diff --git a/bin/check.sh b/bin/check.sh
index 99005fd2..5d190c29 100755
--- a/bin/check.sh
+++ b/bin/check.sh
@@ -281,6 +281,7 @@ function run_sipp
 
   local base=""
   local pid=""
+  local responder_pid=""
 
   # test LOG_DIR
   # we dont want to remove "/*" don't we?
@@ -324,13 +325,13 @@ function run_sipp
       PORT="5060"
     fi
 
-    echo "$(date) - Running ${base} $ip:${PORT}-${MPORT}"
     if [ -f ${SCEN_CHECK_DIR}/${base}_reg.xml ]; then
       echo "$(date) - Register ${base} $ip:${PORT}-${MPORT}"
       ${BIN_DIR}/sipp.sh -T $transport -i $ip -p ${PORT} -r ${SCEN_CHECK_DIR}/${base}_reg.xml
     fi
-    ${BIN_DIR}/sipp.sh -T $transport -i $ip -p ${PORT} -m ${MPORT} -r ${SCEN_CHECK_DIR}/${base}.xml &
-    responder_pid="${responder_pid} ${base}:$!"
+    pid=$(${BIN_DIR}/sipp.sh -b -T $transport -i $ip -p ${PORT} -m ${MPORT} -r ${SCEN_CHECK_DIR}/${base}.xml)
+    echo "$(date) - Running ${base}[${pid}] ${ip}:${PORT}-${MPORT}"
+    responder_pid="${responder_pid} ${base}:${pid}"
 
     if [ "${foreign_dom}" == "no" ]; then
       check_port ${PORT}
@@ -367,7 +368,7 @@ function run_sipp
       ps_status=$?
       if [ ${ps_status} -eq 0 ]; then
         echo "$(date) - sipp responder $base pid $pid not finished yet. Killing it"
-        kill -9 ${pid}
+        kill -SIGUSR1 ${pid}
       fi
     fi
   done
diff --git a/bin/sipp.sh b/bin/sipp.sh
index 3554634d..32616a8a 100755
--- a/bin/sipp.sh
+++ b/bin/sipp.sh
@@ -27,11 +27,13 @@ function usage
   echo -e "\t-t: timeout. default 10/25(responder)"
   echo -e "\t-i: IP. default 127.0.0.1"
   echo -e "\t-T: transport [UDP|TCP] default UDP"
+  echo -e "\t-r: responder"
+  echo -e "\t-b: run sipp in background (responder)"
   echo "Arguments:"
   echo -e "\t sipp_scenario.xml file"
 }
 
-while getopts 'hrp:m:t:i:T:' opt; do
+while getopts 'hrp:m:t:i:T:b' opt; do
   case $opt in
     h) usage; exit 0;;
     r) RESP=1;;
@@ -40,6 +42,7 @@ while getopts 'hrp:m:t:i:T:' opt; do
     t) TIMEOUT=$OPTARG;;
     i) IP=$OPTARG;;
     T) TRANSPORT=${OPTARG,,};;
+    b) BACK="-bg";;
   esac
 done
 shift $(($OPTIND - 1))
@@ -86,13 +89,24 @@ else
   PORT=${PORT:-"50603"}
   TIMEOUT=${TIMEOUT:-"25"}
 
-  sipp -max_socket $MAX ${TRANSPORT_ARG}\
-    -inf ${BASE_DIR}/callee.csv -inf ${BASE_DIR}/caller.csv \
-    -sf $1 -i $IP -p $PORT \
-    -nr -nd -t ul -m 1 ${MPORT_ARG} \
-    -timeout ${TIMEOUT} -timeout_error -trace_err \
-    $IP_SERVER &> /dev/null
-  status=$?
+  if [ -z ${BACK} ]; then
+    sipp -max_socket $MAX ${TRANSPORT_ARG}\
+      -inf ${BASE_DIR}/callee.csv -inf ${BASE_DIR}/caller.csv \
+      -sf $1 -i $IP -p $PORT \
+      -nr -nd -t ul -m 1 ${MPORT_ARG} \
+      -timeout ${TIMEOUT} -timeout_error -trace_err \
+      $IP_SERVER &> /dev/null
+    status=$?
+  else
+    tmp=$(sipp $BACK -max_socket $MAX ${TRANSPORT_ARG}\
+      -inf ${BASE_DIR}/callee.csv -inf ${BASE_DIR}/caller.csv \
+      -sf $1 -i $IP -p $PORT \
+      -nr -nd -t ul -m 1 ${MPORT_ARG} \
+      -timeout ${TIMEOUT} -timeout_error -trace_err \
+      $IP_SERVER)
+    echo $(echo $tmp | cut -d= -f2 | sed -e 's_\[__' -e 's_\]__')
+    status=0
+  fi
 fi
 
 exit $status