Let’s get one thing straight right from the top—these are not your mother’s appliances!
Let’s use that opening statement as a springboard for our discussion on exactly what SOA appliances are, how they are used, and how they are similar and dissimilar to traditional household appliances. The use of the term appliance to describe this new class of IT products is no accident. It is meant to convey certain parallels to the term that is familiar to us. Think about it—what are the characteristics of your typical household appliances? Visualize the appliances of yesteryear rather than the more complex ones we see on the market today. Certain attributes should come to mind:
- Purpose-built—Appliances at home are typically for specialized uses—one for washing clothes, one for keeping food cold, and so on.
- Simple—Most appliances have few knobs and controls. They have simple designs due to the dedicated purpose for which they are designed. They are also reliable, so they don’t need to be serviced or replaced often.
Get the picture? Now let’s move the discussion to a realm where we as IT professionals are more comfortable—for many, that is not the realm of domestic chores!
There is a current trend in IT shops to use specialized appliances wherever possible. This is due to several factors, the primary ones being total cost of ownership (TCO), return on investment (ROI), performance, integration, ease of use, and security. To get started, we introduce you to IBM’s WebSphere DataPower SOA appliances, and then talk about how appliances can help in each of these areas. Of course, we go into much greater detail throughout this book.
Meet the Family!
The primary1 three products in the DataPower family are the DataPower XA35, XS40, and XI50, as shown in Figure 1-1. As you can see, the products are outwardly similar in appearance. Each is a hardened 1U rack-mount device in a tamper-proof case with four RJ-45 Ethernet ports, a DB-9 serial port, and a power switch. We are speaking about the base configuration—there are options available, such as adding a Hardware Security Module, which could alter the outward physical profile. There are also replaceable fan trays, batteries, power supplies, and compact flash cards or hard drives.
Figure 1-1 The DataPower product family.
In the following sections, we discuss the feature set for each model and then move on to scenarios in which appliances can be of great value before taking a closer look at what’s under the covers.
The DataPower XA35 (on the bottom in Figure 1-1) is the entry level product in the line and most representative of the beginnings of the product and DataPower company. The appliance is green, which represents its primary function: to make XML “go faster.” This is also the impetus behind the designation of the “A” in XA; it stands for acceleration. The XA35 is at its core a highly efficient XML processing engine. It makes use of DataPower’s purpose-built features, such as optimized caches and dedicated SSL hardware to process XML at near wire-speed.
The XA35 is a hardened appliance, but it has limited security processing functionality; for example, it does not have the full XML threat protection or encryption/digital signature capabilities as the other models that we discuss. For these reasons, it generally sits behind the DMZ,2 in the trusted zone to augment the processing of XML files. For example, it may be configured to do validation and transformation of XML before it reaches (or for traffic flowing between) the backend servers. It should be used in-line in the network topology, not as a co-processor hanging off a particular server (although this latter usage is how the appliances were first designed). A popular usage is to receive XML responses from backend servers and transform those into HTML before continuing the response to the client. It has full SSL and SNMP capabilities to fit into the network infrastructure.
The DataPower XS40 (in the middle in Figure 1-1) is called the security appliance, and justifiably it is yellow, which represents caution or yield. The “S” in XS stands for security. This model is often found in the DMZ, as its security capabilities are extensive.
The XS40 has all the capabilities of the XA35, plus the following:
- Encryption/decryption utilizing purpose-built hardware for RSA operations
- Digital signature creation/verification
- Fine grained Authentication, Authorization, and Auditing (AAA)
- Full XML threat protection
- Tivoli® Access Manager (TAM) integration option
- Hardware Storage Module (HSM) option
- Dynamic routing
- Message filtering
- Fetching content from remote servers
- MIME, DIME, and Message Transmission Optimization Mechanism (MTOM) attachment processing
- XML Generation 4 (XG4) accelerator module option
- Web services management
- Service level monitoring
The DataPower XI50 (at the top in Figure 1-1) is truly the star of the show. It is the integration appliance, as represented by the “I” in XI, and it is IBM blue (what else!) in color. Due to its integration capabilities, it is often found in the backend private network, functioning in an ESB capacity but is just as suitable for the DMZ. The majority of this book focuses on the XI50, as it is a superset of the other two models.
The XI50 has all the features of the XS40 (and hence the XA35) plus the following:
- WebSphere MQ client option
- WebSphere Java Message Service (JMS) Jetstream protocol connectivity
- TIBCO Enterprise Message Service (EMS) connectivity
- IBM IMS Connect client
- Database option (DB2, Sybase, Oracle, SQL Server)
- Optimized run-time engine for non-XML transformations
This might seem like a short list compared to all the capabilities that the XS40 heaps on what the XA35 had, but these are some big-ticket items! Throughout this book, you will see just how important these features are and how to leverage them.
Now that we’ve had our brief introduction, let’s talk about where appliances are being used in corporate information technology shops, and what kinds of problems they can help solve.