The testing process for cable modems has become much more complex today as cable networks have
grown into two-way communication systems. As a result, designers and manufacturers of cable modems
have to not only test the forwarding capabilities of the downstream traffic from head-end to subscribers, but also the upstream forwarding capabilities as more subscribers get on the Internet for on-line shopping and browsing.

The access to the cable modems on the network is controlled by a cable modem termination system
(CMTS), which is located in the premises of the cable operator called the head-end. Traffic is routed from cable modems to the CMTS, which in turn is routed to the Internet. The traffic routed from the CMTS to the cable modems is called downstream traffic, and the traffic routed from the cable modems to the CMTS is called upstream traffic. A cable network is capable of transferring information downstream anywhere in the range of 10 Mbps to 43 Mbps, and in the upstream direction in the range of 500 kbps to 10 Mbps.

For more information, visit
Ixia Communications’ Web site.