Iteration 1
Client makes just one request, to the NetworkUpdateService.
NetworkUpdateService makes multiple requests to gather the data from all the services. These requests are made in parallel.
The results are aggregated and returned to the client together.
Pull-based architecture.
They rolled out this new system to everyone at LinkedIn, which caused problems while the system was stabilizing. In hindsight, should have tried it out on a small subset of users first.