diff --git a/src/ca/bhe.cpp b/src/ca/bhe.cpp
index 3b842d107..cc3700c02 100644
--- a/src/ca/bhe.cpp
+++ b/src/ca/bhe.cpp
@@ -65,13 +65,15 @@ void bhe::beaconAnomalyNotify ()
  * updates beacon period, and looks for beacon anomalies
  */
 bool bhe::updatePeriod ( const epicsTime & programBeginTime, 
-                        const epicsTime & currentTime )
+    const epicsTime & currentTime, unsigned beaconNumber, 
+    unsigned protocolRevision )
 {
-    double currentPeriod;
-    bool netChange = false;
-
     if ( this->timeStamp == epicsTime () ) {
 
+        if ( CA_V410 ( protocolRevision ) ) {
+            this->lastBeaconNumber = beaconNumber;
+        }
+
         this->beaconAnomalyNotify ();
 
         /* 
@@ -82,13 +84,23 @@ bool bhe::updatePeriod ( const epicsTime & programBeginTime,
          */
         this->timeStamp = currentTime;
 
-        return netChange;
+        return false;
+    }
+
+    // detect beacon duplications due to IP redundant packet routes
+    if ( CA_V410 ( protocolRevision ) ) {
+        unsigned lastBeaconNumberSave = this->lastBeaconNumber;
+        this->lastBeaconNumber = beaconNumber;
+        if ( beaconNumber != lastBeaconNumberSave + 1 ) {
+            return false;
+        }
     }
 
     /*
      * compute the beacon period (if we have seen at least two beacons)
      */
-    currentPeriod = currentTime - this->timeStamp;
+    bool netChange = false;
+    double currentPeriod = currentTime - this->timeStamp;
     if ( this->averagePeriod < 0.0 ) {
         double totalRunningTime;
 
diff --git a/src/ca/bhe.h b/src/ca/bhe.h
index 95ea8be4e..7ab3743ef 100644
--- a/src/ca/bhe.h
+++ b/src/ca/bhe.h
@@ -16,6 +16,7 @@
 
 #include "shareLib.h"
 
+#include <limits.h>
 #include <float.h>
 
 #ifdef epicsExportSharedSymbols
@@ -42,7 +43,8 @@ public:
     epicsShareFunc bhe ( const epicsTime &initialTimeStamp, const inetAddrID &addr );
     epicsShareFunc void destroy ();
     epicsShareFunc bool updatePeriod ( const epicsTime & programBeginTime, 
-                        const epicsTime & currentTime );
+                        const epicsTime & currentTime, unsigned beaconNumber, 
+                        unsigned protocolRevision );
     epicsShareFunc double period () const;
     epicsShareFunc void show ( unsigned level) const;
     epicsShareFunc void registerIIU ( tcpiiu & );
@@ -55,6 +57,7 @@ private:
     tsDLList < tcpiiu > iiuList;
     epicsTime timeStamp;
     double averagePeriod;
+    unsigned lastBeaconNumber;
     void beaconAnomalyNotify ();
     static tsFreeList < class bhe, 1024 > freeList;
     static epicsMutex freeListMutex;
@@ -77,7 +80,8 @@ private:
  * between the 1st and 2nd beacons)
  */
 inline bhe::bhe ( const epicsTime & initialTimeStamp, const inetAddrID & addr ) :
-    inetAddrID ( addr ), timeStamp ( initialTimeStamp ), averagePeriod ( - DBL_MAX )
+    inetAddrID ( addr ), timeStamp ( initialTimeStamp ), averagePeriod ( - DBL_MAX ),
+    lastBeaconNumber ( UINT_MAX )
 {
 #   ifdef DEBUG
     {
diff --git a/src/ca/caProto.h b/src/ca/caProto.h
index 7b4dc4fb5..7028e29ee 100644
--- a/src/ca/caProto.h
+++ b/src/ca/caProto.h
@@ -52,6 +52,7 @@
 #   define CA_V47(MINOR) ((MINOR)>=7u)
 #   define CA_V48(MINOR) ((MINOR)>=8u)
 #   define CA_V49(MINOR) ((MINOR)>=9u)
+#   define CA_V410(MINOR) ((MINOR)>=10u) /* beacon counter */
 #elif CA_MAJOR_PROTOCOL_REVISION > 4u
 #   define CA_V41(MINOR) ( 1u )
 #   define CA_V42(MINOR) ( 1u )
@@ -62,6 +63,7 @@
 #   define CA_V47(MINOR) ( 1u )
 #   define CA_V48(MINOR) ( 1u )
 #   define CA_V49(MINOR) ( 1u )
+#   define CA_V410(MINOR) ( 1u )
 #else
 #   define CA_V41(MINOR) ( 0u )
 #   define CA_V42(MINOR) ( 0u )
@@ -72,6 +74,7 @@
 #   define CA_V47(MINOR) ( 0u )
 #   define CA_V48(MINOR) ( 0u )
 #   define CA_V49(MINOR) ( 0u )
+#   define CA_V410(MINOR) ( 0u )
 #endif 
 
 /*
diff --git a/src/ca/cac.h b/src/ca/cac.h
index 4f7ad6b11..6b4141fa7 100644
--- a/src/ca/cac.h
+++ b/src/ca/cac.h
@@ -59,8 +59,8 @@ public:
     virtual ~cac ();
 
     // beacon management
-    void beaconNotify ( const inetAddrID & addr, 
-        const epicsTime & currentTime );
+    void beaconNotify ( const inetAddrID & addr, const epicsTime & currentTime, 
+        unsigned beaconNumber, unsigned protocolRevision );
     void repeaterSubscribeConfirmNotify ();
 
     // outstanding IO count management routines
@@ -172,7 +172,7 @@ private:
     epicsMutex                  callbackMutex; 
     epicsEvent                  ioDone;
     epicsEvent                  noRecvThreadsPending;
-    epicsEvent                  iiuUninstal;
+    epicsEvent                  iiuUninstall;
     epicsTimerQueueActive       & timerQueue;
     char                        * pUserName;
     class udpiiu                * pudpiiu;
@@ -192,7 +192,6 @@ private:
 
     void privateUninstallIIU ( tcpiiu &iiu ); 
     void flushRequestPrivate ();
-    void uninstallChannelPrivate ( nciu & );
     void run ();
     bool setupUDP ();
     void connectAllIO ( nciu &chan );
diff --git a/src/ca/casw.cpp b/src/ca/casw.cpp
index 8348cbda5..86a0251a4 100644
--- a/src/ca/casw.cpp
+++ b/src/ca/casw.cpp
@@ -121,8 +121,15 @@ int main ( int, char ** )
             continue;
         }
         
+        unsigned byteCount = static_cast <unsigned> ( status );
         pCurMsg = reinterpret_cast < const caHdr * > ( ( pCurBuf = buf ) );
-        while ( status >= static_cast < int > ( sizeof ( *pCurMsg ) ) ) {
+        while ( byteCount ) {
+            size_t msgSize = epicsNTOH32 ( pCurMsg->m_postsize ) + sizeof (*pCurMsg) ;
+            if ( msgSize > byteCount ) {
+                errlogPrintf ( "CASW: udp input protocol violation\n" );
+                break;
+            }
+
             if ( epicsNTOH16 ( pCurMsg->m_cmmd ) == CA_PROTO_RSRV_IS_UP ) {
                 struct sockaddr_in ina;
 
@@ -154,6 +161,9 @@ int main ( int, char ** )
                     ina.sin_port = epicsNTOH16 ( serverPort );
                 }
 
+                unsigned beaconNumber = ntohl ( pCurMsg->m_cid );
+                unsigned protocolRevision = ntohs ( pCurMsg->m_dataType );
+
                 bool netChange;
                 epicsTime currentTime = epicsTime::getCurrent();
 
@@ -162,7 +172,7 @@ int main ( int, char ** )
                  */
                 bhe *pBHE = beaconTable.lookup ( ina );
                 if ( pBHE ) {
-                    netChange = pBHE->updatePeriod ( programBeginTime, currentTime );
+                    netChange = pBHE->updatePeriod ( programBeginTime, currentTime, beaconNumber, protocolRevision );
                 }
                 else {
                     /*
@@ -189,9 +199,9 @@ int main ( int, char ** )
                     errlogPrintf ("CA server beacon anomaly: %s %s\n", date, host );
                 }
             }
-            pCurBuf += sizeof ( *pCurMsg ) + epicsNTOH32 ( pCurMsg->m_postsize );
+            pCurBuf += msgSize;
             pCurMsg = reinterpret_cast < const caHdr * > ( pCurBuf );
-            status -= sizeof ( *pCurMsg ) + epicsNTOH32 ( pCurMsg->m_postsize );
+            byteCount -= msgSize;
         }
     }
 }
diff --git a/src/ca/udpiiu.cpp b/src/ca/udpiiu.cpp
index 84a1c5cb9..03b9e6fa6 100644
--- a/src/ca/udpiiu.cpp
+++ b/src/ca/udpiiu.cpp
@@ -608,17 +608,20 @@ bool udpiiu::beaconAction ( const caHdr &msg,
     ina.sin_family = AF_INET;
     ina.sin_addr.s_addr = msg.m_available;
     if ( msg.m_count != 0 ) {
-        ina.sin_port = epicsHTON16 ( msg.m_count );
+        ina.sin_port = epicsNTOH16 ( msg.m_count );
     }
     else {
         /*
          * old servers dont supply this and the
          * default port must be assumed
          */
-        ina.sin_port = epicsHTON16 ( this->serverPort );
+        ina.sin_port = epicsNTOH16 ( this->serverPort );
     }
+    unsigned protocolRevision = epicsNTOH16 ( msg.m_dataType );
+    unsigned beaconNumber = epicsNTOH32 ( msg.m_cid );
 
-    this->pCAC ()->beaconNotify ( ina, currentTime );
+    this->pCAC ()->beaconNotify ( ina, currentTime, 
+        beaconNumber, protocolRevision );
 
     return true;
 }