diff --git a/core/io_info.go b/core/io_info.go
new file mode 100644
index 0000000..4252509
--- /dev/null
+++ b/core/io_info.go
@@ -0,0 +1,69 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package core
+
+import (
+	"errors"
+	"github.com/google/gopacket/pcap"
+	"log"
+)
+
+type Ioinfo struct {
+	name    string
+	iotype  string //nni or uni
+	ioloc   string //inside or outsode
+	intfid  uint32
+	onuid   uint32
+	handler *pcap.Handle
+}
+
+func (s *Server) identifyUniIoinfo(ioloc string, intfid uint32, onuid uint32) (*Ioinfo, error) {
+	for _, ioinfo := range s.Ioinfos {
+		if ioinfo.iotype == "uni" && ioinfo.intfid == intfid && ioinfo.onuid == onuid && ioinfo.ioloc == ioloc {
+			return ioinfo, nil
+		}
+	}
+	err := errors.New("No matched Ioinfo is found !")
+	log.Println(err)
+	return nil, err
+}
+
+func (s *Server) identifyNniIoinfo(ioloc string) (*Ioinfo, error) {
+	for _, ioinfo := range s.Ioinfos {
+		if ioinfo.iotype == "nni" && ioinfo.ioloc == ioloc {
+			return ioinfo, nil
+		}
+	}
+	err := errors.New("No matched Ioinfo is found !")
+	log.Println(err)
+	return nil, err
+}
+
+func (s *Server) getUniIoinfos(ioloc string) ([]*Ioinfo, error) {
+	ioinfos := []*Ioinfo{}
+	for _, ioinfo := range s.Ioinfos {
+		if ioinfo.iotype == "uni" && ioinfo.ioloc == ioloc {
+			ioinfos = append(ioinfos, ioinfo)
+		}
+	}
+	if len(ioinfos) == 0 {
+		err := errors.New("No matched Ioinfo is found !")
+		log.Println(err)
+		return nil, err
+	}
+	return ioinfos, nil
+}