我想問香港寬頻~i-cable~和記~網上行~

Seem you are doing research. Can just briefly give you typical answer

Transmission Layer(HOME)

HKBN uses Fast Ethernet

i-cable uses docsis 2.0 HFC network

HGC uses Fast ethernet, ADSL, VDSL

Netvigator uses ADSL,VDSL

All the customer termination using fastethernet interface.

Network layer.

HKBN uses DHCP/IP

i-cable uses DHCP/IP

HGC uses DHCP/IP + PPPOE

Netvigator uses PPPOE