Index: channels/chan_iax2.c
===================================================================
--- channels/chan_iax2.c	(revision 43263)
+++ channels/chan_iax2.c	(working copy)
@@ -157,6 +157,7 @@
 #ifdef NEWJB
 static int resyncthreshold=1000;
 static int maxjitterinterps=10;
+static int jittertargetextra = 40; /* number of milliseconds the new jitter buffer adds on to its size */
 #endif
 static int jittershrinkrate=2;
 static int trunkfreq = 20;
@@ -932,6 +933,7 @@
 			jbconf.max_jitterbuf = maxjitterbuffer;
 			jbconf.resync_threshold = resyncthreshold;
 			jbconf.max_contig_interp = maxjitterinterps;
+			jbconf.target_extra = jittertargetextra;
 			jb_setconf(tmp->jb,&jbconf);
 		}
 #endif
@@ -8772,6 +8774,8 @@
 			resyncthreshold = atoi(v->value);
 		else if (!strcasecmp(v->name, "maxjitterinterps")) 
 			maxjitterinterps = atoi(v->value);
+		else if (!strcasecmp(v->name, "jittertargetextra")) 
+			jittertargetextra = atoi(v->value);
 #endif
 		else if (!strcasecmp(v->name, "jittershrinkrate")) 
 			jittershrinkrate = atoi(v->value);
Index: jitterbuf.c
===================================================================
--- jitterbuf.c	(revision 43263)
+++ jitterbuf.c	(working copy)
@@ -77,7 +77,7 @@
 	memset(jb,0,sizeof(jitterbuf));
 	jb->info.conf = s;
 
-	/* initialize length */
+	/* initialize length, using the default value */
 	jb->info.current = jb->info.target = JB_TARGET_EXTRA; 
 	jb->info.silence_begin_ts = -1; 
 }
@@ -552,7 +552,7 @@
 	dbg_cnt++;
 
 	/* target */
-	jb->info.target = jb->info.jitter + jb->info.min + JB_TARGET_EXTRA; 
+	jb->info.target = jb->info.jitter + jb->info.min + jb->info.conf.target_extra; 
 
 	/* if a hard clamp was requested, use it */
 	if ((jb->info.conf.max_jitterbuf) && ((jb->info.target - jb->info.min) > jb->info.conf.max_jitterbuf)) {
@@ -638,7 +638,7 @@
 		/* unless we don't have a frame, then shrink 1 frame */
 		/* every 80ms (though perhaps we can shrink even faster */
 		/* in this case) */
-		if (diff < -JB_TARGET_EXTRA && 
+		if (diff < -jb->info.conf.target_extra && 
 			((!frame && jb->info.last_adjustment + 80 < now) || 
 			(jb->info.last_adjustment + 500 < now))) {
 
@@ -716,7 +716,7 @@
 		/* jb->info.silence_begin_ts = 0; */
 
  		/* shrink interpl len every 10ms during silence */
- 		if (diff < -JB_TARGET_EXTRA &&
+ 		if (diff < -jb->info.conf.target_extra &&
  			jb->info.last_adjustment + 10 <= now) {
  			jb->info.current -= interpl;
  			jb->info.last_adjustment = now;
@@ -765,7 +765,7 @@
 		if (next > 0) { 
 			history_get(jb);
 			/* shrink during silence */
-			if (jb->info.target - jb->info.current < -JB_TARGET_EXTRA)
+			if (jb->info.target - jb->info.current < -jb->info.conf.target_extra)
 				return jb->info.last_adjustment + 10;
 			return next + jb->info.target;
 		}
@@ -824,6 +824,16 @@
  	jb->info.conf.resync_threshold = conf->resync_threshold;
 	jb->info.conf.max_contig_interp = conf->max_contig_interp;
 
+	/* -1 indicates use of the default JB_TARGET_EXTRA value */
+	jb->info.conf.target_extra = ( conf->target_extra == -1 )
+		? JB_TARGET_EXTRA
+		: conf->target_extra
+		;
+		
+	/* update these to match new target_extra setting */
+	jb->info.current = jb->info.conf.target_extra;
+	jb->info.target = jb->info.conf.target_extra;
+
 	return JB_OK;
 }
 
Index: jitterbuf.h
===================================================================
--- jitterbuf.h	(revision 43263)
+++ jitterbuf.h	(working copy)
@@ -56,6 +56,7 @@
 	long max_jitterbuf;	/* defines a hard clamp to use in setting the jitter buffer delay */
  	long resync_threshold;  /* the jb will resync when delay increases to (2 * jitter) + this param */
 	long max_contig_interp; /* the max interp frames to return in a row */
+	long target_extra ;      /* amount of additional jitterbuffer adjustment, overrides JB_TARGET_EXTRA */
 } jb_conf;
 
 typedef struct jb_info {
Index: configs/iax.conf.sample
===================================================================
--- configs/iax.conf.sample	(revision 43263)
+++ configs/iax.conf.sample	(working copy)
@@ -136,6 +136,13 @@
 ; changing.  An example: if you set this to 2, then the jitter buffer
 ; size will change by 100 millisecs per second.
 ; [This option is not applicable to, and ignored by the new jitterbuffer implementation]
+;
+; jittertargetextra: number of milliseconds by which the new jitter buffer
+; will pad its size. the default is 40, so without modification, the new
+; jitter buffer will set its size to the jitter value plus 40 milliseconds.
+; increasing this value may help if your network normally has low jitter, 
+; but occasionally has spikes.
+;
 
 jitterbuffer=no
 forcejitterbuffer=no
@@ -146,6 +153,7 @@
 ;maxexcessbuffer=80
 ;minexcessbuffer=10
 ;jittershrinkrate=1
+;jittertargetextra=40
 
 ;trunkfreq=20			; How frequently to send trunk msgs (in ms)