HP-UX SNAplus2 R7 Administration Guide

Introduction to SNAplus2

SNAplus2 Components

Passthrough Services

Passthrough services enable downstream computers on a LAN to access host resources through a server running

SNAplus2, or enable computers to access SNA resources across mixed SNA and IP networks. SNAplus2 provides

the following passthrough services:

• PU concentration (see Section 2.3.1,

Node Components).

• Dependent LU requester (see Figure 2–7, PU Concentration).

• TN server (see Figure 2–7, PU Concentration).

• Enterprise Extender (see Figure 2–8, TN Server).

PU Concentration

In addition to providing direct access to a host computer, SNAplus2 can provide PU concentration facilities. This

feature enables other computers to access a host computer through the SNAplus2 node, instead of requiring a

separate connection to the host from each computer.

The PU concentration feature is shown in Figure 2–7, PU Concentration.

Figure 2–7 PU Concentration

Downstream

Computers

Host

Controller

SNA Node Providing

SNA Gateway

The downstream computer must contain an SNA PU type 2.0 or 2.1 to support dependent LUs. For example,

the downstream computer could be a PC running Microsoft Host Integration Server for Windows NT, or another

SNAplus2 computer.

When the local SNAplus2 node uses the PU concentration feature, all the data transferred between the host and

the downstream computer is routed through the local node. This enables a downstream computer to share a host

connection with SNAplus2 or with other downstream computers, instead of requiring a direct link. For example,

you could set up several downstream computers connected to SNAplus2 over a local token ring network, so that

they could all access the same long-distance leased line from SNAplus2 to the host.

Using PU concentration also simpliﬁes the conﬁguration at the host, because you do not need to deﬁne the

downstream computers and the communication links to them. The host conﬁguration needs to include only the

SNAplus2 computer and its host communication link; the LUs at the downstream computers are conﬁgured as part

of the resources of the SNAplus2 computer. The host computer is not aware that PU concentration is being used.