diff --git a/src/org/jgroups/demos/RelayDemo.java b/src/org/jgroups/demos/RelayDemo.java
index 879745ab0d..d449097845 100644
--- a/src/org/jgroups/demos/RelayDemo.java
+++ b/src/org/jgroups/demos/RelayDemo.java
@@ -138,6 +138,14 @@ protected boolean process(String line) {
             System.out.printf("configured sites: %s\n", relay.getSites());
             return true;
         }
+        if(line.startsWith("tp")) { // topo-print
+            System.out.printf("\n%s\n", relay.topo().print());
+            return true;
+        }
+        if(line.startsWith("tc")) { // topo-clean
+            relay.topo().removeAll(null);
+            return true;
+        }
         if(line.startsWith("topo")) {
             String sub=line.substring("topo".length()).trim();
             String site=null;
diff --git a/src/org/jgroups/protocols/relay/RELAY2.java b/src/org/jgroups/protocols/relay/RELAY2.java
index d4a2715b67..07af180e30 100644
--- a/src/org/jgroups/protocols/relay/RELAY2.java
+++ b/src/org/jgroups/protocols/relay/RELAY2.java
@@ -40,7 +40,7 @@
 @MBean(description="RELAY2 protocol")
 public class RELAY2 extends Protocol {
     // reserved flags
-    public static final short can_become_site_master_flag = 1 << 1;
+    public static final short                          can_become_site_master_flag = 1 << 1;
 
     /* ------------------------------------------    Properties     ---------------------------------------------- */
     @Property(description="Name of the site; must be defined in the configuration",writable=false)
@@ -79,14 +79,10 @@ public class RELAY2 extends Protocol {
     @Property(description="Fully qualified name of a class implementing SiteMasterPicker")
     protected String                                   site_master_picker_impl;
 
-
     @Property(description="Time during which identical errors about no route to host will be suppressed. " +
       "0 disables this (every error will be logged).",type=AttributeType.TIME)
     protected long                                     suppress_time_no_route_errors=60000;
 
-
-    /* ---------------------------------------------    Fields    ------------------------------------------------ */
-
     /** A map containing site names (e.g. "LON") as keys and SiteConfigs as values */
     protected final Map<String,RelayConfig.SiteConfig> sites=new HashMap<>();
 
@@ -145,7 +141,7 @@ public class RELAY2 extends Protocol {
     protected final LongAdder                          forward_to_local_mbr_time=new LongAdder();
 
     @Component(description="Maintains a cache of sites and members",name="topo")
-    protected Topology                                 topo=new Topology(this);
+    protected final Topology                           topo=new Topology(this);
 
     /** Log to suppress identical errors for messages to non-existing sites ('no route to site X') */
     protected SuppressLog<String>                      suppress_log_no_route;
@@ -581,7 +577,8 @@ protected boolean handleAdminMessage(Relay2Header hdr, Message msg) {
                 return true;
             case TOPO_RSP:
                 Members mbrs=msg.getObject();
-                topo.handleResponse(mbrs);
+                if(mbrs != null)
+                    topo.handleResponse(mbrs);
                 return true;
         }
         return false;
diff --git a/src/org/jgroups/protocols/relay/Topology.java b/src/org/jgroups/protocols/relay/Topology.java
index 1e5ab8957d..e1ccd997a0 100644
--- a/src/org/jgroups/protocols/relay/Topology.java
+++ b/src/org/jgroups/protocols/relay/Topology.java
@@ -27,7 +27,7 @@
 public class Topology {
     protected final RELAY2                      relay;
     protected final Map<String,Set<MemberInfo>> cache=new ConcurrentHashMap<>(); // cache of sites and members
-    protected BiConsumer<String,MemberInfo>     rsp_handler;
+    protected BiConsumer<String,Members>        rsp_handler;
 
 
     public Topology(RELAY2 relay) {
@@ -38,9 +38,10 @@ public Topology(RELAY2 relay) {
 
     /**
      * Sets a response handler
-     * @param c The response handler. Arguments are the site and MemberInfo of the member from which we received the rsp
+     * @param c The response handler. Arguments are the site and {@link Members}
+     *          ({@link MemberInfo} of joined and left members)
      */
-    public Topology setResponseHandler(BiConsumer<String,MemberInfo> c) {rsp_handler=c; return this;}
+    public Topology setResponseHandler(BiConsumer<String,Members> c) {rsp_handler=c; return this;}
 
 
     @ManagedOperation(description="Fetches information (site, address, IP address) from all members")
@@ -118,20 +119,14 @@ protected void handleResponse(Members rsp) {
         Set<MemberInfo> infos=cache.computeIfAbsent(site,s -> new ConcurrentSkipListSet<>());
         if(rsp.joined != null) {
             infos.addAll(rsp.joined);
-            if(rsp_handler != null)
-                for(MemberInfo mi: rsp.joined)
-                    rsp_handler.accept(site, mi);
         }
-
         if(rsp.left != null) {
             // todo: implement
         }
+        if(rsp_handler != null)
+            rsp_handler.accept(site, rsp);
     }
 
-    @FunctionalInterface
-    public interface ResponseHandler {
-        void handle(String site, MemberInfo rsp);
-    }
 
     /** Contains information about joined and left members for a given site */
     public static class Members implements SizeStreamable {