Comtech EF Data DTMX5000 SpectraCast - Manual (Page 142)

Central Configuration Unit DTMX5000 IP Gateway
B-6 Rev. 1
B.4 Processing Information Requests
The subscriber requests information by, for example, browsing the Internet with
a web browser, or using an FTP client application. These applications generate
Internet Protocol (IP) packets, which contain the information requests. These
applications must be configured with the IP address of one of the Proxy Server(s)
situated at the hub.
The subscriber’s information requests are routed towards the Proxy Server at the
hub. The requests reach the Proxy Server in the hub through the subscriber’s
existing Internet connection (such as dial-up modem).
B.4.1 Proxy Server Requests/Receives Information
The Proxy Server reads the subscriber’s information request and creates a new
request on behalf of the subscriber, which contains the same details as the
original request. The only difference is that the source (originator) IP address of
the request is changed to that of the Proxy Server, instead of the IP address of the
subscriber.
The new request is routed from the Proxy Server through the Internet to the
destination server (for example, the web server at the web site that is currently
being browsed by the subscriber). The destination server sends a reply to the
Proxy Server with the requested information, and the Proxy Server receives this
reply.
B.4.2 Proxy Server Sends Information to DTMX5000 Gateway
Proxy Server replies to subscribers are forwarded via the DTMX5000 Gateway,
and not through the subscriber’s existing Internet connection. By sending
downstream information to the subscriber through the DVB link, instead of
through the subscriber'’ existing Internet connection, the system makes use of the
tremendous speed advantage of the DVB link.
The routing table enables the Proxy Server to identify that the packet is to be
routed to the subscriber through the DTMX5000 Gateway, and not through the
subscriber’s existing Internet connection. The CCU maintains and updates the
Proxy Server’s routing table with every subscriber that connects/disconnects
from the system.
B.4.3 DTMX5000 Gateway Routes Information to Subscriber
The packet exits the DTMX5000 Gateway, and is sent over the DVB link back to
the subscriber. This completes the cycle in which the subscriber requests and
receives information from the Internet.