Packet loss at around 6AM for everyone!

[#1]

Hi, as its the summer holidays I have been staying up really late and I have noticed that for the last couple of weeks that on some days at around 6am that packet loss occurs and connection acts a bit wierd.
At first I though it was only on my connection (Unlimited Fibre) but looking at the TBB ping graphs for other members I see that the packet loss doesn't occur only on my connection but for everyone too.
Just look at the ping graphs on the TBB Ping Graphs thread or the community ping graphs page.
All the graphs show packet loss at around 6am.
Now I don't know if this is a normal thing for plusnet or if this is a known issue or if its new or its a problem with thinkbroadband's Broadband Quality Monitor, but can someone tell what is going here?

[#2]

That i think is caused by a re config in routing/peering links and was network wide

[#3]

It was some core router maintenance, mentioned over on this thread: http://community.plus.net/forum/index.php/topic,117527.0.html

[#4]

Oh ok, no problem, just wanted to know what was going. Thanks for the replies.
This 6am maintenance isn't even going to effect me for much longer anyway, especially now that my 3rd year starts soon, lol.