Cisco Multipath Channel, TN3270 Server, BC-251

Overview of IBM Networking

CMCC Adapter Features for SNA Environments

Cisco Multipath Channel

CMPC is Cisco System’s implementation of IBM’s MultiPath Channel (MPC) feature on Cisco 7500, Cisco 7200, and Cisco 7000 with RSP7000 series routers. CMPC allows VTAM to establish Advanced-Peer-to-Peer Networking (APPN) connections using both High Performance Routing (HPR) and Intermediate Session Routing (ISR) through channel-attached router platforms.

Routers configured for CMPC can be deployed in Parallel MVS Systems Complex (sysplex) configurations.

CMPC can be used to establish an APPN connection between VTAM and the following types of APPN nodes:

•VTAM on another host that is channel-attached to the same CMCC adapter

•VTAM on another host that is channel-attached to a different CMCC adapter in the same router

•TN3270 server using Dependent LU Requester (DLUR) in the same CMCC adapter

•SNASw in the router with the CMCC adapter

•Other APPN nodes external to the CMCC adapter and router such as Communications Server/2, AS/400, other LAN- or WAN-attached VTAM hosts, or remote routers

One read subchannel and one write subchannel are supported for each MPC transmission group. The read subchannel and write subchannel may be split over two physical channel connections on the same CMCC adapter.

CMPC insulates VTAM from the actual network topology. The MPC protocols are terminated on the CMCC adapter and converted to LLC protocols. After they are converted to LLC protocols, other Cisco features can be used to connect VTAM to other APPN nodes in the network. CMPC can be used in conjunction with DLSw+, RSRB, SR/TLB, SRB, SDLLC, QLLC, ATM LAN emulation, and FRAS host to provide connectivity to VTAM.

CMPC supports connections to PU 2.1 nodes: APPN NN, APPN EN, and LEN. Subarea connections are not supported.

The CMPC feature can coexist with the CLAW, TCP/IP Offload, CSNA, CMPC+, and TN3270 server features on the same CMCC adapter.

For details about configuring a CMCC adapter for CMPC, see the “Configuring CSNA and CMPC” chapter of this guide.

TN3270 Server

TN3270 communications in a TCP/IP network consist of the following basic elements:

•TN3270 client—Emulates a 3270 display device for communication with a mainframe application through a TN3270 server over an IP network. The client can support the standard TN3270 functions (as defined by RFC 1576) or the enhanced functionality provided by TN3270E (defined in RFC 2355). TN3270 clients are available on a variety of operating system platforms.

•TN3270 server—Converts the client TN3270 data stream to SNA 3270 and transfers the data to and from the mainframe.

•Mainframe—Provides the application for the TN3270 client and communicates with the TN3270 server using VTAM.

Cisco IOS Bridging and IBM Networking Configuration Guide