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Chapter 12
Configuring Other Routing Protocols
Phase Four: IP Centric
Summary of Four-Phase Model
OL-2031-02
In the fourth and final stage of SNA-to-IP integration, the mainframe and
midrange systems natively support TCP/IP. They share files with and transfer
data to other, non-SNA systems. Corporate databases are securely accessed in a
standard way from a variety of different end-user applications. The remaining
applications that are based on traditional "green-on-black," character-based
terminals are accessed transparently through standard emulation screens or
through intuitive, user-friendly Web pages.
TCP/IP-based mainframe and midrange systems offer advanced redundancy and
high-availability features similar to those provided to SNA-based applications
today. With the full, native support of TCP/IP, the mainframe and midrange
systems can be fully participating members in the corporate intranet.
The four-phase model of SNA-to-IP integration is based on Cisco experience
helping to integrate some of the world's largest and most complex SNA networks.
In reality, very few organizations go through a stepwise, linear migration from
SNA centric to IP transport, to IP client, to IP centric.
For example, many large organizations have run TCP/IP stacks on their
mainframes for years, alongside ACF/VTAM, whether they have implemented
TCP/IP in the enterprise backbone network or not. Most large organizations will
find elements from all four phases represented somewhere in their network. The
model, however, is useful to describe the various issues of SNA-to-IP integration,
their common solutions, and the characteristics of the network at various points
in the change.
Catalyst 4224 Access Gateway Switch Software Configuration Guide
IBM SNA
12-9
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Troubleshooting
