diff --git a/src/spore/core/ClusterManager.cpp b/src/spore/core/ClusterManager.cpp
index a0a53d7..5b084ed 100644
--- a/src/spore/core/ClusterManager.cpp
+++ b/src/spore/core/ClusterManager.cpp
@@ -158,53 +158,72 @@ void ClusterManager::onNodeUpdate(const char* msg) {
         return;
     }
 
-    // Update the specific node in memberlist
+    // The NODE_UPDATE contains info about the target node (hostname from message)
+    // but is sent FROM the responding node (ctx.udp->remoteIP())
+    // We need to find the responding node in the memberlist, not the target node
+    IPAddress respondingNodeIP = ctx.udp->remoteIP();
     auto& memberList = *ctx.memberList;
-    auto it = memberList.find(hostname);
-    if (it != memberList.end()) {
-        NodeInfo& node = it->second;
 
-        // Update basic info if provided
+    // Find the responding node by IP address
+    NodeInfo* respondingNode = nullptr;
+    for (auto& pair : memberList) {
+        if (pair.second.ip == respondingNodeIP) {
+            respondingNode = &pair.second;
+            break;
+        }
+    }
+
+    if (respondingNode) {
+        // Calculate latency if we recently sent a heartbeat
+        unsigned long latency = 0;
+        if (lastHeartbeatSentAt != 0) {
+            unsigned long now = millis();
+            latency = now - lastHeartbeatSentAt;
+            lastHeartbeatSentAt = 0; // Reset for next calculation
+        }
+
+        // Update the responding node's information
         if (doc["hostname"].is<const char*>()) {
-            node.hostname = doc["hostname"].as<const char*>();
+            respondingNode->hostname = doc["hostname"].as<const char*>();
         }
         if (doc["uptime"].is<unsigned long>()) {
-            node.uptime = doc["uptime"];
+            respondingNode->uptime = doc["uptime"];
         }
 
         // Update labels if provided
         if (doc["labels"].is<JsonObject>()) {
-            node.labels.clear();
+            respondingNode->labels.clear();
             JsonObject labelsObj = doc["labels"].as<JsonObject>();
             for (JsonPair kvp : labelsObj) {
                 const char* key = kvp.key().c_str();
                 const char* value = labelsObj[kvp.key()];
-                node.labels[key] = String(value);
+                respondingNode->labels[key] = String(value);
             }
         }
 
-        node.lastSeen = millis();
-        node.status = NodeInfo::ACTIVE;
+        respondingNode->lastSeen = millis();
+        respondingNode->status = NodeInfo::ACTIVE;
+        respondingNode->latency = latency;
 
-        LOG_DEBUG("Cluster", String("Updated node ") + hostname + " from NODE_UPDATE");
+        LOG_DEBUG("Cluster", String("Updated responding node ") + respondingNode->hostname + " @ " + respondingNodeIP.toString() + " | latency: " + String(latency) + "ms");
     } else {
-        LOG_WARN("Cluster", String("Received NODE_UPDATE for unknown node: ") + hostname);
+        LOG_WARN("Cluster", String("Received NODE_UPDATE from unknown node: ") + respondingNodeIP.toString());
     }
 }
 
-void ClusterManager::sendNodeInfo(const String& hostname, const IPAddress& targetIP) {
+void ClusterManager::sendNodeInfo(const String& targetHostname, const IPAddress& targetIP) {
     JsonDocument doc;
 
-    // Get our node info for the response
+    // Get our node info for the response (we're the responding node)
     auto& memberList = *ctx.memberList;
     auto it = memberList.find(ctx.hostname);
     if (it != memberList.end()) {
         const NodeInfo& node = it->second;
 
-        // Minimal response: hostname, ip, uptime, labels
+        // Response contains info about ourselves (the responding node)
         doc["hostname"] = node.hostname;
         doc["ip"] = node.ip.toString();
-        doc["uptime"] = millis() - node.lastSeen; // Approximate uptime
+        doc["uptime"] = node.uptime;
 
         // Add labels if present
         if (!node.labels.empty()) {
@@ -223,12 +242,13 @@ void ClusterManager::sendNodeInfo(const String& hostname, const IPAddress& targe
     String json;
     serializeJson(doc, json);
 
+    // Send NODE_UPDATE:targetHostname:{json about responding node}
     ctx.udp->beginPacket(targetIP, ctx.config.udp_port);
-    String msg = String(ClusterProtocol::NODE_UPDATE_MSG) + ":" + hostname + ":" + json;
+    String msg = String(ClusterProtocol::NODE_UPDATE_MSG) + ":" + targetHostname + ":" + json;
     ctx.udp->write(msg.c_str());
     ctx.udp->endPacket();
 
-    LOG_DEBUG("Cluster", String("Sent NODE_UPDATE response to ") + hostname + " @ " + targetIP.toString());
+    LOG_DEBUG("Cluster", String("Sent NODE_UPDATE response to ") + targetHostname + " @ " + targetIP.toString());
 }
 
 void ClusterManager::onClusterEvent(const char* msg) {