The Optus cable network is due to be dismantled over the next 2-3 years.
NBNCo will connect you to the NBN network via a new HFC cable or as you say FTTC (or perhaps FTTN) technology. If they do use FTTN or FTTC then there's zero you need to be involved. If its a new cable then they'll install the new cable (you don't need to be involved in that either)
You have no choice in the technology used. You can check the expected date and type of technology on the NBN website
Once NBNCo has connected your suburb to the NBN, the area will officially go RFS (Ready for Service).
Your address should also go RTC (Ready To Connect). Around this time you will get lots of letters and emails from various ISPs to say they can connect you to the NBN. One of the great things about the NBN is you can now use any ISP to access high speed broadband as they all now connect via the NBN.
Optus will tell you you have three months before your existing cable connection is disconnected. You can choose to just rollover to a new contract with Optus (probably the easiest option) however check the specifics as NBN plans can differ from pre-NBN plans. You can also elect to go elsewhere. Optus staff may try to suggest you must stay with them but as OPtus are the ones breaking your contract (by shutting down there cable network) then you are free to finish up without penalty.
Thanks Peter for your detailed reply.
I am listed as fiber to the curb. How does the internet get from the curb to the house? Can it be cable, is there an advantage in cable from the street to the house.
My last few years with Optus have been really frustrating and disappointing so the arrival of the NBN will be my chance to start with a provider who provides a better service, who treats customers with respect and care and who can deliver the service they advertise. My fingers are crossed that I'll be able to actually load Netflix in the evenings, unlike now with my top of the range, speed boosted optus cable broadband to the home.
One of the main advantages of FTTC is there's no need for NBNCo to even step onto your property. The fibre is rolled out all the way to the outside of your house and then just connected to your existing copper phone line in the street. You just need to get a NBN compatible modem (most are) and you should be looking at 100Mbps without issue. If you no longer have a old copper phone line to the house, NBNCo will install one for you for free.
FTTC vs HFC Cable NBN is likely to give similar performance (and both are able to be upgraded to 1000Mbps down the track so that's a plus). However as I say, you don't get any choice in what technology NBNCo assigns your house so there's no point in debating the merits of different connection types. You'll be gett FTTC.
As a quick summary (FYI), ADSL2, FTTN and FTTC all basically use the same idea of using the existing copper cable all homes have for their telephone. The main difference is simply the distance of copper used in each case. ADSL2 can have about 5km of copper max speed equals 20Mbps. FTTN uses about the last 800m and while it should get 100Mbs a third of homes will only get up to 50Mbps (be glad you're not FTTN). FTTC only uses about 20m of copper and can do 100Mbps easily.
I'm sorry your experience with cable speeds with Optus has been so poor lately. FWIW once connected to the NBN you will be on a totaly new network so even if you remain with Optus you'll likely find the speeds increase dramatically. I would definitely recommend a M2M plan with whichever NBN RSP you end up using. Then if you don't like the service switching is just a phone call and you're set.
WARNING WARNING WARNING!! Hi If you track down my post you can follow my drama here. Fiber to curb will not use your cable but will use your original copper line which in many case could be currupt. What I do suggest is that with the switch you ask for a new modem and run both your original ADSL setup (They still haven't cut mine off) and your new NBN. This way you can monitor your new setup to see if it is stable over time (SPEEDS but primarily dropouts are my issue) and when all is hunkydori then you cankill the ADSL. At this point I'm over a month in on this very disturbing situation of getting a stable NBN connection and if I didn't have the ADSL as backup my kids would have fried me alive!!!!