I agree that's a fair amount of time, but sometimes during maintenance or other disruptions rather bad problems may be encountered I'm afraid.
There's a full description of what's happening there available via the following Service Status link: http://servicestatus.telstra.com/servicestatus/goc.do?q=summary.html
With prolonged disruptions you can normally make contact with Telstra via 13 22 00 or chat via Live Chat to discuss compensation where applicanle. Telstra compensation for downtime associated with Internet services isn't covered by their Customer Service Guarantee (that's for Telephone services only) so isn't automatically provided.
https://livechat.telstra.com/TCOM:Crowdsupport:Consumer
