Index: /head/sys/netinet/cc/cc_htcp.c
===================================================================
--- /head/sys/netinet/cc/cc_htcp.c
+++ /head/sys/netinet/cc/cc_htcp.c
@@ -366,7 +366,12 @@
 			pipe = CCV(ccv, snd_max) - ccv->curack;
 		
 		if (pipe < CCV(ccv, snd_ssthresh))
-			CCV(ccv, snd_cwnd) = pipe + CCV(ccv, t_maxseg);
+			/*
+			 * Ensure that cwnd does not collapse to 1 mss under
+			 * adverse conditions. RFC6582 (Std)
+			 */		
+			CCV(ccv, snd_cwnd) = max(pipe, CCV(ccv, t_maxseg)) + 
+			    CCV(ccv, t_maxseg);
 		else
 			CCV(ccv, snd_cwnd) = max(1, ((htcp_data->beta *
 			    htcp_data->prev_cwnd / CCV(ccv, t_maxseg))
Index: /head/sys/netinet/cc/cc_newreno.c
===================================================================
--- /head/sys/netinet/cc/cc_newreno.c
+++ /head/sys/netinet/cc/cc_newreno.c
@@ -299,9 +299,14 @@
 			pipe = tcp_compute_pipe(ccv->ccvc.tcp);
 		else
 			pipe = CCV(ccv, snd_max) - ccv->curack;
-
+		
 		if (pipe < CCV(ccv, snd_ssthresh))
-			CCV(ccv, snd_cwnd) = pipe + CCV(ccv, t_maxseg);
+			/*
+			 * Ensure that cwnd does not collapse to 1 mss under
+			 * adverse conditions. RFC6582 (Std)
+			 */	
+			CCV(ccv, snd_cwnd) = max(pipe, CCV(ccv, t_maxseg) + 
+		        CCV(ccv, t_maxseg);
 		else
 			CCV(ccv, snd_cwnd) = CCV(ccv, snd_ssthresh);
 	}
Index: sys/netinet/cc/cc_cubic.c
===================================================================
--- sys/netinet/cc/cc_cubic.c
+++ sys/netinet/cc/cc_cubic.c
@@ -349,7 +349,12 @@
 			pipe = CCV(ccv, snd_max) - ccv->curack;
 
 		if (pipe < CCV(ccv, snd_ssthresh))
-			CCV(ccv, snd_cwnd) = pipe + CCV(ccv, t_maxseg);
+			/*
+			 * Ensure that cwnd does not collapse to 1 mss under
+			 * adverse conditions. RFC6582 (Std)
+			 */
+			CCV(ccv, snd_cwnd) = max(pipe, CCV(ccv, t_maxseg)) + 
+				CCV(ccv, t_maxseg);
 		else
 			/* Update cwnd based on beta and adjusted max_cwnd. */
 			CCV(ccv, snd_cwnd) = max(1, ((CUBIC_BETA *