diff --git a/README.md b/README.md
index 6afbf63b1..1c0f9e26d 100755
--- a/README.md
+++ b/README.md
@@ -12,6 +12,7 @@ SRS is a simple, high efficiency and realtime video server, supports RTMP/WebRTC
 SRS is licenced under [MIT][LICENSE], but some depended libraries are distributed using their [own licenses][LicenseMixing].
 
 <a name="product"></a>
+<a name="usage-docker"></a>
 ## Usage
 
 Run SRS by [docker][docker-srs4], images is [here](https://hub.docker.com/r/ossrs/srs/tags) or [there](https://cr.console.aliyun.com/repository/cn-hangzhou/ossrs/srs/images), 
@@ -23,6 +24,7 @@ docker run --rm -it -p 1935:1935 -p 1985:1985 -p 8080:8080 \
     ossrs/srs:v4.0.117 ./objs/srs -c conf/srs.conf
 ```
 
+<a name="usage-source"></a>
 Or build SRS from source(or [mirrors](#mirrors)), by CentOS7(or Linux([CN][v4_CN_Build],[EN][v4_EN_Build])):
 
 ```
diff --git a/trunk/3rdparty/signaling/www/demos/js/srs.sdk.js b/trunk/3rdparty/signaling/www/demos/js/srs.sdk.js
index 2e3cd87d1..6d4c6a8b4 100644
--- a/trunk/3rdparty/signaling/www/demos/js/srs.sdk.js
+++ b/trunk/3rdparty/signaling/www/demos/js/srs.sdk.js
@@ -330,6 +330,7 @@ function SrsRtcPlayerAsync() {
         await self.pc.setRemoteDescription(
             new RTCSessionDescription({type: 'answer', sdp: session.sdp})
         );
+        session.simulator = conf.schema + '//' + conf.urlObject.server + ':' + conf.port + '/rtc/v1/nack/';
         return session;
     };
 
diff --git a/trunk/research/players/js/srs.sdk.js b/trunk/research/players/js/srs.sdk.js
index 2e3cd87d1..8983eb919 100644
--- a/trunk/research/players/js/srs.sdk.js
+++ b/trunk/research/players/js/srs.sdk.js
@@ -330,6 +330,8 @@ function SrsRtcPlayerAsync() {
         await self.pc.setRemoteDescription(
             new RTCSessionDescription({type: 'answer', sdp: session.sdp})
         );
+        session.simulator = conf.schema + '//' + conf.urlObject.server + ':' + conf.port + '/rtc/v1/nack/';
+
         return session;
     };