Straight from the IBM site, this is the definition of DataPower -
IBM® WebSphere® DataPower® SOA Appliances are purpose-built, easy-to-deploy network devices that simplify, help secure, and accelerate your XML and Web services deployments while extending your SOA infrastructure.
Lets stop with that and talk a little bit about SOA, the current architecture and how DataPower fits in.
The middleware infrastructure of an enterprise need to support XML and Web Services, since its emergence and popularity. This meant that the ESB or enterprise service bus had to support the emerging technology. This was proving to be an problem because of -
- Traditional middleware installation has increased installation and maintenance costs
- Operational costs involved in supporting the new data format (XML) and the existing formats (flatfile, cobol copybook etc)
- Security – New forms of attack on the infrastructure
[1]DataPower SOA appliances address these three challenges with the creation of specialized, purpose-built, consumable SOA appliances that redefine the boundaries of middleware. As the “hardware ESB,” DataPower SOA appliances are an increasingly important part of the IBM ESB family.
As mentioned earlier DataPower is an appliance. So why exactly do we need an appliance what can it do?. Lets looks a typical infrastructure – (this is not how it is but helps to explain the situation 
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