diff -Nru a/Makefile b/Makefile
--- a/Makefile	Tue Nov 26 15:55:05 2002
+++ b/Makefile	Tue Nov 26 15:55:05 2002
@@ -1,7 +1,7 @@
 VERSION = 2
 PATCHLEVEL = 4
 SUBLEVEL = 19
-EXTRAVERSION =
+EXTRAVERSION = -hstcp
 
 KERNELRELEASE=$(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)
 
diff -Nru a/include/linux/sysctl.h b/include/linux/sysctl.h
--- a/include/linux/sysctl.h	Tue Nov 26 15:55:05 2002
+++ b/include/linux/sysctl.h	Tue Nov 26 15:55:05 2002
@@ -291,7 +291,8 @@
 	NET_IPV4_NONLOCAL_BIND=88,
 	NET_IPV4_ICMP_RATELIMIT=89,
 	NET_IPV4_ICMP_RATEMASK=90,
-	NET_TCP_TW_REUSE=91
+	NET_TCP_TW_REUSE=91,
+	NET_TCP_ALTAIMD=95
 };
 
 enum {
diff -Nru a/include/net/tcp.h b/include/net/tcp.h
--- a/include/net/tcp.h	Tue Nov 26 15:55:05 2002
+++ b/include/net/tcp.h	Tue Nov 26 15:55:05 2002
@@ -147,6 +147,15 @@
 	return (lport & (tcp_bhash_size - 1));
 }
 
+#ifdef CONFIG_ALTAIMD
+extern int sysctl_tcp_altAIMD;
+struct hstcp_entry {
+	__u32			cwnd;
+	__u8			a_val;
+	__u8			b_val;
+};
+#endif
+
 /* This is a TIME_WAIT bucket.  It works around the memory consumption
  * problems of sockets in such a state on heavily loaded servers, but
  * without violating the protocol specification.
@@ -1072,6 +1081,30 @@
 	return tp->packets_out - tp->left_out + tp->retrans_out;
 }
 
+/* Should we use the standard TCP AIMD behaviour? If so, the standard
+ * code path is used; this only changes things when non-standard AIMD
+ * (such as for Sally Floyd's HSTCP) is included in the kernel.
+ */
+#ifndef CONFIG_ALTAIMD
+#define tcp_standard_aimd(tp,val1,val2) (val1)
+#else
+static inline int __tcp_standard_aimd(struct tcp_opt *tp)
+{
+	extern struct hstcp_entry hstcp_table[];
+	return ((!sysctl_tcp_altAIMD) ||
+	       (sysctl_tcp_altAIMD && (tp->snd_cwnd < hstcp_table[0].cwnd)));
+}
+#define tcp_standard_aimd(tp,val1,val2) \
+    ((__tcp_standard_aimd(tp)) ? (val1) : (val2))
+
+extern struct hstcp_entry get_hstcp_val(struct tcp_opt *tp);
+
+static inline __u32 tcp_var_reduce(struct tcp_opt *tp)
+{
+	return (tp->snd_cwnd * (256 - get_hstcp_val(tp).b_val)) >> 8;
+}
+#endif
+
 /* Recalculate snd_ssthresh, we want to set it to:
  *
  * 	one half the current congestion window, but no
@@ -1079,7 +1112,8 @@
  */
 static inline __u32 tcp_recalc_ssthresh(struct tcp_opt *tp)
 {
-	return max(tp->snd_cwnd >> 1U, 2U);
+	return tcp_standard_aimd(tp, max(tp->snd_cwnd >> 1U, 2U),
+			max(tcp_var_reduce(tp), 2U));
 }
 
 /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
diff -Nru a/net/ipv4/Config.in b/net/ipv4/Config.in
--- a/net/ipv4/Config.in	Tue Nov 26 15:55:05 2002
+++ b/net/ipv4/Config.in	Tue Nov 26 15:55:05 2002
@@ -40,6 +40,12 @@
    bool '  IP: ARP daemon support (EXPERIMENTAL)' CONFIG_ARPD
 fi
 bool '  IP: TCP Explicit Congestion Notification support' CONFIG_INET_ECN
+if [ "$CONFIG_EXPERIMENTAL" = "y" ]; then
+   bool '  IP: High-Speed TCP [Sally Floyd] available (EXPERIMENTAL)' CONFIG_ALTAIMD
+   if [ "$CONFIG_ALTAIMD" = "y" ]; then
+      bool '    IP: High-Speed TCP on by default' CONFIG_ALTAIMD_ON
+   fi
+fi
 bool '  IP: TCP syncookie support (disabled per default)' CONFIG_SYN_COOKIES
 if [ "$CONFIG_NETFILTER" != "n" ]; then
    source net/ipv4/netfilter/Config.in
diff -Nru a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
--- a/net/ipv4/sysctl_net_ipv4.c	Tue Nov 26 15:55:05 2002
+++ b/net/ipv4/sysctl_net_ipv4.c	Tue Nov 26 15:55:05 2002
@@ -221,6 +221,10 @@
 	 &sysctl_icmp_ratemask, sizeof(int), 0644, NULL, &proc_dointvec},
 	{NET_TCP_TW_REUSE, "tcp_tw_reuse",
 	 &sysctl_tcp_tw_reuse, sizeof(int), 0644, NULL, &proc_dointvec},
+#ifdef CONFIG_ALTAIMD
+	{NET_TCP_ALTAIMD, "tcp_altAIMD",
+	 &sysctl_tcp_altAIMD, sizeof(int), 0644, NULL, &proc_dointvec},
+#endif
 	{0}
 };
 
diff -Nru a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
--- a/net/ipv4/tcp_input.c	Tue Nov 26 15:55:05 2002
+++ b/net/ipv4/tcp_input.c	Tue Nov 26 15:55:05 2002
@@ -87,6 +87,107 @@
 int sysctl_tcp_rfc1337 = 0;
 int sysctl_tcp_max_orphans = NR_FILE;
 
+#ifdef CONFIG_ALTAIMD
+#ifdef CONFIG_ALTAIMD_ON
+int sysctl_tcp_altAIMD = 1;
+#else
+int sysctl_tcp_altAIMD = 0;
+#endif
+
+struct hstcp_entry hstcp_table[] = {
+{38, 1, 128},
+{118, 2, 112},
+{221, 3, 104},
+{347, 4, 98},
+{495, 5, 93},
+{663, 6, 89},
+{851, 7, 86},
+{1058, 8, 83},
+{1284, 9, 81},
+{1529, 10, 78},
+{1793, 11, 76},
+{2076, 12, 74},
+{2378, 13, 72},
+{2699, 14, 71},
+{3039, 15, 69},
+{3399, 16, 68},
+{3778, 17, 66},
+{4177, 18, 65},
+{4596, 19, 64},
+{5036, 20, 62},
+{5497, 21, 61},
+{5979, 22, 60},
+{6483, 23, 59},
+{7009, 24, 58},
+{7558, 25, 57},
+{8130, 26, 56},
+{8726, 27, 55},
+{9346, 28, 54},
+{9991, 29, 53},
+{10661, 30, 52},
+{11358, 31, 52},
+{12082, 32, 51},
+{12834, 33, 50},
+{13614, 34, 49},
+{14424, 35, 48},
+{15265, 36, 48},
+{16137, 37, 47},
+{17042, 38, 46},
+{17981, 39, 45},
+{18955, 40, 45},
+{19965, 41, 44},
+{21013, 42, 43},
+{22101, 43, 43},
+{23230, 44, 42},
+{24402, 45, 41},
+{25618, 46, 41},
+{26881, 47, 40},
+{28193, 48, 39},
+{29557, 49, 39},
+{30975, 50, 38},
+{32450, 51, 38},
+{33986, 52, 37},
+{35586, 53, 36},
+{37253, 54, 36},
+{38992, 55, 35},
+{40808, 56, 35},
+{42707, 57, 34},
+{44694, 58, 33},
+{46776, 59, 33},
+{48961, 60, 32},
+{51258, 61, 32},
+{53677, 62, 31},
+{56230, 63, 30},
+{58932, 64, 30},
+{61799, 65, 29},
+{64851, 66, 28},
+{68113, 67, 28},
+{71617, 68, 27},
+{75401, 69, 26},
+{79517, 70, 26},
+{84035, 71, 25},
+{89053, 72, 24},
+{94717, 73, 23},
+};
+static short hstcp_max_entry=72;
+
+struct hstcp_entry get_hstcp_val(struct tcp_opt *tp) {
+	short left,right,mid;
+	__u32 this_cwnd = tp->snd_cwnd;
+	left = 0;
+	right = hstcp_max_entry;
+	while (right-left) {
+		mid = (left + right)>>1;
+		if (hstcp_table[mid].cwnd < this_cwnd) {
+			left = mid + 1;
+		} else {
+			right = mid;
+		}
+	}
+	return hstcp_table[right];
+}
+#endif
+
 #define FLAG_DATA		0x01 /* Incoming frame contained data.		*/
 #define FLAG_WIN_UPDATE		0x02 /* Incoming ACK was a window update.	*/
 #define FLAG_DATA_ACKED		0x04 /* This ACK acknowledged new data.		*/
@@ -1693,6 +1794,13 @@
 		tcp_ack_no_tstamp(tp, seq_rtt, flag);
 }
 
+static inline int tcp_should_inc_cwnd(struct tcp_opt *tp)
+{
+	return tcp_standard_aimd(tp, (tp->snd_cwnd_cnt >= tp->snd_cwnd),
+				((tp->snd_cwnd_cnt * get_hstcp_val(tp).a_val)
+			 		>= tp->snd_cwnd));
+}
+
 /* This is Jacobson's slow start and congestion avoidance. 
  * SIGCOMM '88, p. 328.
  */
@@ -1706,7 +1814,7 @@
                 /* In dangerous area, increase slowly.
 		 * In theory this is tp->snd_cwnd += 1 / tp->snd_cwnd
 		 */
-		if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
+		if (tcp_should_inc_cwnd(tp)) {
 			if (tp->snd_cwnd < tp->snd_cwnd_clamp)
 				tp->snd_cwnd++;
 			tp->snd_cwnd_cnt=0;
diff -Nru a/net/netsyms.c b/net/netsyms.c
--- a/net/netsyms.c	Tue Nov 26 15:55:05 2002
+++ b/net/netsyms.c	Tue Nov 26 15:55:05 2002
@@ -530,6 +530,9 @@
 EXPORT_SYMBOL(sysctl_rmem_max);
 #ifdef CONFIG_INET
 EXPORT_SYMBOL(sysctl_ip_default_ttl);
+#ifdef CONFIG_ALTAIMD
+EXPORT_SYMBOL(sysctl_tcp_altAIMD);
+#endif
 #endif
 #endif