Hi and ty for welcome.
In essence I have found the problem. The following is the full tale but the summary is that I have proven (as far as I am concerned) that the router gets noisier (creates more internal network traffic) the longer it is in operation until it virtually stops all attached devices. Simple solution is regular rebooting. Best solution is fixing it so it does not require frequent rebooting.
We went to NBN on FTTC in January. NBN installed an NBN device and the TP-Link Arverh VR1600v Router to handle our NBN connection.
We are receiving 6 phone lines through the router and into two ATA-4 devices and then into our PABX system as if they were POTS circuits.
There were some configuration changes that I had to make that iiNet/TPG were unware of to make the Port Forwarding work correctly (I advised iiNet/TPG at the time what I had to do so they could help other new FTTC business connections who would have the same issues.
All was then well, very good in fact.
Our typical speeds achieved over the connections were around 80MBps down and 23MBps up which I was very happy with (we are on the NBN 100 plan).
Recently speeds had dropped to below 40Mbps down and 4Mbs up which was a concern.
At first I thought it simply a matter of the entire network being busy (it was just after ATO EOY) so I put off further testing until last Friday.
Speeds were still around the 40Mbps and 4Mbs respectively.
All our internal equipment was running slow on in house applications (mail, spreadsheets etc.).
At first I suspected virus and tested every piece of hardware in the intranet. All clean.
I rebooted our three servers (SBS2011 and Server 2012 x 2) and all PCs.
The sytems were still running like pigs and the NBN speeds had not changed.
I installed WireShark and monitored traffic flows for two hours. The Router was making a lot (almost 20% of all traffic) of tcp/ip packets on the network (mainly dns/dhcp/browser announcements), almost producing a DenialOfService situation.
This seemed extraordinarily high to me so I rebooted the router.
Immediately my speeds returned to 77.8 and 9.7 respectively and my entire intranet is faster, not just my NBN speeds.
Wireshark now shows the Router creating minimal announcement packages (less than 1% of all traffic) and the amount of intranet traffic has reduced overal by nearly 70% (because the servers/pcs are responding to less packets from the Router), so I surmise that the traffic on our intranet was the cause of our slow downs and that the router was creating all the un-necessary traffic congestion on the lan.
I have put the Router onto my Weekly reboot tasks until such time as someone agrees with me that the router is being uneccessarily noisy and fixes it :-)
