An asymmetrical network for coupling customer-premises Internet hosts such as
personal computers to the Internet. The head end of a CATV system has a high-bandwidth
connection to the Internet. The down link connecting the personal computers to
the Internet is the cables provided by the CATV system; the up link is a telephone
connection to the head end. A router is connected to the down link by means of
a RF modem, to the up link by means of an analog modem, and to a LAN which is connected
to the Pcs. The router routes IP packets for the hosts that are received on the
CATV cable to the hosts via the LAN; it routes IP packets from the hosts that are
destined for the Internet to the head end via the telephone line. The asymmetrical
network conserves IP addresses and addresses on the CATV cable by dynamically allocating
the IP addresses for an RF modem's hosts and an address on the CATV cable for the
RF modem in response to a request made by the RF modem via the telephone line.
It further saves IP addresses by assigning a non-unique IP address to the router
for use inside the LAN. When the CATV system fails, the asymmetrical network automatically
begins to use the telephone line as both the up link and the down link, and when
the CATV system is restored, the asymmetrical network automatically returns to
using the CATV cable as the down link and the telephone line as the up link. A
further feature of the asymmetrical network is that the head end components and
the RF modem have IP addresses, so that standard TCP/IP protocols can be used to
control the asymmetrical network.