diff --git a/Control/CallControl.cpp b/Control/CallControl.cpp
index bf5e235..891562b 100644
--- a/Control/CallControl.cpp
+++ b/Control/CallControl.cpp
@@ -136,8 +136,10 @@ void forceSIPClearing(TransactionEntry *transaction)
 		transaction->MODWaitForCANCELOK();
 	}
 	else { //we received, respond and then don't send ok
-		//changed state immediately to canceled
-		transaction->MODSendUnavail();
+		//changed state immediately to canceling
+		transaction->MODSendUNAVAIL();
+		//then canceled
+		transaction->MODWaitForUNAVAILACK();
 	}
 }
 
@@ -335,8 +337,8 @@ bool callManagementDispatchGSM(TransactionEntry *transaction, GSM::LogicalChanne
 				transaction->MODWaitFor487();
 			}
 			else { //if we received it, send a 4** instead
-				transaction->MODSendUnavail();
-				//enventually wait for ACK here -kurtis
+				transaction->MODSendUNAVAIL();
+				transaction->MODWaitForUNAVAILACK();
 			}
 			transaction->GSMState(GSM::NullState);
 			return true;
diff --git a/Control/TransactionTable.cpp b/Control/TransactionTable.cpp
index f7dc840..4cff71a 100644
--- a/Control/TransactionTable.cpp
+++ b/Control/TransactionTable.cpp
@@ -420,10 +420,10 @@ SIP::SIPState TransactionEntry::MODSendBYE()
 	return state;
 }
 
-SIP::SIPState TransactionEntry::MODSendUnavail()
+SIP::SIPState TransactionEntry::MODSendUNAVAIL()
 {
 	ScopedLock lock(mLock);
-	SIP::SIPState state = mSIP.MODSendUnavail();
+	SIP::SIPState state = mSIP.MODSendUNAVAIL();
 	echoSIPState(state);
 	return state;
 }
@@ -452,6 +452,14 @@ SIP::SIPState TransactionEntry::MODResendCANCEL()
 	return state;
 }
 
+SIP::SIPState TransactionEntry::MODResendUNAVAIL()
+{
+	ScopedLock lock(mLock);
+	SIP::SIPState state = mSIP.MODResendUNAVAIL();
+	echoSIPState(state);
+	return state;
+}
+
 SIP::SIPState TransactionEntry::MODWaitForBYEOK()
 {
 	ScopedLock lock(mLock);
@@ -468,6 +476,14 @@ SIP::SIPState TransactionEntry::MODWaitForCANCELOK()
 	return state;
 }
 
+SIP::SIPState TransactionEntry::MODWaitForUNAVAILACK()
+{
+	ScopedLock lock(mLock);
+	SIP::SIPState state = mSIP.MODWaitForUNAVAILACK();
+	echoSIPState(state);
+	return state;
+}
+
 SIP::SIPState TransactionEntry::MODWaitFor487()
 {
 	ScopedLock lock(mLock);
diff --git a/Control/TransactionTable.h b/Control/TransactionTable.h
index b666dd8..7cfceed 100644
--- a/Control/TransactionTable.h
+++ b/Control/TransactionTable.h
@@ -202,12 +202,14 @@ class TransactionEntry {
 	void MTCInitRTP() { ScopedLock lock(mLock); mSIP.MTCInitRTP(); }
 
 	SIP::SIPState MODSendBYE();
-	SIP::SIPState MODSendUnavail();
+	SIP::SIPState MODSendUNAVAIL();
 	SIP::SIPState MODSendCANCEL();
 	SIP::SIPState MODResendBYE();
 	SIP::SIPState MODResendCANCEL();
+	SIP::SIPState MODResendUNAVAIL();
 	SIP::SIPState MODWaitForBYEOK();
 	SIP::SIPState MODWaitForCANCELOK();
+	SIP::SIPState MODWaitForUNAVAILACK();
 	SIP::SIPState MODWaitFor487();
 
 	SIP::SIPState MTDCheckBYE();
diff --git a/SIP/SIPEngine.cpp b/SIP/SIPEngine.cpp
index 4e606a5..fae102d 100644
--- a/SIP/SIPEngine.cpp
+++ b/SIP/SIPEngine.cpp
@@ -96,8 +96,8 @@ SIPEngine::SIPEngine(const char* proxy, const char* IMSI)
 	mSIPPort(gConfig.getNum("SIP.Local.Port")),
 	mSIPIP(gConfig.getStr("SIP.Local.IP")),
 	mINVITE(NULL), mLastResponse(NULL), mBYE(NULL),
-	mCANCEL(NULL), mSession(NULL), mTxTime(0), mRxTime(0),
-	mState(NullState),
+	mCANCEL(NULL), mUNAVAIL(NULL), mSession(NULL), 
+	mTxTime(0), mRxTime(0), mState(NullState),
 	mDTMF('\0'),mDTMFDuration(0)
 {
 	assert(proxy);
@@ -133,6 +133,7 @@ SIPEngine::~SIPEngine()
 	if (mLastResponse!=NULL) osip_message_free(mLastResponse);
 	if (mBYE!=NULL) osip_message_free(mBYE);
 	if (mCANCEL!=NULL) osip_message_free(mCANCEL);
+	if (mUNAVAIL!=NULL) osip_message_free(mUNAVAIL);
 	// FIXME -- Do we need to dispose of the RtpSesion *mSesison?
 }
 
@@ -200,6 +201,15 @@ void SIPEngine::saveCANCEL(const osip_message_t *CANCEL, bool mine)
 	osip_message_clone(CANCEL,&mCANCEL);
 }
 
+void SIPEngine::saveUNAVAIL(const osip_message_t *UNAVAIL, bool mine)
+{
+	// Instead of cloning, why not just keep the old one?
+	// Because that doesn't work in all calling contexts.
+	// This simplifies the call-handling logic.
+	if (mUNAVAIL!=NULL) osip_message_free(mUNAVAIL);
+	osip_message_clone(UNAVAIL,&mUNAVAIL);
+}
+
 /* we're going to figure if the from field is us or not */
 bool SIPEngine::instigator()
 {
@@ -492,11 +502,13 @@ SIPState  SIPEngine::MOCWaitForOK()
 	LOG(DEBUG) << "received status " << status;
 	saveResponse(msg);
 	switch (status) {
-		case 100:	// Trying
-		case 183:	// Progress
+		case 100:	// Trying - this maybe should go to ringing too -kurtis
 			mState = Proceeding;
 			break;
 		case 180:	// Ringing
+		case 183:	// Progress - 
+			//We keep sending invited until we 
+			//enter Ringing, so 183 need to do that -kurtis
 			mState = Ringing;
 			break;
 		case 200:	// OK
@@ -523,16 +535,10 @@ SIPState  SIPEngine::MOCWaitForOK()
 }
 
 
-//this isn't working right now -kurtis
 SIPState SIPEngine::MOCSendACK()
 {
 	assert(mLastResponse);
 
-	// new branch
-	char tmp[50];
-	make_branch(tmp);
-	mViaBranch = tmp;
-
 	LOG(INFO) << "user " << mSIPUsername << " state " << mState;
 
 	osip_message_t* ack = sip_ack( mRemoteDomain.c_str(),
@@ -572,7 +578,7 @@ SIPState SIPEngine::MODSendBYE()
 	return mState;
 }
 
-SIPState SIPEngine::MODSendUnavail()
+SIPState SIPEngine::MODSendUNAVAIL()
 {
 	LOG(INFO) << "user " << mSIPUsername << " state " << mState;
 	assert(mINVITE);
@@ -580,8 +586,9 @@ SIPState SIPEngine::MODSendUnavail()
 	osip_message_t * unavail = sip_temporarily_unavailable(mINVITE, mSIPIP.c_str(),
 							       mSIPUsername.c_str(), mSIPPort);
 	gSIPInterface.write(&mProxyAddr,unavail);
+	saveUNAVAIL(unavail, true);
 	osip_message_free(unavail);
-	mState = Canceled;
+	mState = MODCanceling;
 	return mState;
 }
 
@@ -618,6 +625,15 @@ SIPState SIPEngine::MODResendCANCEL()
 	return mState;
 }
 
+SIPState SIPEngine::MODResendUNAVAIL()
+{
+	LOG(INFO) << "user " << mSIPUsername << " state " << mState;
+	assert(mState==MODCanceling);
+	assert(mUNAVAIL);
+	gSIPInterface.write(&mProxyAddr,mUNAVAIL);
+	return mState;
+}
+
 /* there shouldn't be any more communications on this fifo, but we might
    get a 487 RequestTerminated. We only need to respond and move on -kurtis */
 SIPState SIPEngine::MODWaitFor487()
@@ -710,6 +726,35 @@ SIPState SIPEngine::MODWaitForCANCELOK()
 	return mState;
 }
 
+SIPState SIPEngine::MODWaitForUNAVAILACK()
+{
+	LOG(INFO) << "user " << mSIPUsername << " state " << mState;
+	bool responded = false;
+	Timeval timeout(gConfig.getNum("SIP.Timer.F")); 
+	while (!timeout.passed()) {
+		try {
+			osip_message_t * ack = gSIPInterface.read(mCallID, gConfig.getNum("SIP.Timer.E"));
+			responded = true;
+			saveResponse(ack);
+			if (!strncmp(ack->sip_method,"ACK", 4)) {
+				LOG(WARNING) << "unexpected " << ack->sip_method << " response to UNAVAIL, from proxy " << mProxyIP << ":" << mProxyPort << ". Assuming other end has cleared";
+			}
+			osip_message_free(ack);
+			break;
+		}
+		catch (SIPTimeout& e) {
+			LOG(NOTICE) << "response timeout, resending UNAVAIL";
+			MODResendUNAVAIL();
+		}
+	}
+
+	if (!responded) { LOG(ALERT) << "lost contact with proxy " << mProxyIP << ":" << mProxyPort; }
+
+	mState = Canceled;
+
+	return mState;
+}
+
 SIPState SIPEngine::MTDCheckBYE()
 {
 	//LOG(DEBUG) << "user " << mSIPUsername << " state " << mState;
diff --git a/SIP/SIPEngine.h b/SIP/SIPEngine.h
index bca3161..1933294 100644
--- a/SIP/SIPEngine.h
+++ b/SIP/SIPEngine.h
@@ -110,8 +110,10 @@ private:
 	//@{
 	osip_message_t * mINVITE;	///< the INVITE message for this transaction
 	osip_message_t * mLastResponse;	///< the last response received for this transaction
+	//we should maybe push these together sometime? -kurtis
 	osip_message_t * mBYE;		///< the BYE message for this transaction
 	osip_message_t * mCANCEL;	///< the CANCEL message for this transaction
+	osip_message_t * mUNAVAIL;	///< the UNAVAIL message for this transaction
 	//@}
 
 	/**@name RTP state and parameters. */
@@ -277,7 +279,7 @@ public:
 	//@{
 	SIPState MODSendBYE();
 
-	SIPState MODSendUnavail();
+	SIPState MODSendUNAVAIL();
 
 	SIPState MODSendCANCEL();
 
@@ -285,10 +287,14 @@ public:
 
 	SIPState MODResendCANCEL();
 
+	SIPState MODResendUNAVAIL();
+
 	SIPState MODWaitForBYEOK();
 
 	SIPState MODWaitForCANCELOK();
 
+	SIPState MODWaitForUNAVAILACK();
+
 	SIPState MODWaitFor487();
 	//@}
 
@@ -349,6 +355,9 @@ public:
 	/** Save a copy of a CANCEL message in the engine. */
 	void saveCANCEL(const osip_message_t *CANCEL, bool mine);
 
+	/** Save a copy of a UNAVAIL message in the engine. */
+	void saveUNAVAIL(const osip_message_t *UNAVAIL, bool mine);
+
 
 
 	private: