Cisco Cisco MC28C Universal Broadband Router Line Card

This feature module describes configuring the Cisco uBR-MC28C cable modem card. The card contains 
two downstream and eight upstream ports configured in two independent Cable Modem Termination 
System (CMTS) media access control (MAC) domains. A MAC domain is a collection of upstream and 
downstream channels for which a single MAC allocation and management protocol operates. Each 
domain on the Cisco uBR-MC28C cable modem card includes one downstream and four upstream ports. 
Both domains operate independently of each other.

This feature module includes the following sections:

The Cisco uBR-MC28C cable modem card resides in a Cisco uBR7200 series universal broadband 
router and supports downstream and upstream traffic to and from Data-Over-Cable Service Interface 
Specification (DOCSIS)-based cable modems (CMs). The card supports 6-MHz National Television 
Systems Committee (NTSC) channel operation, using standard (STD), Harmonic Related Carrier 
(HRC), or Incremental Related Carrier (IRC) frequency plans conforming to EIA-S542. The card 
supports downstream channels in the 54-to-860 MHz range, therefore, with upstream ranges of 
5 to 42 MHz. 

While you can use the Cisco uBR-MC28C cable modem card in 8-MHz international cable 
plants, the card ignores 2 MHz of available channel width, operates at a maximum 
downstream bandwidth of 27 Mbps, and limits upstream choices to the range below 
42 MHz.