diff --git a/cluster/cluster.go b/cluster/cluster.go
index 627d3268..51364707 100644
--- a/cluster/cluster.go
+++ b/cluster/cluster.go
@@ -52,6 +52,7 @@ func (c *cluster) Register(_ context.Context, req *clusterpb.RegisterRequest) (*
 	}
 
 	resp := &clusterpb.RegisterResponse{}
+	c.mu.Lock()
 	for k, m := range c.members {
 		if m.memberInfo.ServiceAddr == req.MemberInfo.ServiceAddr {
 			// 节点异常崩溃，不会执行unregister，此时再次启动该节点，由于已存在注册信息，将再也无法成功注册，这里做个修改，先移除后重新注册
@@ -64,6 +65,7 @@ func (c *cluster) Register(_ context.Context, req *clusterpb.RegisterRequest) (*
 			//return nil, fmt.Errorf("address %s has registered", req.MemberInfo.ServiceAddr)
 		}
 	}
+	c.mu.Unlock()
 
 	// Notify registered node to update remote services
 	newMember := &clusterpb.NewMemberRequest{MemberInfo: req.MemberInfo}
diff --git a/examples/cluster/main.go b/examples/cluster/main.go
index a1cc9c99..c2e31c0c 100644
--- a/examples/cluster/main.go
+++ b/examples/cluster/main.go
@@ -146,6 +146,7 @@ func runGate(args *cli.Context) error {
 		nano.WithWSPath("/nano"),
 		nano.WithCheckOriginFunc(func(_ *http.Request) bool { return true }),
 		nano.WithDebugMode(),
+		nano.WithNodeId(2), // if you deploy multi gate, option set nodeId, default nodeId = os.Getpid()
 	)
 	return nil
 }
diff --git a/go.mod b/go.mod
index 311cf128..c240e5ef 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,7 @@ module github.com/lonng/nano
 go 1.12
 
 require (
+	github.com/bwmarrin/snowflake v0.3.0 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.0 // indirect
 	github.com/google/uuid v1.2.0 // indirect
 	github.com/gorilla/websocket v1.4.2 // indirect
diff --git a/go.sum b/go.sum
index 074497b1..9cbc15db 100644
--- a/go.sum
+++ b/go.sum
@@ -4,6 +4,8 @@ github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
 github.com/benbjohnson/clock v1.1.0/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
+github.com/bwmarrin/snowflake v0.3.0 h1:xm67bEhkKh6ij1790JB83OujPR5CzNe8QuQqAgISZN0=
+github.com/bwmarrin/snowflake v0.3.0/go.mod h1:NdZxfVWX+oR6y2K0o6qAYv6gIOP9rjG0/E9WsDpxqwE=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
 github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
diff --git a/options.go b/options.go
index 5ae6f615..8f656213 100644
--- a/options.go
+++ b/options.go
@@ -11,6 +11,7 @@ import (
 	"github.com/lonng/nano/internal/message"
 	"github.com/lonng/nano/pipeline"
 	"github.com/lonng/nano/serialize"
+	"github.com/lonng/nano/service"
 	"google.golang.org/grpc"
 )
 
@@ -152,3 +153,10 @@ func WithHandshakeValidator(fn func([]byte) error) Option {
 		env.HandshakeValidator = fn
 	}
 }
+
+// WithNodeId set nodeId use snowflake nodeId generate sessionId, default: pid
+func WithNodeId(nodeId uint64) Option {
+	return func(opt *cluster.Options) {
+		service.ResetNodeId(nodeId)
+	}
+}
diff --git a/service/connection.go b/service/connection.go
index 38eb4f0a..7c08c05e 100644
--- a/service/connection.go
+++ b/service/connection.go
@@ -21,11 +21,25 @@
 package service
 
 import (
+	"os"
 	"sync/atomic"
 )
 
+type Connection interface {
+	Increment()
+	Decrement()
+	Count() int64
+	Reset()
+	SessionID() int64
+}
+
+func ResetNodeId(nodeId uint64) {
+	Connections = newDefaultConnectionServer(nodeId)
+}
+
 // Connections is a global variable which is used by session.
-var Connections = newConnectionService()
+//var Connections  = newConnectionService()
+var Connections Connection = newDefaultConnectionServer(uint64(os.Getpid()))
 
 type connectionService struct {
 	count int64
diff --git a/service/default.go b/service/default.go
new file mode 100644
index 00000000..4f79709e
--- /dev/null
+++ b/service/default.go
@@ -0,0 +1,48 @@
+package service
+
+import (
+	"sync/atomic"
+
+	"github.com/bwmarrin/snowflake"
+)
+
+// implement Connection
+type defaultConnectionServer struct {
+	count int64
+	node  *snowflake.Node
+}
+
+func newDefaultConnectionServer(node uint64) *defaultConnectionServer {
+	dcs := &defaultConnectionServer{
+		count: 0,
+		node:  nil,
+	}
+	n := int64(node % 1000) // safety node value
+	dcs.node, _ = snowflake.NewNode(n)
+	return dcs
+}
+
+// Increment increment the connection count
+func (dcs *defaultConnectionServer) Increment() {
+	atomic.AddInt64(&dcs.count, 1)
+}
+
+// Decrement decrement the connection count
+func (dcs *defaultConnectionServer) Decrement() {
+	atomic.AddInt64(&dcs.count, -1)
+}
+
+// Count returns the connection numbers in current
+func (dcs *defaultConnectionServer) Count() int64 {
+	return atomic.LoadInt64(&dcs.count)
+}
+
+// Reset reset the connection service status
+func (dcs *defaultConnectionServer) Reset() {
+	atomic.StoreInt64(&dcs.count, 0)
+}
+
+// SessionID returns the session id, (snowflake impl)
+func (dcs *defaultConnectionServer) SessionID() int64 {
+	return dcs.node.Generate().Int64()
+}
diff --git a/service/default_test.go b/service/default_test.go
new file mode 100644
index 00000000..6e711967
--- /dev/null
+++ b/service/default_test.go
@@ -0,0 +1,31 @@
+package service
+
+import (
+	"testing"
+)
+
+func TestNewDefaultConnectionServer(t *testing.T) {
+	service := newDefaultConnectionServer(101024)
+	w := make(chan bool, paraCount)
+	sidChan := make(chan int64, paraCount)
+	for i := 0; i < paraCount; i++ {
+		go func() {
+			service.Increment()
+			w <- true
+			sidChan <- service.SessionID()
+		}()
+	}
+	smap := make(map[int64]struct{}, paraCount)
+	for i := 0; i < paraCount; i++ {
+		<-w
+		sid := <-sidChan
+		if _, ok := smap[sid]; ok {
+			t.Error("wrong session id repeat")
+		} else {
+			smap[sid] = struct{}{}
+		}
+	}
+	if service.Count() != paraCount {
+		t.Error("wrong connection count")
+	}
+}