diff --git a/lib/core-net/close.c b/lib/core-net/close.c
index c8893479f..d7b54decf 100644
--- a/lib/core-net/close.c
+++ b/lib/core-net/close.c
@@ -264,7 +264,7 @@ __lws_close_free_wsi(struct lws *wsi, enum lws_close_status reason,
 #endif
 
 #if defined(LWS_WITH_HTTP2)
-	if (wsi->h2_stream_immortal)
+	if (wsi->mux_stream_immortal)
 		lws_http_close_immortal(wsi);
 #endif
 
diff --git a/lib/core-net/dummy-callback.c b/lib/core-net/dummy-callback.c
index 37d884795..851a2b128 100644
--- a/lib/core-net/dummy-callback.c
+++ b/lib/core-net/dummy-callback.c
@@ -57,7 +57,7 @@ stream_close(struct lws *wsi)
 
 	wsi->http.did_stream_close = 1;
 
-	if (wsi->http2_substream) {
+	if (wsi->mux_substream) {
 		if (lws_write(wsi, (unsigned char *)buf + LWS_PRE, 0,
 			      LWS_WRITE_HTTP_FINAL) < 0) {
 			lwsl_info("%s: COMPL_CLIENT_HTTP: h2 fin wr failed\n",
@@ -115,7 +115,7 @@ lws_callback_ws_proxy(struct lws *wsi, enum lws_callback_reasons reason,
 		lws_process_ws_upgrade2(wsi->parent);
 
 #if defined(LWS_WITH_HTTP2)
-		if (wsi->parent->http2_substream)
+		if (wsi->parent->mux_substream)
 			lwsl_info("%s: proxied h2 -> h1 ws established\n", __func__);
 #endif
 		break;
@@ -330,7 +330,7 @@ lws_callback_http_dummy(struct lws *wsi, enum lws_callback_reasons reason,
 		}
 
 		if (wsi->reason_bf & LWS_CB_REASON_AUX_BF__CGI_CHUNK_END) {
-			if (!wsi->http2_substream) {
+			if (!wsi->mux_substream) {
 				memcpy(buf + LWS_PRE, "0\x0d\x0a\x0d\x0a", 5);
 				lwsl_debug("writing chunk term and exiting\n");
 				n = lws_write(wsi, (unsigned char *)buf +
@@ -508,7 +508,7 @@ lws_callback_http_dummy(struct lws *wsi, enum lws_callback_reasons reason,
 		proxy_header(parent, wsi, end, 256,
 			     WSI_TOKEN_HTTP_LOCATION, &p, end);
 
-		if (!parent->http2_substream)
+		if (!parent->mux_substream)
 			if (lws_add_http_header_by_token(parent,
 				WSI_TOKEN_CONNECTION, (unsigned char *)"close",
 				5, &p, end))
@@ -522,7 +522,7 @@ lws_callback_http_dummy(struct lws *wsi, enum lws_callback_reasons reason,
 		 * our own chunking since we still don't know the size.
 		 */
 
-		if (!parent->http2_substream &&
+		if (!parent->mux_substream &&
 		    !lws_hdr_total_length(wsi, WSI_TOKEN_HTTP_CONTENT_LENGTH)) {
 			lwsl_debug("downstream parent chunked\n");
 			if (lws_add_http_header_by_token(parent,
@@ -661,7 +661,7 @@ lws_callback_http_dummy(struct lws *wsi, enum lws_callback_reasons reason,
 		lwsl_debug("LWS_CALLBACK_CGI_TERMINATED: %d %" PRIu64 "\n",
 				wsi->http.cgi->explicitly_chunked,
 				(uint64_t)wsi->http.cgi->content_length);
-		if (!(wsi->http.cgi->explicitly_chunked && wsi->http2_substream) &&
+		if (!(wsi->http.cgi->explicitly_chunked && wsi->mux_substream) &&
 		    !wsi->http.cgi->content_length) {
 			/* send terminating chunk */
 			lwsl_debug("LWS_CALLBACK_CGI_TERMINATED: ending\n");
@@ -670,7 +670,7 @@ lws_callback_http_dummy(struct lws *wsi, enum lws_callback_reasons reason,
 			lws_set_timeout(wsi, PENDING_TIMEOUT_CGI, 3);
 			break;
 		}
-		if (wsi->http2_substream && !wsi->cgi_stdout_zero_length)
+		if (wsi->mux_substream && !wsi->cgi_stdout_zero_length)
 			lws_write(wsi, (unsigned char *)buf + LWS_PRE, 0,
 						      LWS_WRITE_HTTP_FINAL);
 
diff --git a/lib/core-net/output.c b/lib/core-net/output.c
index cc1276ce5..46c5b15f9 100644
--- a/lib/core-net/output.c
+++ b/lib/core-net/output.c
@@ -93,7 +93,7 @@ lws_issue_raw(struct lws *wsi, unsigned char *buf, size_t len)
 	if (!len || !buf)
 		return 0;
 
-	if (!wsi->http2_substream && !lws_socket_is_valid(wsi->desc.sockfd))
+	if (!wsi->mux_substream && !lws_socket_is_valid(wsi->desc.sockfd))
 		lwsl_warn("** error invalid sock but expected to send\n");
 
 	/* limit sending */
diff --git a/lib/core-net/pollfd.c b/lib/core-net/pollfd.c
index 69ea94152..7080838d7 100644
--- a/lib/core-net/pollfd.c
+++ b/lib/core-net/pollfd.c
@@ -147,7 +147,7 @@ _lws_change_pollfd(struct lws *wsi, int _and, int _or, struct lws_pollargs *pa)
 	pa->prev_events = pfd->events;
 	pa->events = pfd->events = (pfd->events & ~_and) | _or;
 
-	if (wsi->http2_substream)
+	if (wsi->mux_substream)
 		return 0;
 
 #if defined(LWS_WITH_EXTERNAL_POLL)
diff --git a/lib/core-net/private-lib-core-net.h b/lib/core-net/private-lib-core-net.h
index 57081fff9..46bf8ceb2 100644
--- a/lib/core-net/private-lib-core-net.h
+++ b/lib/core-net/private-lib-core-net.h
@@ -29,6 +29,21 @@
 #define _POSIX_C_SOURCE 200112L
 #endif
 
+/*
+ * Generic pieces needed to manage muxable stream protocols like h2
+ */
+
+struct lws_muxable {
+	struct lws	*parent_wsi;
+	struct lws	*child_list;
+	struct lws	*sibling_list;
+
+	unsigned int	my_sid;
+	unsigned int	child_count;
+
+	uint8_t		requested_POLLOUT;
+};
+
 #include "private-lib-roles.h"
 
 #ifdef LWS_WITH_IPV6
@@ -576,6 +591,32 @@ struct lws_vhost {
 void
 __lws_vhost_destroy2(struct lws_vhost *vh);
 
+#define mux_to_wsi(_m) lws_container_of(_m, struct lws, mux)
+
+void
+lws_wsi_mux_insert(struct lws *wsi, struct lws *parent_wsi, int sid);
+int
+lws_wsi_mux_mark_parents_needing_writeable(struct lws *wsi);
+struct lws *
+lws_wsi_mux_move_child_to_tail(struct lws **wsi2);
+int
+lws_wsi_mux_action_pending_writeable_reqs(struct lws *wsi);
+
+void
+lws_wsi_mux_dump_children(struct lws *wsi);
+
+void
+lws_wsi_mux_close_children(struct lws *wsi, int reason);
+
+void
+lws_wsi_mux_sibling_disconnect(struct lws *wsi);
+
+void
+lws_wsi_mux_dump_waiting_children(struct lws *wsi);
+
+int
+lws_wsi_mux_apply_queue(struct lws *wsi);
+
 /*
  * struct lws
  */
@@ -584,47 +625,51 @@ struct lws {
 	/* structs */
 
 #if defined(LWS_ROLE_H1) || defined(LWS_ROLE_H2)
-	struct _lws_http_mode_related http;
+	struct _lws_http_mode_related	http;
 #endif
 #if defined(LWS_ROLE_H2)
-	struct _lws_h2_related h2;
+	struct _lws_h2_related		h2;
 #endif
 #if defined(LWS_ROLE_WS)
-	struct _lws_websocket_related *ws; /* allocated if we upgrade to ws */
+	struct _lws_websocket_related	*ws; /* allocated if we upgrade to ws */
 #endif
 #if defined(LWS_ROLE_DBUS)
-	struct _lws_dbus_mode_related dbus;
+	struct _lws_dbus_mode_related	dbus;
+#endif
+
+#if defined(LWS_ROLE_H2)
+	struct lws_muxable		mux;
 #endif
 
 	/* lifetime members */
 
 #if defined(LWS_WITH_LIBEV) || defined(LWS_WITH_LIBUV) || \
     defined(LWS_WITH_LIBEVENT)
-	struct lws_io_watcher w_read;
+	struct lws_io_watcher		w_read;
 #endif
 #if defined(LWS_WITH_LIBEV) || defined(LWS_WITH_LIBEVENT)
-	struct lws_io_watcher w_write;
+	struct lws_io_watcher		w_write;
 #endif
 
 #if defined(LWS_WITH_DETAILED_LATENCY)
 	lws_detlat_t	detlat;
 #endif
 
-	lws_sorted_usec_list_t sul_timeout;
-	lws_sorted_usec_list_t sul_hrtimer;
-	lws_sorted_usec_list_t sul_validity;
+	lws_sorted_usec_list_t		sul_timeout;
+	lws_sorted_usec_list_t		sul_hrtimer;
+	lws_sorted_usec_list_t		sul_validity;
 
-	struct lws_dll2 dll_buflist; /* guys with pending rxflow */
-	struct lws_dll2 same_vh_protocol;
-	struct lws_dll2 vh_awaiting_socket;
+	struct lws_dll2			dll_buflist; /* guys with pending rxflow */
+	struct lws_dll2			same_vh_protocol;
+	struct lws_dll2			vh_awaiting_socket;
 #if defined(LWS_WITH_SYS_ASYNC_DNS)
-	struct lws_dll2 adns;	/* on adns list of guys to tell result */
-	lws_async_dns_cb_t adns_cb;	/* callback with result */
+	struct lws_dll2			adns; /* on adns list of guys to tell result */
+	lws_async_dns_cb_t		adns_cb; /* callback with result */
 #endif
 #if defined(LWS_WITH_CLIENT)
-	struct lws_dll2 dll_cli_active_conns;
-	struct lws_dll2_owner dll2_cli_txn_queue_owner;
-	struct lws_dll2 dll2_cli_txn_queue;
+	struct lws_dll2			dll_cli_active_conns;
+	struct lws_dll2			dll2_cli_txn_queue;
+	struct lws_dll2_owner		dll2_cli_txn_queue_owner;
 #endif
 
 #if defined(LWS_WITH_ACCESS_LOG)
@@ -632,134 +677,134 @@ struct lws {
 #endif
 	/* pointers */
 
-	struct lws_context *context;
-	struct lws_vhost *vhost;
-	struct lws *parent; /* points to parent, if any */
-	struct lws *child_list; /* points to first child */
-	struct lws *sibling_list; /* subsequent children at same level */
-	const struct lws_role_ops *role_ops;
-	const struct lws_protocols *protocol;
-	struct lws_sequencer *seq;	/* associated sequencer if any */
-	const lws_retry_bo_t *retry_policy;
+	struct lws_context		*context;
+	struct lws_vhost		*vhost;
+	struct lws			*parent; /* points to parent, if any */
+	struct lws			*child_list; /* points to first child */
+	struct lws			*sibling_list; /* subsequent children at same level */
+	const struct lws_role_ops	*role_ops;
+	const struct lws_protocols	*protocol;
+	struct lws_sequencer		*seq;	/* associated sequencer if any */
+	const lws_retry_bo_t		*retry_policy;
 
 #if defined(LWS_WITH_THREADPOOL)
-	struct lws_threadpool_task *tp_task;
+	struct lws_threadpool_task	*tp_task;
 #endif
 
 #if defined(LWS_WITH_PEER_LIMITS)
-	struct lws_peer *peer;
+	struct lws_peer			*peer;
 #endif
 
 #if defined(LWS_WITH_UDP)
-	struct lws_udp *udp;
+	struct lws_udp			*udp;
 #endif
 #if defined(LWS_WITH_CLIENT)
-	struct client_info_stash *stash;
-	char *cli_hostname_copy;
-	const struct addrinfo *dns_results;
-	const struct addrinfo *dns_results_next;
+	struct client_info_stash	*stash;
+	char				*cli_hostname_copy;
+	const struct addrinfo		*dns_results;
+	const struct addrinfo		*dns_results_next;
 #endif
-	void *user_space;
-	void *opaque_parent_data;
-	void *opaque_user_data;
+	void				*user_space;
+	void				*opaque_parent_data;
+	void				*opaque_user_data;
 
-	struct lws_buflist *buflist;		/* input-side buflist */
-	struct lws_buflist *buflist_out;	/* output-side buflist */
+	struct lws_buflist		*buflist; /* input-side buflist */
+	struct lws_buflist		*buflist_out; /* output-side buflist */
 
 #if defined(LWS_WITH_TLS)
-	struct lws_lws_tls tls;
+	struct lws_lws_tls		tls;
 #endif
 
-	lws_sock_file_fd_type desc; /* .filefd / .sockfd */
+	lws_sock_file_fd_type		desc; /* .filefd / .sockfd */
 #if defined(LWS_WITH_STATS)
 	uint64_t active_writable_req_us;
 #if defined(LWS_WITH_TLS)
 	uint64_t accept_start_us;
 #endif
 #endif
-	lws_wsi_state_t	wsistate;
-	lws_wsi_state_t wsistate_pre_close;
+	lws_wsi_state_t			wsistate;
+	lws_wsi_state_t			wsistate_pre_close;
 
 	/* ints */
 #define LWS_NO_FDS_POS (-1)
-	int position_in_fds_table;
+	int				position_in_fds_table;
 
 #if defined(LWS_WITH_CLIENT)
-	int chunk_remaining;
-	int flags;
+	int				chunk_remaining;
+	int				flags;
 #endif
-	unsigned int cache_secs;
+	unsigned int			cache_secs;
 
-	unsigned int hdr_parsing_completed:1;
-	unsigned int http2_substream:1;
-	unsigned int upgraded_to_http2:1;
-	unsigned int h2_stream_immortal:1;
-	unsigned int h2_stream_carries_ws:1; /* immortal set as well */
-	unsigned int h2_stream_carries_sse:1; /* immortal set as well */
-	unsigned int h2_acked_settings:1;
-	unsigned int seen_nonpseudoheader:1;
-	unsigned int listener:1;
-	unsigned int pf_packet:1;
-	unsigned int do_broadcast:1;
-	unsigned int user_space_externally_allocated:1;
-	unsigned int socket_is_permanently_unusable:1;
-	unsigned int rxflow_change_to:2;
-	unsigned int conn_stat_done:1;
-	unsigned int cache_reuse:1;
-	unsigned int cache_revalidate:1;
-	unsigned int cache_intermediaries:1;
-	unsigned int favoured_pollin:1;
-	unsigned int sending_chunked:1;
-	unsigned int interpreting:1;
-	unsigned int already_did_cce:1;
-	unsigned int told_user_closed:1;
-	unsigned int told_event_loop_closed:1;
-	unsigned int waiting_to_send_close_frame:1;
-	unsigned int close_needs_ack:1;
-	unsigned int ipv6:1;
-	unsigned int parent_pending_cb_on_writable:1;
-	unsigned int cgi_stdout_zero_length:1;
-	unsigned int seen_zero_length_recv:1;
-	unsigned int rxflow_will_be_applied:1;
-	unsigned int event_pipe:1;
-	unsigned int handling_404:1;
-	unsigned int protocol_bind_balance:1;
-	unsigned int unix_skt:1;
-	unsigned int close_when_buffered_out_drained:1;
-	unsigned int h1_ws_proxied:1;
-	unsigned int proxied_ws_parent:1;
-	unsigned int do_bind:1;
-	unsigned int oom4:1;
-	unsigned int validity_hup:1;
+	unsigned int			hdr_parsing_completed:1;
+	unsigned int			mux_substream:1;
+	unsigned int			upgraded_to_http2:1;
+	unsigned int			mux_stream_immortal:1;
+	unsigned int			h2_stream_carries_ws:1; /* immortal set as well */
+	unsigned int			h2_stream_carries_sse:1; /* immortal set as well */
+	unsigned int			h2_acked_settings:1;
+	unsigned int			seen_nonpseudoheader:1;
+	unsigned int			listener:1;
+	unsigned int			pf_packet:1;
+	unsigned int			do_broadcast:1;
+	unsigned int			user_space_externally_allocated:1;
+	unsigned int			socket_is_permanently_unusable:1;
+	unsigned int			rxflow_change_to:2;
+	unsigned int			conn_stat_done:1;
+	unsigned int			cache_reuse:1;
+	unsigned int			cache_revalidate:1;
+	unsigned int			cache_intermediaries:1;
+	unsigned int			favoured_pollin:1;
+	unsigned int			sending_chunked:1;
+	unsigned int			interpreting:1;
+	unsigned int			already_did_cce:1;
+	unsigned int			told_user_closed:1;
+	unsigned int			told_event_loop_closed:1;
+	unsigned int			waiting_to_send_close_frame:1;
+	unsigned int			close_needs_ack:1;
+	unsigned int			ipv6:1;
+	unsigned int			parent_pending_cb_on_writable:1;
+	unsigned int			cgi_stdout_zero_length:1;
+	unsigned int			seen_zero_length_recv:1;
+	unsigned int			rxflow_will_be_applied:1;
+	unsigned int			event_pipe:1;
+	unsigned int			handling_404:1;
+	unsigned int			protocol_bind_balance:1;
+	unsigned int			unix_skt:1;
+	unsigned int			close_when_buffered_out_drained:1;
+	unsigned int			h1_ws_proxied:1;
+	unsigned int			proxied_ws_parent:1;
+	unsigned int			do_bind:1;
+	unsigned int			oom4:1;
+	unsigned int			validity_hup:1;
 
-	unsigned int could_have_pending:1; /* detect back-to-back writes */
-	unsigned int outer_will_close:1;
-	unsigned int shadow:1; /* we do not control fd lifecycle at all */
+	unsigned int			could_have_pending:1; /* detect back-to-back writes */
+	unsigned int			outer_will_close:1;
+	unsigned int			shadow:1; /* we do not control fd lifecycle at all */
 
 #ifdef LWS_WITH_ACCESS_LOG
-	unsigned int access_log_pending:1;
+	unsigned int			access_log_pending:1;
 #endif
 #if defined(LWS_WITH_CLIENT)
-	unsigned int do_ws:1; /* whether we are doing http or ws flow */
-	unsigned int chunked:1; /* if the clientside connection is chunked */
-	unsigned int client_rx_avail:1;
-	unsigned int client_http_body_pending:1;
-	unsigned int transaction_from_pipeline_queue:1;
-	unsigned int keepalive_active:1;
-	unsigned int keepalive_rejected:1;
-	unsigned int redirected_to_get:1;
-	unsigned int client_pipeline:1;
-	unsigned int client_h2_alpn:1;
-	unsigned int client_h2_substream:1;
-	unsigned int client_h2_migrated:1;
+	unsigned int			do_ws:1; /* whether we are doing http or ws flow */
+	unsigned int			chunked:1; /* if the clientside connection is chunked */
+	unsigned int			client_rx_avail:1;
+	unsigned int			client_http_body_pending:1;
+	unsigned int			transaction_from_pipeline_queue:1;
+	unsigned int			keepalive_active:1;
+	unsigned int			keepalive_rejected:1;
+	unsigned int			redirected_to_get:1;
+	unsigned int			client_pipeline:1;
+	unsigned int			client_h2_alpn:1;
+	unsigned int			client_mux_substream:1;
+	unsigned int			client_mux_migrated:1;
 #endif
 
 #ifdef _WIN32
 	unsigned int sock_send_blocking:1;
 #endif
 
-	uint16_t ocport, c_port;
-	uint16_t retry;
+	uint16_t			ocport, c_port;
+	uint16_t			retry;
 
 	/* chars */
 
@@ -1110,7 +1155,7 @@ lws_prepare_access_log_info(struct lws *wsi, char *uri_ptr, int len, int meth);
 #endif
 
 void
-lws_http_mark_immortal(struct lws *wsi);
+lws_mux_mark_immortal(struct lws *wsi);
 void
 lws_http_close_immortal(struct lws *wsi);
 
diff --git a/lib/core-net/wsi-timeout.c b/lib/core-net/wsi-timeout.c
index e95e84805..f3d14939b 100644
--- a/lib/core-net/wsi-timeout.c
+++ b/lib/core-net/wsi-timeout.c
@@ -156,8 +156,8 @@ lws_set_timeout(struct lws *wsi, enum pending_timeout reason, int secs)
 	if (secs == LWS_TO_KILL_ASYNC)
 		secs = 0;
 
-	// assert(!secs || !wsi->h2_stream_immortal);
-	if (secs && wsi->h2_stream_immortal)
+	// assert(!secs || !wsi->mux_stream_immortal);
+	if (secs && wsi->mux_stream_immortal)
 		lwsl_err("%s: on immortal stream %d %d\n", __func__, reason, secs);
 
 	lws_pt_lock(pt, __func__);
diff --git a/lib/core-net/wsi.c b/lib/core-net/wsi.c
index d8677b0c4..66b35c3c6 100644
--- a/lib/core-net/wsi.c
+++ b/lib/core-net/wsi.c
@@ -86,29 +86,29 @@ lws_vhost_unbind_wsi(struct lws *wsi)
 	lws_context_unlock(wsi->context); /* } context ---------- */
 }
 
-LWS_VISIBLE struct lws *
+struct lws *
 lws_get_network_wsi(struct lws *wsi)
 {
 	if (!wsi)
 		return NULL;
 
 #if defined(LWS_WITH_HTTP2)
-	if (!wsi->http2_substream
+	if (!wsi->mux_substream
 #if defined(LWS_WITH_CLIENT)
-			&& !wsi->client_h2_substream
+			&& !wsi->client_mux_substream
 #endif
 	)
 		return wsi;
 
-	while (wsi->h2.parent_wsi)
-		wsi = wsi->h2.parent_wsi;
+	while (wsi->mux.parent_wsi)
+		wsi = wsi->mux.parent_wsi;
 #endif
 
 	return wsi;
 }
 
 
-LWS_VISIBLE LWS_EXTERN const struct lws_protocols *
+const struct lws_protocols *
 lws_vhost_name_to_protocol(struct lws_vhost *vh, const char *name)
 {
 	int n;
@@ -222,7 +222,7 @@ lws_rx_flow_control(struct lws *wsi, int _enable)
 	int en = _enable;
 
 	// h2 ignores rx flow control atm
-	if (lwsi_role_h2(wsi) || wsi->http2_substream ||
+	if (lwsi_role_h2(wsi) || wsi->mux_substream ||
 	    lwsi_role_h2_ENCAPSULATION(wsi))
 		return 0; // !!!
 
@@ -312,7 +312,7 @@ __lws_rx_flow_control(struct lws *wsi)
 	struct lws *wsic = wsi->child_list;
 
 	// h2 ignores rx flow control atm
-	if (lwsi_role_h2(wsi) || wsi->http2_substream ||
+	if (lwsi_role_h2(wsi) || wsi->mux_substream ||
 	    lwsi_role_h2_ENCAPSULATION(wsi))
 		return 0; // !!!
 
@@ -898,11 +898,11 @@ lws_http_close_immortal(struct lws *wsi)
 {
 	struct lws *nwsi;
 
-	if (!wsi->http2_substream)
+	if (!wsi->mux_substream)
 		return;
 
-	assert(wsi->h2_stream_immortal);
-	wsi->h2_stream_immortal = 0;
+	assert(wsi->mux_stream_immortal);
+	wsi->mux_stream_immortal = 0;
 
 	nwsi = lws_get_network_wsi(wsi);
 	lwsl_debug("%s: %p %p %d\n", __func__, wsi, nwsi,
@@ -920,15 +920,15 @@ lws_http_close_immortal(struct lws *wsi)
 }
 
 void
-lws_http_mark_immortal(struct lws *wsi)
+lws_mux_mark_immortal(struct lws *wsi)
 {
 	struct lws *nwsi;
 
 	lws_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 
-	if (!wsi->http2_substream
+	if (!wsi->mux_substream
 #if defined(LWS_WITH_CLIENT)
-			&& !wsi->client_h2_substream
+			&& !wsi->client_mux_substream
 #endif
 	) {
 		lwsl_err("%s: not h2 substream\n", __func__);
@@ -940,7 +940,7 @@ lws_http_mark_immortal(struct lws *wsi)
 	lwsl_debug("%s: %p %p %d\n", __func__, wsi, nwsi,
 				     nwsi->immortal_substream_count);
 
-	wsi->h2_stream_immortal = 1;
+	wsi->mux_stream_immortal = 1;
 	assert(nwsi->immortal_substream_count < 255); /* largest count */
 	nwsi->immortal_substream_count++;
 	if (nwsi->immortal_substream_count == 1)
@@ -952,14 +952,15 @@ int
 lws_http_mark_sse(struct lws *wsi)
 {
 	lws_http_headers_detach(wsi);
-	lws_http_mark_immortal(wsi);
+	lws_mux_mark_immortal(wsi);
 
-	if (wsi->http2_substream)
+	if (wsi->mux_substream)
 		wsi->h2_stream_carries_sse = 1;
 
 	return 0;
 }
 
+#if defined(LWS_WITH_CLIENT)
 
 const char *
 lws_wsi_client_stash_item(struct lws *wsi, int stash_idx, int hdr_idx)
@@ -975,3 +976,216 @@ lws_wsi_client_stash_item(struct lws *wsi, int stash_idx, int hdr_idx)
 	return NULL;
 #endif
 }
+#endif
+
+#if defined(LWS_ROLE_H2)
+
+void
+lws_wsi_mux_insert(struct lws *wsi, struct lws *parent_wsi, int sid)
+{
+	wsi->mux.my_sid = sid;
+	wsi->mux.parent_wsi = parent_wsi;
+	wsi->role_ops = parent_wsi->role_ops;
+
+	/* new guy's sibling is whoever was the first child before */
+	wsi->mux.sibling_list = parent_wsi->mux.child_list;
+
+	/* first child is now the new guy */
+	parent_wsi->mux.child_list = wsi;
+
+	parent_wsi->mux.child_count++;
+}
+
+struct lws *
+lws_wsi_mux_from_id(struct lws *parent_wsi, unsigned int sid)
+{
+	lws_start_foreach_ll(struct lws *, wsi, parent_wsi->mux.child_list) {
+		if (wsi->mux.my_sid == sid)
+			return wsi;
+	} lws_end_foreach_ll(wsi, mux.sibling_list);
+
+	return NULL;
+}
+
+void
+lws_wsi_mux_dump_children(struct lws *wsi)
+{
+#if defined(_DEBUG)
+	if (!wsi->mux.parent_wsi || !lwsl_visible(LLL_INFO))
+		return;
+
+	lws_start_foreach_llp(struct lws **, w,
+			      wsi->mux.parent_wsi->mux.child_list) {
+		lwsl_info("   \\---- child %s %p\n",
+			  (*w)->role_ops ? (*w)->role_ops->name : "?", *w);
+	} lws_end_foreach_llp(w, mux.sibling_list);
+#endif
+}
+
+void
+lws_wsi_mux_close_children(struct lws *wsi, int reason)
+{
+	struct lws *wsi2;
+
+	if (!wsi->mux.child_list)
+		return;
+
+	lws_start_foreach_llp(struct lws **, w, wsi->mux.child_list) {
+		lwsl_info("   closing child %p\n", *w);
+		/* disconnect from siblings */
+		wsi2 = (*w)->mux.sibling_list;
+		(*w)->mux.sibling_list = NULL;
+		(*w)->socket_is_permanently_unusable = 1;
+		__lws_close_free_wsi(*w, reason, "mux child recurse");
+		*w = wsi2;
+		continue;
+	} lws_end_foreach_llp(w, mux.sibling_list);
+}
+
+
+void
+lws_wsi_mux_sibling_disconnect(struct lws *wsi)
+{
+	struct lws *wsi2;
+
+	lws_start_foreach_llp(struct lws **, w,
+			      wsi->mux.parent_wsi->mux.child_list) {
+
+		/* disconnect from siblings */
+		if (*w == wsi) {
+			wsi2 = (*w)->mux.sibling_list;
+			(*w)->mux.sibling_list = NULL;
+			*w = wsi2;
+			lwsl_debug("  %p disentangled from sibling %p\n",
+				  wsi, wsi2);
+			break;
+		}
+	} lws_end_foreach_llp(w, mux.sibling_list);
+	wsi->mux.parent_wsi->mux.child_count--;
+	wsi->mux.parent_wsi = NULL;
+}
+
+void
+lws_wsi_mux_dump_waiting_children(struct lws *wsi)
+{
+#if defined(_DEBUG)
+	lwsl_info("%s: %p: children waiting for POLLOUT service:\n",
+		  __func__, wsi);
+
+	wsi = wsi->mux.child_list;
+	while (wsi) {
+		lwsl_info("  %c %p %s %s\n",
+			  wsi->mux.requested_POLLOUT ? '*' : ' ',
+			  wsi, wsi->role_ops->name, wsi->protocol ?
+					  wsi->protocol->name : "noprotocol");
+
+		wsi = wsi->mux.sibling_list;
+	}
+#endif
+}
+
+int
+lws_wsi_mux_mark_parents_needing_writeable(struct lws *wsi)
+{
+	struct lws *network_wsi = lws_get_network_wsi(wsi), *wsi2;
+	int already = network_wsi->mux.requested_POLLOUT;
+
+	/* mark everybody above him as requesting pollout */
+
+	wsi2 = wsi;
+	while (wsi2) {
+		wsi2->mux.requested_POLLOUT = 1;
+		lwsl_info("mark %p pending writable\n", wsi2);
+		wsi2 = wsi2->mux.parent_wsi;
+	}
+
+	return already;
+}
+
+struct lws *
+lws_wsi_mux_move_child_to_tail(struct lws **wsi2)
+{
+	struct lws *w = *wsi2;
+
+	while (w) {
+		if (!w->mux.sibling_list) { /* w is the current last */
+			lwsl_debug("w=%p, *wsi2 = %p\n", w, *wsi2);
+
+			if (w == *wsi2) /* we are already last */
+				break;
+
+			/* last points to us as new last */
+			w->mux.sibling_list = *wsi2;
+
+			/* guy pointing to us until now points to
+			 * our old next */
+			*wsi2 = (*wsi2)->mux.sibling_list;
+
+			/* we point to nothing because we are last */
+			w->mux.sibling_list->mux.sibling_list = NULL;
+
+			/* w becomes us */
+			w = w->mux.sibling_list;
+			break;
+		}
+		w = w->mux.sibling_list;
+	}
+
+	/* clear the waiting for POLLOUT on the guy that was chosen */
+
+	if (w)
+		w->mux.requested_POLLOUT = 0;
+
+	return w;
+}
+
+int
+lws_wsi_mux_action_pending_writeable_reqs(struct lws *wsi)
+{
+	struct lws *w = wsi->mux.child_list;
+
+	while (w) {
+		if (w->mux.requested_POLLOUT) {
+			if (lws_change_pollfd(wsi, 0, LWS_POLLOUT))
+				return -1;
+			break;
+		}
+		w = w->mux.sibling_list;
+	}
+
+	return 0;
+}
+
+#if defined(LWS_WITH_CLIENT)
+
+int
+lws_wsi_mux_apply_queue(struct lws *wsi)
+{
+	/* we have a transaction queue that wants to pipeline */
+
+	lws_vhost_lock(wsi->vhost);
+	lws_start_foreach_dll_safe(struct lws_dll2 *, d, d1,
+				   wsi->dll2_cli_txn_queue_owner.head) {
+		struct lws *w = lws_container_of(d, struct lws,
+						 dll2_cli_txn_queue);
+
+		if (lwsi_role_http(wsi) &&
+		    lwsi_state(w) == LRS_H1C_ISSUE_HANDSHAKE2) {
+			lwsl_info("%s: cli pipeq %p to be h2\n", __func__, w);
+
+			/* remove ourselves from client queue */
+			lws_dll2_remove(&w->dll2_cli_txn_queue);
+
+			/* attach ourselves as an h2 stream */
+			lws_wsi_h2_adopt(wsi, w);
+		}
+
+	} lws_end_foreach_dll_safe(d, d1);
+	lws_vhost_unlock(wsi->vhost);
+
+	return 0;
+}
+
+#endif
+
+#endif
diff --git a/lib/roles/cgi/cgi-server.c b/lib/roles/cgi/cgi-server.c
index b34a33dad..a0f3bc891 100644
--- a/lib/roles/cgi/cgi-server.c
+++ b/lib/roles/cgi/cgi-server.c
@@ -597,7 +597,7 @@ lws_cgi_write_split_stdout_headers(struct lws *wsi)
 					WSI_TOKEN_HTTP_TRANSFER_ENCODING,
 					(unsigned char *)"chunked", 7, &p, end))
 				return 1;
-			if (!(wsi->http2_substream))
+			if (!(wsi->mux_substream))
 				if (lws_add_http_header_by_token(wsi,
 						WSI_TOKEN_CONNECTION,
 						(unsigned char *)"close", 5,
@@ -615,7 +615,7 @@ lws_cgi_write_split_stdout_headers(struct lws *wsi)
 			 * Let's redo them at headers_pos forward using the
 			 * correct coding for http/1 or http/2
 			 */
-			if (!wsi->http2_substream)
+			if (!wsi->mux_substream)
 				goto post_hpack_recode;
 
 			p = wsi->http.cgi->headers_start;
@@ -750,7 +750,7 @@ post_hpack_recode:
 		if (!wsi->http.cgi->headers_buf) {
 			/* if we don't already have a headers buf, cook one */
 			n = 2048;
-			if (wsi->http2_substream)
+			if (wsi->mux_substream)
 				n = 4096;
 			wsi->http.cgi->headers_buf = lws_malloc(n + LWS_PRE,
 							   "cgi hdr buf");
@@ -921,7 +921,7 @@ agin:
 
 	/* payload processing */
 
-	m = !wsi->http.cgi->implied_chunked && !wsi->http2_substream &&
+	m = !wsi->http.cgi->implied_chunked && !wsi->mux_substream &&
 	//    !wsi->http.cgi->explicitly_chunked &&
 	    !wsi->http.cgi->content_length;
 	n = lws_get_socket_fd(wsi->http.cgi->stdwsi[LWS_STDOUT]);
@@ -936,7 +936,7 @@ agin:
 	if (n > 0) {
 		// lwsl_hexdump_notice(buf, n);
 
-		if (!wsi->http2_substream && m) {
+		if (!wsi->mux_substream && m) {
 			char chdr[LWS_HTTP_CHUNK_HDR_SIZE];
 			m = lws_snprintf(chdr, LWS_HTTP_CHUNK_HDR_SIZE - 3,
 					 "%X\x0d\x0a", n);
@@ -948,7 +948,7 @@ agin:
 
 
 #if defined(LWS_WITH_HTTP2)
-		if (wsi->http2_substream) {
+		if (wsi->mux_substream) {
 			struct lws *nwsi = lws_get_network_wsi(wsi);
 
 			__lws_set_timeout(wsi,
@@ -974,7 +974,7 @@ agin:
 		wsi->http.cgi->content_length_seen += n;
 	} else {
 
-		if (!wsi->http2_substream && m) {
+		if (!wsi->mux_substream && m) {
 			uint8_t term[LWS_PRE + 6];
 
 			lwsl_notice("%s: sent trailer\n", __func__);
@@ -991,7 +991,7 @@ agin:
 
 		if (wsi->cgi_stdout_zero_length) {
 			lwsl_debug("%s: stdout is POLLHUP'd\n", __func__);
-			if (wsi->http2_substream)
+			if (wsi->mux_substream)
 				m = lws_write(wsi, (unsigned char *)start, 0,
 					      LWS_WRITE_HTTP_FINAL);
 			else
diff --git a/lib/roles/h1/ops-h1.c b/lib/roles/h1/ops-h1.c
index cc48aaae6..6007a1a06 100644
--- a/lib/roles/h1/ops-h1.c
+++ b/lib/roles/h1/ops-h1.c
@@ -212,7 +212,7 @@ postbody_completion:
 				if (n)
 					goto bail;
 
-				if (wsi->http2_substream)
+				if (wsi->mux_substream)
 					lwsi_set_state(wsi, LRS_ESTABLISHED);
 			}
 
diff --git a/lib/roles/h2/hpack.c b/lib/roles/h2/hpack.c
index 5ca884132..74bc1dcf5 100644
--- a/lib/roles/h2/hpack.c
+++ b/lib/roles/h2/hpack.c
@@ -1363,7 +1363,7 @@ int lws_add_http2_header_by_name(struct lws *wsi, const unsigned char *name,
 		if (name[len - 1] == ':')
 			len--;
 
-	if (wsi->http2_substream && !strncmp((const char *)name,
+	if (wsi->mux_substream && !strncmp((const char *)name,
 					     "transfer-encoding", len)) {
 		lwsl_header("rejecting %s\n", name);
 
diff --git a/lib/roles/h2/http2.c b/lib/roles/h2/http2.c
index 403d013d6..4525b969a 100644
--- a/lib/roles/h2/http2.c
+++ b/lib/roles/h2/http2.c
@@ -173,7 +173,7 @@ lws_wsi_server_new(struct lws_vhost *vh, struct lws *parent_wsi,
 	}
 
 	/* no more children allowed by parent */
-	if (parent_wsi->h2.child_count + 1 >
+	if (parent_wsi->mux.child_count + 1 >
 	    parent_wsi->h2.h2n->set.s[H2SET_MAX_CONCURRENT_STREAMS]) {
 		lwsl_notice("reached concurrent stream limit\n");
 		return NULL;
@@ -185,19 +185,12 @@ lws_wsi_server_new(struct lws_vhost *vh, struct lws *parent_wsi,
 	}
 
 	h2n->highest_sid_opened = sid;
-	wsi->h2.my_sid = sid;
-	wsi->http2_substream = 1;
+
+	lws_wsi_mux_insert(wsi, parent_wsi, sid);
+
+	wsi->mux_substream = 1;
 	wsi->seen_nonpseudoheader = 0;
 
-	wsi->h2.parent_wsi = parent_wsi;
-	wsi->role_ops = parent_wsi->role_ops;
-	/* new guy's sibling is whoever was the first child before */
-	wsi->h2.sibling_list = parent_wsi->h2.child_list;
-	/* first child is now the new guy */
-	parent_wsi->h2.child_list = wsi;
-	parent_wsi->h2.child_count++;
-
-	wsi->h2.my_priority = 16;
 	wsi->h2.tx_cr = nwsi->h2.h2n->set.s[H2SET_INITIAL_WINDOW_SIZE];
 	wsi->h2.peer_tx_cr_est =
 			nwsi->vhost->h2.set.s[H2SET_INITIAL_WINDOW_SIZE];
@@ -225,8 +218,8 @@ lws_wsi_server_new(struct lws_vhost *vh, struct lws *parent_wsi,
 
 bail1:
 	/* undo the insert */
-	parent_wsi->h2.child_list = wsi->h2.sibling_list;
-	parent_wsi->h2.child_count--;
+	parent_wsi->mux.child_list = wsi->mux.sibling_list;
+	parent_wsi->mux.child_count--;
 
 	vh->context->count_wsi_allocated--;
 
@@ -245,7 +238,7 @@ lws_wsi_h2_adopt(struct lws *parent_wsi, struct lws *wsi)
 	struct lws *nwsi = lws_get_network_wsi(parent_wsi);
 
 	/* no more children allowed by parent */
-	if (parent_wsi->h2.child_count + 1 >
+	if (parent_wsi->mux.child_count + 1 >
 	    parent_wsi->h2.h2n->set.s[H2SET_MAX_CONCURRENT_STREAMS]) {
 		lwsl_notice("reached concurrent stream limit\n");
 		return NULL;
@@ -255,18 +248,12 @@ lws_wsi_h2_adopt(struct lws *parent_wsi, struct lws *wsi)
 
 	wsi->seen_nonpseudoheader = 0;
 #if defined(LWS_WITH_CLIENT)
-	wsi->client_h2_substream = 1;
+	wsi->client_mux_substream = 1;
 #endif
 	wsi->h2.initialized = 1;
 
-	wsi->h2.parent_wsi = parent_wsi;
-	/* new guy's sibling is whoever was the first child before */
-	wsi->h2.sibling_list = parent_wsi->h2.child_list;
-	/* first child is now the new guy */
-	parent_wsi->h2.child_list = wsi;
-	parent_wsi->h2.child_count++;
+	lws_wsi_mux_insert(wsi, parent_wsi, wsi->mux.my_sid);
 
-	wsi->h2.my_priority = 16;
 	wsi->h2.tx_cr = nwsi->h2.h2n->set.s[H2SET_INITIAL_WINDOW_SIZE];
 	wsi->h2.peer_tx_cr_est =
 			nwsi->vhost->h2.set.s[H2SET_INITIAL_WINDOW_SIZE];
@@ -287,8 +274,8 @@ lws_wsi_h2_adopt(struct lws *parent_wsi, struct lws *wsi)
 
 bail1:
 	/* undo the insert */
-	parent_wsi->h2.child_list = wsi->h2.sibling_list;
-	parent_wsi->h2.child_count--;
+	parent_wsi->mux.child_list = wsi->mux.sibling_list;
+	parent_wsi->mux.child_count--;
 
 	if (wsi->user_space)
 		lws_free_set_NULL(wsi->user_space);
@@ -326,32 +313,6 @@ int lws_h2_issue_preface(struct lws *wsi)
 	return 0;
 }
 
-struct lws *
-lws_h2_wsi_from_id(struct lws *parent_wsi, unsigned int sid)
-{
-	lws_start_foreach_ll(struct lws *, wsi, parent_wsi->h2.child_list) {
-		if (wsi->h2.my_sid == sid)
-			return wsi;
-	} lws_end_foreach_ll(wsi, h2.sibling_list);
-
-	return NULL;
-}
-
-int lws_remove_server_child_wsi(struct lws_context *context, struct lws *wsi)
-{
-	lws_start_foreach_llp(struct lws **, w, wsi->h2.child_list) {
-		if (*w == wsi) {
-			*w = wsi->h2.sibling_list;
-			(wsi->h2.parent_wsi)->h2.child_count--;
-			return 0;
-		}
-	} lws_end_foreach_llp(w, h2.sibling_list);
-
-	lwsl_err("%s: can't find %p\n", __func__, wsi);
-
-	return 1;
-}
-
 void
 lws_pps_schedule(struct lws *wsi, struct lws_h2_protocol_send *pps)
 {
@@ -408,9 +369,9 @@ lws_h2_rst_stream(struct lws *wsi, uint32_t err, const char *reason)
 		return 1;
 
 	lwsl_info("%s: RST_STREAM 0x%x, sid %d, REASON '%s'\n", __func__, (int)err,
-			wsi->h2.my_sid, reason);
+			wsi->mux.my_sid, reason);
 
-	pps->u.rs.sid = wsi->h2.my_sid;
+	pps->u.rs.sid = wsi->mux.my_sid;
 	pps->u.rs.err = err;
 
 	lws_pps_schedule(wsi, pps);
@@ -486,7 +447,7 @@ lws_h2_settings(struct lws *wsi, struct http2_settings *settings,
 			 */
 
 			lws_start_foreach_ll(struct lws *, w,
-					     nwsi->h2.child_list) {
+					     nwsi->mux.child_list) {
 				lwsl_info("%s: adi child tc cr %d +%d -> %d",
 					    __func__,
 					    w->h2.tx_cr, b - (unsigned int)settings->s[a],
@@ -496,7 +457,7 @@ lws_h2_settings(struct lws *wsi, struct http2_settings *settings,
 				    w->h2.tx_cr <=
 						  (int32_t)(b - settings->s[a]))
 					lws_callback_on_writable(w);
-			} lws_end_foreach_ll(w, h2.sibling_list);
+			} lws_end_foreach_ll(w, mux.sibling_list);
 
 			break;
 		case H2SET_MAX_FRAME_SIZE:
@@ -553,7 +514,7 @@ lws_h2_tx_cr_get(struct lws *wsi)
 	int c = wsi->h2.tx_cr;
 	struct lws *nwsi = lws_get_network_wsi(wsi);
 
-	if (!wsi->http2_substream && !nwsi->upgraded_to_http2)
+	if (!wsi->mux_substream && !nwsi->upgraded_to_http2)
 		return ~0x80000000;
 
 	lwsl_info ("%s: %p: own tx credit %d: nwsi credit %d\n",
@@ -794,7 +755,7 @@ int lws_h2_do_pps_send(struct lws *wsi)
 			lwsl_info("send %d %d\n", n, m);
 			goto bail;
 		}
-		cwsi = lws_h2_wsi_from_id(wsi, pps->u.rs.sid);
+		cwsi = lws_wsi_mux_from_id(wsi, pps->u.rs.sid);
 		if (cwsi) {
 			lwsl_debug("%s: closing cwsi %p %s %s (wsi %p)\n",
 				   __func__, cwsi, cwsi->role_ops->name,
@@ -870,7 +831,7 @@ lws_h2_parse_frame_header(struct lws *wsi)
 					wsi->vhost->keepalive_timeout : 31);
 
 	if (h2n->sid)
-		h2n->swsi = lws_h2_wsi_from_id(wsi, h2n->sid);
+		h2n->swsi = lws_wsi_mux_from_id(wsi, h2n->sid);
 
 	lwsl_debug("%p (%p): fr hdr: typ 0x%x, fla 0x%x, sid 0x%x, len 0x%x\n",
 		  wsi, h2n->swsi, h2n->type, h2n->flags, (unsigned int)h2n->sid,
@@ -1127,7 +1088,7 @@ lws_h2_parse_frame_header(struct lws *wsi)
 #if defined(LWS_WITH_CLIENT)
 		if (wsi->client_h2_alpn) {
 			if (h2n->sid) {
-				h2n->swsi = lws_h2_wsi_from_id(wsi, h2n->sid);
+				h2n->swsi = lws_wsi_mux_from_id(wsi, h2n->sid);
 				lwsl_info("HEADERS: nwsi %p: sid %u mapped "
 					  "to wsi %p\n", wsi,
 					  (unsigned int)h2n->sid, h2n->swsi);
@@ -1140,7 +1101,7 @@ lws_h2_parse_frame_header(struct lws *wsi)
 
 		if (!h2n->swsi) {
 			/* no more children allowed by parent */
-			if (wsi->h2.child_count + 1 >
+			if (wsi->mux.child_count + 1 >
 			    wsi->h2.h2n->set.s[H2SET_MAX_CONCURRENT_STREAMS]) {
 				lws_h2_goaway(wsi, H2_ERR_PROTOCOL_ERROR,
 				"Another stream not allowed");
@@ -1195,12 +1156,12 @@ lws_h2_parse_frame_header(struct lws *wsi)
 		 * transitions to the "closed" state when the first frame for
 		 * stream 7 is sent or received.
 		 */
-		lws_start_foreach_ll(struct lws *, w, wsi->h2.child_list) {
-			if (w->h2.my_sid < h2n->sid &&
+		lws_start_foreach_ll(struct lws *, w, wsi->mux.child_list) {
+			if (w->mux.my_sid < h2n->sid &&
 			    w->h2.h2_state == LWS_H2_STATE_IDLE)
 				lws_close_free_wsi(w, 0, "h2 sid close");
-			assert(w->h2.sibling_list != w);
-		} lws_end_foreach_ll(w, h2.sibling_list);
+			assert(w->mux.sibling_list != w);
+		} lws_end_foreach_ll(w, mux.sibling_list);
 
 		if (lws_check_opt(h2n->swsi->vhost->options,
 			       LWS_SERVER_OPTION_VH_H2_HALF_CLOSED_LONG_POLL)) {
@@ -1210,7 +1171,7 @@ lws_h2_parse_frame_header(struct lws *wsi)
 			 * half-closed remote state, allowing immortal long
 			 * poll
 			 */
-			lws_http_mark_immortal(h2n->swsi);
+			lws_mux_mark_immortal(h2n->swsi);
 			lwsl_info("%s: %p: h2 stream entering long poll\n",
 					__func__, h2n->swsi);
 
@@ -1299,7 +1260,7 @@ lws_h2_parse_end_of_frame(struct lws *wsi)
 	h2n->count = 0;
 
 	if (h2n->sid)
-		h2n->swsi = lws_h2_wsi_from_id(wsi, h2n->sid);
+		h2n->swsi = lws_wsi_mux_from_id(wsi, h2n->sid);
 
 	if (h2n->sid > h2n->highest_sid)
 		h2n->highest_sid = h2n->sid;
@@ -1322,7 +1283,7 @@ lws_h2_parse_end_of_frame(struct lws *wsi)
 	case LWS_H2_FRAME_TYPE_SETTINGS:
 
 #if defined(LWS_WITH_CLIENT)
-		if (wsi->client_h2_alpn && !wsi->client_h2_migrated &&
+		if (wsi->client_h2_alpn && !wsi->client_mux_migrated &&
 		    !(h2n->flags & LWS_H2_FLAG_SETTINGS_ACK)) {
 			struct lws_h2_protocol_send *pps;
 
@@ -1331,7 +1292,7 @@ lws_h2_parse_end_of_frame(struct lws *wsi)
 			wsi->http.fop_fd = NULL;
 #endif
 			lwsl_info("%s: migrating\n", __func__);
-			wsi->client_h2_migrated = 1;
+			wsi->client_mux_migrated = 1;
 			/*
 			 * we need to treat the headers from the upgrade as the
 			 * first job.  So these need to get shifted to sid 1.
@@ -1341,7 +1302,7 @@ lws_h2_parse_end_of_frame(struct lws *wsi)
 				return 1;
 			h2n->sid = 1;
 
-			assert(lws_h2_wsi_from_id(wsi, 1) == h2n->swsi);
+			assert(lws_wsi_mux_from_id(wsi, 1) == h2n->swsi);
 
 			lws_role_transition(wsi, LWSIFR_CLIENT,
 					    LRS_H2_WAITING_TO_SEND_HEADERS,
@@ -1353,7 +1314,7 @@ lws_h2_parse_end_of_frame(struct lws *wsi)
 
 			/* pass on the initial headers to SID 1 */
 			h2n->swsi->http.ah = wsi->http.ah;
-			h2n->swsi->client_h2_substream = 1;
+			h2n->swsi->client_mux_substream = 1;
 #if defined(LWS_WITH_CLIENT)
 			h2n->swsi->flags = wsi->flags;
 #endif
@@ -1383,39 +1344,20 @@ lws_h2_parse_end_of_frame(struct lws *wsi)
 
 			lws_callback_on_writable(h2n->swsi);
 
-			if (!wsi->h2_acked_settings
-#if defined(LWS_WITH_CLIENT)
-				|| !(wsi->flags & LCCSCF_H2_QUIRK_NGHTTP2_END_STREAM)
-#endif
+			if (!wsi->h2_acked_settings ||
+			    !(wsi->flags & LCCSCF_H2_QUIRK_NGHTTP2_END_STREAM)
 			) {
 				pps = lws_h2_new_pps(LWS_H2_PPS_ACK_SETTINGS);
 				if (!pps)
 					return 1;
 				lws_pps_schedule(wsi, pps);
-				lwsl_info("%s: scheduled settings ack PPS\n", __func__);
+				lwsl_info("%s: SETTINGS ack PPS\n", __func__);
 				wsi->h2_acked_settings = 1;
 			}
 
 			/* also attach any queued guys */
 
-			/* we have a transaction queue that wants to pipeline */
-			lws_vhost_lock(wsi->vhost);
-			lws_start_foreach_dll_safe(struct lws_dll2 *, d, d1,
-				  wsi->dll2_cli_txn_queue_owner.head) {
-				struct lws *w = lws_container_of(d, struct lws,
-						dll2_cli_txn_queue);
-
-				if (lwsi_state(w) == LRS_H1C_ISSUE_HANDSHAKE2) {
-					lwsl_info("%s: cli pipeq %p to be h2\n",
-							__func__, w);
-					/* remove ourselves from client queue */
-					lws_dll2_remove(&w->dll2_cli_txn_queue);
-
-					/* attach ourselves as an h2 stream */
-					lws_wsi_h2_adopt(wsi, w);
-				}
-			} lws_end_foreach_dll_safe(d, d1);
-			lws_vhost_unlock(wsi->vhost);
+			lws_wsi_mux_apply_queue(wsi);
 		}
 #endif
 		break;
@@ -1468,7 +1410,7 @@ lws_h2_parse_end_of_frame(struct lws *wsi)
 		h2n->swsi->hdr_parsing_completed = 1;
 
 #if defined(LWS_WITH_CLIENT)
-		if (h2n->swsi->client_h2_substream) {
+		if (h2n->swsi->client_mux_substream) {
 			if (lws_client_interpret_server_handshake(h2n->swsi)) {
 				lwsl_info("%s: cli int serv hs closed it\n", __func__);
 				break;
@@ -1538,7 +1480,7 @@ lws_h2_parse_end_of_frame(struct lws *wsi)
 		}
 
 #if defined(LWS_WITH_CLIENT)
-		if (h2n->swsi->client_h2_substream) {
+		if (h2n->swsi->client_mux_substream) {
 			lwsl_info("%s: headers: client path\n", __func__);
 			break;
 		}
@@ -1622,7 +1564,7 @@ lws_h2_parse_end_of_frame(struct lws *wsi)
 		 * send anything else anyway.
 		 */
 
-		if (h2n->swsi->client_h2_substream &&
+		if (h2n->swsi->client_mux_substream &&
 		    (h2n->flags & LWS_H2_FLAG_END_STREAM)) {
 			lwsl_info("%s: %p: DATA: end stream\n",
 				  __func__, h2n->swsi);
@@ -1719,9 +1661,9 @@ lws_h2_parse_end_of_frame(struct lws *wsi)
 		 * It did change sendability... for us and any children waiting
 		 * on us... reassess blockage for all children first
 		 */
-		lws_start_foreach_ll(struct lws *, w, wsi->h2.child_list) {
+		lws_start_foreach_ll(struct lws *, w, wsi->mux.child_list) {
 			lws_callback_on_writable(w);
-		} lws_end_foreach_ll(w, h2.sibling_list);
+		} lws_end_foreach_ll(w, mux.sibling_list);
 
 		if (eff_wsi->h2.skint && lws_h2_tx_cr_get(eff_wsi)) {
 			lwsl_info("%s: %p: skint\n", __func__, wsi);
@@ -1974,7 +1916,7 @@ lws_h2_parser(struct lws *wsi, unsigned char *in, lws_filepos_t inlen,
 					lwsl_debug("---- restricting len to %d vs %ld\n", n, (long)inlen + 1);
 				}
 #if defined(LWS_WITH_CLIENT)
-				if (h2n->swsi->client_h2_substream) {
+				if (h2n->swsi->client_mux_substream) {
 					if (!h2n->swsi->protocol) {
 						lwsl_err("%s: swsi %pdoesn't have protocol\n", __func__, h2n->swsi);
 						m = 1;
@@ -2245,10 +2187,10 @@ lws_h2_client_handshake(struct lws *wsi)
 	int sid = nwsi->h2.h2n->highest_sid_opened + 2;
 
 	nwsi->h2.h2n->highest_sid_opened = sid;
-	wsi->h2.my_sid = sid;
+	wsi->mux.my_sid = sid;
 
 	lwsl_info("%s: CLIENT_WAITING_TO_SEND_HEADERS: pollout (sid %d)\n",
-			__func__, wsi->h2.my_sid);
+			__func__, wsi->mux.my_sid);
 
 	pps = lws_h2_new_pps(LWS_H2_PPS_UPDATE_WINDOW);
 	if (!pps)
@@ -2526,7 +2468,7 @@ int
 lws_h2_client_stream_long_poll_rxonly(struct lws *wsi)
 {
 
-	if (!wsi->http2_substream)
+	if (!wsi->mux_substream)
 		return 1;
 
 	/*
diff --git a/lib/roles/h2/ops-h2.c b/lib/roles/h2/ops-h2.c
index d54bd94da..7e6a02195 100644
--- a/lib/roles/h2/ops-h2.c
+++ b/lib/roles/h2/ops-h2.c
@@ -164,7 +164,7 @@ rops_handle_POLLIN_h2(struct lws_context_per_thread *pt, struct lws *wsi,
 #endif
 	}
 
-	if (wsi->http2_substream || wsi->upgraded_to_http2) {
+	if (wsi->mux_substream || wsi->upgraded_to_http2) {
 		wsi1 = lws_get_network_wsi(wsi);
 		if (wsi1 && lws_has_buffered_out(wsi1))
 			/*
@@ -386,7 +386,7 @@ rops_write_role_protocol_h2(struct lws *wsi, unsigned char *buf, size_t len,
 
 	/* if not in a state to send stuff, then just send nothing */
 
-	if (!lwsi_role_ws(wsi) && !wsi->h2_stream_immortal &&
+	if (!lwsi_role_ws(wsi) && !wsi->mux_stream_immortal &&
 	    base != LWS_WRITE_HTTP &&
 	    base != LWS_WRITE_HTTP_FINAL &&
 	    base != LWS_WRITE_HTTP_HEADERS_CONTINUATION &&
@@ -477,7 +477,7 @@ rops_write_role_protocol_h2(struct lws *wsi, unsigned char *buf, size_t len,
 		wsi->h2.send_END_STREAM = 1;
 	}
 
-	n = lws_h2_frame_write(wsi, n, flags, wsi->h2.my_sid, (int)len, buf);
+	n = lws_h2_frame_write(wsi, n, flags, wsi->mux.my_sid, (int)len, buf);
 	if (n < 0)
 		return n;
 
@@ -500,7 +500,7 @@ rops_check_upgrades_h2(struct lws *wsi)
 	 */
 	p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP_COLON_METHOD);
 	if (!wsi->vhost->h2.set.s[H2SET_ENABLE_CONNECT_PROTOCOL] ||
-	    !wsi->http2_substream || !p || strcmp(p, "CONNECT"))
+	    !wsi->mux_substream || !p || strcmp(p, "CONNECT"))
 		return LWS_UPG_RET_CONTINUE;
 
 	p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_COLON_PROTOCOL);
@@ -511,7 +511,7 @@ rops_check_upgrades_h2(struct lws *wsi)
 	wsi->vhost->conn_stats.ws_upg++;
 #endif
 	lwsl_info("Upgrade h2 to ws\n");
-	lws_http_mark_immortal(wsi);
+	lws_mux_mark_immortal(wsi);
 	wsi->h2_stream_carries_ws = 1;
 
 	if (lws_process_ws_upgrade(wsi))
@@ -599,7 +599,7 @@ rops_destroy_role_h2(struct lws *wsi)
 	lws_http_compression_destroy(wsi);
 #endif
 
-	if (wsi->upgraded_to_http2 || wsi->http2_substream) {
+	if (wsi->upgraded_to_http2 || wsi->mux_substream) {
 		lws_hpack_destroy_dynamic_header(wsi);
 
 		if (wsi->h2.h2n)
@@ -612,7 +612,6 @@ rops_destroy_role_h2(struct lws *wsi)
 static int
 rops_close_kill_connection_h2(struct lws *wsi, enum lws_close_status reason)
 {
-	struct lws *wsi2;
 
 #if defined(LWS_WITH_HTTP_PROXY)
 	if (wsi->http.proxy_clientside) {
@@ -628,53 +627,28 @@ rops_close_kill_connection_h2(struct lws *wsi, enum lws_close_status reason)
 	}
 #endif
 
-	if (wsi->http2_substream && wsi->h2_stream_carries_ws)
+	if (wsi->mux_substream && wsi->h2_stream_carries_ws)
 		lws_h2_rst_stream(wsi, 0, "none");
 /*	else
-		if (wsi->http2_substream)
+		if (wsi->mux_substream)
 			lws_h2_rst_stream(wsi, H2_ERR_STREAM_CLOSED, "swsi got closed");
 */
 
-	if (wsi->h2.parent_wsi && lwsl_visible(LLL_INFO)) {
-		lwsl_info(" wsi: %p, his parent %p: siblings:\n", wsi,
-			  wsi->h2.parent_wsi);
-		lws_start_foreach_llp(struct lws **, w,
-				      wsi->h2.parent_wsi->h2.child_list) {
-			lwsl_info("   \\---- child %s %p\n",
-				  (*w)->role_ops ? (*w)->role_ops->name : "?", *w);
-		} lws_end_foreach_llp(w, h2.sibling_list);
-	}
+	lwsl_info(" wsi: %p, his parent %p: siblings:\n", wsi, wsi->mux.parent_wsi);
+	lws_wsi_mux_dump_children(wsi);
 
-	if (wsi->upgraded_to_http2 || wsi->http2_substream
+	if (wsi->upgraded_to_http2 || wsi->mux_substream
 #if defined(LWS_WITH_CLIENT)
-			|| wsi->client_h2_substream
+			|| wsi->client_mux_substream
 #endif
 	) {
-		lwsl_info("closing %p: parent %p\n", wsi, wsi->h2.parent_wsi);
+		lwsl_info("closing %p: parent %p\n", wsi, wsi->mux.parent_wsi);
 
-		if (wsi->h2.child_list && lwsl_visible(LLL_INFO)) {
+		if (wsi->mux.child_list && lwsl_visible(LLL_INFO)) {
 			lwsl_info(" parent %p: closing children: list:\n", wsi);
-			lws_start_foreach_llp(struct lws **, w,
-					      wsi->h2.child_list) {
-				lwsl_info("   \\---- child %s %p\n",
-					  (*w)->role_ops ? (*w)->role_ops->name : "?",
-					  *w);
-			} lws_end_foreach_llp(w, h2.sibling_list);
-		}
-		if (wsi->h2.child_list) {
-			/* trigger closing of all of our http2 children first */
-			lws_start_foreach_llp(struct lws **, w,
-					      wsi->h2.child_list) {
-				lwsl_info("   closing child %p\n", *w);
-				/* disconnect from siblings */
-				wsi2 = (*w)->h2.sibling_list;
-				(*w)->h2.sibling_list = NULL;
-				(*w)->socket_is_permanently_unusable = 1;
-				__lws_close_free_wsi(*w, reason, "h2 child recurse");
-				*w = wsi2;
-				continue;
-			} lws_end_foreach_llp(w, h2.sibling_list);
+			lws_wsi_mux_dump_children(wsi);
 		}
+		lws_wsi_mux_close_children(wsi, reason);
 	}
 
 	if (wsi->upgraded_to_http2) {
@@ -691,25 +665,11 @@ rops_close_kill_connection_h2(struct lws *wsi, enum lws_close_status reason)
 
 	if ((
 #if defined(LWS_WITH_CLIENT)
-			wsi->client_h2_substream ||
+			wsi->client_mux_substream ||
 #endif
-			wsi->http2_substream) &&
-	     wsi->h2.parent_wsi) {
-		lws_start_foreach_llp(struct lws **, w,
-				wsi->h2.parent_wsi->h2.child_list) {
-
-			/* disconnect from siblings */
-			if (*w == wsi) {
-				wsi2 = (*w)->h2.sibling_list;
-				(*w)->h2.sibling_list = NULL;
-				*w = wsi2;
-				lwsl_debug("  %p disentangled from sibling %p\n",
-					  wsi, wsi2);
-				break;
-			}
-		} lws_end_foreach_llp(w, h2.sibling_list);
-		wsi->h2.parent_wsi->h2.child_count--;
-		wsi->h2.parent_wsi = NULL;
+			wsi->mux_substream) &&
+	     wsi->mux.parent_wsi) {
+		lws_wsi_mux_sibling_disconnect(wsi);
 		if (wsi->h2.pending_status_body)
 			lws_free_set_NULL(wsi->h2.pending_status_body);
 	}
@@ -720,7 +680,9 @@ rops_close_kill_connection_h2(struct lws *wsi, enum lws_close_status reason)
 static int
 rops_callback_on_writable_h2(struct lws *wsi)
 {
-	struct lws *network_wsi, *wsi2;
+#if defined(LWS_WITH_CLIENT)
+	struct lws *network_wsi;
+#endif
 	int already;
 
 	//lwsl_notice("%s: %p (wsistate 0x%x)\n", __func__, wsi, wsi->wsistate);
@@ -728,7 +690,7 @@ rops_callback_on_writable_h2(struct lws *wsi)
 //	if (!lwsi_role_h2(wsi) && !lwsi_role_h2_ENCAPSULATION(wsi))
 //		return 0;
 
-	if (wsi->h2.requested_POLLOUT
+	if (wsi->mux.requested_POLLOUT
 #if defined(LWS_WITH_CLIENT)
 			&& !wsi->client_h2_alpn
 #endif
@@ -755,24 +717,17 @@ rops_callback_on_writable_h2(struct lws *wsi)
 	}
 
 	wsi->h2.skint = 0;
+#if defined(LWS_WITH_CLIENT)
 	network_wsi = lws_get_network_wsi(wsi);
-	already = network_wsi->h2.requested_POLLOUT;
-
-	/* mark everybody above him as requesting pollout */
-
-	wsi2 = wsi;
-	while (wsi2) {
-		wsi2->h2.requested_POLLOUT = 1;
-		lwsl_info("mark %p pending writable\n", wsi2);
-		wsi2 = wsi2->h2.parent_wsi;
-	}
+#endif
+	already = lws_wsi_mux_mark_parents_needing_writeable(wsi);
 
 	/* for network action, act only on the network wsi */
 
 	if (already
 #if defined(LWS_WITH_CLIENT)
 			&& !network_wsi->client_h2_alpn
-			&& !network_wsi->client_h2_substream
+			&& !network_wsi->client_mux_substream
 #endif
 			)
 		return 1;
@@ -780,25 +735,6 @@ rops_callback_on_writable_h2(struct lws *wsi)
 	return 0;
 }
 
-static void
-lws_h2_dump_waiting_children(struct lws *wsi)
-{
-#if defined(_DEBUG)
-	lwsl_info("%s: %p: children waiting for POLLOUT service:\n",
-		  __func__, wsi);
-
-	wsi = wsi->h2.child_list;
-	while (wsi) {
-		lwsl_info("  %c %p %s %s\n",
-			  wsi->h2.requested_POLLOUT ? '*' : ' ',
-			  wsi, wsi->role_ops->name, wsi->protocol ?
-					  wsi->protocol->name : "noprotocol");
-
-		wsi = wsi->h2.sibling_list;
-	}
-#endif
-}
-
 #if defined(LWS_WITH_SERVER)
 static int
 lws_h2_bind_for_post_before_action(struct lws *wsi)
@@ -859,7 +795,7 @@ lws_h2_bind_for_post_before_action(struct lws *wsi)
 static int
 rops_perform_user_POLLOUT_h2(struct lws *wsi)
 {
-	struct lws **wsi2, *wsi2a;
+	struct lws **wsi2;
 #if defined(LWS_ROLE_WS)
 	int write_type = LWS_WRITE_PONG;
 #endif
@@ -867,23 +803,23 @@ rops_perform_user_POLLOUT_h2(struct lws *wsi)
 
 	wsi = lws_get_network_wsi(wsi);
 
-	wsi->h2.requested_POLLOUT = 0;
+	wsi->mux.requested_POLLOUT = 0;
 	if (!wsi->h2.initialized) {
 		lwsl_info("pollout on uninitialized http2 conn\n");
 		return 0;
 	}
 
-	lws_h2_dump_waiting_children(wsi);
+	lws_wsi_mux_dump_waiting_children(wsi);
 
-	wsi2 = &wsi->h2.child_list;
+	wsi2 = &wsi->mux.child_list;
 	if (!*wsi2)
 		return 0;
 
 	do {
 		struct lws *w, **wa;
 
-		wa = &(*wsi2)->h2.sibling_list;
-		if (!(*wsi2)->h2.requested_POLLOUT)
+		wa = &(*wsi2)->mux.sibling_list;
+		if (!(*wsi2)->mux.requested_POLLOUT)
 			goto next_child;
 
 		/*
@@ -893,32 +829,13 @@ rops_perform_user_POLLOUT_h2(struct lws *wsi)
 
 		lwsl_debug("servicing child %p\n", *wsi2);
 
-		w = *wsi2;
-		while (w) {
-			if (!w->h2.sibling_list) { /* w is the current last */
-				lwsl_debug("w=%p, *wsi2 = %p\n", w, *wsi2);
-				if (w == *wsi2) /* we are already last */
-					break;
-				/* last points to us as new last */
-				w->h2.sibling_list = *wsi2;
-				/* guy pointing to us until now points to
-				 * our old next */
-				*wsi2 = (*wsi2)->h2.sibling_list;
-				/* we point to nothing because we are last */
-				w->h2.sibling_list->h2.sibling_list = NULL;
-				/* w becomes us */
-				w = w->h2.sibling_list;
-				break;
-			}
-			w = w->h2.sibling_list;
-		}
+		w = lws_wsi_mux_move_child_to_tail(wsi2);
 
 		if (!w) {
-			wa = &wsi->h2.child_list;
+			wa = &wsi->mux.child_list;
 			goto next_child;
 		}
 
-		w->h2.requested_POLLOUT = 0;
 		lwsl_info("%s: child %p (wsistate 0x%x)\n", __func__, w,
 			  (unsigned int)w->wsistate);
 
@@ -930,11 +847,11 @@ rops_perform_user_POLLOUT_h2(struct lws *wsi)
 				lwsl_info("%s signalling to close\n", __func__);
 				lws_close_free_wsi(w, LWS_CLOSE_STATUS_NOSTATUS,
 						   "h2 end stream 1");
-				wa = &wsi->h2.child_list;
+				wa = &wsi->mux.child_list;
 				goto next_child;
 			}
 			lws_callback_on_writable(w);
-			wa = &wsi->h2.child_list;
+			wa = &wsi->mux.child_list;
 			goto next_child;
 		}
 
@@ -956,7 +873,7 @@ rops_perform_user_POLLOUT_h2(struct lws *wsi)
 						   "comp write fail");
 			}
 			lws_callback_on_writable(w);
-			wa = &wsi->h2.child_list;
+			wa = &wsi->mux.child_list;
 			goto next_child;
 		}
 #endif
@@ -967,7 +884,7 @@ rops_perform_user_POLLOUT_h2(struct lws *wsi)
 			w->socket_is_permanently_unusable = 1;
 			lws_close_free_wsi(w, LWS_CLOSE_STATUS_NOSTATUS,
 					   "h2 end stream 1");
-			wa = &wsi->h2.child_list;
+			wa = &wsi->mux.child_list;
 			goto next_child;
 		}
 
@@ -984,7 +901,7 @@ rops_perform_user_POLLOUT_h2(struct lws *wsi)
 			lws_free_set_NULL(w->h2.pending_status_body);
 			lws_close_free_wsi(w, LWS_CLOSE_STATUS_NOSTATUS,
 					   "h2 end stream 1");
-			wa = &wsi->h2.child_list;
+			wa = &wsi->mux.child_list;
 			goto next_child;
 		}
 
@@ -1031,11 +948,11 @@ rops_perform_user_POLLOUT_h2(struct lws *wsi)
 				lwsl_info("closing stream after h2 action\n");
 				lws_close_free_wsi(w, LWS_CLOSE_STATUS_NOSTATUS,
 						   "h2 end stream");
-				wa = &wsi->h2.child_list;
+				wa = &wsi->mux.child_list;
 			}
 
 			if (n < 0)
-				wa = &wsi->h2.child_list;
+				wa = &wsi->mux.child_list;
 
 			goto next_child;
 		}
@@ -1063,7 +980,7 @@ rops_perform_user_POLLOUT_h2(struct lws *wsi)
 				lwsl_debug("Closing POLLOUT child %p\n", w);
 				lws_close_free_wsi(w, LWS_CLOSE_STATUS_NOSTATUS,
 						   "h2 end stream file");
-				wa = &wsi->h2.child_list;
+				wa = &wsi->mux.child_list;
 				goto next_child;
 			}
 			if (n > 0)
@@ -1071,7 +988,7 @@ rops_perform_user_POLLOUT_h2(struct lws *wsi)
 					return -1;
 			if (!n) {
 				lws_callback_on_writable(w);
-				(w)->h2.requested_POLLOUT = 1;
+				(w)->mux.requested_POLLOUT = 1;
 			}
 
 			goto next_child;
@@ -1126,12 +1043,12 @@ rops_perform_user_POLLOUT_h2(struct lws *wsi)
 				lwsi_set_state(w, LRS_RETURNED_CLOSE);
 				lws_close_free_wsi(w, LWS_CLOSE_STATUS_NOSTATUS,
 						   "returned close packet");
-				wa = &wsi->h2.child_list;
+				wa = &wsi->mux.child_list;
 				goto next_child;
 			}
 
 			lws_callback_on_writable(w);
-			(w)->h2.requested_POLLOUT = 1;
+			(w)->mux.requested_POLLOUT = 1;
 
 			/* otherwise for PING, leave POLLOUT active both ways */
 			goto next_child;
@@ -1154,7 +1071,7 @@ rops_perform_user_POLLOUT_h2(struct lws *wsi)
 							 &wp)) {
 				lwsl_info("%s: wsi %p: entering ro long poll\n",
 					  __func__, w);
-				lws_http_mark_immortal(w);
+				lws_mux_mark_immortal(w);
 			} else
 				lwsl_err("%s: wsi %p: failed to set long poll\n",
 						__func__, w);
@@ -1166,7 +1083,7 @@ rops_perform_user_POLLOUT_h2(struct lws *wsi)
 				  w->h2.send_END_STREAM);
 			lws_close_free_wsi(w, LWS_CLOSE_STATUS_NOSTATUS,
 					   "h2 pollout handle");
-			wa = &wsi->h2.child_list;
+			wa = &wsi->mux.child_list;
 		} else
 			 if (w->h2.send_END_STREAM)
 				lws_h2_state(w, LWS_H2_STATE_HALF_CLOSED_LOCAL);
@@ -1175,17 +1092,10 @@ next_child:
 		wsi2 = wa;
 	} while (wsi2 && *wsi2 && !lws_send_pipe_choked(wsi));
 
-	// lws_h2_dump_waiting_children(wsi);
+	// lws_wsi_mux_dump_waiting_children(wsi);
 
-	wsi2a = wsi->h2.child_list;
-	while (wsi2a) {
-		if (wsi2a->h2.requested_POLLOUT) {
-			if (lws_change_pollfd(wsi, 0, LWS_POLLOUT))
-				return -1;
-			break;
-		}
-		wsi2a = wsi2a->h2.sibling_list;
-	}
+	if (lws_wsi_mux_action_pending_writeable_reqs(wsi))
+		return -1;
 
 	return 0;
 }
@@ -1193,8 +1103,8 @@ next_child:
 static struct lws *
 rops_encapsulation_parent_h2(struct lws *wsi)
 {
-	if (wsi->h2.parent_wsi)
-		return wsi->h2.parent_wsi;
+	if (wsi->mux.parent_wsi)
+		return wsi->mux.parent_wsi;
 
 	return NULL;
 }
diff --git a/lib/roles/h2/private-lib-roles-h2.h b/lib/roles/h2/private-lib-roles-h2.h
index 6c3b382d3..82c624bfc 100644
--- a/lib/roles/h2/private-lib-roles-h2.h
+++ b/lib/roles/h2/private-lib-roles-h2.h
@@ -315,37 +315,25 @@ struct lws_h2_netconn {
 
 struct _lws_h2_related {
 
-	struct lws_h2_netconn *h2n; /* malloc'd for root net conn */
-	struct lws *parent_wsi;
-	struct lws *child_list;
-	struct lws *sibling_list;
+	struct lws_h2_netconn	*h2n; /* malloc'd for root net conn */
 
-	char *pending_status_body;
+	char			*pending_status_body;
 
-	int tx_cr;
-	int peer_tx_cr_est;
-	unsigned int my_sid;
-	unsigned int child_count;
-	int my_priority;
-	uint32_t dependent_on;
+	int			tx_cr;
+	int			peer_tx_cr_est;
 
-	uint16_t END_STREAM:1;
-	uint16_t END_HEADERS:1;
-	uint16_t send_END_STREAM:1;
-	uint16_t long_poll:1;
-	uint16_t GOING_AWAY;
-	uint16_t requested_POLLOUT:1;
-	uint16_t skint:1;
+	uint8_t			END_STREAM:1;
+	uint8_t			END_HEADERS:1;
+	uint8_t			send_END_STREAM:1;
+	uint8_t			long_poll:1;
+	uint8_t			GOING_AWAY;
+	uint8_t			skint:1;
+	uint8_t			initialized:1;
 
-	uint16_t round_robin_POLLOUT;
-	uint16_t count_POLLOUT_children;
-
-	uint8_t h2_state; /* the RFC7540 state of the connection */
-	uint8_t weight;
-	uint8_t initialized;
+	uint8_t			h2_state; /* RFC7540 state of the connection */
 };
 
-#define HTTP2_IS_TOPLEVEL_WSI(wsi) (!wsi->h2.parent_wsi)
+#define HTTP2_IS_TOPLEVEL_WSI(wsi) (!wsi->mux.parent_wsi)
 
 int
 lws_h2_rst_stream(struct lws *wsi, uint32_t err, const char *reason);
@@ -363,7 +351,7 @@ LWS_EXTERN int
 lws_h2_frame_write(struct lws *wsi, int type, int flags, unsigned int sid,
 		   unsigned int len, unsigned char *buf);
 LWS_EXTERN struct lws *
-lws_h2_wsi_from_id(struct lws *wsi, unsigned int sid);
+lws_wsi_mux_from_id(struct lws *wsi, unsigned int sid);
 LWS_EXTERN int
 lws_hpack_interpret(struct lws *wsi, unsigned char c);
 LWS_EXTERN int
diff --git a/lib/roles/http/client/client-handshake.c b/lib/roles/http/client/client-handshake.c
index 496b5315f..83f6301f0 100644
--- a/lib/roles/http/client/client-handshake.c
+++ b/lib/roles/http/client/client-handshake.c
@@ -1099,7 +1099,7 @@ lws_client_reset(struct lws **pwsi, int ssl, const char *address, int port,
 	lws_free_set_NULL(stash);
 
 #if defined(LWS_WITH_HTTP2)
-	if (wsi->client_h2_substream)
+	if (wsi->client_mux_substream)
 		wsi->h2.END_STREAM = wsi->h2.END_HEADERS = 0;
 #endif
 
diff --git a/lib/roles/http/client/client-http.c b/lib/roles/http/client/client-http.c
index a1b8176d8..de3357fd3 100644
--- a/lib/roles/http/client/client-http.c
+++ b/lib/roles/http/client/client-http.c
@@ -642,7 +642,7 @@ lws_http_transaction_completed_client(struct lws *wsi)
 	n = _lws_generic_transaction_completed_active_conn(wsi);
 
 	if (wsi->http.ah) {
-		if (wsi->client_h2_substream)
+		if (wsi->client_mux_substream)
 			/*
 			 * As an h2 client, once we did our transaction, that is
 			 * it for us.  Further transactions will happen as new
@@ -729,7 +729,7 @@ lws_client_interpret_server_handshake(struct lws *wsi)
 		/* we are being an http client...
 		 */
 #if defined(LWS_ROLE_H2)
-		if (wsi->client_h2_alpn || wsi->client_h2_substream) {
+		if (wsi->client_h2_alpn || wsi->client_mux_substream) {
 			lwsl_debug("%s: %p: transitioning to h2 client\n",
 				   __func__, wsi);
 			lws_role_transition(wsi, LWSIFR_CLIENT,
@@ -767,7 +767,7 @@ lws_client_interpret_server_handshake(struct lws *wsi)
 	 */
 
 	wsi->http.conn_type = HTTP_CONNECTION_KEEP_ALIVE;
-	if (!wsi->client_h2_substream) {
+	if (!wsi->client_mux_substream) {
 		p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP);
 		if (wsi->do_ws && !p) {
 			lwsl_info("no URI\n");
@@ -910,7 +910,7 @@ lws_client_interpret_server_handshake(struct lws *wsi)
 
 		/* if h1 KA is allowed, enable the queued pipeline guys */
 
-		if (!wsi->client_h2_alpn && !wsi->client_h2_substream &&
+		if (!wsi->client_h2_alpn && !wsi->client_mux_substream &&
 		    w == wsi) { /* ie, coming to this for the first time */
 			if (wsi->http.conn_type == HTTP_CONNECTION_KEEP_ALIVE)
 				wsi->keepalive_active = 1;
diff --git a/lib/roles/http/header.c b/lib/roles/http/header.c
index 167de36b1..adcdc9ead 100644
--- a/lib/roles/http/header.c
+++ b/lib/roles/http/header.c
@@ -186,7 +186,7 @@ lws_add_http_common_headers(struct lws *wsi, unsigned int code,
 		/* there was no length... it normally means CONNECTION_CLOSE */
 #if defined(LWS_WITH_HTTP_STREAM_COMPRESSION)
 
-		if (!wsi->http2_substream && wsi->http.lcs) {
+		if (!wsi->mux_substream && wsi->http.lcs) {
 			/* so...
 			 *  - h1 connection
 			 *  - http compression transform active
@@ -208,7 +208,7 @@ lws_add_http_common_headers(struct lws *wsi, unsigned int code,
 				t = 1;
 		}
 #endif
-		if (!wsi->http2_substream) {
+		if (!wsi->mux_substream) {
 			if (lws_add_http_header_by_token(wsi,
 						 WSI_TOKEN_CONNECTION,
 						 (unsigned char *)ka[t],
@@ -437,7 +437,7 @@ lws_return_http_status(struct lws *wsi, unsigned int code,
 		return 1;
 
 #if defined(LWS_WITH_HTTP2)
-	if (wsi->http2_substream) {
+	if (wsi->mux_substream) {
 
 		/*
 		 * for HTTP/2, the headers must be sent separately, since they
diff --git a/lib/roles/http/parsers.c b/lib/roles/http/parsers.c
index 985e7d601..4cae75e0a 100644
--- a/lib/roles/http/parsers.c
+++ b/lib/roles/http/parsers.c
@@ -575,7 +575,7 @@ lws_hdr_custom_length(struct lws *wsi, const char *name, int nlen)
 {
 	ah_data_idx_t ll;
 
-	if (!wsi->http.ah || wsi->http2_substream)
+	if (!wsi->http.ah || wsi->mux_substream)
 		return -1;
 
 	ll = wsi->http.ah->unk_ll_head;
@@ -601,7 +601,7 @@ lws_hdr_custom_copy(struct lws *wsi, char *dst, int len, const char *name,
 	ah_data_idx_t ll;
 	int n;
 
-	if (!wsi->http.ah || wsi->http2_substream)
+	if (!wsi->http.ah || wsi->mux_substream)
 		return -1;
 
 	*dst = '\0';
@@ -1085,7 +1085,7 @@ swallow:
 			 * a known header, we'll snip this.
 			 */
 
-			if (!wsi->http2_substream && !ah->unk_pos) {
+			if (!wsi->mux_substream && !ah->unk_pos) {
 				ah->unk_pos = ah->pos;
 				/*
 				 * Prepare new unknown header linked-list entry
@@ -1107,7 +1107,7 @@ swallow:
 			pos = ah->lextable_pos;
 
 #if defined(LWS_WITH_CUSTOM_HEADERS)
-			if (!wsi->http2_substream && pos < 0 && c == ':') {
+			if (!wsi->mux_substream && pos < 0 && c == ':') {
 #if defined(_DEBUG)
 				char dotstar[64];
 				int uhlen;
@@ -1181,7 +1181,7 @@ nope:
 				/* b7 = 0, end or 3-byte */
 				if (lextable[pos] < FAIL_CHAR) {
 #if defined(LWS_WITH_CUSTOM_HEADERS)
-					if (!wsi->http2_substream) {
+					if (!wsi->mux_substream) {
 						/*
 						 * We hit a terminal marker, so
 						 * we recognized this header...
@@ -1227,7 +1227,7 @@ nope:
 #if !defined(LWS_WITH_CUSTOM_HEADERS)
 						ah->parser_state = WSI_TOKEN_SKIPPING;
 #endif
-						if (wsi->http2_substream)
+						if (wsi->mux_substream)
 							ah->parser_state = WSI_TOKEN_SKIPPING;
 						break;
 					}
@@ -1238,7 +1238,7 @@ nope:
 					 * We have the method, this is just an
 					 * unknown header then
 					 */
-					if (!wsi->http2_substream)
+					if (!wsi->mux_substream)
 						goto unknown_hdr;
 					else
 						break;
@@ -1266,7 +1266,7 @@ nope:
 			}
 			if (ah->lextable_pos < 0) {
 #if defined(LWS_WITH_CUSTOM_HEADERS)
-				if (!wsi->http2_substream)
+				if (!wsi->mux_substream)
 					goto unknown_hdr;
 #endif
 				/*
@@ -1321,7 +1321,7 @@ nope:
 unknown_hdr:
 			//ah->parser_state = WSI_TOKEN_SKIPPING;
 			//break;
-			if (!wsi->http2_substream)
+			if (!wsi->mux_substream)
 				break;
 #endif
 
diff --git a/lib/roles/http/server/access-log.c b/lib/roles/http/server/access-log.c
index f59dbaabf..0ac261066 100644
--- a/lib/roles/http/server/access-log.c
+++ b/lib/roles/http/server/access-log.c
@@ -70,7 +70,7 @@ lws_prepare_access_log_info(struct lws *wsi, char *uri_ptr, int uri_len, int met
 	else
 		strcpy(da, "01/Jan/1970:00:00:00 +0000");
 
-	if (wsi->http2_substream)
+	if (wsi->mux_substream)
 		me = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP_COLON_METHOD);
 	else
 		me = method_names[meth];
diff --git a/lib/roles/http/server/server.c b/lib/roles/http/server/server.c
index 303c4af6c..53ee8eacf 100644
--- a/lib/roles/http/server/server.c
+++ b/lib/roles/http/server/server.c
@@ -697,7 +697,7 @@ lws_http_serve(struct lws *wsi, char *uri, const char *origin,
 		if (n > (int)strlen(pvo->name) &&
 		    !strcmp(&path[n - strlen(pvo->name)], pvo->name)) {
 			wsi->interpreting = 1;
-			if (!wsi->http2_substream)
+			if (!wsi->mux_substream)
 				wsi->sending_chunked = 1;
 
 			wsi->protocol_interpret_idx = (char)(
@@ -777,7 +777,7 @@ lws_find_mount(struct lws *wsi, const char *uri_ptr, int uri_len)
 			     lws_hdr_total_length(wsi, WSI_TOKEN_GET_URI) ||
 			     lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI) ||
 			     lws_hdr_total_length(wsi, WSI_TOKEN_HEAD_URI) ||
-			     (wsi->http2_substream &&
+			     (wsi->mux_substream &&
 				lws_hdr_total_length(wsi,
 						WSI_TOKEN_HTTP_COLON_PATH)) ||
 			     hm->protocol) &&
@@ -930,7 +930,7 @@ lws_http_get_uri_and_method(struct lws *wsi, char **puri_ptr, int *puri_len)
 	}
 
 	if (count != 1 &&
-	    !((wsi->http2_substream || wsi->h2_stream_carries_ws) &&
+	    !((wsi->mux_substream || wsi->h2_stream_carries_ws) &&
 	      lws_hdr_total_length(wsi, WSI_TOKEN_HTTP_COLON_PATH))) {
 		lwsl_warn("multiple methods?\n");
 		return -1;
@@ -1311,7 +1311,7 @@ lws_http_action(struct lws *wsi)
 		}
 	}
 
-	if (wsi->http2_substream) {
+	if (wsi->mux_substream) {
 		wsi->http.request_version = HTTP_VERSION_2;
 	} else {
 		/* http_version? Default to 1.0, override with token: */
@@ -1359,7 +1359,7 @@ lws_http_action(struct lws *wsi)
 	 * if there is content supposed to be coming,
 	 * put a timeout on it having arrived
 	 */
-	if (!wsi->h2_stream_immortal)
+	if (!wsi->mux_stream_immortal)
 		lws_set_timeout(wsi, PENDING_TIMEOUT_HTTP_CONTENT,
 				wsi->context->timeout_secs);
 #ifdef LWS_WITH_TLS
@@ -1659,7 +1659,7 @@ deal_body:
 		/* Prepare to read body if we have a content length: */
 		lwsl_debug("wsi->http.rx_content_length %lld %d %d\n",
 			   (long long)wsi->http.rx_content_length,
-			   wsi->upgraded_to_http2, wsi->http2_substream);
+			   wsi->upgraded_to_http2, wsi->mux_substream);
 
 		if (wsi->http.content_length_explicitly_zero &&
 		    lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI)) {
@@ -2265,7 +2265,7 @@ lws_http_transaction_completed(struct lws *wsi)
 #endif
 
 	/* if we can't go back to accept new headers, drop the connection */
-	if (wsi->http2_substream)
+	if (wsi->mux_substream)
 		return 1;
 
 	if (wsi->seen_zero_length_recv)
@@ -2414,7 +2414,7 @@ lws_serve_http_file(struct lws *wsi, const char *file, const char *content_type,
 			if (lws_return_http_status(wsi, HTTP_STATUS_NOT_FOUND,
 						   NULL))
 						return -1;
-			return !wsi->http2_substream;
+			return !wsi->mux_substream;
 		}
 	}
 
@@ -2558,7 +2558,7 @@ lws_serve_http_file(struct lws *wsi, const char *file, const char *content_type,
 		goto bail;
 #endif
 
-	if (!wsi->http2_substream) {
+	if (!wsi->mux_substream) {
 		/* for http/1.1 ... */
 		if (!wsi->sending_chunked
 #if defined(LWS_WITH_HTTP_STREAM_COMPRESSION)
@@ -2686,7 +2686,7 @@ LWS_VISIBLE int lws_serve_http_file_fragment(struct lws *wsi)
 #endif
 	int n, m;
 
-	lwsl_debug("wsi->http2_substream %d\n", wsi->http2_substream);
+	lwsl_debug("wsi->mux_substream %d\n", wsi->mux_substream);
 
 	do {
 
@@ -2924,7 +2924,7 @@ all_sent:
 					 * state, not the root connection at the
 					 * network level
 					 */
-					if (wsi->http2_substream)
+					if (wsi->mux_substream)
 						return 1;
 					else
 						return -1;
diff --git a/lib/roles/ws/client-ws.c b/lib/roles/ws/client-ws.c
index fe117bf6a..8f6b9e767 100644
--- a/lib/roles/ws/client-ws.c
+++ b/lib/roles/ws/client-ws.c
@@ -257,7 +257,7 @@ lws_client_ws_upgrade(struct lws *wsi, const char **cce)
 		wsi->detlat.earliest_write_req_pre_write = 0;
 #endif
 
-	if (wsi->client_h2_substream) {/* !!! client ws-over-h2 not there yet */
+	if (wsi->client_mux_substream) {/* !!! client ws-over-h2 not there yet */
 		lwsl_warn("%s: client ws-over-h2 upgrade not supported yet\n",
 			  __func__);
 		*cce = "HS: h2 / ws upgrade unsupported";
diff --git a/lib/roles/ws/ops-ws.c b/lib/roles/ws/ops-ws.c
index baf150fa0..012448b99 100644
--- a/lib/roles/ws/ops-ws.c
+++ b/lib/roles/ws/ops-ws.c
@@ -1052,7 +1052,7 @@ rops_handle_POLLIN_ws(struct lws_context_per_thread *pt, struct lws *wsi,
 		return LWS_HPI_RET_HANDLED;
 
 #if defined(LWS_WITH_HTTP2)
-	if (wsi->http2_substream || wsi->upgraded_to_http2) {
+	if (wsi->mux_substream || wsi->upgraded_to_http2) {
 		wsi1 = lws_get_network_wsi(wsi);
 		if (wsi1 && lws_has_buffered_out(wsi1))
 			/* We cannot deal with any kind of new RX
@@ -1329,7 +1329,7 @@ int rops_handle_POLLOUT_ws(struct lws *wsi)
 
 		lwsl_info("%s: issuing ping on wsi %p: %s %s h2: %d\n", __func__, wsi,
 				wsi->role_ops->name, wsi->protocol->name,
-				wsi->http2_substream);
+				wsi->mux_substream);
 		wsi->ws->send_check_ping = 0;
 		n = lws_write(wsi, &wsi->ws->ping_payload_buf[LWS_PRE],
 			      0, LWS_WRITE_PING);
@@ -1914,7 +1914,7 @@ rops_close_kill_connection_ws(struct lws *wsi, enum lws_close_status reason)
 {
 	/* deal with ws encapsulation in h2 */
 #if defined(LWS_WITH_HTTP2)
-	if (wsi->http2_substream && wsi->h2_stream_carries_ws)
+	if (wsi->mux_substream && wsi->h2_stream_carries_ws)
 		return role_ops_h2.close_kill_connection(wsi, reason);
 
 	return 0;
diff --git a/lib/roles/ws/server-ws.c b/lib/roles/ws/server-ws.c
index 3f1813aa5..862564e3d 100644
--- a/lib/roles/ws/server-ws.c
+++ b/lib/roles/ws/server-ws.c
@@ -420,7 +420,7 @@ lws_process_ws_upgrade(struct lws *wsi)
 	 */
 
 #if defined(LWS_WITH_HTTP2)
-	if (!wsi->http2_substream) {
+	if (!wsi->mux_substream) {
 #endif
 
 		lws_tokenize_init(&ts, buf, LWS_TOKENIZE_F_COMMA_SEP_LIST |
diff --git a/minimal-examples/selftests-library.sh b/minimal-examples/selftests-library.sh
index 4bd6b06a7..5a924ac16 100755
--- a/minimal-examples/selftests-library.sh
+++ b/minimal-examples/selftests-library.sh
@@ -57,7 +57,7 @@ dotest() {
 	T=$3
 	(
 		{
-			/usr/bin/time -p /usr/bin/valgrind $1/lws-$MYTEST $4 $5 $6 $7 $8 $9 > $2/$MYTEST/$T.log 2> $2/$MYTEST/$T.log ;
+			/usr/bin/time -p /usr/bin/valgrind -q $1/lws-$MYTEST $4 $5 $6 $7 $8 $9 > $2/$MYTEST/$T.log 2> $2/$MYTEST/$T.log ;
 			echo $? > $2/$MYTEST/$T.result
 		} 2> $2/$MYTEST/$T.time >/dev/null
 	) >/dev/null 2> /dev/null &