diff --git a/src/core/job.c b/src/core/job.c
index d6ec27bc..7a0e0eef 100644
--- a/src/core/job.c
+++ b/src/core/job.c
@@ -26,10 +26,11 @@
  *
  */
 
-void done ( struct job_interface *job, int rc ) {
+void job_done ( struct job_interface *job, int rc ) {
 	struct job_interface *dest = job_dest ( job );
 
 	dest->op->done ( dest, rc );
+	job_unplug ( job );
 }
 
 /****************************************************************************
@@ -41,24 +42,29 @@ void done ( struct job_interface *job, int rc ) {
  *
  */
 
-void ignore_done ( struct job_interface *job __unused, int rc __unused ) {
+void ignore_job_start ( struct job_interface *job __unused ) {
 	/* Nothing to do */
 }
 
-void ignore_kill ( struct job_interface *job __unused ) {
+void ignore_job_done ( struct job_interface *job __unused, int rc __unused ) {
 	/* Nothing to do */
 }
 
-void ignore_progress ( struct job_interface *job __unused,
-		       struct job_progress *progress ) {
+void ignore_job_kill ( struct job_interface *job __unused ) {
+	/* Nothing to do */
+}
+
+void ignore_job_progress ( struct job_interface *job __unused,
+			   struct job_progress *progress ) {
 	memset ( progress, 0, sizeof ( *progress ) );
 }
 
 /** Null job control interface operations */
 struct job_interface_operations null_job_ops = {
-	.done		= ignore_done,
-	.kill		= ignore_kill,
-	.progress	= ignore_progress,
+	.start		= ignore_job_start,
+	.done		= ignore_job_done,
+	.kill		= ignore_job_kill,
+	.progress	= ignore_job_progress,
 };
 
 /**
diff --git a/src/core/xfer.c b/src/core/xfer.c
index f927269e..8a5d03d8 100644
--- a/src/core/xfer.c
+++ b/src/core/xfer.c
@@ -32,7 +32,7 @@
  * @v xfer		Data transfer interface
  * @v rc		Reason for close
  */
-void close ( struct xfer_interface *xfer, int rc ) {
+void xfer_close ( struct xfer_interface *xfer, int rc ) {
 	struct xfer_interface *dest = xfer_dest ( xfer );
 
 	dest->op->close ( dest, rc );
@@ -46,7 +46,7 @@ void close ( struct xfer_interface *xfer, int rc ) {
  * @v pos		New position
  * @ret rc		Return status code
  */
-int seek ( struct xfer_interface *xfer, size_t pos ) {
+int xfer_seek ( struct xfer_interface *xfer, size_t pos ) {
 	struct xfer_interface *dest = xfer_dest ( xfer );
 
 	return dest->op->seek ( dest, pos );
@@ -60,7 +60,7 @@ int seek ( struct xfer_interface *xfer, size_t pos ) {
  * @v args		Remaining arguments depend upon location type
  * @ret rc		Return status code
  */
-int vredirect ( struct xfer_interface *xfer, int type, va_list args ) {
+int xfer_vredirect ( struct xfer_interface *xfer, int type, va_list args ) {
 	struct xfer_interface *dest = xfer_dest ( xfer );
 
 	return dest->op->vredirect ( dest, type, args );
@@ -74,12 +74,12 @@ int vredirect ( struct xfer_interface *xfer, int type, va_list args ) {
  * @v ...		Remaining arguments depend upon location type
  * @ret rc		Return status code
  */
-int redirect ( struct xfer_interface *xfer, int type, ... ) {
+int xfer_redirect ( struct xfer_interface *xfer, int type, ... ) {
 	va_list args;
 	int rc;
 
 	va_start ( args, type );
-	rc = vredirect ( xfer, type, args );
+	rc = xfer_vredirect ( xfer, type, args );
 	va_end ( args );
 	return rc;
 }
@@ -91,7 +91,7 @@ int redirect ( struct xfer_interface *xfer, int type, ... ) {
  * @v iobuf		Datagram I/O buffer
  * @ret rc		Return status code
  */
-int deliver ( struct xfer_interface *xfer, struct io_buffer *iobuf ) {
+int xfer_deliver ( struct xfer_interface *xfer, struct io_buffer *iobuf ) {
 	struct xfer_interface *dest = xfer_dest ( xfer );
 
 	return dest->op->deliver ( dest, iobuf );
@@ -104,7 +104,8 @@ int deliver ( struct xfer_interface *xfer, struct io_buffer *iobuf ) {
  * @v iobuf		Datagram I/O buffer
  * @ret rc		Return status code
  */
-int deliver_raw ( struct xfer_interface *xfer, const void *data, size_t len ) {
+int xfer_deliver_raw ( struct xfer_interface *xfer,
+		       const void *data, size_t len ) {
 	struct xfer_interface *dest = xfer_dest ( xfer );
 
 	return dest->op->deliver_raw ( dest, data, len );
@@ -120,36 +121,47 @@ int deliver_raw ( struct xfer_interface *xfer, const void *data, size_t len ) {
  */
 
 /**
- * Ignore close()
+ * Ignore start() event
  *
  * @v xfer		Data transfer interface
- * @v rc		Reason for close
  */
-void ignore_close ( struct xfer_interface *xfer __unused, int rc __unused ) {
+void ignore_xfer_start ( struct xfer_interface *xfer __unused ) {
 	/* Nothing to do */
 }
 
 /**
- * Ignore vredirect()
+ * Ignore close() event
+ *
+ * @v xfer		Data transfer interface
+ * @v rc		Reason for close
+ */
+void ignore_xfer_close ( struct xfer_interface *xfer __unused,
+			 int rc __unused ) {
+	/* Nothing to do */
+}
+
+/**
+ * Ignore vredirect() event
  *
  * @v xfer		Data transfer interface
  * @v type		New location type
  * @v args		Remaining arguments depend upon location type
  * @ret rc		Return status code
  */
-int ignore_vredirect ( struct xfer_interface *xfer __unused,
-		       int type __unused, va_list args __unused ) {
+int ignore_xfer_vredirect ( struct xfer_interface *xfer __unused,
+			    int type __unused, va_list args __unused ) {
 	return 0;
 }
 
 /**
- * Ignore seek()
+ * Ignore seek() event
  *
  * @v xfer		Data transfer interface
  * @v pos		New position
  * @ret rc		Return status code
  */
-int ignore_seek ( struct xfer_interface *xfer __unused, size_t pos __unused ) {
+int ignore_xfer_seek ( struct xfer_interface *xfer __unused,
+		       size_t pos __unused ) {
 	return 0;
 }
 
@@ -163,8 +175,8 @@ int ignore_seek ( struct xfer_interface *xfer __unused, size_t pos __unused ) {
  * This function is intended to be used as the deliver() method for
  * data transfer interfaces that prefer to handle raw data.
  */
-int deliver_as_raw ( struct xfer_interface *xfer,
-		     struct io_buffer *iobuf ) {
+int xfer_deliver_as_raw ( struct xfer_interface *xfer,
+			  struct io_buffer *iobuf ) {
 	int rc;
 
 	rc = xfer->op->deliver_raw ( xfer, iobuf->data, iob_len ( iobuf ) );
@@ -183,8 +195,8 @@ int deliver_as_raw ( struct xfer_interface *xfer,
  * This function is intended to be used as the deliver_raw() method
  * for data transfer interfaces that prefer to handle I/O buffers.
  */
-int deliver_as_iobuf ( struct xfer_interface *xfer,
-		       const void *data, size_t len ) {
+int xfer_deliver_as_iobuf ( struct xfer_interface *xfer,
+			    const void *data, size_t len ) {
 	struct io_buffer *iobuf;
 
 	iobuf = alloc_iob ( len );
@@ -196,15 +208,15 @@ int deliver_as_iobuf ( struct xfer_interface *xfer,
 }
 
 /**
- * Ignore datagram as raw data
+ * Ignore datagram as raw data event
  *
  * @v xfer		Data transfer interface
  * @v data		Data buffer
  * @v len		Length of data buffer
  * @ret rc		Return status code
  */
-int ignore_deliver_raw ( struct xfer_interface *xfer,
-			 const void *data __unused, size_t len ) {
+int ignore_xfer_deliver_raw ( struct xfer_interface *xfer,
+			      const void *data __unused, size_t len ) {
 	DBGC ( xfer, "XFER %p %zd bytes delivered %s\n", xfer, len,
 	       ( ( xfer == &null_xfer ) ?
 		 "before connection" : "after termination" ) );
@@ -213,11 +225,12 @@ int ignore_deliver_raw ( struct xfer_interface *xfer,
 
 /** Null data transfer interface operations */
 struct xfer_interface_operations null_xfer_ops = {
-	.close		= ignore_close,
-	.vredirect	= ignore_vredirect,
-	.seek		= ignore_seek,
-	.deliver	= deliver_as_raw,
-	.deliver_raw	= ignore_deliver_raw,
+	.start		= ignore_xfer_start,
+	.close		= ignore_xfer_close,
+	.vredirect	= ignore_xfer_vredirect,
+	.seek		= ignore_xfer_seek,
+	.deliver	= xfer_deliver_as_raw,
+	.deliver_raw	= ignore_xfer_deliver_raw,
 };
 
 /**
diff --git a/src/include/gpxe/job.h b/src/include/gpxe/job.h
index ded6c846..23077e7a 100644
--- a/src/include/gpxe/job.h
+++ b/src/include/gpxe/job.h
@@ -33,6 +33,11 @@ struct job_interface;
 
 /** Job control interface operations */
 struct job_interface_operations {
+	/** Start job
+	 *
+	 * @v job		Job control interface
+	 */
+	void ( * start ) ( struct job_interface *job );
 	/** Job completed
 	 *
 	 * @v job		Job control interface
@@ -64,12 +69,13 @@ struct job_interface {
 extern struct job_interface null_job;
 extern struct job_interface_operations null_job_ops;
 
-extern void done ( struct job_interface *job, int rc );
+extern void job_done ( struct job_interface *job, int rc );
 
-extern void ignore_done ( struct job_interface *job, int rc );
-extern void ignore_kill ( struct job_interface *job );
-extern void ignore_progress ( struct job_interface *job,
-			      struct job_progress *progress );
+extern void ignore_job_start ( struct job_interface *job );
+extern void ignore_job_done ( struct job_interface *job, int rc );
+extern void ignore_job_kill ( struct job_interface *job );
+extern void ignore_job_progress ( struct job_interface *job,
+				  struct job_progress *progress );
 
 /**
  * Initialise a job control interface
@@ -108,6 +114,37 @@ job_dest ( struct job_interface *job ) {
 	return intf_to_job ( job->intf.dest );
 }
 
+/**
+ * Plug a job control interface into a new destination interface
+ *
+ * @v job		Job control interface
+ * @v dest		New destination interface
+ */
+static inline void job_plug ( struct job_interface *job,
+			       struct job_interface *dest ) {
+	plug ( &job->intf, &dest->intf );
+}
+
+/**
+ * Plug two job control interfaces together
+ *
+ * @v a			Job control interface A
+ * @v b			Job control interface B
+ */
+static inline void job_plug_plug ( struct job_interface *a,
+				    struct job_interface *b ) {
+	plug_plug ( &a->intf, &b->intf );
+}
+
+/**
+ * Unplug a job control interface
+ *
+ * @v job		Job control interface
+ */
+static inline void job_unplug ( struct job_interface *job ) {
+	plug ( &job->intf, &null_job.intf );
+}
+
 /**
  * Stop using a job control interface
  *
diff --git a/src/include/gpxe/xfer.h b/src/include/gpxe/xfer.h
index 2423c03c..3c46cdf2 100644
--- a/src/include/gpxe/xfer.h
+++ b/src/include/gpxe/xfer.h
@@ -21,15 +21,17 @@ struct xfer_interface_operations {
 	 *
 	 * notification of non-close status - e.g. connected/opened, ...
 	 *
-	 * seek
-	 *
 	 * prompt for data delivery
 	 *
 	 * I/O buffer preparation
 	 *
 	 */
 
-
+	/** Start data transfer
+	 *
+	 * @v xfer		Data transfer interface
+	 */
+	void ( * start ) ( struct xfer_interface *xfer );
 	/** Close interface
 	 *
 	 * @v xfer		Data transfer interface
@@ -60,7 +62,7 @@ struct xfer_interface_operations {
 	 *
 	 * A data transfer interface that wishes to support only raw
 	 * data delivery should set this method to
-	 * deliver_as_raw().
+	 * xfer_deliver_as_raw().
 	 */
 	int ( * deliver ) ( struct xfer_interface *xfer,
 			    struct io_buffer *iobuf );
@@ -73,7 +75,7 @@ struct xfer_interface_operations {
 	 *
 	 * A data transfer interface that wishes to support only I/O
 	 * buffer delivery should set this method to
-	 * deliver_as_iobuf().
+	 * xfer_deliver_as_iobuf().
 	 */
 	int ( * deliver_raw ) ( struct xfer_interface *xfer,
 				const void *data, size_t len );
@@ -90,24 +92,30 @@ struct xfer_interface {
 extern struct xfer_interface null_xfer;
 extern struct xfer_interface_operations null_xfer_ops;
 
-extern void close ( struct xfer_interface *xfer, int rc );
-extern int seek ( struct xfer_interface *xfer, size_t pos );
-extern int vredirect ( struct xfer_interface *xfer, int type, va_list args );
-extern int redirect ( struct xfer_interface *xfer, int type, ... );
-extern int deliver ( struct xfer_interface *xfer, struct io_buffer *iobuf );
-extern int deliver_raw ( struct xfer_interface *xfer,
-			 const void *data, size_t len );
-
-extern void ignore_close ( struct xfer_interface *xfer, int rc );
-extern int ignore_vredirect ( struct xfer_interface *xfer,
-			      int type, va_list args );
-extern int ignore_seek ( struct xfer_interface *xfer, size_t pos );
-extern int deliver_as_raw ( struct xfer_interface *xfer,
-			    struct io_buffer *iobuf );
-extern int deliver_as_iobuf ( struct xfer_interface *xfer,
+extern void xfer_start ( struct xfer_interface *xfer );
+extern void xfer_close ( struct xfer_interface *xfer, int rc );
+extern int xfer_seek ( struct xfer_interface *xfer, size_t pos );
+extern int xfer_vredirect ( struct xfer_interface *xfer, int type,
+			    va_list args );
+extern int xfer_redirect ( struct xfer_interface *xfer, int type, ... );
+extern int xfer_deliver ( struct xfer_interface *xfer,
+			  struct io_buffer *iobuf );
+extern int xfer_deliver_raw ( struct xfer_interface *xfer,
 			      const void *data, size_t len );
-extern int ignore_deliver_raw ( struct xfer_interface *xfer,
-				const void *data __unused, size_t len );
+
+extern void ignore_xfer_start ( struct xfer_interface *xfer );
+extern void ignore_xfer_close ( struct xfer_interface *xfer, int rc );
+extern int ignore_xfer_vredirect ( struct xfer_interface *xfer,
+				   int type, va_list args );
+extern int default_xfer_vredirect ( struct xfer_interface *xfer,
+				    int type, va_list args );
+extern int ignore_xfer_seek ( struct xfer_interface *xfer, size_t pos );
+extern int xfer_deliver_as_raw ( struct xfer_interface *xfer,
+				 struct io_buffer *iobuf );
+extern int xfer_deliver_as_iobuf ( struct xfer_interface *xfer,
+				   const void *data, size_t len );
+extern int ignore_xfer_deliver_raw ( struct xfer_interface *xfer,
+				     const void *data __unused, size_t len );
 
 /**
  * Initialise a data transfer interface
@@ -157,6 +165,17 @@ static inline void xfer_plug ( struct xfer_interface *xfer,
 	plug ( &xfer->intf, &dest->intf );
 }
 
+/**
+ * Plug two data transfer interfaces together
+ *
+ * @v a			Data transfer interface A
+ * @v b			Data transfer interface B
+ */
+static inline void xfer_plug_plug ( struct xfer_interface *a,
+				    struct xfer_interface *b ) {
+	plug_plug ( &a->intf, &b->intf );
+}
+
 /**
  * Unplug a data transfer interface
  *