anchor.diff:  
   * Diego's [Bulletin Board System](../diego/diego-architecture.html#bbs) (BBS) stores more frequently updated and disposable data such as cell and application status, unallocated work, and heartbeat messages. The BBS stores data in MySQL, using the [Go MySQL Driver](https://github.com/go-sql-driver/mysql).
   
  -The route-emitter component uses the NATS protocol to broadcast the latest routing tables to the routers. In pre-Diego CF architecture, the [NATS Message Bus](../diego/dea-vs-diego.html#nats) carried all internal component communications.
  +The route-emitter component uses the NATS protocol to broadcast the latest routing tables to the routers.
   
   ## <a id='metrics-logging'></a>Metrics and Logging
   
  
positive.code: 
  Each application VM has a Diego Cell that executes application start and stop actions locally, manages the VM's containers, and reports app status and other data to the BBS and [Loggregator](#metrics-logging).
  
  <%=vars.pre_diego_node%>
  
  ## <a id='services'></a>Services
  
  ### <a id='broker'></a> Service Brokers
  
negative.code: 
  ### <a id='nsync-bbs'></a> nsync, BBS, and Cell Reps
  
  To keep applications available, cloud deployments must constantly monitor their states and reconcile them with their expected states, starting and stopping processes as required.
  
  ![Cloud Foundry Architecture](../images/diego/app-monitor-sync-diego.png)
  
  