hiero-ledger · netopyr · Aug 14, 2026 · Aug 13, 2026
@@ -2,7 +2,6 @@
 package org.hiero.otter.fixtures.internal;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.hiero.otter.fixtures.internal.AbstractNetwork.BandwidthControlSupport.BANDWIDTH_CONTROL_SUPPORTED;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
@@ -11,6 +10,7 @@
 import java.time.Duration;
 import java.util.List;
 import java.util.Map;
+import java.util.Random;
 import org.assertj.core.data.Percentage;
 import org.hiero.consensus.model.node.KeysAndCerts;
 import org.hiero.consensus.model.node.NodeId;
@@ -275,7 +275,7 @@ private static class TestableNetwork extends AbstractNetwork {
         private final ControllableTopology controllableTopology;
 
         TestableNetwork() {
-            super(new java.util.Random(42), false, BANDWIDTH_CONTROL_SUPPORTED);
+            super(new Random(42), false);
             this.controllableTopology = new ControllableTopology(super.topology());
         }
 

@@ -3,7 +3,6 @@
 
 import static java.time.temporal.ChronoUnit.MILLIS;
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.hiero.otter.fixtures.internal.AbstractNetwork.BandwidthControlSupport.BANDWIDTH_CONTROL_SUPPORTED;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
@@ -12,6 +11,7 @@
 import java.time.Duration;
 import java.util.List;
 import java.util.Map;
+import java.util.Random;
 import org.assertj.core.data.Percentage;
 import org.hiero.consensus.model.node.KeysAndCerts;
 import org.hiero.consensus.model.node.NodeId;
@@ -223,7 +223,7 @@ void multipleConnectionObjectsReferSameUnderlyingConnection() {
     private static class TestableNetwork extends AbstractNetwork {
 
         TestableNetwork() {
-            super(new java.util.Random(42), false, BANDWIDTH_CONTROL_SUPPORTED);
+            super(new Random(42), false);
         }
 
         @Override

@@ -2,7 +2,6 @@
 package org.hiero.otter.fixtures.container;
 
 import static java.util.Objects.requireNonNull;
-import static org.hiero.otter.fixtures.internal.AbstractNetwork.BandwidthControlSupport.BANDWIDTH_CONTROL_SUPPORTED;
 
 import com.hedera.hapi.node.state.roster.Roster;
 import edu.umd.cs.findbugs.annotations.NonNull;
@@ -74,7 +73,7 @@ public ContainerNetwork(
             final boolean proxyEnabled,
             final boolean gcLoggingEnabled,
             @NonNull final List<String> jvmArgs) {
-        super(new Random(), useRandomNodeIds, BANDWIDTH_CONTROL_SUPPORTED);
+        super(new Random(), useRandomNodeIds);
         this.timeManager = requireNonNull(timeManager);
         this.transactionGenerator = requireNonNull(transactionGenerator);
         this.rootOutputDirectory = requireNonNull(rootOutputDirectory);

@@ -96,11 +96,6 @@
  */
 public abstract class AbstractNetwork implements Network {
 
-    public enum BandwidthControlSupport {
-        BANDWIDTH_CONTROL_SUPPORTED,
-        BANDWIDTH_CONTROL_NOT_SUPPORTED
-    }
-
     /**
      * The fraction of nodes that must consider a node behind for the node to be considered behind by the network.
      */
@@ -129,7 +124,7 @@ protected enum Lifecycle {
     /** The default timeout duration for network operations. */
     private static final Duration DEFAULT_TIMEOUT = Duration.ofMinutes(2L);
 
-    private final Random random;
+    protected final Random random;
     private final Map<NodeId, PartitionImpl> networkPartitions = new HashMap<>();
     private final Map<ConnectionKey, Boolean> connected = new HashMap<>();
     private final Map<ConnectionKey, LatencyOverride> latencyOverrides = new HashMap<>();
@@ -139,8 +134,6 @@ protected enum Lifecycle {
     private Topology currentTopology;
     protected final NetworkConfiguration networkConfiguration;
 
-    private final boolean bandwidthControlNotSupported;
-
     protected Lifecycle lifecycle = Lifecycle.INIT;
 
     protected WeightGenerator weightGenerator = WeightGenerators.REAL_NETWORK_GAUSSIAN;
@@ -152,18 +145,13 @@ protected enum Lifecycle {
 
     private NodeId nextNodeId = NodeId.FIRST_NODE_ID;
 
-    protected AbstractNetwork(
-            @NonNull final Random random,
-            final boolean useRandomNodeIds,
-            @NonNull final BandwidthControlSupport bandwidthControlSupport) {
+    protected AbstractNetwork(@NonNull final Random random, final boolean useRandomNodeIds) {
         this.random = requireNonNull(random);
         this.useRandomNodeIds = useRandomNodeIds;
         // Initialize with default GeoMeshTopology
         this.currentTopology = new GeoMeshTopologyImpl(
                 GeoMeshTopologyConfiguration.DEFAULT, random, this::createNodes, this::createInstrumentedNode);
         this.networkConfiguration = new NetworkConfiguration();
-        this.bandwidthControlNotSupported =
-                bandwidthControlSupport != BandwidthControlSupport.BANDWIDTH_CONTROL_SUPPORTED;
     }
 
     /**
@@ -613,9 +601,6 @@ private void setLatencyRange(
      */
     @Override
     public void setBandwidthForAllConnections(@NonNull final Node node, @NonNull final BandwidthLimit bandwidthLimit) {
-        if (bandwidthControlNotSupported && !bandwidthLimit.isUnlimited()) {
-            throw new UnsupportedOperationException("Bandwidth control is not supported.");
-        }
         log.info("Setting bandwidth for all connections from node {} to {}", node.selfId(), bandwidthLimit);
         for (final Node otherNode : nodes()) {
             if (!node.equals(otherNode)) {
@@ -1346,9 +1331,6 @@ public BandwidthLimit bandwidthLimit() {
         @Override
         public void bandwidthLimit(@NonNull final BandwidthLimit bandwidthLimit) {
             requireNonNull(bandwidthLimit);
-            if (bandwidthControlNotSupported && !bandwidthLimit.isUnlimited()) {
-                throw new UnsupportedOperationException("Bandwidth control is not supported.");
-            }
             log.info(
                     "Setting bandwidth limit from node {} to node {} to {}",
                     sender.selfId(),

@@ -97,7 +97,7 @@ protected AbstractNode(
         if (networkConfiguration.weight() != UNSET_WEIGHT) {
             weight(networkConfiguration.weight());
         }
-        version(networkConfiguration.version());
+        this.version = networkConfiguration.version();
         final Path savedStateDirectory = networkConfiguration.savedStateDirectory();
         if (savedStateDirectory != null) {
             startFromSavedState(savedStateDirectory);

@@ -3,11 +3,11 @@
 
 import edu.umd.cs.findbugs.annotations.NonNull;
 import java.nio.file.Path;
+import java.util.Random;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.hiero.consensus.model.node.KeysAndCerts;
 import org.hiero.consensus.model.node.NodeId;
-import org.hiero.consensus.test.fixtures.Randotron;
 import org.hiero.otter.fixtures.InstrumentedNode;
 import org.hiero.otter.fixtures.internal.NetworkConfiguration;
 import org.hiero.otter.fixtures.internal.result.ConsensusRoundPool;
@@ -24,7 +24,7 @@ public class InstrumentedTurtleNode extends TurtleNode implements InstrumentedNo
     /**
      * Constructor for the {@link InstrumentedTurtleNode} class.
      *
-     * @param randotron the random number generator
+     * @param random the random number generator
      * @param timeManager the time provider
      * @param selfId the node ID of the node
      * @param keysAndCerts the keys and certificates of the node
@@ -35,7 +35,7 @@ public class InstrumentedTurtleNode extends TurtleNode implements InstrumentedNo
      * @param consensusRoundPool the shared pool for deduplicating consensus rounds
      */
     public InstrumentedTurtleNode(
-            @NonNull final Randotron randotron,
+            @NonNull final Random random,
             @NonNull final TurtleTimeManager timeManager,
             @NonNull final NodeId selfId,
             @NonNull final KeysAndCerts keysAndCerts,
@@ -45,7 +45,7 @@ public InstrumentedTurtleNode(
             @NonNull final NetworkConfiguration networkConfiguration,
             @NonNull final ConsensusRoundPool consensusRoundPool) {
         super(
-                randotron,
+                random,
                 timeManager,
                 selfId,
                 keysAndCerts,

@@ -14,13 +14,6 @@ public class SecureRandomBuilder implements Supplier<SecureRandom> {
 
     private final Random seedSource;
 
-    /**
-     * Constructor. Random seed is used.
-     */
-    public SecureRandomBuilder() {
-        seedSource = new Random();
-    }
-
     /**
      * Constructor.
      *

@@ -2,7 +2,6 @@
 package org.hiero.otter.fixtures.turtle;
 
 import static java.util.Objects.requireNonNull;
-import static org.hiero.otter.fixtures.internal.AbstractNetwork.BandwidthControlSupport.BANDWIDTH_CONTROL_NOT_SUPPORTED;
 import static org.junit.jupiter.api.Assertions.fail;
 
 import com.hedera.hapi.node.state.roster.Roster;
@@ -12,6 +11,7 @@
 import java.time.Duration;
 import java.time.Instant;
 import java.util.Map;
+import java.util.Random;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
@@ -20,7 +20,6 @@
 import org.hiero.consensus.model.node.KeysAndCerts;
 import org.hiero.consensus.model.node.NodeId;
 import org.hiero.consensus.model.quiescence.QuiescenceCommand;
-import org.hiero.consensus.test.fixtures.Randotron;
 import org.hiero.otter.fixtures.InstrumentedNode;
 import org.hiero.otter.fixtures.Network;
 import org.hiero.otter.fixtures.TimeManager;
@@ -45,7 +44,6 @@ public class TurtleNetwork extends AbstractNetwork implements TimeTickReceiver {
 
     private static final Logger log = LogManager.getLogger();
 
-    private final Randotron randotron;
     private final TurtleTimeManager timeManager;
     private final TurtleLogging logging;
     private final Path rootOutputDirectory;
@@ -58,27 +56,26 @@ public class TurtleNetwork extends AbstractNetwork implements TimeTickReceiver {
     /**
      * Constructor for TurtleNetwork.
      *
-     * @param randotron the random generator
+     * @param random the random generator
      * @param timeManager the time manager
      * @param logging the logging utility
      * @param rootOutputDirectory the directory where the node output will be stored, like saved state and so on
      * @param transactionGenerator the transaction generator that generates a steady flow of transactions to all nodes
      * @param useRandomNodeIds {@code true} if the node IDs should be selected randomly; {@code false} otherwise
      */
     public TurtleNetwork(
-            @NonNull final Randotron randotron,
+            @NonNull final Random random,
             @NonNull final TurtleTimeManager timeManager,
             @NonNull final TurtleLogging logging,
             @NonNull final Path rootOutputDirectory,
             @NonNull final TurtleTransactionGenerator transactionGenerator,
             final boolean useRandomNodeIds) {
-        super(randotron, useRandomNodeIds, BANDWIDTH_CONTROL_NOT_SUPPORTED);
-        this.randotron = requireNonNull(randotron);
+        super(random, useRandomNodeIds);
         this.timeManager = requireNonNull(timeManager);
         this.logging = requireNonNull(logging);
         this.rootOutputDirectory = requireNonNull(rootOutputDirectory);
         this.transactionGenerator = requireNonNull(transactionGenerator);
-        this.simulatedNetwork = new SimulatedNetwork(randotron);
+        this.simulatedNetwork = new SimulatedNetwork(random);
     }
 
     /**
@@ -104,6 +101,11 @@ protected TransactionGenerator transactionGenerator() {
      */
     @Override
     protected void onConnectionsChanged(@NonNull final Map<ConnectionKey, ConnectionState> connections) {
+        final boolean limited = connections.values().stream()
+                .anyMatch(state -> !state.bandwidthLimit().isUnlimited());
+        if (limited) {
+            throw new UnsupportedOperationException("Bandwidth limits are not supported in Turtle.");
+        }
         simulatedNetwork.setConnections(connections);
     }
 
@@ -122,7 +124,7 @@ protected TurtleNode doCreateNode(@NonNull final NodeId nodeId, @NonNull final K
         simulatedNetwork.addNode(nodeId, simulatedGossip);
         final Path outputDir = rootOutputDirectory.resolve(NODE_IDENTIFIER_FORMAT.formatted(nodeId.id()));
         return new TurtleNode(
-                randotron,
+                random,
                 timeManager,
                 nodeId,
                 keysAndCerts,
@@ -144,7 +146,7 @@ protected InstrumentedNode doCreateInstrumentedNode(
         simulatedNetwork.addNode(nodeId, simulatedGossip);
         final Path outputDir = rootOutputDirectory.resolve(NODE_IDENTIFIER_FORMAT.formatted(nodeId.id()));
         return new InstrumentedTurtleNode(
-                randotron,
+                random,
                 timeManager,
                 nodeId,
                 keysAndCerts,

@@ -57,7 +57,6 @@
 import org.hiero.consensus.roster.RosterStateId;
 import org.hiero.consensus.roster.WritableRosterStore;
 import org.hiero.consensus.state.signed.ReservedSignedState;
-import org.hiero.consensus.test.fixtures.Randotron;
 import org.hiero.consensus.wiring.framework.model.DeterministicWiringModel;
 import org.hiero.consensus.wiring.framework.model.WiringModelBuilder;
 import org.hiero.otter.fixtures.Node;
@@ -101,7 +100,7 @@ public class TurtleNode extends AbstractNode implements Node, TurtleTimeManager.
      */
     private static final Logger startupLogger = LogManager.getLogger("com.swirlds.platform.node.startup");
 
-    private final Randotron randotron;
+    private final Random random;
     private final TurtleTimeManager timeManager;
     private final SimulatedGossip gossip;
     private final TurtleLogging logging;
@@ -130,7 +129,7 @@ public class TurtleNode extends AbstractNode implements Node, TurtleTimeManager.
     /**
      * Constructor of {@link TurtleNode}.
      *
-     * @param randotron the random number generator
+     * @param random the random number generator
      * @param timeManager the time manager for this test
      * @param selfId the node ID of the node
      * @param keysAndCerts the keys and certificates of the node
@@ -141,7 +140,7 @@ public class TurtleNode extends AbstractNode implements Node, TurtleTimeManager.
      * @param consensusRoundPool the shared pool for deduplicating consensus rounds
      */
     public TurtleNode(
-            @NonNull final Randotron randotron,
+            @NonNull final Random random,
             @NonNull final TurtleTimeManager timeManager,
             @NonNull final NodeId selfId,
             @NonNull final KeysAndCerts keysAndCerts,
@@ -155,7 +154,7 @@ public TurtleNode(
             this.outputDirectory = requireNonNull(outputDirectory);
             logging.addNodeLogging(selfId, outputDirectory);
 
-            this.randotron = requireNonNull(randotron);
+            this.random = requireNonNull(random);
             this.timeManager = requireNonNull(timeManager);
             this.gossip = requireNonNull(gossip);
             this.logging = requireNonNull(logging);
@@ -262,8 +261,7 @@ protected void doStart(@NonNull final Duration timeout) {
             final RosterHistory rosterHistory = rosterStore.getRosterHistory();
             final String eventStreamLoc = Long.toString(selfId.id());
 
-            this.executionLayer =
-                    new OtterExecutionLayer(new Random(randotron.nextLong()), metrics, timeManager.time());
+            this.executionLayer = new OtterExecutionLayer(new Random(random.nextLong()), metrics, timeManager.time());
 
             final TestPlatformBuilder builder = new TestPlatformBuilder(
                             currentConfiguration,
@@ -283,7 +281,7 @@ protected void doStart(@NonNull final Duration timeout) {
                             eventStreamLoc,
                             OtterApp.DEFAULT_TRANSACTION_OFFSET_NANOS)
                     .withWiringModel(model)
-                    .withSecureRandom(new SecureRandomBuilder(randotron.nextLong()).get())
+                    .withSecureRandom(new SecureRandomBuilder(random.nextLong()).get())
                     .withAdditionalProperties(Map.of("simulatedGossip", gossip));
 
             platform = builder.build();
@@ -473,7 +471,7 @@ public SingleNodeEventStreamResult newEventStreamResult() {
     @Override
     @NonNull
     protected Random random() {
-        return randotron;
+        return random;
     }
 
     /**