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Second Router set up causing NAS CPU to spike

1K views 17 replies 2 participants last post by  GentleArrow 
#1 ·
Hi all
I have a gneral query about my whole network, I hope I am in the right area for a bit of advice.
Here is my setup:
I have a BT smart hub (BT's newest router) which I have set up fine, quite seamless and good speeds. I also have a Synology NAS which I have attached to the router by ethernet. The network and the NAS were working fine together.
But I have since added a TP Link W8980 router into my network, in my sons bedroom at the back of the house, via a long ethernet cable round the outside of the house.
I have set this router up as a "Wireless access point" in effect, my son gets great wifi in his bedroom, he plugs his desktop into it so he's got a wired connection, and I can also get great wifi on the garden. I have set the SSID to the same as the BT Router, so all through the house we all seamlessly connect, and have great wifi.
I have disabled the DHCP on the second router, and have given it a static IP address outside of the DHCP range of the main router. The network itself is great.
Now comes the issue.......The NAS has high cpu, all of the time. I have had a ticket open with Synology, looking around, and the conclusion we have come to is that when the second router is plugged in, that causes the issue. When I unplug or turn off the second router the NAS behaves normally. Obviously this doens't suit my son now he has got used to having his own router! So now I need to know the best way to isolate the second router so it doesnt interfere with the NAS. Firewall? Different
subnet so he has his own mini network in his bedroom? Bridge mode?
As far as I can see I have set it up fine, and the network is fine, with average 40mbps download or better, but it is somehow interfering with NAS.
Here are the IP's I am using
BT Home hub - 192.168.1.254
DHCP Range of BT - 192.168.1.64 to 192.168.1.253
IP address of TP Link - 192.168.1.60 (outside of BT Hub dhcp range)
IP address of NAS - 192.168.1.50 (outside of BT Hub dhcp range)
I have Wireshark, but don't really know how to use it properly and haven't really had time to master it, but I can see the TP Link IP address knocking about in there
I hope the above is enough info for someone to help me make sense of it
Any advice gratefully received
Thanks
Richard
 
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#2 ·
It would be very unusual for one device to cause another device to have high cpu utilization. Subnet, ip addressing does not cause this type of issue.

Does your router provide lan port stats? That would be one way of tracking if you saw a lot of errors on that port.

I would also be curious if you had just the 2nd router connected but not your son's pc to see what the nas cpu utilization is about.
 
#3 ·
Hi

thanks for your reply

I have checked the lan stats and will try to attach to this post, hope you can see them. I can't see any errors as such, but it certainly seems to be interacting more with the NAS (192.168.1.50) more than anything else.

Previously when I have tested the cpu with PC switched off and it remains an issue. I have left the Ethernet plugged in but will try tomorrow unplugging that aswell, but if the pc is off, I cant see that unplugging Ethernet would make a difference... but will see.

Let me know what you think to the LAN stats

Thanks again
Richard
 

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#5 ·
Hi

Thanks once again for your reply. .108 was my smart tv, located right next to the BT router. I had previously had this wired and set static IP address, since decorating last week I've not wired it back to the BT router, but I have now, and given it a static IP of .55

So even now, its wired to my BT router, with static IP outside of DHCP, the TP link is still picking it up....

See below screenshot

For info

.50 = NAS
.55 = Smart TV
.64 = Laptop I'm using now
.117 = BT router tells me this is a games console - but we have none on or connected - I can't find which device this is
.254 = BT Router

Sorry if I'm being a little vague, or not too knowledgeable, but not sure how to sort.

I'll have a read into VLAN, not something I'm too familiar with

thanks again
Richard
 

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#7 ·
Hi

Yes these are screen shots from the tp link as I feel sure this is where the issue lies (due to when it's not on, the nas behaves normally)

Bt and tp link are connected via lan ports.

Nas has wifi function as it can act as a router in some way but I have not set this up

Cheers
Richard
 
#10 · (Edited)
You wrote that dhcp was disabled on the tplink. but the screen shot has a revoke on it which you usually see with a dhcp lease.

Make sure the tplink dhcp server is disabled.

Can you post the connected devices page from the bt hub for review?

BTW I am not seeing any conflicts. I am curious as to why the TV is accessing the NAS so much especially if not doing any nas to tv streaming.

Might just turn off the tv to see if the nas utilization goes down.
 
#11 ·
Good morning

And thanks once again for taking your time to look at this.

Ok, so I have turned TV completely off, no change. I have turned TP link off again, cpu drops.

I have confirmed DHCP is disabled on TP link (attached) and have done screen shots of both routers, and what is connected. You can see the same devices are showing connecting to both, wired or wireless. The only extra device showing on the TP link is my wifes Iphone (not sure why, but don't think that is the culprit as there is still an issue when she is not home)

Maybe I can block the sky box and Samsung tv from hitting the TP link, somehow on the TP link settings? but not even sure they are being picked up by wifi, it just seems whatever is connected to the BT, seems to show up on the TP link?

Hope it makes sense

Thanks
Richard
 

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#12 ·
can you provide a port stats screen for the BT hub?

Have you tried disconnecting everything from the tplink except its connection to the bt hub? Results?

When you ran the cable to the tplink what standard did you use for the ends? A or B?
https://en.wikipedia.org/wiki/TIA/EIA-568

Are their any logs as to what is using the cpu on the nas?

I don't see any way to block the nas on the tplink. With a lan to lan connection not lan to wan you bypass the firewall and any restrictions you enter into the firewall. Unfortunately you can't block the tplink in the bt hub or your son would have no internet.
 
#13 ·
Hi

I can't find any details for any ports stats screen in the BT hub, all it has is an event log, which has every event, and is 163 pages long.

Once my sons PC is logged off, and he is out of the house with his Iphone, there should be nothing connected to his TP link, but even when I am sat right next to my BT hub, my phone shows as connected to TP aswell in the stats, along with Sky Box and NAS and other devices

I wired the cable up using B, on both ends

The only thing I have from the NAS is a resource monitor that is high, and when I get a putty session to it, it is always high - I run a top and see the processes. Synology could find nothing wrong with the NAS itself, only when I unplugged the TP link did it settle, so they said nothing else can be done from their side, NAS was ok, but must be my network

Again not much to go on....sorry
 
#14 ·
Sorry also. Out of ideas except I wonder what would happen if you configured the tplink as a nat device instead of a glorified switch. This would mean you would need to connect to the wan port not the lan port. You would first engage its dhcp server and set the lan subnet to 192.168.2.x /24 so the lan is a separate subnet.
 
#17 ·
Hi. Sorry for lack of reply. Just to update you, I borrowed an apple AirPort Extreme from a mate, connected that instead of my tp link, and all is sweet. The nas is behaving, my network is fine. So that's enough of investigating the tp link, it's going. I'll run it for a week or two, and if it stays stable, I'll buy my own apple AirPort Extreme. No idea where the issue was, but seems fine now I've permanently got rid of the tp link.

Thanks once again for helping look into this

Cheers
 
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