Star topology of SAP Systems

I have found that not many SAP admins notice that SAP system architecture resembles a star topology and that this was a conscious decision on SAP's part.

If there is any confusion on realising this--the central services instance forms the central node of a star topology and the individual instances are the connected nodes.

The biggest advantages of this topology are:
1. Central hub controls and communicates with rest of the nodes through client-server connectivity, keeping track of load levels, availability and non-duplication of changes.
2. The network connections grow linearly with the number of nodes added, as opposed to exponential growth with other topologies. This not only reduces cost, but also complexity.

The major disadvantage is that the loss of the central node will cause the entire system to go down. This is where High Availability comes to play.

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