The PA-1C mainframe Channel Port Adapter (CPA) is an extension of Cisco`s family of channel-attached products. The CPA joins the Channel Interface Processor (CIP) and channel applications software (IP Datagram, Cisco SNA (CSNA), TCP/IP Offload, TN3270 Server, and TCP Assist) to make the most powerful and wide ranging family of channel-attached router products in the industry.