and the second device to the switch. As a result, the second device resides within your WAN segment, rather than where it needs to be ... on the router LAN.
... though part of the problem is the indiscriminate use of the term "modem" as a label for combo modem/router (aka gateway) devices.
 
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krkaufman

Senior Member
I disconnected everything not in use. I powered down all devices on the network. I then powered up only the Second Device. It worked. I then powered up only the WiFi Router. It did not work.

I then powered everything down and went in the other order. Now WiFi Router works and Second Device does not.
This is the behavior to be expected, with your ISP provisioning a single IP address via your modem to a downstream device.
 

krkaufman

Senior Member
Of course, you could also try the more traditional setup with your equipment on-hand, sans isolation of the DOCSIS and MoCA signals, if your signal strength allows, by moving the Motorola modem to the TP-Link router location. (Short-term, the PPC amp could substitute for the MoCA filter and attached 2-way splitter in the diagram -- though the incoming cable from the ISP *would* now need to be connected to the amp's Input port, to get the cable signal delivered to the modem.)

And the TP-Link router would need to be configured in "router" mode (as opposed to "AP" or "Extender" modes).

e.g.
wiring_diagram - non-isolated.PNG
 
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jmshapir

New Around Here
Thanks very much. Seems like we are getting to the bottom of this and I really appreciate the help running down the issue.

I'd like to leave the TPLink Router where it is because its current location gives a good signal throughout the house.

In terms of moving the modem, every time I've had anything but a modem tied directly to the line from the street, I've had stability issues.

Is there another kind of device I can put between the modem and the first Actiontec to replace the functionality I was getting from the router part of the modem/router combo I was using before?

For example I have on hand an ASUS RT-AC68U Router, and a Cisco SD205 switch. Is one of those useful in this situation? Or is there something else I could buy that would do the job?
 

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