Operating Systems

Like the mainframe, many people have predicted the death of SNA networking. This article examines the current state of SNA networking and applications, and explores the reasons why many enterprises choose to maintain their investment in SNA applications. We also examine some alternatives for transporting your SNA data across an IP network and help you determine the best way to do this.

Not long ago, people were saying the mainframe was dead. Along with the mainframe is a perception that SNA is also dying. Compound these feelings with IBM announcing the end of marketing for its SNA networking hardware, and it is natural to assume that SNA is going away. In actuality, after digging deep into the inner-workings of enterprises around the world, IT archeologists have found that SNA applications are a critical piece of the core processing for many businesses. Given the importance of these applications, it’s natural to wonder what you should do with your SNA applications.

At the same time, you might be dealing with a number of other issues. For example, you may be trying to simplify your infrastructures. After all, supporting two network infrastructures is expensive in terms of equipment, connectivity, and management. A common business problem today is that solutions implemented by different organizations within an enterprise have created overly complicated, redundant, and nearly unmanageable collections of hardware and software. Infrastructure simplification initiatives are needed to get control of these environments.

Perhaps you are also looking at branch transformation projects to build new solutions, which can help improve end-user productivity or deliver new business offerings. Before you decide whether to keep your existing SNA applications or to build new solutions, you need to ask the following questions:

  • Is there a benefit to keeping an SNA application in the branch office?
  • Which applications are candidates for consolidation?
  • What do we plan to do with the applications running on OS/2 servers?


Linux has become an important platform to help solve some of these problems. IBM’s recently announced Communications Server for Linux on zSeries enables SNA support on the open Linux platform. This opens up possibilities such as consolidating large numbers of branch office servers onto one machine or a small number of machines in the data center. The resulting savings in hardware, software, and management expense can then be used to invest in developing new business applications.


The question facing many enterprises is, “Should we rewrite our SNA applications to IP or maintain the investment we’ve already made?” Most enterprises, especially those whose business has grown with and is integrated with their applications, choose to keep much of their existing investment. The following section examines items to consider when deciding to maintain or rewrite.


More than 90 percent of the world’s corporate data resides on z/OS-resident SNA applications. Today, major corporations find themselves relying on the same SNA applications that have driven their business for more than 20 years. The business logic incorporated in these applications is as sound today as it has ever been, but the infrastructure supporting those applications has many IT managers tossing and turning at night, wondering how they can maintain their application investment while expanding their networking capabilities with the latest technology.

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