HP-UX SNAplus2 R7 Administration Guide

Introduction to SNAplus2

SNAplus2 Components

Dependent LU Requester

This section does not apply to LEN nodes.

In addition to providing direct access to a host computer, SNAplus2 can provide dependent LU requester (DLUR)

facilities. This feature enables sessions for dependent LUs to span multiple nodes in an APPN network, instead of

requiring a direct connection to the host.

DLUR on the SNAplus2 node works in conjunction with dependent LU server (DLUS) at the host. Together, they

route sessions across the network from dependent LUs in the APPN network to the DLUS host. The route to the

host can span multiple nodes and can take advantage of APPN’s network management, dynamic resource location,

and route calculation facilities.

If the local node is a network node, dependent LUs on downstream computers connected to the SNAplus2 node can

also use passthrough DLUR on the SNAplus2 node—in the same way that LUs internal to the node do—to access

the host across the network.

TN Server

3270 emulation programs that communicate over TCP/IP (rather than over an SNA network) are referred to as

TN3270 programs (Telnet 3270 emulation programs).

TN3270 programs can also include support for TN3270E (Telnet 3270 standard extensions). TN3270E supports

3270 device emulation (including both terminals and printers) using Telnet. It enables a Telnet client to select a

particular device (by specifying the LU name), and provides enhanced support for various functions, including the

ATTN and SYSREQ keys and SNA response handling.

Note

This guide uses the term TN3270 for information that applies equally to the TN3270,

TN3287, and TN3270E protocols.

SNAplus2 TN server provides access to 3270 host computers for TN3270 users on other computers. TN server en-

ables TN3270 users to share a host connection with SNAplus2 or with other TN3270 users, instead of requiring a

direct link. TN server also enables TN3270 users to access hosts that are not running TCP/IP.

SNAplus2 TN server supports all TN3270 client emulation programs that correctly implement the protocols deﬁned

in RFCs 1123, 1576, 1646, and 1647.

The SNAplus2 TN server function is shown in Figure 2–8,

TN Server.