Scalability If congestion does begin to occur due to high usage, cable operators have the flexibility to add more bandwidth for data services. A cable operator can simply allocate an additional 6 MHz video channel for high-speed data, doubling the downstream bandwidth available to users.
Another option for adding bandwidth is to subdivide the physical cable network by running fiber-optic lines deeper into neighborhoods.
This reduces the number of homes served by each network segment, and thus, increases the amount of bandwidth available to end users.
Return Path Because some cable networks are suited for broadcast television services, cable modems may use either a standard telephone line or a QPSK/16 QAM modem over a two-way cable system to transmit data upstream from a user location to the network. When a telephone line is used in conjunction with a one-way broadcast network, the cable data system is referred to as a telephony return interface (TRI) system.