Using CA AppLogic › Appliance Developer Guide › Appliance Overview › Configure Appliance › Set Class Boundary › Interfaces

Interfaces

Interfaces provide the means for an appliance to communicate with the outside world. To communication with other appliances in the same application, an appliance uses terminals, which include inputs and outputs.

The types of terminals and interfaces are as follows:

Terminals

There are two types of terminals:

• Input - defines the services the appliance provides to other appliances

  You need to define a different terminal for every service that the appliance provides. For example, if an appliance provides a data-type input and web user interface, those services are provided on two different terminals. This allows the connection to these services to be explicit and visible on the diagrams.

• Output - defines the point-to-point connections to the outside services that the appliance needs to perform its function.

  You should define separate outputs for every service that the appliance needs. For example, if you have database and mail server services, you would need to define two different outputs. This separation provides more versatility when connecting the services and makes the connection more visible on the diagram.

  In addition, CA AppLogic defines a gateway output terminal. The gateway output is a specialized output for accessing a subnet or external network. You use these primarily to connect appliances that refer to external IP addresses and connect to the outside world through a specialized appliance, such as NET2.

Raw Interfaces

Raw interfaces allow an appliance to communicate with the outside of the appliance as well as communicate with other appliances. This is unlike terminals that communicate with appliances in the same application. Raw interfaces are very similar to virtual network interfaces in virtual machines and to NICs in traditional servers.

The application configuration assigns the IP address to the raw interface. In addition, you can use a raw interface to communicate with an appliance when point-to-point outputs are not sufficient. For example, many to one and many to many connections, especially those using multicast.

Legacy Raw Interfaces

Prior to supporting multiple raw interfaces, a single external interface was used for all communication. This legacy raw interface is provided for backward compatibility and should not be used.

Default Raw Interface

This is a network specialized interface that the appliance uses to communicate with the grid controller. It is not necessary to firewall the default interface. Any traffic that is not specifically allowed is dropped.

If you would like to setup firewall rules, the list of valid communications are located in Firewall Default Interface in the Appliance Troubleshooting section.

Follow these steps:

1. On the Interfaces tab, define the input and output terminals and raw interface by selecting the row and entering the information, as needed.
   • Name - typically, terminal names are lower case and only three to four characters to fit in the appliance terminal shape.
   • Protocol - defines the protocol connecting the input and output of the terminal and provide constraints to types of traffic, such as limiting ports, or direction. In addition, it provides protocol-specific statistics, such as response time for the traffic passing through the terminal.

     To allow all constraints for all traffic, set the protocol to Any. Any allows any protocols limited to MAC and IP address.

     You can configure additional protocol types for the appliance boundary by selecting Configure Application, then selecting the Protocol tab.

   • Alias - used inside the appliance to refer to the terminal. The alias can be any valid DNS name, according to RFC 1035. That DNS name is available inside the appliance as an alias to the terminal name. Aliases are useful when an application inside the appliance is hard-coded to access an external service using a fixed host name, such as server1.mycompany.com. The alias attribute is available only for output terminals.
2. Set the following optional parameters, as needed.
   • Mandatory - indicates the attribute must be configured for the appliance to function. This is a design constraint. If configured and not set, the appliance fails to start. Typically, inputs are non-mandatory and outputs are mandatory.
   • Switch Side - moves the visual elements between the sides of the appliance. Only the visual appearance is affected. There is no runtime impact.

     Normally inputs are on the left side and outputs on the right. This also applies to the raw interfaces. This is useful for feedback terminals with connection direction that go opposite to the general left-to-right flow.

   • Gateway - makes an output terminal a default gateway interface for the appliance and allows the appliance to access multiple hosts and resolve DNS names through that output.

     Typically, gateway outputs are used to connect appliances to the subnet gateway appliance. Only one output of an appliance can be selected as a gateway. Most appliances do not have gateway outputs.

     Visually highlights the outputs specified as gateway connections with a dark blue indicator on the appliance icon.

   • Share - allows multiple terminals share one NIC and decreases the total number of interfaces that an appliance uses. This is useful since the number of interfaces and terminals an appliance can have is limited.

     The share attribute cannot be specified on raw interfaces and should not be enabled for Windows appliances. It should not be set on appliances that need separate network traffic statistics. Appliances that provide network traffic statistics to the Monitor appliance provide only aggregated statistics for shared terminals.

3. To add additional input terminals, output terminals, or raw interfaces, click the corresponding button. A new row displays in the table.
4. To continue, select the Volumes tab.