Packet Loss on Existing AV500 setup

[Samir]

Someone responsible for getting the cat5 run to the study in my parents house somehow must have left the wire in the crawl space back in the mid-1990s. This wasn't a big deal until we really started using the study for work and needed wired connections.

I didn't want the unreliability or security issues of wireless and av500 powerline adapters (Netgear Nano av500) had just come out and were on sale at Staples. So I tried out a pair, putting one in an adjacent room that has an Ethernet jack and the other in the study. Worked great! Since then we expanded the powerline part of the network to a total of 4 units including one in another room where the room's Ethernet jack was on the opposite wall from where we needed it.

Just recently (in the last week in fact), I noticed some very intermittent lag in remote desktop from the study to the attic where the actual system is. It happened a few times more, so I nailed up a ping and noticed some intermittent packet loss--just a few packets--but enough that if you're in the middle of working, it's annoying.

I've now nailed up a ping to devices on all 4 segments of powerlines to help figure what's going on here or if one is failing after nearly a decade of being on 24x7.

One of the things that occurred to me is that all these powerlines are relying on just one 'gateway' back to the wired Ethernet. If that's the unit with issues, then the entire powerline network will have issues.

I have 2 more spares (decommissioned from a business where they were being used because of the excellent performance at the house), and I could put them in other rooms with Ethernet jacks to provide more 'gateways' back to the Ethernet network. But without an understanding of if this would help (redundancy/failover), it might be a waste of time.

I'm looking for any other suggestions to diagnose what might be going on, as well as if adding more powerlines wired to the Ethernet network might help. Thank you in advance for any ideas.

 

[Samir]

A little more information. So as I was writing the post, there were some ping timeouts--but only back to the main network, ie the unit that connects to the wired Ethernet network. Even while there were these timeouts on this segment, pings to the other 2 segments (I'm on one of them so I'm pinging 3 places) were rock solid. So does this look like the powerline that plugged into the Ethernet is going bad? Or the Ethernet cable? Or the jack? Or is it something else?

 

[Richard Castreje]

It sounds like you are having a performance issue with that 1 unit or that 1 electrical connection. To isolate the hardware has being the issue, have you tried switching the 3rd PLC and the Gateway PLC? If your "ping" issue migrates with the Gateway PLC to the new location, it is likely a hardware issue. If the problem persists at the Gateway location, you many have a power line interference issue on the outlet.

Additionally, I don't know if I would recommend establishing redundant paths back to the Gateway with other PLCs. Unless the PLCs are prepared for this configuration, you are likely to create a network loop. That would be bad.

-rich

 

[Samir]

Thank you for the reply! I'm going to do that swap right now and see what happens. This problem is so utterly annoying.

That's kind of what I was afraid of with redundant connections--network loops. But that all depends on how the powerline standard handles such things.

 

[Samir]

Nope, still happening at the 'gateway', so either that Ethernet jack is going bad or the cable (but the cable I already replaced with a new one a few days ago, so I don't think it's the cable).

I'm going to move the 'gateway' powerline to another room with an Ethernet jack and see if that helps.

If this move fixed it, I'm going to have to run a ping at that jack and see if that's the root cause so I can fix the jack. If only these cabling monkeys followed spec--in some places they untwisted well over an inch.

 

[sfx2000]

Look for noise sources on the mains - something as simple as a cell phone charger can cause interference - also heavy appliances can do bursts that can affect intermittently...

 

[Samir]

Yep, looked for all of those things when we initially set everything up to make sure it wouldn't be an issue. This seems to be something new for sure.

I just checked the ping now that I moved the 'gateway' one to another Ethernet jack--zero packets lost. Looks like it was the other Ethernet jack staring to fail after being in service since 1995. I guess 23 years isn't too bad for some craptastic wiring. I bet once I fix it, it will be good for another 25 years.

I'm glad that it wasn't the powerlines--they've been pretty much bulletproof.

 

[Samir]

I am still curious about the multiple powerlines connected to Ethernet though if anyone has an answer to that.

This is a pretty critical network so if it goes down and I'm not here I have to get on a plane and come fix it immediately.

 

[ColinTaylor]

I am still curious about the multiple powerlines connected to Ethernet though if anyone has an answer to that.

This is a pretty critical network so if it goes down and I'm not here I have to get on a plane and come fix it immediately.

I'm not really sure what kind of scenario you're talking about. Presumably it relates to this:

One of the things that occurred to me is that all these powerlines are relying on just one 'gateway' back to the wired Ethernet. If that's the unit with issues, then the entire powerline network will have issues.

I have 2 more spares (decommissioned from a business where they were being used because of the excellent performance at the house), and I could put them in other rooms with Ethernet jacks to provide more 'gateways' back to the Ethernet network. But without an understanding of if this would help (redundancy/failover), it might be a waste of time.

All powerline adaptors are equal, so there's no concept of master/slave. So if one adaptor becomes faulty just throw it away a plug in another one. You could move one that's currently located elsewhere in the house or plug in a spare that's sitting in a box. If using a spare it will need to have previously been setup on your powerline network, or you will have to "pair" it using the normal procedure.

This is assuming all your powerline adaptors are using the same standard and are therefore compatible with each other. Also, if your current powerline network uses something other than the default network name then that might be a consideration when adding a new adaptor to an existing network.

 

[Samir]

Nope, that wasn't it. Let me try to explain it again.

4 powerlines, 1 plugged into an Ethernet jack that leads to the rest of the existing LAN. The other 3 powerlines have devices connected to it that use their powerline to get to the main lan.

Device--Powerline--Powerline--Lan

But what happens if I add another powerline that is on the same powerline network, but is also plugged into an Ethernet jack that leads to the rest of the existing LAN? Would there now be 2 'routes' for the other 3 powerlines with devices attached that use the powerline connection to reach the LAN?

Or would the powerlines simply use only one of the powerlines to get back to the LAN? What happens if one of these powerlines connected to an Ethernet jack fails?

I ask this because if plugging in more adapters to more Ethernet jacks helps potential issues by providing more 'routes' back to the Ethernet network, that's exactly what I have spares I can use to do.

 

[Richard Castreje]

Since the Powerline Adapter is functioning like a Layer-1 Connection, I think it will cause a Network Loop. Easy way to find out. Connect the 2nd Route back to the LAN. If it does cause a loop, you will know it in about 2 seconds. Your entire network will stall.

If it does stall the network, just remove the device and your network should recover in a few seconds.

Needless to say, only try this when you are OK with a network interruption.

-rich

 

[ColinTaylor]

I'd agree with @Richard Castreje . I'd expect it to create a network loop. IIRC the router has STP turned on by default so that might prevent broadcast storms and the like. But it's not a network design that I would be happy with.

 

[Samir]

Thank you for the feedback. A good ol' packet storm is what I'm expecting as well since my understanding of it is a shared medium.

Since more than likely it's going to be a disruption, I'll definitely try it sometime when nothing is being used. And I will post back with my results.