I'm on FTTP WA6084 and also have a Optus mobile service; I've been having latency issues with connection to the Xbox for over a week now and as of today no connection. I've run speedtest and cannot connect to Telstra servers on either my FTTP or Mobile service.
My overall speeds seem fine when connecting to Optus servers.
I've done the usual rebooting... Unlikly to be a modem issue as my mobile telephone service is crook as well.
Tried the 27/7 Tech web chat but it's suffering high demand.