5.1 Node types

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A Runtime pattern consists of several nodes representing specific functions. Most Runtime patterns consist of a core set of common nodes, with the addition of one or more nodes unique to that pattern. To understand the Runtime pattern, you will need to review the following node definitions.

Application Server/Services

The Application Server/Services node provides the infrastructure for application logic and can be part of a Web application server. It is capable of running both presentation and business logic but generally does not serve HTTP requests. When used with a Web server redirector, the Application Server/Services node can run both presentation and business logic. In other situations, it can be used for business logic only. The Application Server/Services node supports hosting of Web services applications.

Applications may also rely on services provided by their hosting server to interact with other applications. Examples of services provided by the Application Server/Services node include:

A TCP/IP pipe established using the hosting operating system
A servlet or EJB invoked by WebSphere Application Server
The JMS or J2EE Connector APIs provided by WebSphere

Broker

The Broker node allows distribution and decomposition/recomposition of messages so a single interaction from a source component can be switched, split, and joined to multiple target components concurrently. It separates the application logic from the distribution logic based on broker rules. The broker also manages the decomposition/recomposition of the interaction using these rules.

Exposed Broker

The Exposed Broker node is an extension of the Broker node. It exposes external processes to the broker functions within the node. A variation of this would be to use the Exposed Broker to expose internal processes to external partners.

Router

The Router node is a variation of the Broker node. It allows a single interaction from a source component to be switched and adapted to only one of multiple target components. It separates the application logic from the distribution logic based on router rules.

Exposed Router

The Exposed Router node is an extension of the Router node. It exposes external processes to the Router functions in the node. A variation of this would be to use the Exposed Router node to expose internal processes to external partners.

Rules Repository

The Rules Repository node contains the rules generally used to control the mode of operation of an interaction, depending on external factors. Examples of such rules are:

Business data mapping rules (for adapter connectors)
Autonomic rules (such as priority in a shared environment)
Security rules
Capacity and availability rules

The rules directory may or may not exist. If it does exist, it could still be left off the Runtime pattern, for example, when analysis determines that interaction rules are not an important part of the solution.

Domain QoS providers

The integration pattern for a domain is composed of a topology pattern and domain QoS providers. Intra-enterprise integration and inter-enterprise integration are both examples of domains. This combination of topology pattern and QoS providers is used to describe observed patterns in the domain:

Integration pattern = topology pattern + QoS providers

The QoS capabilities framework can be used to address the particular QoS concerns for the domain:

Autonomic
Availability
Federation
Performance
Security
Standards compliance
Transactionality

The domain QoS providers may or may not exist. If they do exist, they can still be left off the Runtime pattern, for example, when analysis determines that domain QoS providers are not an important part of the solution.

Protocol firewall node

A firewall is a hardware/software system that manages the flow of information between the Internet and an organization's private network. Firewalls can prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets, and can block some virus attacks (as long as those viruses are coming from the Internet). A firewall can separate two or more parts of a local network to control data exchange between departments. Components of firewalls include filters or screens, each of which controls transmission of certain classes of traffic. Firewalls provide the first line of defense for protecting private information, but comprehensive security systems combine firewalls with encryption and other complementary services, such as content filtering and intrusion detection.

Firewalls control access from a less trusted network to a more trusted network. Traditional implementations of firewall services include:

Screening routers (the protocol firewall)
Application gateways (the domain firewall)

A pair of firewall nodes provides increasing levels of protection at the expense of increasing computing resource requirements. The protocol firewall is typically implemented as an IP router.

Domain firewall node

The domain firewall is typically implemented as a dedicated server node.

A domain firewall is usually used to separate a secure zone, such as the internal network, from a demilitarized zone. This provides added security protection from the un-secure zone, such as the Internet.

Partner infrastructure

Partner infrastructure includes the partner's installed applications, data, computing, and network infrastructure. Partner infrastructure has unspecified internal characteristics; only the means with which to interact with it are specified.

Inter-enterprise network infrastructure

Inter-enterprise network infrastructure includes the network infrastructure allowing connectivity between enterprises. Inter-enterprise network infrastructure has unspecified internal characteristics; only the means with which to interact with it are specified.

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