In split- transaction protocol, performance is improved at the cost of increased bus complexity.

There are two reasons why complexity increases:

• Since a memory module needs to know which source initiated a given read request,
  a source identification tag must be attached to the request.
  
• Complexity also increases because all modules, not just the processor, must be
  able to act as bus muster.

The main limitation of a single bus is that the number of modules that can be connected to the bus is not that large. Networks that allow multiple independent transfer operations to proceed in parallel can provide significantly increased data transfer rate.