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As the local branch diversifies into the financial services sector, the bank wishes to integrate new peer-based applications into its existing network while maintaining its existing investment in corporate host-based applications. The financial services division has its own APPN network that supports local applications, while also providing connectivity to the host at headquarters, as shown in SNA Network Including APPN.
A peer network is connected to the existing multiple client/server system. APPN is especially appropriate for groups of PCs and workstations on LANs, because such networks undergo high levels of change. The dynamic configuration and route calculation of APPN is of crucial importance to the scalable growth of the network.
The original SNAP-IX servers can connect simultaneously to both APPN and pre-APPN nodes. The server provides PU concentration functionality to downstream LUs. PU concentration enables host-based SNA applications to be run on the APPN network, while reducing the number of links required to the host in a fashion that is completely transparent-both to the host and to the downstream LU. This function enables legacy applications to run on the APPN network without modification, and reduces the connectivity requirements for communication with the host from the APPN network.
In addition, the financial services division writes new distributed applications that run on the SNAP-IX network nodes and end nodes in the APPN part of the network. The APPN network enables new machines to access the applications automatically as they are connected to the network, without requiring reconfiguration at the host for every new computer that is added.
These new applications make use of the increased processing power that is available on local workstations, without increasing the volume of the traffic to the host.
By doing more processing locally, this configuration decreases the demand for host processing so that the remaining corporate central processing can be done more quickly.
As the APPN part of the network grows, SNAP-IX DLUR functionality (running in conjunction with DLUS on the host) supports corporate back-level applications (such as 3270) transparently across the APPN network. DLUR provides a migration path from subarea SNA applications to APPN.
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