diff --git a/README.md b/README.md
index 4168b2030..2e7c57c0d 100755
--- a/README.md
+++ b/README.md
@@ -186,6 +186,7 @@ Please select your language:
 
 ### V3 changes
 
+* v3.0, 2017-03-26, Fix [#820][bug #820], extract service for modules. 3.0.21
 * v3.0, 2017-03-02, Fix [#786][bug #786], simply don't reuse object. 3.0.20
 * v3.0, 2017-03-01, For [#110][bug #110], refine thread object. 3.0.19
 * v3.0, 2017-02-12, Fix [#301][bug #301], User must config the codec in right way for HLS. 3.0.18
@@ -1388,6 +1389,7 @@ Winlin
 [bug #742]: https://github.com/ossrs/srs/issues/742
 [bug #738]: https://github.com/ossrs/srs/issues/738
 [bug #786]: https://github.com/ossrs/srs/issues/786
+[bug #820]: https://github.com/ossrs/srs/issues/820
 [bug #xxxxxxxxxxxxx]: https://github.com/ossrs/srs/issues/xxxxxxxxxxxxx
 
 [exo #828]: https://github.com/google/ExoPlayer/pull/828
diff --git a/trunk/configure b/trunk/configure
index 72e2b4fdb..ac20e046c 100755
--- a/trunk/configure
+++ b/trunk/configure
@@ -220,19 +220,19 @@ MODULE_FILES=("srs_librtmp" "srs_lib_simple_socket" "srs_lib_bandwidth")
 LIBS_INCS="src/libs"; MODULE_DIR=${LIBS_INCS} . auto/modules.sh
 LIBS_OBJS="${MODULE_OBJS[@]}"
 #
-#Main Module, for SRS.
+#Server Module, for SRS only.
 if [ $SRS_EXPORT_LIBRTMP_PROJECT = NO ]; then
-    MODULE_ID="MAIN" 
+    MODULE_ID="SERVER"
     MODULE_DEPENDS=("CORE" "KERNEL" "PROTOCOL" "SERVICE" "APP")
     ModuleLibIncs=(${LibSTRoot} ${SRS_OBJS_DIR} ${LibGperfRoot})
     MODULE_FILES=("srs_main_server")
-    MAIN_INCS="src/main"; MODULE_DIR=${MAIN_INCS} . auto/modules.sh
-    MAIN_OBJS="${MODULE_OBJS[@]}"
+    SERVER_INCS="src/main"; MODULE_DIR=${SERVER_INCS} . auto/modules.sh
+    SERVER_OBJS="${MODULE_OBJS[@]}"
 fi
 #
 #Main Module, for app from modules.
 if [ $SRS_EXPORT_LIBRTMP_PROJECT = NO ]; then
-    MODULE_ID="MAIN2"
+    MODULE_ID="MAIN"
     MODULE_DEPENDS=("CORE" "KERNEL" "PROTOCOL" "SERVICE")
     ModuleLibIncs=(${LibSTRoot} ${SRS_OBJS_DIR} ${LibGperfRoot})
     MODULE_FILES=()
@@ -243,8 +243,8 @@ if [ $SRS_EXPORT_LIBRTMP_PROJECT = NO ]; then
         MODULE_FILES+=("${SRS_MODULE_MAIN[*]}")
         DEFINES="${DEFINES} ${SRS_MODULE_DEFINES}"
     done
-    MAIN2_INCS="src/main"; MODULE_DIR=${MAIN2_INCS} . auto/modules.sh
-    MAIN2_OBJS="${MODULE_OBJS[@]}"
+    MAIN_INCS="src/main"; MODULE_DIR=${MAIN_INCS} . auto/modules.sh
+    MAIN_OBJS="${MODULE_OBJS[@]}"
 fi
 
 #####################################################################################
@@ -263,14 +263,14 @@ if [ $SRS_EXPORT_LIBRTMP_PROJECT = NO ]; then
     # all depends libraries
     ModuleLibFiles=(${LibSTfile} ${LibSSLfile} ${LibGperfFile})
     # all depends objects
-    MODULE_OBJS="${CORE_OBJS[@]} ${KERNEL_OBJS[@]} ${PROTOCOL_OBJS[@]} ${SERVICE_OBJS[@]} ${APP_OBJS[@]} ${MAIN_OBJS[@]}"
+    MODULE_OBJS="${CORE_OBJS[@]} ${KERNEL_OBJS[@]} ${PROTOCOL_OBJS[@]} ${SERVICE_OBJS[@]} ${APP_OBJS[@]} ${SERVER_OBJS[@]}"
     LINK_OPTIONS="${SrsLinkOptions}${SrsGprofLink}${SrsGperfLink}"
     #
     # srs: srs(simple rtmp server) over st(state-threads)
     BUILD_KEY="srs" APP_MAIN="srs_main_server" APP_NAME="srs" . auto/apps.sh
     #
     # For modules, without the app module.
-    MODULE_OBJS="${CORE_OBJS[@]} ${KERNEL_OBJS[@]} ${PROTOCOL_OBJS[@]} ${SERVICE_OBJS[@]} ${MAIN2_OBJS[@]}"
+    MODULE_OBJS="${CORE_OBJS[@]} ${KERNEL_OBJS[@]} ${PROTOCOL_OBJS[@]} ${SERVICE_OBJS[@]} ${MAIN_OBJS[@]}"
     #
     for SRS_MODULE in ${SRS_MODULES[*]}; do
         . $SRS_MODULE/config
diff --git a/trunk/research/librtmp/srs_bandwidth_check.c b/trunk/research/librtmp/srs_bandwidth_check.c
index d5d4fc071..8de7e3812 100644
--- a/trunk/research/librtmp/srs_bandwidth_check.c
+++ b/trunk/research/librtmp/srs_bandwidth_check.c
@@ -112,23 +112,14 @@ int main(int argc, char** argv)
         goto rtmp_destroy;
     }
     
-    srs_human_trace("\n%s, %s, %s\n"
-        "%s, %d.%d.%d.%d, srs_pid=%d, srs_id=%d\n"
-        "duration: %dms(%d+%d)\n"
-        "play: %dkbps\n"
-        "publish: %dkbps",
-        (char*)sig, NULL, NULL,
-        (char*)ip, major, minor, revision, build, pid, cid,
-        (int)(end_time - start_time), play_duration, publish_duration,
-        play_kbps,
-        publish_kbps);
+    srs_human_trace("\n%s, %s, %d.%d.%d.%d, srs_pid=%d, srs_id=%d\n"
+        "duration: %dms(%d+%d), play: %dkbps, publish: %dkbps",
+        (char*)sig, (char*)ip, major, minor, revision, build, pid, cid,
+        (int)(end_time - start_time), play_duration, publish_duration, play_kbps, publish_kbps);
     
 rtmp_destroy:
     fprintf(stderr, "{\"code\":%d,"
-        "\"srs_server\":\"%s\", "
-        "\"srs_primary\":\"%s\", "
-        "\"srs_authors\":\"%s\", "
-        "\"srs_server_ip\":\"%s\", "
+        "\"srs_server\":\"%s\", \"srs_primary\":\"\", \"srs_authors\":\"\", \"srs_server_ip\":\"%s\", "
         "\"srs_version\":\"%d.%d.%d.%d\", "
         "\"srs_pid\":%d, "
         "\"srs_id\":%d, "
@@ -139,8 +130,8 @@ rtmp_destroy:
         "\"publish_kbps\":%d"
         "}",
         ret,
-        (char*)sig, NULL, NULL,
-        (char*)ip, major, minor, revision, build, pid, cid,
+        (char*)sig, (char*)ip,
+        major, minor, revision, build, pid, cid,
         (int)(end_time - start_time), play_duration, publish_duration,
         play_kbps, publish_kbps);
     srs_rtmp_destroy(rtmp);
diff --git a/trunk/src/core/srs_core.hpp b/trunk/src/core/srs_core.hpp
index 19b52eabf..56a178a2c 100644
--- a/trunk/src/core/srs_core.hpp
+++ b/trunk/src/core/srs_core.hpp
@@ -27,7 +27,7 @@
 // current release version
 #define VERSION_MAJOR       3
 #define VERSION_MINOR       0
-#define VERSION_REVISION    20
+#define VERSION_REVISION    21
 
 // generated by configure, only macros.
 #include <srs_auto_headers.hpp>