@Test
  public void createEntryAndVerifyUpdate() {
    int locatorPort = createLocator(getVM(0));
    for (int i = 1; i <= NUM_SERVERS; i++) {
      createCacheAndRegion(getVM(i), locatorPort);
    }
    performCreate(getVM(1));
    for (int i = 1; i <= NUM_SERVERS; i++) {
      verifyCreatedEntry(getVM(i));
    }
    for (int iteration = 1; iteration < 6; iteration++) {
      performUpdate(getVM(1));
    }
    for (int i = 1; i <= NUM_SERVERS; i++) {
      verifyUpdatedEntry(getVM(i));
    }
  }
This class tests cluster tcp/ip communications both with and without SSL enabled
geode-core/src/upgradeTest/java/org/apache/geode/ClusterCommunicationsDUnitTest.java