diff --git a/client/backoff.go b/client/backoff.go
index d548b724..0aed7c60 100644
--- a/client/backoff.go
+++ b/client/backoff.go
@@ -2,7 +2,6 @@ package client
 
 import (
 	"context"
-	"math"
 	"time"
 
 	"go.unistack.org/micro/v3/util/backoff"
@@ -11,20 +10,6 @@ import (
 // BackoffFunc is the backoff call func
 type BackoffFunc func(ctx context.Context, req Request, attempts int) (time.Duration, error)
 
-// BackoffExp using exponential backoff func
-func BackoffExp(_ context.Context, _ Request, attempts int) (time.Duration, error) {
+func exponentialBackoff(ctx context.Context, req Request, attempts int) (time.Duration, error) {
 	return backoff.Do(attempts), nil
 }
-
-// BackoffInterval specifies randomization interval for backoff func
-func BackoffInterval(min time.Duration, max time.Duration) BackoffFunc {
-	return func(_ context.Context, _ Request, attempts int) (time.Duration, error) {
-		td := time.Duration(time.Duration(math.Pow(float64(attempts), math.E)) * time.Millisecond * 100)
-		if td < min {
-			return min, nil
-		} else if td > max {
-			return max, nil
-		}
-		return td, nil
-	}
-}
diff --git a/client/backoff_test.go b/client/backoff_test.go
index 2ab854f7..5b9b60b8 100644
--- a/client/backoff_test.go
+++ b/client/backoff_test.go
@@ -22,7 +22,7 @@ func TestBackoff(t *testing.T) {
 	}
 
 	for i := 0; i < 5; i++ {
-		d, err := BackoffExp(context.TODO(), r, i)
+		d, err := exponentialBackoff(context.TODO(), r, i)
 		if err != nil {
 			t.Fatal(err)
 		}
diff --git a/client/client.go b/client/client.go
index 71bedfd9..63cb4f85 100644
--- a/client/client.go
+++ b/client/client.go
@@ -14,8 +14,8 @@ var (
 	DefaultClient Client = NewClient()
 	// DefaultContentType is the default content-type if not specified
 	DefaultContentType = "application/json"
-	// DefaultBackoff is the default backoff function for retries (minimum 10 millisecond and maximum 5 second)
-	DefaultBackoff = BackoffInterval(10*time.Millisecond, 5*time.Second)
+	// DefaultBackoff is the default backoff function for retries
+	DefaultBackoff = exponentialBackoff
 	// DefaultRetry is the default check-for-retry function for retries
 	DefaultRetry = RetryNever
 	// DefaultRetries is the default number of times a request is tried
diff --git a/client/retry.go b/client/retry.go
index a218b3fe..40272fd2 100644
--- a/client/retry.go
+++ b/client/retry.go
@@ -19,32 +19,18 @@ func RetryNever(ctx context.Context, req Request, retryCount int, err error) (bo
 	return false, nil
 }
 
-// RetryOnError retries a request on a 500 or 408 (timeout) error
+// RetryOnError retries a request on a 500 or timeout error
 func RetryOnError(_ context.Context, _ Request, _ int, err error) (bool, error) {
 	if err == nil {
 		return false, nil
 	}
+
 	me := errors.FromError(err)
 	switch me.Code {
 	// retry on timeout or internal server error
 	case 408, 500:
 		return true, nil
 	}
+
 	return false, nil
 }
-
-// RetryOnErrors retries a request on specified error codes
-func RetryOnErrors(codes ...int32) RetryFunc {
-	return func(_ context.Context, _ Request, _ int, err error) (bool, error) {
-		if err == nil {
-			return false, nil
-		}
-		me := errors.FromError(err)
-		for _, code := range codes {
-			if me.Code == code {
-				return true, nil
-			}
-		}
-		return false, nil
-	}
-}
diff --git a/router/context.go b/router/context.go
new file mode 100644
index 00000000..2f156cfc
--- /dev/null
+++ b/router/context.go
@@ -0,0 +1,34 @@
+package router
+
+import (
+	"context"
+)
+
+type routerKey struct{}
+
+// FromContext get router from context
+func FromContext(ctx context.Context) (Router, bool) {
+	if ctx == nil {
+		return nil, false
+	}
+	c, ok := ctx.Value(routerKey{}).(Router)
+	return c, ok
+}
+
+// NewContext put router in context
+func NewContext(ctx context.Context, c Router) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	return context.WithValue(ctx, routerKey{}, c)
+}
+
+// SetOption returns a function to setup a context with given value
+func SetOption(k, v interface{}) Option {
+	return func(o *Options) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, k, v)
+	}
+}
diff --git a/util/jitter/random.go b/util/jitter/random.go
index c3caa5d3..eb03b29f 100644
--- a/util/jitter/random.go
+++ b/util/jitter/random.go
@@ -13,3 +13,8 @@ func Random(d time.Duration) time.Duration {
 	v := rng.Float64() * float64(d.Nanoseconds())
 	return time.Duration(v)
 }
+
+func RandomInterval(min, max time.Duration) time.Duration {
+	var rng rand.Rand
+	return time.Duration(rng.Int63n(max.Nanoseconds()-min.Nanoseconds())+min.Nanoseconds()) * time.Nanosecond
+}