TheArchitect.co.uk - Jorgen Thelin's weblog

Roger Session's Software Fortress Model

The latest issue of the ObjectWatch newsletter from Roger Sessions arrived in my mailbox after a long gap, and I was reminded again how much I like Roger's "Software Fortress" architecture model as a true reflection of the real world of enterprise systems and architecture.

The software fortress model decomposes a large enterprise into multiple discrete functional units called software fortresses. A typical software fortress might run an accounts receivable system, for example.

The software fortress model recognizes six different categories of fortresses.
These are:

• Presentation fortresses, that deal with browsers
• Web service fortresses, that deal with SOAP requests coming over the Internet
• Business application fortresses, that run mission critical business systems
• Treaty management fortresses, that manage workflow
• Legacy fortresses, that provide front-ends for legacy systems
• Service fortresses, that provide enterprise wide common services

[ Roger Sessions - ObjectWatch Newsletter, Issue 43 ]

Given that the "Web Services fortress" is actually a "Web Services Gateway" in functionality (SOAP-in, SOAP-out), to me the Software Fortress model highlights perfectly the general places where Web Service technology is so important and vital in an enterprise architecture - BETWEEN the fortresses.

The concepts of the Fortress model pretty much highlights and explains all the problem areas that Web Services are tackling today (technology integration, application intagration, and loosely-coupled service integration), so is a useful logical architectural framework to keep in mind.

Roger Sessions has written a book about the Software Fortress model which is worth a read by Enterprise Architects everywhere, and he also teaches classes on the subject too.
Alternatively can just read his newsletter - but try not to throw chairs through windows while doing so, like a certain Don Box felt like doing in his younger days! ;-)