During the BlackBerry® Attachment Service installation process, the setup application writes data about the BlackBerry Attachment Service instance to the BlackBerry Configuration Database. You can create a BlackBerry Attachment Service pool for each BlackBerry® Enterprise Server by associating multiple BlackBerry Attachment Service instances with each BlackBerry Enterprise Server. Within each pool, you can create primary and secondary groups.

For more information, see the BlackBerry Enterprise Server Planning Guide.

1. In the BlackBerry Administration Service, on the Servers and components menu, expand BlackBerry Solution topology > BlackBerry Domain > Component view > Attachment > Connector.
2. Click the BlackBerry Attachment Connector that you installed with the BlackBerry Enterprise Server that you want to create the BlackBerry Attachment Service pool for. By default, the name of the BlackBerry Attachment Connector is <computername>_EMAIL_AC_13.
3. Click Edit instance.
4. On the Supported Attachment Server Instances tab, in the Name drop-down list, click the instance that you want to add.
5. In the Results Query Period(s) field, type the number of seconds that you want the BlackBerry Enterprise Server to wait for a response before it sends the request to another BlackBerry Attachment Service instance.
6. In the Dedicated Server drop-down list, click yes if you want the BlackBerry Attachment Service instance to process only specific content types for the BlackBerry Enterprise Server.
7. In the Pool drop-down list, complete one of the following actions:
   • To include the BlackBerry Attachment Service instance in the primary group of instances within a pool, click Primary.
   • To include the BlackBerry Attachment Service instance in the secondary group, click Secondary.
8. Complete the following actions:
   • To turn on support for an attachment file format, in the Extensions section, type the file extension of the format. Click the Add icon that is located beside the extension that you typed.
   • To turn off support for an attachment file format, in the Extensions section, click the Delete icon that is located beside the file extension.
9. Click the Add icon.
10. Repeat steps 5 to 9 for each BlackBerry Attachment Service instance that you want to add to the pool.
11. Click Save all.
12. Repeat steps 2 to 11 for each BlackBerry Enterprise Server instance that you want to use a BlackBerry Attachment Service pool.

The BlackBerry Administration Service writes the data about the BlackBerry Attachment Service pool to the BlackBerry Configuration Database. The BlackBerry Messaging Agent caches the pool data and uses the data to determine which BlackBerry Attachment Service instance can process a request.

The instances in the BlackBerry® Administration Service pool use multicast UDP to communicate with each other. If the BlackBerry Administration Service instances are located in different network subnets and your organization's network configuration does not permit multicast UDP across the network subnets, you must configure the BlackBerry Administration Service instances to use TCP to communicate with each other. For example, if your organization uses a UDP peer-to-peer firewall filter, you must configure the BlackBerry Administration Service instances to use TCP to communicate across the network subnets.

1. Make sure that no BlackBerry Administration Service instance is in the process of restarting.
2. In the BlackBerry Administration Service, on the Servers and components menu, expand BlackBerry Solution topology > BlackBerry Domain > Component view > BlackBerry Administration Service.
3. Click Edit component.
4. In the BlackBerry Administration Service pool drop-down list, click TCP with TCP PING.
5. Click Save all.
6. Restart the BlackBerry Administration Service instances.