diff --git a/skywalking-commons/skywalking-trace/src/main/java/com/a/eye/skywalking/trace/tag/Tags.java b/skywalking-commons/skywalking-trace/src/main/java/com/a/eye/skywalking/trace/tag/Tags.java
index d0881dc1b..9d7cab61d 100644
--- a/skywalking-commons/skywalking-trace/src/main/java/com/a/eye/skywalking/trace/tag/Tags.java
+++ b/skywalking-commons/skywalking-trace/src/main/java/com/a/eye/skywalking/trace/tag/Tags.java
@@ -23,51 +23,56 @@ public final class Tags {
     public static final IntTag HTTP_STATUS = new IntTag("http.status_code");
 
     /**
-     *  SPAN_KIND represents the kind of span.
+     *
+     */
+    public static final StringTag SPAN_KIND = new StringTag("span.kind");
+
+    /**
+     *  SPAN_LAYER represents the kind of span.
      *  e.g. db=database, rpc=Remote Procedure Call, nosql=something like redis/memcache
      */
-    public static final class SPAN_KIND{
-        private static StringTag SPAN_KIND_TAG = new StringTag("span.kind");
+    public static final class SPAN_LAYER {
+        private static StringTag SPAN_LAYER_TAG = new StringTag("span.layer");
 
-        private static final String DB_KIND = "db";
-        private static final String RPC_KIND = "rpc";
-        private static final String NOSQL_KIND = "nosql";
-        private static final String HTTP_KIND = "http";
+        private static final String DB_LAYER = "db";
+        private static final String RPC_LAYER = "rpc";
+        private static final String NOSQL_LAYER = "nosql";
+        private static final String HTTP_LAYER = "http";
 
         public static void asDBAccess(Span span){
-            SPAN_KIND_TAG.set(span, DB_KIND);
+            SPAN_LAYER_TAG.set(span, DB_LAYER);
         }
 
         public static void asRPC(Span span){
-            SPAN_KIND_TAG.set(span, RPC_KIND);
+            SPAN_LAYER_TAG.set(span, RPC_LAYER);
         }
 
         public static void asNoSQL(Span span){
-            SPAN_KIND_TAG.set(span, NOSQL_KIND);
+            SPAN_LAYER_TAG.set(span, NOSQL_LAYER);
         }
 
         public static void asHttp(Span span){
-            SPAN_KIND_TAG.set(span, HTTP_KIND);
+            SPAN_LAYER_TAG.set(span, HTTP_LAYER);
         }
 
         public static String get(Span span){
-            return SPAN_KIND_TAG.get(span);
+            return SPAN_LAYER_TAG.get(span);
         }
 
         public static boolean isDBAccess(Span span){
-            return DB_KIND.equals(get(span));
+            return DB_LAYER.equals(get(span));
         }
 
         public static boolean isRPC(Span span){
-            return RPC_KIND.equals(get(span));
+            return RPC_LAYER.equals(get(span));
         }
 
         public static boolean isNoSQL(Span span){
-            return NOSQL_KIND.equals(get(span));
+            return NOSQL_LAYER.equals(get(span));
         }
 
         public static boolean isHttp(Span span){
-            return HTTP_KIND.equals(get(span));
+            return HTTP_LAYER.equals(get(span));
         }
     }
 
@@ -83,9 +88,9 @@ public final class Tags {
     public static final BooleanTag ERROR = new BooleanTag("error");
 
     /**
-     *  PEER_HOST_IPV4 records IPv4 host address of the peer.
+     *  PEER_HOST records host address of the peer, maybe IPV4, IPV6 or hostname.
      */
-    public static final IntTag PEER_HOST_IPV4 = new IntTag("peer.ipv4");
+    public static final StringTag PEER_HOST = new StringTag("peer.host");
 
     /**
      *  DB_URL records the url of the database access.
diff --git a/skywalking-commons/skywalking-trace/src/test/java/com/a/eye/skywalking/trace/SpanTestCase.java b/skywalking-commons/skywalking-trace/src/test/java/com/a/eye/skywalking/trace/SpanTestCase.java
index f26b22f23..e297e58d6 100644
--- a/skywalking-commons/skywalking-trace/src/test/java/com/a/eye/skywalking/trace/SpanTestCase.java
+++ b/skywalking-commons/skywalking-trace/src/test/java/com/a/eye/skywalking/trace/SpanTestCase.java
@@ -1,7 +1,6 @@
 package com.a.eye.skywalking.trace;
 
 import com.a.eye.skywalking.trace.tag.Tags;
-import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import org.junit.Assert;
@@ -38,9 +37,9 @@ public class SpanTestCase {
     @Test
     public void testSetTag() {
         Span span1 = new Span(0, "serviceA");
-        Tags.SPAN_KIND.asHttp(span1);
+        Tags.SPAN_LAYER.asHttp(span1);
         Tags.COMPONENT.set(span1, "Spring");
-        Tags.PEER_HOST_IPV4.set(span1, ipToInt("127.0.0.1"));
+        Tags.PEER_HOST.set(span1, ipToInt("127.0.0.1"));
         Tags.ERROR.set(span1, true);
         Tags.HTTP_STATUS.set(span1, 302);
         Tags.HTTP_URL.set(span1, "http://127.0.0.1/serviceA");
@@ -49,8 +48,8 @@ public class SpanTestCase {
 
         Map<String, Object> tags = span1.getTags();
         Assert.assertEquals(8, tags.size());
-        Assert.assertTrue(Tags.SPAN_KIND.isHttp(span1));
-        Assert.assertEquals("127.0.0.1", intToIp(Tags.PEER_HOST_IPV4.get(span1)));
+        Assert.assertTrue(Tags.SPAN_LAYER.isHttp(span1));
+        Assert.assertEquals("127.0.0.1", intToIp(Tags.PEER_HOST.get(span1)));
         Assert.assertTrue(Tags.ERROR.get(span1));
     }
 
diff --git a/skywalking-sniffer/skywalking-api/src/test/java/com/a/eye/skywalking/context/ContextManagerTestCase.java b/skywalking-sniffer/skywalking-api/src/test/java/com/a/eye/skywalking/context/ContextManagerTestCase.java
index 80ee01c42..fe9c2ba9a 100644
--- a/skywalking-sniffer/skywalking-api/src/test/java/com/a/eye/skywalking/context/ContextManagerTestCase.java
+++ b/skywalking-sniffer/skywalking-api/src/test/java/com/a/eye/skywalking/context/ContextManagerTestCase.java
@@ -3,6 +3,7 @@ package com.a.eye.skywalking.context;
 import com.a.eye.skywalking.trace.Span;
 import com.a.eye.skywalking.trace.TraceSegment;
 import com.a.eye.skywalking.trace.tag.Tags;
+import org.junit.After;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -24,4 +25,9 @@ public class ContextManagerTestCase {
 
         Assert.assertEquals(span, segment.getSpans().get(0));
     }
+
+    @After
+    public void reset(){
+        TracerContext.ListenerManager.remove(TestTracerContextListener.INSTANCE);
+    }
 }
diff --git a/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/PreparedStatementTracing.java b/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/PreparedStatementTracing.java
index 464ea055d..85d1557aa 100644
--- a/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/PreparedStatementTracing.java
+++ b/skywalking-sniffer/skywalking-sdk-plugin/jdbc-plugin/src/main/java/com/a/eye/skywalking/plugin/jdbc/PreparedStatementTracing.java
@@ -17,7 +17,7 @@ public class PreparedStatementTracing {
         throws SQLException {
         Span span = ContextManager.INSTANCE.createSpan("JDBC/PreparedStatement/" + method);
         try {
-            Tags.SPAN_KIND.asDBAccess(span);
+            Tags.SPAN_LAYER.asDBAccess(span);
             Tags.DB_URL.set(span, connectInfo);
             Tags.DB_SQL.set(span, sql);
             return exec.exe(realStatement, sql);