>> the width of comunication that Oracle uses
That would be 2k. However, you determine the packet size (assuming that the satelitte uses TCP/IP protocols). The TDU is the default packet size used within Oracle Net to group data together. http://www.dba-oracle.com/art_builder_tns.htm
The frequency and size of network packets, however, can be controlled by the Oracle DBA. Oracle has a wealth of tools to change packet frequency and size. A simple example involves changing the refresh interval for a snapshot to ship larger amounts at less frequent intervals.
Oracle Net connections between servers can be tuned using several parameters. Keep in mind, however, that network tuning is outside the scope of Oracle, and a qualified network administrator should be consulted for tuning the network. The frequency and size of packet shipping across the network can be affected by using settings contained in the following parameter files:
The tnsnames.ora and listener.ora files—The SDU and TDU parameters
The protocol.ora file—The tcp.nodelay parameter
The TDU is the default packet size used within Oracle Net to group data together. The TDU parameter should ideally be a multiple of the SDU parameter. The default value for both SDU and TDU is 2,048, and the maximum value is 32,767 bytes.