Refactoring file structure for protobufs.

Change-Id: I50daf100d54750f97158304d87813e67861b1422
diff --git a/incubator/protobuf/models/src/main/proto/LinkDescriptionProto.proto b/incubator/protobuf/models/src/main/proto/LinkDescriptionProto.proto
new file mode 100644
index 0000000..16fe534
--- /dev/null
+++ b/incubator/protobuf/models/src/main/proto/LinkDescriptionProto.proto
@@ -0,0 +1,14 @@
+syntax = "proto3";
+option java_package = "org.onosproject.grpc.net.models";
+
+package Link;
+
+import "ConnectPointProto.proto";
+import "LinkEnums.proto";
+
+message LinkDescription {
+    ConnectPoint.ConnectPoint src = 1;
+    ConnectPoint.ConnectPoint dst = 2;
+    Link.LinkType type = 3;
+    map<string, string> annotations = 4;
+}
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