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FBR_Central
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SH3 Fails to Maintain Gbit Ethernet Connection (Modem Mode)

I have this setup, professionally wired with tested Cat6 throughout:

Simple_Network.jpg

This week I installed the third (IIRC) SH3, but the new hub is showing the same symptoms as my old one.  In short, the WAN connector on the SH3 falls back to 100mbit mode every couple of hours, with a hard reset being the only thing to reliably restore Gbit throughput.  This is what it should look like:

Gig_Modem_Online.jpg

But after a short time this is what I get: 

back_to_100.jpg.png

 Obviously at this point my entire network is throttled to ~90mbps due to the 100mbit connection.  I've tried:

  • Using different ports on my router
  • Using different cables
  • Restarting router and leaving SH3 powered
  • Restarting SH3 from the GUI
  • Restarting SH3 by physically switching off (this sometimes restores Gb for an hour or two)
  • Following this process (same result as above, only good for an hour or two)

Eventially my SH3 always reverts to 100mbit within a couple of hours.  Any ideas?  

Working perfectly:

Good_Result.jpg

Throttled by 100mbit connection:

after_100mbit_modem_fail.jpg

 

 

 

 

 

 

 

 

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Very Insightful Person
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Re: SH3 Fails to Maintain Gbit Ethernet Connection (Modem Mode)

And it's the same Asus router that you've had during all of this?

Have you done any bypass tests to ensure that it's not actually the router that's causing the behaviour?
**********************************
I work for Virgin Media - but all opinions posted here are my own
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FBR_Central
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Re: SH3 Fails to Maintain Gbit Ethernet Connection (Modem Mode)

Hi Ben - 

Yes, I've wired a laptop directly into the SH3 in router mode and I can't seem to replicate the fault.  

Someone on the phone also got me to do a loopback test (a patch cable into 2 ethernet ports on the same SH3) and they said that indicated that the WAN socket was functioning.  

I have also plugged the cable from the SH3 into different sockets on the router, which had no effect.  I haven't yet bought an entirely different router because (aside from the cost) there would be a big admin overhead on me to set it up properly.

Thanks.

EDIT: I guess I could plug the cable from the SH3 into my gb switch, but I haven't tried that yet.  All gb connections on the Asus router have been solid for the entire time I've had it.

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jbrennand
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Message 4 of 53
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Re: SH3 Fails to Maintain Gbit Ethernet Connection (Modem Mode)

This may be a bit obvious but having 3 Hubs giving the same fault means that the problem lies elsewhere. It could be a network connection issue (which VM could check) but it seems more likely that it is a problem in your hardware. Can you be more specific (sorry cant see you inserts yet - need Mods approval). Your title says "modem mode" so what Router have you got attached? What devices are you connecting by cable - and have you tried wifi ? Are you sure that the devices are gigabit enabled and not being throttled by a 10/100 network card? Do you have powerline adpters anywhere in the loop?

--------------------
John
--------------------

My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired 2 WiFi,) SH2 in modem mode with Airport Extreme Router. On VIVID200, Talk Anytime Phone, x2 Mobile SIM only iPhones.
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FBR_Central
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Message 5 of 53
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Re: SH3 Fails to Maintain Gbit Ethernet Connection (Modem Mode)

Hi - thanks for the reply.

The house is wired with CAT6 everywhere.  I run up to 50 clients, including web and media servers, several NAS devices and an IP-based security system.  The router is an RT-N66U running Merlin firmware, with WiFi disabled and a 16 port Cisco switch attached.  For WiFi I'm using the Linksys VELOP mesh system (which will happily provide full fibre bandwidth of 220mbit over wifi when tested).  

The layout of the SH3 and router might be relevant.  There's a 5m run of CAT6 under the floor, with 2 physical cables.  Normally this is WAN traffic from SH3 to router on one cable, and LAN traffic from switch to my Mac-based media server on the other cable.  As with many people, my coax enters the house in an inconvenient place behind the TV.  The underfloor cables terminate in a small networking cabinet under the stairs.

I have tested the media server and the SH3 on both underfloor cables and on a separate CAT6 patch cable running through the room.  The cable makes no difference to SH3 symptoms, and the media server maintains rock solid gbit on any of the three wires for months on end.

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FBR_Central
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Message 6 of 53
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Re: SH3 Fails to Maintain Gbit Ethernet Connection (Modem Mode)

@jbrennand - I take your point about several hubs seeing the same issue - it could also indicate a design / throughput fault with SH3 hardware perhaps?

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legacy1
Alessandro Volta
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Message 7 of 53
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Re: SH3 Fails to Maintain Gbit Ethernet Connection (Modem Mode)


@FBR_Central wrote:
  • Restarting router and leaving SH3 powered

Does that fix the issue?  is the link between the hub and router at 1Gb?

 

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FBR_Central
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Re: SH3 Fails to Maintain Gbit Ethernet Connection (Modem Mode)


@legacy1 wrote:

@FBR_Central wrote:
  • Restarting router and leaving SH3 powered

Does that fix the issue?  is the link between the hub and router at 1Gb?

 


No, the only thing that resets the 1Gb connection is a power cycle of the SH3, which is what makes me suspicious.

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legacy1
Alessandro Volta
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Message 9 of 53
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Re: SH3 Fails to Maintain Gbit Ethernet Connection (Modem Mode)


@FBR_Central wrote:

 


No, the only thing that resets the 1Gb connection is a power cycle of the SH3, which is what makes me suspicious.


So you can see the link speed at 100Mb between hub and router when your speed drops? Or does the speed drop but the link shows 1Gb between hub and router ?

Probably is a fault with the hub.

 

 

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Sam-T
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Message 10 of 53
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Re: SH3 Fails to Maintain Gbit Ethernet Connection (Modem Mode)

Certainly an odd problem. I'm running a hub 3 in modem mode with a Netgear R7000 Nighthawk. Never had an issue with having to reboot to maintain Gbit connection. 

 

Ex Virgin Media 2nd Line Support
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