This diagram contains the following elements in three sections, from left to right.
The left section contains:
A portable phone and a PDA connecting to a cloud representing GPRS and EDGE, and then connecting to a load balancer through a firewall on ports 80 or 443.
A mobile device connecting to a VPN through a firewall.
The middle section (the DMZ) contains:
A load balancer connected to two Oracle Mobile Data Sync servers on ports 7777 or 4443.
Two Oracle Mobile Data Sync servers. These connect on port 5730 to two Oracle Calendar servers that are behind the DMZ. The two Oracle Mobile Data Sync servers also connect to a common NFS datastore.
A representation of a VPN which is used by mobile devices to tunnel through to the load balancer.
The right section contains:
Two Oracle Calendar servers behind the DMZ.
A PDA that connects through the intranet to the load balancer that is in the DMZ.