diff -ubdr linux-2.6.16.16-l2tp/drivers/net/ppp_generic.c linux-2.6.16.16-l2tp-mppp/drivers/net/ppp_generic.c
--- linux-2.6.16.16-l2tp/drivers/net/ppp_generic.c	2006-05-11 02:56:24.000000000 +0100
+++ linux-2.6.16.16-l2tp-mppp/drivers/net/ppp_generic.c	2007-07-03 18:23:35.000000000 +0100
@@ -64,7 +64,7 @@
 
 #define MPHDRLEN	6	/* multilink protocol header length */
 #define MPHDRLEN_SSN	4	/* ditto with short sequence numbers */
-#define MIN_FRAG_SIZE	64
+#define MIN_FRAG_SIZE	256
 
 /*
  * An instance of /dev/ppp can be associated with either a ppp
@@ -120,6 +120,7 @@
 	unsigned long	last_recv;	/* jiffies when last pkt rcvd a0 */
 	struct net_device *dev;		/* network interface device a4 */
 #ifdef CONFIG_PPP_MULTILINK
+        int             minfragsize;    /* minimum size for a fragment */
 	int		nxchan;		/* next channel to send something on */
 	u32		nxseq;		/* next sequence number to send */
 	int		mrru;		/* MP: max reconst. receive unit */
@@ -767,6 +768,15 @@
 		ppp_recv_unlock(ppp);
 		err = 0;
 		break;
+
+	case PPPIOCSMINFRAG:
+	        if (get_user(val, p))
+	                break;
+	        ppp_recv_lock(ppp);
+	        ppp->minfragsize = val < 0 ? 0 : val;
+	        ppp_recv_unlock(ppp);
+	        err = 0;
+	        break;
 #endif /* CONFIG_PPP_MULTILINK */
 
 	default:
@@ -1254,7 +1264,7 @@
 	int len, fragsize;
 	int i, bits, hdrlen, mtu;
 	int flen;
-	int navail, nfree;
+	int navail, nfree, nfrag;
 	int nbigger;
 	unsigned char *p, *q;
 	struct list_head *list;
@@ -1285,7 +1295,7 @@
 	 * the channels are free.  This gives much better TCP
 	 * performance if we have a lot of channels.
 	 */
-	if (nfree == 0 || nfree < navail / 2)
+	if (nfree == 0 || (nfree < navail / 2 && ppp->minfragsize == 0))
 		return 0;	/* can't take now, leave it in xmit_pending */
 
 	/* Do protocol field compression (XXX this should be optional) */
@@ -1302,13 +1312,24 @@
 	 * how small they are (i.e. even 0 length) in order to minimize
 	 * the time that it will take to detect when a channel drops
 	 * a fragment.
+         * However, if ppp->minfragsize > 0 we try to avoid creating
+         * fragments smaller than ppp->minfragsize and thus do not
+         * always use all free channels
 	 */
+	if (ppp->minfragsize > 0) {
+	  nfrag= len / ppp->minfragsize;
+	  if (nfrag < 1)
+	        nfrag = 1;
+	  else if (nfrag > nfree)
+	        nfrag = nfree;
+	} else
+	        nfrag = nfree;
 	fragsize = len;
-	if (nfree > 1)
-		fragsize = DIV_ROUND_UP(fragsize, nfree);
+	if (nfrag > 1)
+	        fragsize = DIV_ROUND_UP(fragsize, nfrag);
 	/* nbigger channels get fragsize bytes, the rest get fragsize-1,
 	   except if nbigger==0, then they all get fragsize. */
-	nbigger = len % nfree;
+	nbigger = len % nfrag;
 
 	/* skip to the channel after the one we last used
 	   and start at that one */
@@ -1323,7 +1344,7 @@
 
 	/* create a fragment for each channel */
 	bits = B;
-	while (nfree > 0 || len > 0) {
+	while (len > 0 || (nfree > 0 && ppp->minfragsize == 0)) {
 		list = list->next;
 		if (list == &ppp->channels) {
 			i = 0;
@@ -1371,7 +1392,7 @@
 			mtu = 4;
 		if (flen > mtu)
 			flen = mtu;
-		if (flen == len && nfree == 0)
+		if (flen == len && (nfree == 0 || ppp->minfragsize != 0))
 			bits |= E;
 		frag = alloc_skb(flen + hdrlen + (flen == 0), GFP_ATOMIC);
 		if (frag == 0)
@@ -2435,6 +2456,7 @@
 	spin_lock_init(&ppp->rlock);
 	spin_lock_init(&ppp->wlock);
 #ifdef CONFIG_PPP_MULTILINK
+	ppp->minfragsize = MIN_FRAG_SIZE;
 	ppp->minseq = -1;
 	skb_queue_head_init(&ppp->mrq);
 #endif /* CONFIG_PPP_MULTILINK */
diff -ubdr linux-2.6.16.16-l2tp/include/linux/if_ppp.h linux-2.6.16.16-l2tp-mppp/include/linux/if_ppp.h
--- linux-2.6.16.16-l2tp/include/linux/if_ppp.h	2006-05-12 13:45:00.000000000 +0100
+++ linux-2.6.16.16-l2tp-mppp/include/linux/if_ppp.h	2007-07-03 18:15:27.000000000 +0100
@@ -162,6 +162,7 @@
 #define PPPIOCATTCHAN	_IOW('t', 56, int)	/* attach to ppp channel */
 #define PPPIOCGCHAN	_IOR('t', 55, int)	/* get ppp channel number */
 #define PPPIOCGL2TPSTATS _IOR('t', 54, struct pppol2tp_ioc_stats)
+#define PPPIOCSMINFRAG  _IOW('t', 53, int)  /* minimum fragment size */
 
 #define SIOCGPPPSTATS   (SIOCDEVPRIVATE + 0)
 #define SIOCGPPPVER     (SIOCDEVPRIVATE + 1)	/* NEVER change this!! */