okie... I am CON-fused.....
Now... TP>> Huawei ONT (modem)?>>>> Huawei Router....
Your Direct ONT is:
1. TP>> Huawei ONT (Modem) >>> own Routerr??
AND
ByPass mean
2. TP>> own modem >>> own Router???
Sorri, too many jargon for a stoopid Mac/PC user...

current possible connecting your own router and for those interested in using their own router.
Note: 1 to 4 is from easiest to hardest which require some technical knowledge in configuring
"Starhub CSO way"
1. TP -> NC ONT (aka huawei ONT) -> DMZ to your own router (aka starhub way of defining "bridging" which is not true true bridging) -> any router you prefer
DV still can be on fiber
using Vlan + Vlan priority capable switch (example Mikrotik RB250GS)
2. TP -> NC ONT (aka huawei ONT) -> Vlan + Vlan priority capable switch -> any router you prefer
DV still can be on fiber, the huawei or dlink router connected to the vlan switch for voice service
using Asus N56/N66
3. TP -> NC ONT (aka huawei ONT) -> Asus N56/N66 using special configuration in the setting to enable VLAN, you will lose some lan port and may encounter some problem with getting wifi to work
DV no confirmation will work
using custom firmware (ddwrt/openwrt) or router with vlan+vlan priority function. Note: Not all router support high vlan ID, starhub use vlanid 1071/1075/1078 for internet, 1095 for DV, 1099 for the starhub huawei/dlink router. all with vlan priority 1.
4. TP -> NC ONT (aka huawei ONT) -> any router capable of running custom firmware (ddwrt/openwrt) with vlan and vlan priority support or router with built-in support for vlan + vlan priority.
DV still can be bridge to the starhub huawei/dlink router
lastly, pure direct ONT connection, after enabling direct to ONT, DV cannot be on fiber, to use DV, it can only be on starhub cable network (aka need a cable modem with Voice service port)
5. TP -> NC ONT (aka huawei ONT) -> any router you desire, no mac address need to provide to starhub, no special configuration needed