For an overview of several congestion control algorithms see
https://www.geeksforgeeks.org/tcp-congestion-control-algorithms-reno-new-reno-bic-cubic/

diff --git a/usr/src/uts/common/inet/cc.h b/usr/src/uts/common/inet/cc.h
index d92535cd48..aa72c46162 100644
--- a/usr/src/uts/common/inet/cc.h
+++ b/usr/src/uts/common/inet/cc.h
@@ -64,7 +64,7 @@ extern "C" {
 
 #define	CC_ALGO_NAME_MAX	16	/* max congestion control name length */
 
-#define	CC_DEFAULT_ALGO_NAME	"sunreno"
+#define	CC_DEFAULT_ALGO_NAME	"cubic"
 
 struct tcp_s;
 struct sctp_s;