diff --git a/indra/llmessage/aicurl.h b/indra/llmessage/aicurl.h
index a9a2a9d64..ac89fdac3 100644
--- a/indra/llmessage/aicurl.h
+++ b/indra/llmessage/aicurl.h
@@ -274,6 +274,9 @@ class AICurlEasyRequest {
 	// Queue a command to remove this request from the multi session (or cancel a queued command to add it).
 	void removeRequest(void);
 
+	// Returns true when this AICurlEasyRequest wraps a AICurlPrivate::ThreadSafeBufferedCurlEasyRequest.
+	bool isBuffered(void) const { return mCurlEasyRequest->isBuffered(); }
+
   private:
 	// The actual pointer to the ThreadSafeCurlEasyRequest instance.
 	AICurlPrivate::CurlEasyRequestPtr mCurlEasyRequest;
diff --git a/indra/llmessage/aicurlprivate.h b/indra/llmessage/aicurlprivate.h
index 892228bae..0bed1de7f 100644
--- a/indra/llmessage/aicurlprivate.h
+++ b/indra/llmessage/aicurlprivate.h
@@ -318,6 +318,10 @@ class CurlResponderBuffer : protected AICurlEasyHandleEvents {
   public:
 	// Return pointer to the ThreadSafe (wrapped) version of this object.
 	ThreadSafeBufferedCurlEasyRequest* get_lockobj(void);
+
+	// Return true when prepRequest was already called and the object has not been
+	// invalidated as a result of calling timed_out().
+	bool isValid(void) const { return mResponder; }
 };
 
 // This class wraps CurlEasyRequest for thread-safety and adds a reference counter so we can
@@ -333,6 +337,8 @@ class ThreadSafeCurlEasyRequest : public AIThreadSafeSimple<CurlEasyRequest> {
 	virtual ~ThreadSafeCurlEasyRequest()
 	    { Dout(dc::curl, "Destructing ThreadSafeCurlEasyRequest with this = " << (void*)this); }
 
+	/*virtual*/ bool isBuffered(void) const { return false; }
+
   private:
 	LLAtomicU32 mReferenceCount;
 
@@ -351,6 +357,8 @@ class ThreadSafeBufferedCurlEasyRequest : public ThreadSafeCurlEasyRequest, publ
   public:
 	// Throws AICurlNoEasyHandle.
 	ThreadSafeBufferedCurlEasyRequest(void) { new (AIThreadSafeSimple<CurlResponderBuffer>::ptr()) CurlResponderBuffer; }
+
+	/*virtual*/ bool isBuffered(void) const { return true; }
 };
 
 // The curl easy request type wrapped in a reference counting pointer.
diff --git a/indra/llmessage/lliopipe.cpp b/indra/llmessage/lliopipe.cpp
index 8f827f7a3..c8bef05c6 100644
--- a/indra/llmessage/lliopipe.cpp
+++ b/indra/llmessage/lliopipe.cpp
@@ -76,7 +76,14 @@ LLIOPipe::~LLIOPipe()
 }
 
 //virtual 
-bool LLIOPipe::isValid() 
+bool LLIOPipe::hasExpiration(void) const
+{
+	// LLIOPipe::hasNotExpired always returns true.
+	return false;
+}
+
+//virtual 
+bool LLIOPipe::hasNotExpired(void) const
 {
 	return true ;
 }
diff --git a/indra/llmessage/lliopipe.h b/indra/llmessage/lliopipe.h
index 2def3229f..86ae7e425 100644
--- a/indra/llmessage/lliopipe.h
+++ b/indra/llmessage/lliopipe.h
@@ -231,7 +231,16 @@ public:
 	 */
 	virtual ~LLIOPipe();
 
-	virtual bool isValid() ;
+	/**
+	 * @brief External expiration facility.
+	 *
+	 * If hasExpiration() returns true, then we need to check hasNotExpired()
+	 * to see if the LLIOPipe is still valid. In the legacy LL code the
+	 * latter was called isValid() and was overloaded for two purposes:
+	 * either expiration or failure to initialize.
+	 */
+	virtual bool hasExpiration(void) const;
+	virtual bool hasNotExpired(void) const;
 
 protected:
 	/**
diff --git a/indra/llmessage/llpumpio.cpp b/indra/llmessage/llpumpio.cpp
index b498e5e2b..c249d7132 100644
--- a/indra/llmessage/llpumpio.cpp
+++ b/indra/llmessage/llpumpio.cpp
@@ -198,19 +198,25 @@ LLPumpIO::~LLPumpIO()
 	}
 }
 
-bool LLPumpIO::addChain(const chain_t& chain, F32 timeout, bool has_curl_request)
+bool LLPumpIO::addChain(chain_t const& chain, F32 timeout)
 {
 	LLMemType m1(LLMemType::MTYPE_IO_PUMP);
-	if(chain.empty()) return false;
 
-#if LL_THREADS_APR
-	LLScopedLock lock(mChainsMutex);
-#endif
+	chain_t::const_iterator it = chain.begin();
+	chain_t::const_iterator const end = chain.end();
+	if (it == end) return false;
+
 	LLChainInfo info;
-	info.mHasCurlRequest = has_curl_request;
+	for(; it != end; ++it)
+	{
+		if ((*it)->hasExpiration())
+		{
+			info.mHasExpiration = true;
+			break;
+		}
+	}
 	info.setTimeoutSeconds(timeout);
 	info.mData = LLIOPipe::buffer_ptr_t(new LLBufferArray);
-	info.mData->setThreaded(has_curl_request);
 	LLLinkInfo link;
 #if LL_DEBUG_PIPE_TYPE_IN_PUMP
 	lldebugs << "LLPumpIO::addChain() " << chain[0] << " '"
@@ -218,14 +224,16 @@ bool LLPumpIO::addChain(const chain_t& chain, F32 timeout, bool has_curl_request
 #else
 	lldebugs << "LLPumpIO::addChain() " << chain[0] <<llendl;
 #endif
-	chain_t::const_iterator it = chain.begin();
-	chain_t::const_iterator end = chain.end();
+	it = chain.begin();
 	for(; it != end; ++it)
 	{
 		link.mPipe = (*it);
 		link.mChannels = info.mData->nextChannel();
 		info.mChainLinks.push_back(link);
 	}
+#if LL_THREADS_APR
+	LLScopedLock lock(mChainsMutex);
+#endif
 	mPendingChains.push_back(info);
 	return true;
 }
@@ -1086,14 +1094,14 @@ void LLPumpIO::processChain(LLChainInfo& chain)
 
 bool LLPumpIO::isChainExpired(LLChainInfo& chain)
 {
-	if(!chain.mHasCurlRequest)
+	if(!chain.mHasExpiration)
 	{
 		return false ;
 	}
 
 	for(links_t::iterator iter = chain.mChainLinks.begin(); iter != chain.mChainLinks.end(); ++iter)
 	{
-		if(!(*iter).mPipe->isValid())
+		if(!(*iter).mPipe->hasNotExpired())
 		{
 			return true ;
 		}
@@ -1168,7 +1176,7 @@ LLPumpIO::LLChainInfo::LLChainInfo() :
 	mInit(false),
 	mLock(0),
 	mEOS(false),
-	mHasCurlRequest(false),
+	mHasExpiration(false),
 	mDescriptorsPool(new LLAPRPool(LLThread::tldata().mRootPool))
 {
 	LLMemType m1(LLMemType::MTYPE_IO_PUMP);
diff --git a/indra/llmessage/llpumpio.h b/indra/llmessage/llpumpio.h
index 3771be9cf..0d1387257 100644
--- a/indra/llmessage/llpumpio.h
+++ b/indra/llmessage/llpumpio.h
@@ -100,10 +100,9 @@ public:
 	 * @param chain The pipes for the chain
 	 * @param timeout The number of seconds in the future to
 	 * expire. Pass in 0.0f to never expire.
-	 * @param has_curl_request The chain contains LLURLRequest if true.
 	 * @return Returns true if anything was added to the pump.
 	 */
-	bool addChain(const chain_t& chain, F32 timeout, bool has_curl_request = false);
+	bool addChain(const chain_t& chain, F32 timeout);
 	
 	/** 
 	 * @brief Struct to associate a pipe with it's buffer io indexes.
@@ -347,7 +346,7 @@ protected:
 		// basic member data
 		bool mInit;
 		bool mEOS;
-		bool mHasCurlRequest;
+		bool mHasExpiration;
 		S32 mLock;
 		LLFrameTimer mTimer;
 		links_t::iterator mHead;
diff --git a/indra/llmessage/llurlrequest.cpp b/indra/llmessage/llurlrequest.cpp
index 97a8e48d9..9d5b18074 100644
--- a/indra/llmessage/llurlrequest.cpp
+++ b/indra/llmessage/llurlrequest.cpp
@@ -260,11 +260,22 @@ void LLURLRequest::allowCookies()
 }
 
 //virtual 
-bool LLURLRequest::isValid() 
+bool LLURLRequest::hasExpiration(void) const
 {
-	//FIXME - wtf is with this isValid?
-	//return mDetail->mCurlRequest->isValid(); 
-	return true;
+	// Currently, this ALWAYS returns false -- because only AICurlEasyRequestStateMachine uses buffered
+	// AICurlEasyRequest objects, and LLURLRequest uses (unbuffered) AICurlEasyRequest directly, which
+	// have no expiration facility.
+	return mDetail->mCurlEasyRequest.isBuffered();
+}
+
+//virtual 
+bool LLURLRequest::hasNotExpired(void) const
+{
+	if (!mDetail->mCurlEasyRequest.isBuffered())
+	  return true;
+	AICurlEasyRequest_wat buffered_easy_request_w(*mDetail->mCurlEasyRequest);
+	AICurlResponderBuffer_wat buffer_w(*mDetail->mCurlEasyRequest);
+	return buffer_w->isValid();
 }
 
 // virtual
@@ -274,7 +285,7 @@ LLIOPipe::EStatus LLURLRequest::handleError(
 {
 	LLMemType m1(LLMemType::MTYPE_IO_URL_REQUEST);
 	
-	if(!isValid())
+	if(!hasNotExpired())
 	{
 		return STATUS_EXPIRED ;
 	}
diff --git a/indra/llmessage/llurlrequest.h b/indra/llmessage/llurlrequest.h
index 6cfe83a5e..d265a0dae 100644
--- a/indra/llmessage/llurlrequest.h
+++ b/indra/llmessage/llurlrequest.h
@@ -190,7 +190,8 @@ public:
 	 */
 	void allowCookies();
 
-	/*virtual*/ bool isValid() ;
+	/*virtual*/ bool hasExpiration(void) const;
+	/*virtual*/ bool hasNotExpired(void) const;
 
 public:
 	/**