About Blackberry Network Connection Paths

When performing Blackberry application development, there are several paths for network connections with which one should be aware. Each has advantages and disadvantages depending on ones needs.

BIS/BES

The BIS and BES are essentially the same thing to the Blackberry. A BES server with MDS turned on will allow users on that BES to connect through it. Blackberry's Internet Service is simply a public MDS server.

• Connections going through a BIS/BES are proxied and are restricted to a finite request size. Requests exceeding this limit are truncated. This can introduce problems when downloading or uploading large amounts of data or trying to stream.
• The device is allowed to make an unlimited number of connections through the BIS/BES
• There is less overhead on the device when data is being transferred through the BIS/BES

Carrier

The carrier connection is the most widely available. Users on a BES can use it so long as it is not denied by the BES administrator. Sometimes just using the carrier connection is more desirable than dealing with issues that can potentially be introduced by connecting through a BES.

• The device is limited to 6 simultaneous connections
• There is increased processing overhead
• Request size is restricted by carrier if at all. Maximum size is on the order of MB rather than KB
• It may be necessary for users to have correct TCP settings on their phone. (APN information) Most carriers have this information preloaded when a phone is purchased.

WiFi

Wifi was introduced with BB OS 4.3. Connections over WiFi are direct connections

• Limited to 6 simultaneous connections
• There is increased processing overhead
• Request size is unlimited
• Very limited availability