diff --git a/consensus/consensus.go b/consensus/consensus.go
index 75104ade4..8acfa034f 100644
--- a/consensus/consensus.go
+++ b/consensus/consensus.go
@@ -35,6 +35,9 @@ type Consensus struct {
 	responses      *map[uint16]kyber.Scalar
 	finalResponses *map[uint16]kyber.Scalar
 	// map of nodeID to validator Peer object
+	// FIXME: should use PubKey of p2p.Peer as the hashkey
+	// However, we have assumed uint16 in consensus/consensus_leader.go:136
+	// we won't change it now
 	validators map[uint16]p2p.Peer
 	// Leader
 	leader p2p.Peer
@@ -214,3 +217,15 @@ func (consensus *Consensus) String() string {
 	return fmt.Sprintf("[duty:%s, priKey:%s, ShardID:%v, nodeID:%v, state:%s]",
 		duty, consensus.priKey.String(), consensus.ShardID, consensus.nodeID, consensus.state)
 }
+
+func (consensus *Consensus) AddPeers(peers []p2p.Peer) int {
+	count := 0
+	for _, peer := range peers {
+		_, ok := consensus.validators[utils.GetUniqueIdFromPeer(peer)]
+		if !ok {
+			consensus.validators[utils.GetUniqueIdFromPeer(peer)] = peer
+			count++
+		}
+	}
+	return count
+}
diff --git a/node/node.go b/node/node.go
index 986a1d18c..adc693acc 100644
--- a/node/node.go
+++ b/node/node.go
@@ -17,6 +17,8 @@ import (
 	"github.com/harmony-one/harmony/log"
 	"github.com/harmony-one/harmony/p2p"
 	proto_identity "github.com/harmony-one/harmony/proto/identity"
+
+	"github.com/jinzhu/copier"
 )
 
 type NetworkNode struct {
@@ -44,10 +46,9 @@ type Node struct {
 	IsWaiting              bool
 	SelfPeer               p2p.Peer // TODO(minhdoan): it could be duplicated with Self below whose is Alok work.
 	IDCPeer                p2p.Peer
-	SyncNode               bool // TODO(minhdoan): Remove it later.
-
-	// Account Model
-	chain *core.BlockChain
+	SyncNode               bool                 // TODO(minhdoan): Remove it later.
+	chain                  *core.BlockChain     // Account Model
+	Neighbors              map[string]*p2p.Peer // All the neighbor nodes, key is the sha256 of Peer IP/Port
 }
 
 // Add new crossTx and proofs to the list of crossTx that needs to be sent back to client
@@ -85,7 +86,7 @@ func (node *Node) StartServer(port string) {
 		// Disable this temporarily.
 		// node.blockchain = syncing.StartBlockSyncing(node.Consensus.GetValidatorPeers())
 	}
-	fmt.Println("going to start server")
+	fmt.Println("going to start server on port:", port)
 	//node.log.Debug("Starting server", "node", node, "port", port)
 	node.listenOnPort(port)
 }
@@ -200,6 +201,29 @@ func New(consensus *consensus.Consensus, db *db.LDBDatabase) *Node {
 	}
 	// Logger
 	node.log = log.New()
+	node.Neighbors = make(map[string]*p2p.Peer)
 
 	return &node
 }
+
+// Add neighbors nodes
+func (node *Node) AddPeers(peers []p2p.Peer) int {
+	count := 0
+	for _, p := range peers {
+		key := fmt.Sprintf("%v", p.PubKey)
+		_, ok := node.Neighbors[key]
+		if !ok {
+			np := new(p2p.Peer)
+			copier.Copy(np, &p)
+			node.Neighbors[key] = np
+			count++
+		}
+	}
+	node.log.Info("Added", "# of peers", count)
+
+	if count > 0 {
+		c := node.Consensus.AddPeers(peers)
+		node.log.Info("Added in Consensus", "# of peers", c)
+	}
+	return count
+}
diff --git a/node/node_handler.go b/node/node_handler.go
index a83e2524d..bd7ab6e84 100644
--- a/node/node_handler.go
+++ b/node/node_handler.go
@@ -178,6 +178,12 @@ func (node *Node) NodeHandler(conn net.Conn) {
 
 				os.Exit(0)
 			}
+		case proto_node.PING:
+			node.log.Info("NET: received message: PING")
+			node.pingMessageHandler(msgPayload)
+		case proto_node.PONG:
+			node.log.Info("NET: received message: PONG")
+			node.pongMessageHandler(msgPayload)
 		}
 	case proto.CLIENT:
 		actionType := client.ClientMessageType(msgType)
@@ -188,6 +194,8 @@ func (node *Node) NodeHandler(conn net.Conn) {
 				node.Client.TransactionMessageHandler(msgPayload)
 			}
 		}
+	default:
+		node.log.Error("Unknown", "MsgCateory:", msgCategory)
 	}
 }
 
@@ -442,3 +450,23 @@ func (node *Node) UpdateUtxoAndState(newBlock *blockchain.Block) {
 		node.log.Info("LEADER LOCKED UTXO", "num", node.UtxoPool.CountNumOfLockedUtxos(), "ShardID", node.UtxoPool.ShardID)
 	}
 }
+
+func (node *Node) pingMessageHandler(msgPayload []byte) {
+	ping, err := proto_node.GetPingMessage(msgPayload)
+	if err != nil {
+		node.log.Error("Can't get Ping Message")
+		return
+	}
+	node.log.Info("Ping", "Msg", ping)
+	return
+}
+
+func (node *Node) pongMessageHandler(msgPayload []byte) {
+	pong, err := proto_node.GetPongMessage(msgPayload)
+	if err != nil {
+		node.log.Error("Can't get Pong Message")
+		return
+	}
+	node.log.Info("Pong", "Msg", pong)
+	return
+}
diff --git a/node/node_test.go b/node/node_test.go
index 7dad8db4c..e637131b5 100644
--- a/node/node_test.go
+++ b/node/node_test.go
@@ -1,10 +1,18 @@
 package node
 
 import (
+	"fmt"
+	"os"
 	"testing"
+	"time"
+
+	"github.com/harmony-one/harmony/crypto"
+	"github.com/harmony-one/harmony/crypto/pki"
 
 	"github.com/harmony-one/harmony/consensus"
 	"github.com/harmony-one/harmony/p2p"
+
+	proto_node "github.com/harmony-one/harmony/proto/node"
 )
 
 func TestNewNewNode(test *testing.T) {
@@ -45,3 +53,110 @@ func TestCountNumTransactionsInBlockchain(test *testing.T) {
 		test.Error("Count of transactions in the blockchain is incorrect")
 	}
 }
+
+func TestAddPeers(test *testing.T) {
+	priKey1 := crypto.Ed25519Curve.Scalar().SetInt64(int64(333))
+	pubKey1 := pki.GetPublicKeyFromScalar(priKey1)
+
+	priKey2 := crypto.Ed25519Curve.Scalar().SetInt64(int64(999))
+	pubKey2 := pki.GetPublicKeyFromScalar(priKey2)
+
+	peers1 := []p2p.Peer{
+		{
+			Ip:          "127.0.0.1",
+			Port:        "8888",
+			PubKey:      pubKey1,
+			Ready:       true,
+			ValidatorID: 1,
+		},
+		{
+			Ip:          "127.0.0.1",
+			Port:        "9999",
+			PubKey:      pubKey2,
+			Ready:       false,
+			ValidatorID: 2,
+		},
+	}
+	leader := p2p.Peer{Ip: "1", Port: "2"}
+	validator := p2p.Peer{Ip: "3", Port: "5"}
+	consensus := consensus.NewConsensus("1", "2", "0", []p2p.Peer{leader, validator}, leader)
+
+	node := New(consensus, nil)
+	r1 := node.AddPeers(peers1)
+	e1 := 2
+	if r1 != e1 {
+		test.Errorf("Add %v peers, expectd %v", r1, e1)
+	}
+	r2 := node.AddPeers(peers1)
+	e2 := 0
+	if r2 != e2 {
+		test.Errorf("Add %v peers, expectd %v", r2, e2)
+	}
+}
+
+func sendPingMessage(leader p2p.Peer) {
+	priKey1 := crypto.Ed25519Curve.Scalar().SetInt64(int64(333))
+	pubKey1 := pki.GetPublicKeyFromScalar(priKey1)
+
+	p1 := p2p.Peer{
+		Ip:     "127.0.0.1",
+		Port:   "9999",
+		PubKey: pubKey1,
+	}
+
+	ping1 := proto_node.NewPingMessage(p1)
+	buf1 := ping1.ConstructPingMessage()
+
+	fmt.Println("waiting for 5 seconds ...")
+	time.Sleep(5 * time.Second)
+
+	p2p.SendMessage(leader, buf1)
+	fmt.Println("sent ping message ...")
+}
+
+func sendPongMessage(leader p2p.Peer) {
+	priKey1 := crypto.Ed25519Curve.Scalar().SetInt64(int64(333))
+	pubKey1 := pki.GetPublicKeyFromScalar(priKey1)
+	p1 := p2p.Peer{
+		Ip:     "127.0.0.1",
+		Port:   "9998",
+		PubKey: pubKey1,
+	}
+	priKey2 := crypto.Ed25519Curve.Scalar().SetInt64(int64(999))
+	pubKey2 := pki.GetPublicKeyFromScalar(priKey2)
+	p2 := p2p.Peer{
+		Ip:     "127.0.0.1",
+		Port:   "9999",
+		PubKey: pubKey2,
+	}
+
+	pong1 := proto_node.NewPongMessage([]p2p.Peer{p1, p2})
+	buf1 := pong1.ConstructPongMessage()
+
+	fmt.Println("waiting for 10 seconds ...")
+	time.Sleep(10 * time.Second)
+
+	p2p.SendMessage(leader, buf1)
+	fmt.Println("sent pong message ...")
+}
+
+func exitServer() {
+	fmt.Println("wait 15 seconds to terminate the process ...")
+	time.Sleep(15 * time.Second)
+
+	os.Exit(0)
+}
+
+func TestPingPongHandler(test *testing.T) {
+	leader := p2p.Peer{Ip: "127.0.0.1", Port: "8881"}
+	validator := p2p.Peer{Ip: "127.0.0.1", Port: "9991"}
+	consensus := consensus.NewConsensus("127.0.0.1", "8881", "0", []p2p.Peer{leader, validator}, leader)
+
+	node := New(consensus, nil)
+
+	go sendPingMessage(leader)
+	go sendPongMessage(leader)
+	go exitServer()
+
+	node.StartServer("8881")
+}
diff --git a/proto/node/node.go b/proto/node/node.go
index 4928134d7..6ce5f462d 100644
--- a/proto/node/node.go
+++ b/proto/node/node.go
@@ -13,6 +13,10 @@ import (
 // NodeMessageType is to indicate the specific type of message under NODE category
 type NodeMessageType byte
 
+const (
+	PROTOCOL_VERSION = 1
+)
+
 const (
 	Transaction NodeMessageType = iota
 	BLOCK
@@ -20,7 +24,7 @@ const (
 	CONTROL
 	BlockchainSync
 	PING // node send ip/pki to register with leader
-	PONG // leader
+	PONG // node broadcast pubK
 	// TODO: add more types
 )
 
diff --git a/proto/node/pingpong.go b/proto/node/pingpong.go
index 29c05a72d..af0dbddff 100644
--- a/proto/node/pingpong.go
+++ b/proto/node/pingpong.go
@@ -4,11 +4,7 @@ Package proto/node implements the communication protocol among nodes.
 pingpong.go adds support of ping/pong messages.
 
 ping: from node to peers, sending IP/Port/PubKey info
-TODO: add protocol version support
-
 pong: peer responds to ping messages, sending all pubkeys known by peer
-TODO:
-* add the version of the protocol
 
 */
 
@@ -18,25 +14,66 @@ import (
 	"bytes"
 	"encoding/gob"
 	"fmt"
+	"github.com/harmony-one/harmony/p2p"
+	"github.com/harmony-one/harmony/proto"
 	"log"
 )
 
-type PingMessageType struct {
+type nodeInfo struct {
 	IP     string
 	Port   string
 	PubKey string
 }
 
+type PingMessageType struct {
+	Version uint16 // version of the protocol
+	Node    nodeInfo
+}
+
 type PongMessageType struct {
-	PubKeys []string
+	Version uint16 // version of the protocol
+	Peers   []nodeInfo
 }
 
 func (p PingMessageType) String() string {
-	return fmt.Sprintf("%v:%v/%v", p.IP, p.Port, p.PubKey)
+	return fmt.Sprintf("%v=>%v:%v/%v", p.Version, p.Node.IP, p.Node.Port, p.Node.PubKey)
 }
 
 func (p PongMessageType) String() string {
-	return fmt.Sprintf("# Keys: %v", len(p.PubKeys))
+	str := fmt.Sprintf("%v=># Peers: %v", p.Version, len(p.Peers))
+	for _, p := range p.Peers {
+		str = fmt.Sprintf("%v\n%v:%v/%v", str, p.IP, p.Port, p.PubKey)
+	}
+	return str
+}
+
+func NewPingMessage(peer p2p.Peer) *PingMessageType {
+	ping := new(PingMessageType)
+
+	ping.Version = PROTOCOL_VERSION
+	ping.Node.IP = peer.Ip
+	ping.Node.Port = peer.Port
+	ping.Node.PubKey = fmt.Sprintf("%v", peer.PubKey)
+
+	return ping
+}
+
+func NewPongMessage(peers []p2p.Peer) *PongMessageType {
+	pong := new(PongMessageType)
+
+	pong.Version = PROTOCOL_VERSION
+	pong.Peers = make([]nodeInfo, 0)
+
+	for _, p := range peers {
+		n := nodeInfo{}
+		n.IP = p.Ip
+		n.Port = p.Port
+		n.PubKey = fmt.Sprintf("%v", p.PubKey)
+
+		pong.Peers = append(pong.Peers, n)
+	}
+
+	return pong
 }
 
 // Deserialize Ping Message
@@ -71,8 +108,10 @@ func GetPongMessage(payload []byte) (*PongMessageType, error) {
 
 // ConstructPingMessage contructs ping message from node to leader
 func (ping PingMessageType) ConstructPingMessage() []byte {
-	var byteBuffer bytes.Buffer
-	encoder := gob.NewEncoder(&byteBuffer)
+	byteBuffer := bytes.NewBuffer([]byte{byte(proto.NODE)})
+	byteBuffer.WriteByte(byte(PING))
+
+	encoder := gob.NewEncoder(byteBuffer)
 	err := encoder.Encode(ping)
 	if err != nil {
 		log.Panic("Can't serialize Ping message", "error:", err)
@@ -83,8 +122,10 @@ func (ping PingMessageType) ConstructPingMessage() []byte {
 
 // ConstructPongMessage contructs pong message from leader to node
 func (pong PongMessageType) ConstructPongMessage() []byte {
-	var byteBuffer bytes.Buffer
-	encoder := gob.NewEncoder(&byteBuffer)
+	byteBuffer := bytes.NewBuffer([]byte{byte(proto.NODE)})
+	byteBuffer.WriteByte(byte(PONG))
+
+	encoder := gob.NewEncoder(byteBuffer)
 	err := encoder.Encode(pong)
 	if err != nil {
 		log.Panic("Can't serialize Pong message", "error:", err)
diff --git a/proto/node/pingpong_test.go b/proto/node/pingpong_test.go
index 78d8a700c..1d6e71294 100644
--- a/proto/node/pingpong_test.go
+++ b/proto/node/pingpong_test.go
@@ -4,58 +4,91 @@ import (
 	"fmt"
 	"strings"
 	"testing"
+
+	"github.com/harmony-one/harmony/crypto"
+	"github.com/harmony-one/harmony/crypto/pki"
+	"github.com/harmony-one/harmony/p2p"
+	"github.com/harmony-one/harmony/proto"
 )
 
 var (
-	p1 = PingMessageType{"127.0.0.1", "9999", "0x12345678901234567890"}
-	e1 = "127.0.0.1:9999/0x12345678901234567890"
+	priKey1 = crypto.Ed25519Curve.Scalar().SetInt64(int64(333))
+	pubKey1 = pki.GetPublicKeyFromScalar(priKey1)
+	p1      = p2p.Peer{
+		Ip:     "127.0.0.1",
+		Port:   "9999",
+		PubKey: pubKey1,
+	}
+	e1 = "1=>127.0.0.1:9999/5ad91c4440d3a0e83df49ff4a0243da1edf2ec2d9376ed58ea7ac6bc9d745ae4"
 
-	p2 = PongMessageType{
-		[]string{
-			"0x1111111111111",
-			"0x2222222222222",
-			"0x3333333333333",
+	priKey2 = crypto.Ed25519Curve.Scalar().SetInt64(int64(999))
+	pubKey2 = pki.GetPublicKeyFromScalar(priKey2)
+
+	p2 = []p2p.Peer{
+		{
+			Ip:          "127.0.0.1",
+			Port:        "8888",
+			PubKey:      pubKey1,
+			Ready:       true,
+			ValidatorID: 1,
+		},
+		{
+			Ip:          "127.0.0.1",
+			Port:        "9999",
+			PubKey:      pubKey2,
+			Ready:       false,
+			ValidatorID: 2,
 		},
 	}
-	e2 = "# Keys: 3"
+	e2 = "1=># Peers: 2"
 
 	buf1 []byte
 	buf2 []byte
 )
 
 func TestString(test *testing.T) {
-	r1 := fmt.Sprintf("%v", p1)
+	ping1 := NewPingMessage(p1)
+
+	r1 := fmt.Sprintf("%v", *ping1)
 	if strings.Compare(r1, e1) != 0 {
 		test.Errorf("expect: %v, got: %v", e1, r1)
 	} else {
-		fmt.Printf("Ping:%v\n", p1)
+		fmt.Printf("Ping:%v\n", r1)
 	}
 
-	r2 := fmt.Sprintf("%v", p2)
+	pong1 := NewPongMessage(p2)
+	r2 := fmt.Sprintf("%v", *pong1)
 
-	if strings.Compare(r2, e2) != 0 {
+	if !strings.HasPrefix(r2, e2) {
 		test.Errorf("expect: %v, got: %v", e2, r2)
 	} else {
-		fmt.Printf("Pong:%v\n", p2)
+		fmt.Printf("Pong:%v\n", r2)
 	}
 }
 
 func TestSerialize(test *testing.T) {
-	buf1 = p1.ConstructPingMessage()
-	fmt.Printf("buf: %v\n", buf1)
+	ping1 := NewPingMessage(p1)
+	buf1 = ping1.ConstructPingMessage()
+	fmt.Printf("buf ping: %v\n", buf1)
 
-	buf2 = p2.ConstructPongMessage()
-	fmt.Printf("buf: %v\n", buf2)
+	pong1 := NewPongMessage(p2)
+	buf2 = pong1.ConstructPongMessage()
+	fmt.Printf("buf pong: %v\n", buf2)
 }
 
 func TestDeserialize(test *testing.T) {
-	ping, err := GetPingMessage(buf1)
+	msg1, err := proto.GetMessagePayload(buf1)
+	if err != nil {
+		test.Error("GetMessagePayload Failed!")
+	}
+	ping, err := GetPingMessage(msg1)
 	if err != nil {
 		test.Error("Ping failed!")
 	}
 	fmt.Printf("Ping:%v\n", ping)
 
-	pong, err := GetPongMessage(buf2)
+	msg2, err := proto.GetMessagePayload(buf2)
+	pong, err := GetPongMessage(msg2)
 	if err != nil {
 		test.Error("Pong failed!")
 	}