diff --git a/core/tx_pool.go b/core/tx_pool.go
index d0b632f2e8..6e50c4bf4c 100644
--- a/core/tx_pool.go
+++ b/core/tx_pool.go
@@ -457,6 +457,8 @@ func (pool *TxPool) SubscribeTxPreEvent(ch chan<- TxPreEvent) event.Subscription
 	return pool.scope.Track(pool.txFeed.Subscribe(ch))
 }
 
+// SubscribeSpecialTxPreEvent registers a subscription of TxPreEvent and
+// starts sending event to the given channel.
 func (pool *TxPool) SubscribeSpecialTxPreEvent(ch chan<- TxPreEvent) event.Subscription {
 	return pool.scope.Track(pool.specialTxFeed.Subscribe(ch))
 }
diff --git a/core/types/transaction.go b/core/types/transaction.go
index c3bea1ef14..e706358159 100644
--- a/core/types/transaction.go
+++ b/core/types/transaction.go
@@ -268,11 +268,10 @@ func (tx *Transaction) RawSignatureValues() (*big.Int, *big.Int, *big.Int) {
 }
 
 func (tx *Transaction) IsSpecialTransaction() bool {
-	to := ""
-	if tx.To() != nil {
-		to = tx.To().String()
+	if tx.To() == nil {
+		return false
 	}
-	return to == common.RandomizeSMC || to == common.BlockSigners
+	return tx.To().String() == common.RandomizeSMC || tx.To().String() == common.BlockSigners
 }
 
 func (tx *Transaction) String() string {
@@ -403,6 +402,8 @@ type TransactionsByPriceAndNonce struct {
 //
 // Note, the input map is reowned so the caller should not interact any more with
 // if after providing it to the constructor.
+
+// It also classifies special txs and normal txs
 func NewTransactionsByPriceAndNonce(signer Signer, txs map[common.Address]Transactions) (*TransactionsByPriceAndNonce, Transactions) {
 	// Initialize a price based heap with the head transactions
 	heads := TxByPrice{}
@@ -500,4 +501,4 @@ func (m Message) Value() *big.Int      { return m.amount }
 func (m Message) Gas() uint64          { return m.gasLimit }
 func (m Message) Nonce() uint64        { return m.nonce }
 func (m Message) Data() []byte         { return m.data }
-func (m Message) CheckNonce() bool     { return m.checkNonce }
\ No newline at end of file
+func (m Message) CheckNonce() bool     { return m.checkNonce 
\ No newline at end of file
diff --git a/eth/handler.go b/eth/handler.go
index 5ce8934c23..512e32a0ba 100644
--- a/eth/handler.go
+++ b/eth/handler.go
@@ -210,6 +210,7 @@ func (pm *ProtocolManager) Start(maxPeers int) {
 	pm.txSub = pm.txpool.SubscribeTxPreEvent(pm.txCh)
 	go pm.txBroadcastLoop()
 
+    // broadcast special transactions
 	pm.specialTxCh = make(chan core.TxPreEvent, txChanSize)
 	pm.specialTxSub = pm.txpool.SubscribeSpecialTxPreEvent(pm.specialTxCh)
 	go pm.specialTxBroadcastLoop()
diff --git a/eth/peer.go b/eth/peer.go
index 73c479376c..02d7a9a9af 100644
--- a/eth/peer.go
+++ b/eth/peer.go
@@ -55,7 +55,8 @@ type peer struct {
 	id string
 
 	*p2p.Peer
-	rw p2p.MsgReadWriter
+	rw     p2p.MsgReadWriter
+	pairRw p2p.MsgReadWriter
 
 	version  int         // Protocol version negotiated
 	forkDrop *time.Timer // Timed connection dropper if forks aren't validated in time
@@ -66,7 +67,6 @@ type peer struct {
 
 	knownTxs    *set.Set // Set of transaction hashes known to be known by this peer
 	knownBlocks *set.Set // Set of block hashes known to be known by this peer
-	pairRw      p2p.MsgReadWriter
 }
 
 func newPeer(version int, p *p2p.Peer, rw p2p.MsgReadWriter) *peer {
@@ -338,13 +338,13 @@ func (ps *peerSet) Register(p *peer) error {
 	if ps.closed {
 		return errClosed
 	}
-	if exitPeer, ok := ps.peers[p.id]; ok {
-		if exitPeer.pairRw != nil {
+	if existPeer, ok := ps.peers[p.id]; ok {
+		if existPeer.pairRw != nil {
 			return errAlreadyRegistered
 		}
-		exitPeer.PairPeer = p.Peer
-		exitPeer.pairRw = p.rw
-		p.PairPeer = exitPeer.Peer
+		existPeer.PairPeer = p.Peer
+		existPeer.pairRw = p.rw
+		p.PairPeer = existPeer.Peer
 		return p2p.ErrAddPairPeer
 	}
 	ps.peers[p.id] = p
diff --git a/miner/worker.go b/miner/worker.go
index 80015939e3..e2520662f9 100644
--- a/miner/worker.go
+++ b/miner/worker.go
@@ -627,6 +627,7 @@ func (env *Work) commitTransactions(mux *event.TypeMux, txs *types.TransactionsB
 
 	var coalescedLogs []*types.Log
 
+	// first priority for special Txs
 	for _, tx := range specialTxs {
 		if gp.Gas() < params.TxGas && tx.Gas() > 0 {
 			log.Trace("Not enough gas for further transactions", "gp", gp)
diff --git a/p2p/dial.go b/p2p/dial.go
index f65935273c..2236767f28 100644
--- a/p2p/dial.go
+++ b/p2p/dial.go
@@ -266,8 +266,8 @@ func (s *dialstate) checkDial(n *discover.Node, peers map[discover.NodeID]*Peer)
 	case dialing:
 		return errAlreadyDialing
 	case peers[n.ID] != nil:
-		exitPeer := peers[n.ID]
-		if exitPeer.PairPeer != nil {
+		exitsPeer := peers[n.ID]
+		if exitsPeer.PairPeer != nil {
 			return errAlreadyConnected
 		}
 	case s.ntab != nil && n.ID == s.ntab.Self().ID: