[VOL-3622] Stop and restart gRPC server

Change-Id: I443e7ed75f79dd90782a1a4342c8e4d3a7294488
diff --git a/api/bbsim/bbsim.proto b/api/bbsim/bbsim.proto
index da329f7..39e7cea 100644
--- a/api/bbsim/bbsim.proto
+++ b/api/bbsim/bbsim.proto
@@ -176,6 +176,10 @@
     repeated openolt.Flow flows = 2;
 }
 
+message Timeout {
+    uint32 delay = 1;
+}
+
 message Empty {
 }
 
@@ -199,6 +203,15 @@
     // Reboot OLT
     rpc RebootOlt (Empty) returns (Response) {
     }
+    // Closes the Openolt gRPC server
+    rpc StopgRPCServer (Empty) returns (Response) {
+    }
+    // Start the Openolt gRPC server
+    rpc StartgRPCServer (Empty) returns (Response) {
+    }
+    // Restart the Openolt gRPC server after the given timeout
+    rpc RestartgRPCServer (Timeout) returns (Response) {
+    }
 
     // Get status of an ONU by serial number
     rpc GetONU (ONURequest) returns (ONU) {