diff --git a/src/ca/nciu.cpp b/src/ca/nciu.cpp
index bc7bc1b3c..a582cdd37 100644
--- a/src/ca/nciu.cpp
+++ b/src/ca/nciu.cpp
@@ -35,8 +35,8 @@
 tsFreeList < class nciu, 1024 > nciu::freeList;
 epicsMutex nciu::freeListMutex;
 
-nciu::nciu ( cac &cacIn, netiiu &iiuIn, cacChannelNotify &chanIn, 
-            const char *pNameIn ) :
+nciu::nciu ( cac & cacIn, netiiu & iiuIn, cacChannelNotify & chanIn, 
+            const char *pNameIn, cacChannel::priLev pri ) :
     cacChannel ( chanIn ), 
     cacCtx ( cacIn ),
     piiu ( &iiuIn ),
@@ -46,6 +46,7 @@ nciu::nciu ( cac &cacIn, netiiu &iiuIn, cacChannelNotify &chanIn,
     retrySeqNo ( 0u ),
     nameLength ( strlen ( pNameIn ) + 1 ),
     typeCode ( USHRT_MAX ),
+    priority ( pri ),
     f_connected ( false ),
     f_previousConn ( false ),
     f_claimSent ( false ),
@@ -54,7 +55,7 @@ nciu::nciu ( cac &cacIn, netiiu &iiuIn, cacChannelNotify &chanIn,
 {
     // second constraint is imposed by size field in protocol header
     if ( this->nameLength > MAX_UDP_SEND - sizeof ( caHdr ) || this->nameLength > 0xffff ) {
-        throwWithLocation ( caErrorCode ( ECA_BADSTR ) );
+        throw cacChannel::badString ();
     }
 
     this->pNameStr = new char [ this->nameLength ];
@@ -368,8 +369,7 @@ unsigned nciu::searchAttempts () const
 
 double nciu::beaconPeriod () const
 {
-    epicsAutoMutex locker ( this->cacCtx.mutexRef() );
-    return this->piiu->beaconPeriod ();
+    return this->cacCtx.beaconPeriod ( *this );
 }
 
 void nciu::notifyStateChangeFirstConnectInCountOfOutstandingIO ()
@@ -441,8 +441,3 @@ int nciu::printf ( const char *pFormat, ... )
     return status;
 }
 
-
-
-
-
-
diff --git a/src/ca/nciu.h b/src/ca/nciu.h
index 2ef98a056..faa6de12d 100644
--- a/src/ca/nciu.h
+++ b/src/ca/nciu.h
@@ -42,8 +42,8 @@ private:
 class nciu : public cacChannel, public tsDLNode < nciu >,
     public chronIntIdRes < nciu >, public cacPrivateListOfIO {
 public:
-    nciu ( cac &, netiiu &, 
-        cacChannelNotify &, const char *pNameIn );
+    nciu ( cac &, netiiu &, cacChannelNotify &, 
+        const char *pNameIn, cacChannel::priLev );
     void connect ( unsigned nativeType, 
         unsigned nativeCount, unsigned sid, bool v41Ok );
     void connect ();
@@ -62,6 +62,7 @@ public:
     ca_uint32_t getSID () const;
     ca_uint32_t getCID () const;
     netiiu * getPIIU ();
+    const netiiu * getConstPIIU () const;
     cac & getClient ();
     int printf ( const char *pFormat, ... );
     void searchReplySetUp ( netiiu &iiu, unsigned sidIn, 
@@ -75,6 +76,7 @@ public:
     bool connected () const;
     bool previouslyConnected () const;
     void writeException ( int status, const char *pContext, unsigned type, arrayElementCount count );
+    cacChannel::priLev getPriority () const;
 protected:
     ~nciu (); // force pool allocation
 private:
@@ -88,6 +90,7 @@ private:
     ca_uint16_t retrySeqNo; // search retry seq number
     ca_uint16_t nameLength; // channel name length
     ca_uint16_t typeCode;
+    ca_uint8_t priority; 
     unsigned f_connected:1;
     unsigned f_previousConn:1; // T if connected in the past
     unsigned f_claimSent:1;
@@ -188,6 +191,11 @@ inline netiiu * nciu::getPIIU ()
     return this->piiu;
 }
 
+inline const netiiu * nciu::getConstPIIU () const
+{
+    return this->piiu;
+}
+
 inline cac & nciu::getClient ()
 {
     return this->cacCtx;
@@ -219,4 +227,9 @@ inline void nciu::accessRightsNotify () const
     this->notify().accessRightsNotify ( this->accessRightState );
 }
 
+inline cacChannel::priLev nciu::getPriority () const
+{
+    return this->priority;
+}
+
 #endif // ifdef nciuh
diff --git a/src/ca/oldAccess.h b/src/ca/oldAccess.h
index b0b48075f..f57e7172f 100644
--- a/src/ca/oldAccess.h
+++ b/src/ca/oldAccess.h
@@ -29,9 +29,9 @@
 
 struct oldChannelNotify : public cacChannelNotify {
 public:
-    oldChannelNotify ( class oldCAC &, const char *pName, caCh *pConnCallBackIn, void *pPrivateIn );
+    oldChannelNotify ( class oldCAC &, const char *pName, 
+        caCh *pConnCallBackIn, void *pPrivateIn, capri priority );
     void destroy ();
-    bool ioAttachOK ();
     void setPrivatePointer ( void * );
     void * privatePointer () const;
     int changeConnCallBack ( caCh *pfunc );
@@ -73,11 +73,11 @@ public:
 protected:
     ~oldChannelNotify (); // must allocate from pool
 private:
-    cacChannel &io;
-    oldCAC &cacCtx;
-    caCh *pConnCallBack;
-    void *pPrivate;
-    caArh *pAccessRightsFunc;
+    cacChannel & io;
+    oldCAC & cacCtx;
+    caCh * pConnCallBack;
+    void * pPrivate;
+    caArh * pAccessRightsFunc;
     void connectNotify ();
     void disconnectNotify ();
     void accessRightsNotify ( const caAccessRights & );
@@ -127,9 +127,9 @@ public:
 protected:
     ~getCallback (); // allocate only out of pool
 private:
-    oldChannelNotify &chan;
-    caEventCallBackFunc *pFunc;
-    void *pPrivate;
+    oldChannelNotify & chan;
+    caEventCallBackFunc * pFunc;
+    void * pPrivate;
     void completion (
         unsigned type, arrayElementCount count, const void *pData);
     void exception ( int status, 
@@ -164,18 +164,17 @@ public:
         oldChannelNotify &,
         unsigned type, arrayElementCount nElem, unsigned mask, 
         caEventCallBackFunc *pFunc, void *pPrivate );
-    bool ioAttachOK ();
     void destroy ();
     void * operator new ( size_t size );
     void operator delete ( void *pCadaver, size_t size );
-    oldChannelNotify &channel () const;
+    oldChannelNotify & channel () const;
 protected:
     ~oldSubscription (); // must allocate from pool
 private:
-    oldChannelNotify &chan;
+    oldChannelNotify & chan;
     cacChannel::ioid id;
-    caEventCallBackFunc *pFunc;
-    void *pPrivate;
+    caEventCallBackFunc * pFunc;
+    void * pPrivate;
     bool subscribed;
     void current (
         unsigned type, arrayElementCount count, const void *pData );
@@ -194,7 +193,8 @@ public:
     void registerForFileDescriptorCallBack ( CAFDHANDLER *pFunc, void *pArg );
     void replaceErrLogHandler ( caPrintfFunc *ca_printf_func );
     void registerService ( cacService &service );
-    cacChannel & createChannel ( const char *name_str, oldChannelNotify &chan );
+    cacChannel & createChannel ( const char * name_str, 
+        oldChannelNotify & chan, cacChannel::priLev pri );
     void flushRequest ();
     int pendIO ( const double &timeout );
     int pendEvent ( const double &timeout );
@@ -235,11 +235,6 @@ private:
 
 int fetchClientContext ( oldCAC **ppcac );
 
-inline bool oldChannelNotify::ioAttachOK ()
-{
-    return &this->io ? true : false;
-}
-
 inline void oldChannelNotify::destroy ()
 {
     delete this;
@@ -432,9 +427,10 @@ inline void oldCAC::registerService ( cacService &service )
     this->clientCtx.registerService ( service );
 }
 
-inline cacChannel & oldCAC::createChannel ( const char *name_str, oldChannelNotify &chan )
+inline cacChannel & oldCAC::createChannel ( const char * name_str, 
+             oldChannelNotify & chan, cacChannel::priLev pri )
 {
-    return this->clientCtx.createChannel ( name_str, chan );
+    return this->clientCtx.createChannel ( name_str, chan, pri );
 }
 
 inline int oldCAC::pendIO ( const double &timeout )