diff --git a/mgw/MGCP_Test.ttcn b/mgw/MGCP_Test.ttcn
index c54fdb428..a99e2733f 100644
--- a/mgw/MGCP_Test.ttcn
+++ b/mgw/MGCP_Test.ttcn
@@ -85,7 +85,7 @@ module MGCP_Test {
 		PortNumber mp_mgw_statsd_port := 8125;
 		PortNumber mp_mgw_ctrl_port := 4267;
 		/* Maximum number of available endpoints in osmo-mgw.cfg ("number endpoints"): */
-		integer	mp_num_endpoints := 31;
+		integer	mp_num_endpoints := 300;
 	}
 
 	private function f_vty_enable_osmux(boolean osmux_on) runs on dummy_CT {
@@ -1178,6 +1178,51 @@ module MGCP_Test {
 		setverdict(pass);
 	}
 
+	/* test Creating 257 concurrent osmux conns. It should fail since maximum is 256. */
+	testcase TC_crcx_osmux_257() runs on dummy_CT {
+		var MgcpEndpoint ep := c_mgw_ep_rtpbridge & "*@" & c_mgw_domain;
+		var template MgcpCommand cmd;
+		var MgcpResponse resp;
+		var charstring cid_response;
+		var integer i;
+
+		f_init(ep, true);
+
+		for (i := 0; i < 256; i := i + 1) {
+
+			cmd := ts_CRCX_osmux(get_next_trans_id(), ep, "recvonly", int2hex(i, 4), -1);
+			resp := mgcp_transceive_mgw(cmd, tr_CRCX_ACK_osmux);
+			extract_conn_id(resp);
+
+			/* extract Osmux CID we got assigned by the MGW */
+			var MgcpMessage resp_msg := {
+				response := resp
+			}
+
+			if (f_mgcp_find_param(resp_msg, "X-OSMUX", cid_response) == false) {
+				setverdict(fail, "No Osmux CID in MGCP response", resp);
+				mtc.stop;
+			}
+
+			/* Make sure response is no wildcard */
+			if (f_mgcp_osmux_cid_decode(cid_response) == -1) {
+				setverdict(fail, "Osmux CID in MGCP response contains unexpected wildcard");
+				mtc.stop;
+			}
+		}
+
+		/* Now conn num 257, it should fail due to all Osmux conns already allocated: */
+		cmd := ts_CRCX_osmux(get_next_trans_id(), ep, "recvonly", int2hex(i, 4), -1);
+		resp := mgcp_transceive_mgw(cmd, tr_MgcpResp_Err("400"));
+
+		setverdict(pass);
+
+		/* Clean up */
+		for (i := 0; i < 256; i := i + 1) {
+			f_dlcx_ok(ep, int2hex(i, 4));
+		}
+	}
+
 	/* Create one half open connection in receive-only mode. The MGW must accept
 	 * the packets but must not send any. */
 	testcase TC_one_crcx_receive_only_osmux() runs on dummy_CT {
@@ -2851,6 +2896,7 @@ module MGCP_Test {
 		execute(TC_crcx_osmux_wildcard());
 		execute(TC_crcx_osmux_fixed());
 		execute(TC_crcx_osmux_fixed_twice());
+		execute(TC_crcx_osmux_257());
 		execute(TC_one_crcx_receive_only_osmux());
 		execute(TC_one_crcx_loopback_osmux());
 		execute(TC_two_crcx_and_rtp_osmux());
diff --git a/mgw/expected-results.xml b/mgw/expected-results.xml
index 8b17fb1e4..577b6e3fe 100644
--- a/mgw/expected-results.xml
+++ b/mgw/expected-results.xml
@@ -29,6 +29,7 @@
   <testcase classname='MGCP_Test' name='TC_crcx_osmux_wildcard' time='MASKED'/>
   <testcase classname='MGCP_Test' name='TC_crcx_osmux_fixed' time='MASKED'/>
   <testcase classname='MGCP_Test' name='TC_crcx_osmux_fixed_twice' time='MASKED'/>
+  <testcase classname='MGCP_Test' name='TC_crcx_osmux_257' time='MASKED'/>
   <testcase classname='MGCP_Test' name='TC_one_crcx_receive_only_osmux' time='MASKED'/>
   <testcase classname='MGCP_Test' name='TC_one_crcx_loopback_osmux' time='MASKED'/>
   <testcase classname='MGCP_Test' name='TC_two_crcx_and_rtp_osmux' time='MASKED'/>
diff --git a/mgw/osmo-mgw.cfg b/mgw/osmo-mgw.cfg
index 1c5cfce13..417026eb6 100644
--- a/mgw/osmo-mgw.cfg
+++ b/mgw/osmo-mgw.cfg
@@ -44,7 +44,7 @@ mgcp
   sdp audio-payload send-name
   conn-timeout 0
   loop 0
-  number endpoints 31
+  number endpoints 300
   allow-transcoding
   osmux off
   osmux bind-ip 127.0.0.1