diff --git a/code/client/connect.go b/code/client/connect.go
index 2f94ba0..b7cab9a 100644
--- a/code/client/connect.go
+++ b/code/client/connect.go
@@ -50,11 +50,12 @@ func shellCreate(conn *pool.Conn, msg *network.Msg) {
 		Type:   "shell",
 		Exec:   create.GetExec(),
 	})
-	err := sh.Exec(msg.GetLinkId())
+	lk := shell.NewLink(sh, msg.GetLinkId(), msg.GetFrom(), conn)
+	lk.SetTargetIdx(msg.GetFromIdx())
+	err := lk.Exec()
 	if err != nil {
 		logging.Error("create shell failed: %v", err)
 		return
 	}
-	conn.AddLink(msg.GetLinkId())
-	sh.Forward(conn, msg.GetFromIdx())
+	lk.Forward()
 }
diff --git a/code/client/pool/pool.go b/code/client/pool/pool.go
index b08591b..bd2f3dd 100644
--- a/code/client/pool/pool.go
+++ b/code/client/pool/pool.go
@@ -2,7 +2,6 @@ package pool
 
 import (
 	"crypto/tls"
-	"math/rand"
 	"natpass/code/client/global"
 	"natpass/code/network"
 	"sync"
@@ -28,7 +27,7 @@ func New(cfg *global.Configure) *Pool {
 		cfg:   cfg,
 		conns: make(map[uint32]*Conn, cfg.Links),
 		count: cfg.Links,
-		idx:   rand.Uint32(), // random initialize for fast restart
+		idx:   0,
 	}
 }
 
diff --git a/code/client/shell/exec_xx.go b/code/client/shell/exec_xx.go
index 684b084..79329d6 100644
--- a/code/client/shell/exec_xx.go
+++ b/code/client/shell/exec_xx.go
@@ -9,11 +9,10 @@ import (
 	"github.com/creack/pty"
 )
 
-func (shell *Shell) Exec(id string) error {
-	shell.id = id
+func (link *Link) Exec() error {
 	var cmd *exec.Cmd
-	if len(shell.cfg.Exec) > 0 {
-		cmd = exec.Command(shell.cfg.Exec)
+	if len(link.parent.cfg.Exec) > 0 {
+		cmd = exec.Command(link.parent.cfg.Exec)
 	}
 	if cmd == nil {
 		dir, err := exec.LookPath("bash")
@@ -34,14 +33,14 @@ func (shell *Shell) Exec(id string) error {
 	if err != nil {
 		return err
 	}
-	shell.stdin = f
-	shell.stdout = f
-	shell.pid = cmd.Process.Pid
+	link.stdin = f
+	link.stdout = f
+	link.pid = cmd.Process.Pid
 	return nil
 }
 
-func (shell *Shell) onClose() {
-	if shell.stdin != nil {
-		shell.stdin.Close()
+func (link *Link) onClose() {
+	if link.stdin != nil {
+		link.stdin.Close()
 	}
 }
diff --git a/code/client/shell/forward.go b/code/client/shell/forward.go
index f92480f..c8d160b 100644
--- a/code/client/shell/forward.go
+++ b/code/client/shell/forward.go
@@ -1,22 +1,21 @@
 package shell
 
 import (
-	"natpass/code/client/pool"
 	"natpass/code/network"
 	"natpass/code/utils"
 
 	"github.com/lwch/logging"
 )
 
-func (shell *Shell) Forward(remote *pool.Conn, toIdx uint32) {
-	go shell.remoteRead(remote)
-	go shell.localRead(remote, toIdx)
+func (link *Link) Forward() {
+	go link.remoteRead()
+	go link.localRead()
 }
 
-func (shell *Shell) remoteRead(remote *pool.Conn) {
+func (link *Link) remoteRead() {
 	defer utils.Recover("remoteRead")
-	defer shell.Close()
-	ch := remote.ChanRead(shell.id)
+	defer link.Close()
+	ch := link.remote.ChanRead(link.id)
 	for {
 		msg := <-ch
 		if msg == nil {
@@ -26,10 +25,11 @@ func (shell *Shell) remoteRead(remote *pool.Conn) {
 		case network.Msg_shell_resize:
 			// TODO
 		case network.Msg_shell_data:
-			_, err := shell.stdin.Write(msg.GetSdata().GetData())
+			_, err := link.stdin.Write(msg.GetSdata().GetData())
 			if err != nil {
 				// TODO: close
-				logging.Error("write data on shell %s link %s failed, err=%v", shell.Name, shell.id, err)
+				logging.Error("write data on shell %s link %s failed, err=%v",
+					link.parent.Name, link.id, err)
 				return
 			}
 		case network.Msg_shell_close:
@@ -38,23 +38,25 @@ func (shell *Shell) remoteRead(remote *pool.Conn) {
 	}
 }
 
-func (shell *Shell) localRead(remote *pool.Conn, toIdx uint32) {
+func (link *Link) localRead() {
 	defer utils.Recover("localRead")
-	defer shell.Close()
+	defer link.Close()
 	buf := make([]byte, 16*1024)
 	for {
-		n, err := shell.stdout.Read(buf)
+		n, err := link.stdout.Read(buf)
 		if err != nil {
 			// if !link.closeFromRemote {
 			// 	link.remote.SendDisconnect(link.target, link.targetIdx, link.id)
 			// }
-			logging.Error("read data on shell %s link %s failed, err=%v", shell.Name, shell.id, err)
+			logging.Error("read data on shell %s link %s failed, err=%v",
+				link.parent.Name, link.id, err)
 			return
 		}
 		if n == 0 {
 			continue
 		}
-		logging.Debug("link %s on shell %s read from local %d bytes", shell.id, shell.Name, n)
-		remote.SendShellData(shell.cfg.Target, toIdx, shell.id, buf[:n])
+		logging.Debug("link %s on shell %s read from local %d bytes",
+			link.id, link.parent.Name, n)
+		link.remote.SendShellData(link.target, link.targetIdx, link.id, buf[:n])
 	}
 }
diff --git a/code/client/shell/h_ws.go b/code/client/shell/h_ws.go
index e805f6b..11611ea 100644
--- a/code/client/shell/h_ws.go
+++ b/code/client/shell/h_ws.go
@@ -52,6 +52,7 @@ func (shell *Shell) localForward(id string, local *websocket.Conn, remote *pool.
 			return
 		}
 		remote.SendShellData(shell.cfg.Target, remote.Idx, id, data)
+		logging.Info("send: %d", remote.Idx)
 		logging.Debug("local read %d bytes: name=%s, id=%s", len(data), shell.Name, id)
 	}
 }
diff --git a/code/client/shell/link.go b/code/client/shell/link.go
new file mode 100644
index 0000000..4001283
--- /dev/null
+++ b/code/client/shell/link.go
@@ -0,0 +1,48 @@
+package shell
+
+import (
+	"io"
+	"natpass/code/client/pool"
+	"os"
+
+	"github.com/lwch/logging"
+)
+
+type Link struct {
+	parent    *Shell
+	id        string // link id
+	target    string // target id
+	targetIdx uint32 // target idx
+	remote    *pool.Conn
+	// in remote
+	pid    int
+	stdin  io.WriteCloser
+	stdout io.ReadCloser
+}
+
+// NewLink create link
+func NewLink(parent *Shell, id, target string, remote *pool.Conn) *Link {
+	remote.AddLink(id)
+	logging.Info("create shell %s for tunnel %s on connection %d",
+		id, parent.Name, remote.Idx)
+	return &Link{
+		parent: parent,
+		id:     id,
+		target: target,
+		remote: remote,
+	}
+}
+
+// SetTargetIdx set link remote index
+func (link *Link) SetTargetIdx(idx uint32) {
+	link.targetIdx = idx
+}
+
+// Close close link
+func (link *Link) Close() {
+	link.onClose()
+	p, err := os.FindProcess(link.pid)
+	if err == nil {
+		p.Kill()
+	}
+}
diff --git a/code/client/shell/shell.go b/code/client/shell/shell.go
index 28e300a..68f3ef7 100644
--- a/code/client/shell/shell.go
+++ b/code/client/shell/shell.go
@@ -2,23 +2,17 @@ package shell
 
 import (
 	"fmt"
-	"io"
 	"natpass/code/client/global"
 	"natpass/code/client/pool"
 	"net/http"
-	"os"
 
 	"github.com/lwch/logging"
 	"github.com/lwch/runtime"
 )
 
 type Shell struct {
-	Name   string
-	id     string
-	cfg    global.Tunnel
-	pid    int
-	stdin  io.WriteCloser
-	stdout io.ReadCloser
+	Name string
+	cfg  global.Tunnel
 }
 
 // New new shell
@@ -29,14 +23,6 @@ func New(cfg global.Tunnel) *Shell {
 	}
 }
 
-func (shell *Shell) Close() {
-	shell.onClose()
-	p, err := os.FindProcess(shell.pid)
-	if err == nil {
-		p.Kill()
-	}
-}
-
 // Handle handle shell
 func (shell *Shell) Handle(pl *pool.Pool) {
 	defer func() {
diff --git a/code/client/tunnel/link.go b/code/client/tunnel/link.go
index ef99b83..c7f6f10 100644
--- a/code/client/tunnel/link.go
+++ b/code/client/tunnel/link.go
@@ -22,6 +22,7 @@ type Link struct {
 	closeFromRemote bool
 }
 
+// NewLink create link
 func NewLink(parent *Tunnel, id, target string, local net.Conn, remote *pool.Conn) *Link {
 	remote.AddLink(id)
 	logging.Info("create link %s for tunnel %s on connection %d",
@@ -104,6 +105,7 @@ func (link *Link) localRead() {
 	}
 }
 
+// SetTargetIdx set link remote index
 func (link *Link) SetTargetIdx(idx uint32) {
 	link.targetIdx = idx
 }