Data schema      Queries
                                          |             |
                                          \             /
       +-------------+                   +-----------------+
       | ALTO Client | <===============> |  Job Optimizer  |
       +-------------+                   +-----------------+
PV          |   ^ PV                                    |
Request     |   | Response                              |
            |   |                  On-demand resource   |
(Potential  |   | (Network         allocation, demand   |
Data        |   | Resource         vectors, etc.        |
Transfers)  |   | Constraints)     (Non-ALTO interfaces)|
            v   |                                       v
       +-------------+                   +-----------------+
       | ALTO Server | <===============> | Network Manager |
       +-------------+                   +-----------------+
                                           /      |      \
                                           |      |      |
                                          WAN    DC1    DC2