diff --git a/benchmark.go b/benchmark.go
index 1a99fa2ff..ef19246dd 100644
--- a/benchmark.go
+++ b/benchmark.go
@@ -203,7 +203,7 @@ func main() {
 	// Temporary testing code, to be removed.
 	currentNode.AddTestingAddresses(10000)
 
-	currentNode.State = node.WAIT
+	currentNode.State = node.NodeWaitToJoin
 
 	if consensus.IsLeader {
 		if *accountModel {
diff --git a/consensus/consensus.go b/consensus/consensus.go
index bd5136685..8b986a173 100644
--- a/consensus/consensus.go
+++ b/consensus/consensus.go
@@ -38,7 +38,7 @@ type Consensus struct {
 	// 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
+	validators sync.Map // key is uint16, value is p2p.Peer
 
 	// Minimal number of peers in the shard
 	// If the number of validators is less than minPeers, the consensus won't start
@@ -113,13 +113,12 @@ func NewConsensus(ip, port, ShardID string, peers []p2p.Peer, leader p2p.Peer) *
 
 	consensus.commitments = &map[uint16]kyber.Point{}
 	consensus.finalCommitments = &map[uint16]kyber.Point{}
-	consensus.validators = make(map[uint16]p2p.Peer)
 	consensus.responses = &map[uint16]kyber.Scalar{}
 	consensus.finalResponses = &map[uint16]kyber.Scalar{}
 
 	consensus.leader = leader
 	for _, peer := range peers {
-		consensus.validators[utils.GetUniqueIdFromPeer(peer)] = peer
+		consensus.validators.Store(utils.GetUniqueIdFromPeer(peer), peer)
 	}
 
 	// Initialize cosign bitmap
@@ -185,9 +184,15 @@ func (consensus *Consensus) signMessage(message []byte) []byte {
 // GetValidatorPeers returns list of validator peers.
 func (consensus *Consensus) GetValidatorPeers() []p2p.Peer {
 	validatorPeers := make([]p2p.Peer, 0)
-	for _, validatorPeer := range consensus.validators {
-		validatorPeers = append(validatorPeers, validatorPeer)
-	}
+
+	consensus.validators.Range(func(k, v interface{}) bool {
+		if peer, ok := v.(p2p.Peer); ok {
+			validatorPeers = append(validatorPeers, peer)
+			return true
+		}
+		return false
+	})
+
 	return validatorPeers
 }
 
@@ -223,14 +228,37 @@ func (consensus *Consensus) String() string {
 		duty, consensus.priKey.String(), consensus.ShardID, consensus.nodeID, consensus.state)
 }
 
+// AddPeers will add new peers into the validator map of the consensus
+// and add the public keys
 func (consensus *Consensus) AddPeers(peers []p2p.Peer) int {
 	count := 0
 	for _, peer := range peers {
-		_, ok := consensus.validators[utils.GetUniqueIdFromPeer(peer)]
+		_, ok := consensus.validators.Load(utils.GetUniqueIdFromPeer(peer))
 		if !ok {
-			consensus.validators[utils.GetUniqueIdFromPeer(peer)] = peer
+			consensus.validators.Store(utils.GetUniqueIdFromPeer(peer), peer)
+			consensus.publicKeys = append(consensus.publicKeys, peer.PubKey)
 			count++
 		}
 	}
+	if count > 0 {
+		// regenerate bitmaps
+		mask, err := crypto.NewMask(crypto.Ed25519Curve, consensus.publicKeys, consensus.leader.PubKey)
+		if err != nil {
+			panic("Failed to create mask")
+		}
+		finalMask, err := crypto.NewMask(crypto.Ed25519Curve, consensus.publicKeys, consensus.leader.PubKey)
+		if err != nil {
+			panic("Failed to create final mask")
+		}
+		consensus.bitmap = mask
+		consensus.finalBitmap = finalMask
+	}
 	return count
 }
+
+// RemovePeers will remove the peers from the validator list and publicKeys
+// It will be called when leader/node lost connection to peers
+func (consensus *Consensus) RemovePeers(peers []p2p.Peer) int {
+	// TODO (lc) we need to have a corresponding RemovePeers function
+	return 0
+}
diff --git a/consensus/consensus_leader.go b/consensus/consensus_leader.go
index f1ecd7647..f9904430d 100644
--- a/consensus/consensus_leader.go
+++ b/consensus/consensus_leader.go
@@ -31,7 +31,7 @@ func (consensus *Consensus) WaitForNewBlock(blockChannel chan blockchain.Block)
 		newBlock := <-blockChannel
 
 		if !consensus.HasEnoughValidators() {
-			consensus.Log.Debug("Not enough validators", "# Validators", len(consensus.validators))
+			consensus.Log.Debug("Not enough validators", "# Validators", len(consensus.publicKeys))
 			time.Sleep(500 * time.Millisecond)
 			continue
 		}
@@ -157,11 +157,17 @@ func (consensus *Consensus) processCommitMessage(payload []byte, targetState Sta
 	offset += 64
 
 	// Verify signature
-	value, ok := consensus.validators[validatorID]
+	v, ok := consensus.validators.Load(validatorID)
 	if !ok {
 		consensus.Log.Warn("Received message from unrecognized validator", "validatorID", validatorID, "consensus", consensus)
 		return
 	}
+	value, ok := v.(p2p.Peer)
+	if !ok {
+		consensus.Log.Warn("Invalid validator", "validatorID", validatorID, "consensus", consensus)
+		return
+	}
+
 	if schnorr.Verify(crypto.Ed25519Curve, value.PubKey, payload[:offset-64], signature) != nil {
 		consensus.Log.Warn("Received message with invalid signature", "validatorKey", consensus.leader.PubKey, "consensus", consensus)
 		return
@@ -298,11 +304,17 @@ func (consensus *Consensus) processResponseMessage(payload []byte, targetState S
 	}
 
 	// Verify signature
-	value, ok := consensus.validators[validatorID]
+	v, ok := consensus.validators.Load(validatorID)
 	if !ok {
 		consensus.Log.Warn("Received message from unrecognized validator", "validatorID", validatorID, "consensus", consensus)
 		return
 	}
+	value, ok := v.(p2p.Peer)
+	if !ok {
+		consensus.Log.Warn("Invalid validator", "validatorID", validatorID, "consensus", consensus)
+		return
+	}
+
 	if schnorr.Verify(crypto.Ed25519Curve, value.PubKey, payload[:offset-64], signature) != nil {
 		consensus.Log.Warn("Received message with invalid signature", "validatorKey", consensus.leader.PubKey, "consensus", consensus)
 		return
@@ -469,7 +481,7 @@ func (consensus *Consensus) reportMetrics(block blockchain.Block) {
 		"key":             consensus.pubKey.String(),
 		"tps":             tps,
 		"txCount":         numOfTxs,
-		"nodeCount":       len(consensus.validators) + 1,
+		"nodeCount":       len(consensus.publicKeys) + 1,
 		"latestBlockHash": hex.EncodeToString(consensus.blockHash[:]),
 		"latestTxHashes":  txHashes,
 		"blockLatency":    int(timeElapsed / time.Millisecond),
@@ -478,7 +490,7 @@ func (consensus *Consensus) reportMetrics(block blockchain.Block) {
 }
 
 func (consensus *Consensus) HasEnoughValidators() bool {
-	if len(consensus.validators) < consensus.MinPeers {
+	if len(consensus.publicKeys) < consensus.MinPeers {
 		return false
 	}
 	return true
diff --git a/deploy.sh b/deploy.sh
index 6cdf621ae..7629e8b61 100755
--- a/deploy.sh
+++ b/deploy.sh
@@ -13,6 +13,7 @@ USAGE: $ME [OPTIONS] config_file_name
    -p             use peer discovery (default: $PEER)
    -d             enable db support (default: $DB)
    -t             toggle txgen (default: $TXGEN)
+   -D duration    txgen run duration (default: $DURATION)
 
 This script will build all the binaries and start benchmark and txgen based on the configuration file.
 
@@ -28,13 +29,15 @@ EOU
 PEER=
 DB=
 TXGEN=true
+DURATION=60
 
-while getopts "hpdt" option; do
+while getopts "hpdtD:" option; do
    case $option in
       h) usage ;;
       p) PEER='-peer_discovery' ;;
       d) DB='-db_supported' ;;
       t) TXGEN=false ;;
+      D) DURATION=$OPTARG ;;
    esac
 done
 
@@ -72,5 +75,5 @@ while IFS='' read -r line || [[ -n "$line" ]]; do
 done < $config
 
 if [ "$TXGEN" == "true" ]; then
-  ./bin/txgen -config_file $config -log_folder $log_folder
+  ./bin/txgen -config_file $config -log_folder $log_folder -duration $DURATION
 fi
diff --git a/node/node.go b/node/node.go
index 922cdc276..a4dbcbb7e 100644
--- a/node/node.go
+++ b/node/node.go
@@ -32,10 +32,10 @@ import (
 type NodeState byte
 
 const (
-	INIT    NodeState = iota // Node just started, before contacting BeaconChain
-	WAIT                     // Node contacted BeaconChain, wait to join Shard
-	JOIN                     // Node joined Shard, ready for consensus
-	OFFLINE                  // Node is offline
+	NodeInit        NodeState = iota // Node just started, before contacting BeaconChain
+	NodeWaitToJoin                   // Node contacted BeaconChain, wait to join Shard
+	NodeJoinedShard                  // Node joined Shard, ready for consensus
+	NodeOffline                      // Node is offline
 )
 
 type NetworkNode struct {
@@ -245,7 +245,7 @@ func New(consensus *bft.Consensus, db *hdb.LDBDatabase) *Node {
 	}
 	// Logger
 	node.log = log.New()
-	node.State = INIT
+	node.State = NodeInit
 
 	return &node
 }
@@ -275,7 +275,7 @@ func (node *Node) JoinShard(leader p2p.Peer) {
 	// try to join the shard, with 10 minutes time-out
 	backoff := p2p.NewExpBackoff(1*time.Second, 10*time.Minute, 2)
 
-	for node.State == WAIT {
+	for node.State == NodeWaitToJoin {
 		backoff.Sleep()
 		ping := proto_node.NewPingMessage(node.SelfPeer)
 		buffer := ping.ConstructPingMessage()
diff --git a/node/node_handler.go b/node/node_handler.go
index 78c1fcb36..fd3430c84 100644
--- a/node/node_handler.go
+++ b/node/node_handler.go
@@ -555,7 +555,7 @@ func (node *Node) pongMessageHandler(msgPayload []byte) {
 		return
 	}
 	//	node.log.Info("Pong", "Msg", pong)
-	node.State = JOIN
+	node.State = NodeJoinedShard
 
 	peers := make([]p2p.Peer, 0)