diff --git a/libs/libclkarchopenfpga/src/base/clock_network.cpp b/libs/libclkarchopenfpga/src/base/clock_network.cpp
index 3bfc16f40..808286911 100644
--- a/libs/libclkarchopenfpga/src/base/clock_network.cpp
+++ b/libs/libclkarchopenfpga/src/base/clock_network.cpp
@@ -199,6 +199,27 @@ void ClockNetwork::add_spine_switch_point(const ClockSpineId& spine_id, const Cl
   spine_parent_[drive_spine_id] = spine_id;
 }
 
+bool ClockNetwork::link() {
+  for (ClockTreeId& tree_id : trees()) {
+    if (!link_tree(tree_id)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool ClockNetwork::link_tree(const ClockTreeId& tree_id) {
+  tree_top_spines_[tree_id].clear();
+  /* Sort the spines under a tree; assign levels and identify top-level spines */
+  for (ClockSpineId spine_id : spines(tree_id)) {
+    /* Spines that have no parent are the top-level spines*/
+    if (!spine_parent_[spine_id]) {
+      tree_top_spines_[tree_id].push_back(spine_id);
+    }
+  }
+  return true;
+}
+
 /************************************************************************
  * Internal invalidators/validators
  ***********************************************************************/
diff --git a/libs/libclkarchopenfpga/src/base/clock_network.h b/libs/libclkarchopenfpga/src/base/clock_network.h
index c22a7bb93..c566f045f 100644
--- a/libs/libclkarchopenfpga/src/base/clock_network.h
+++ b/libs/libclkarchopenfpga/src/base/clock_network.h
@@ -81,6 +81,8 @@ class ClockNetwork {
   void set_spine_start_point(const ClockSpineId& spine_id, const vtr::Point<int>& coord);
   void set_spine_end_point(const ClockSpineId& spine_id, const vtr::Point<int>& coord);
   void add_spine_switch_point(const ClockSpineId& spine_id, const ClockSpineId& drive_spine_id, const vtr::Point<int>& coord);
+  /* Build internal links between clock tree, spines etc. This is also an validator to verify the correctness of the clock network. Must run before using the data! */
+  bool link();
 
  public: /* Public invalidators/validators */
   /* Show if the tree id is a valid for data queries */
@@ -89,6 +91,10 @@ class ClockNetwork {
   bool valid_spine_id(const ClockSpineId& spine_id) const;
   bool valid_spine_switch_point_id(const ClockSpineId& spine_id, const ClockSwitchPointId& switch_point_id) const;
 
+ private: /* Private mutators */
+  /* Build internal links between spines under a given tree */
+  bool link_tree(const ClockTreeId& tree_id);
+
  private: /* Internal data */
   /* Basic information of each tree */
   vtr::vector<ClockTreeId, ClockTreeId> tree_ids_;