diff --git a/clab/config/template.go b/clab/config/template.go
index ab2610f5a..1e63c97f4 100644
--- a/clab/config/template.go
+++ b/clab/config/template.go
@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"path/filepath"
+	"strconv"
 	"strings"
 	"text/template"
 
@@ -171,7 +172,20 @@ func (c *ConfigSnippet) String() string {
 	return fmt.Sprintf("%s: %s %d lines of config", c.TargetNode.LongName, c.source, len(c.Config))
 }
 
+func typeof(val interface{}) string {
+	switch val.(type) {
+	case string:
+		return "string"
+	case int:
+		return "int"
+	}
+	return ""
+}
+
 var funcMap = map[string]interface{}{
+	"expect": func(val interface{}, format interface{}) (interface{}, error) {
+		return nil, nil
+	},
 	"require": func(val interface{}) (interface{}, error) {
 		if val == nil {
 			return nil, errors.New("required value not set")
@@ -192,21 +206,80 @@ var funcMap = map[string]interface{}{
 		if def == nil {
 			return nil, fmt.Errorf("default value expected")
 		}
-		switch val.(type) {
+
+		switch v := val.(type) {
 		case string:
-			if val == "" {
+			if v == "" {
 				return def, nil
 			}
-		default:
-			if val == nil {
+		case bool:
+			if !v {
 				return def, nil
 			}
 		}
+		if val == nil {
+			return def, nil
+		}
+
+		// If we have a input value, do some type checking
+		tval, tdef := typeof(val), typeof(def)
+		if tval == "string" && tdef == "int" {
+			if _, err := strconv.Atoi(val.(string)); err == nil {
+				tval = "int"
+			}
+		}
+		if tdef != tval {
+			return val, fmt.Errorf("expected type %v, got %v (value=%v)", tdef, tval, val)
+		}
+
+		// Return the value
 		return val, nil
 	},
 	"contains": func(str interface{}, substr interface{}) (interface{}, error) {
 		return strings.Contains(fmt.Sprintf("%v", str), fmt.Sprintf("%v", substr)), nil
 	},
+	"split": func(val interface{}, sep interface{}) (interface{}, error) {
+		// Start and end values
+		if val == nil {
+			return []interface{}{}, nil
+		}
+		s := fmt.Sprintf("%v", sep)
+		if sep == nil {
+			s = " "
+		}
+
+		v := fmt.Sprintf("%v", val)
+
+		res := strings.Split(v, s)
+		r := make([]interface{}, len(res))
+		for i, p := range res {
+			r[i] = p
+		}
+		return r, nil
+	},
+	"join": func(val interface{}, sep interface{}) (interface{}, error) {
+		s := fmt.Sprintf("%s", sep)
+		if sep == nil {
+			s = " "
+		}
+		// Start and end values
+		switch v := val.(type) {
+		case []interface{}:
+			if val == nil {
+				return "", nil
+			}
+			res := make([]string, len(v))
+			for i, v := range v {
+				res[i] = fmt.Sprintf("%v", v)
+			}
+			return strings.Join(res, s), nil
+		case []string:
+			return strings.Join(v, s), nil
+		case []int, []int16, []int32:
+			return strings.Trim(strings.Replace(fmt.Sprint(v), " ", s, -1), "[]"), nil
+		}
+		return nil, fmt.Errorf("expected array [], got %v", val)
+	},
 	"slice": func(val interface{}, start interface{}, end interface{}) (interface{}, error) {
 		// Start and end values
 		var s, e int
diff --git a/clab/config/template_test.go b/clab/config/template_test.go
index 0de3cfc9b..b9a434182 100644
--- a/clab/config/template_test.go
+++ b/clab/config/template_test.go
@@ -10,30 +10,55 @@ func TestFuncMapDefault(t *testing.T) {
 	// parameters & return
 	tSet := map[string][][]interface{}{
 		"default": {
-			{nil, 1, 1},
+			{0, nil, nil, true},
 			{5, 1, 5},
+			{5, "1", 5, "invalid types"},
+			{"a", 1, "a", "invalid types"},
 			{"", "1", "1"},
-			{nil, nil, fmt.Errorf("")},
+			{nil, nil, nil, true},
 		},
 		"contains": {
 			{"aa.", ".", true},
 			{"ss", ".", false},
+		},
+		"split": {
+			{"a.a", ".", "[a a]"},
+			{"a bb", nil, "[a bb]"},
+			{nil, nil, "[]"},
+			{nil, ".", "[]"},
+		},
+		"join": {
+			{[]interface{}{"a", "b"}, ".", "a.b"},
+			{[]string{"a", "b"}, ".", "a.b"},
+			{[]int{1, 2}, ".", "1.2"},
 		}}
 
 	for name, set := range tSet {
 		fn := funcMap[name].(func(interface{}, interface{}) (interface{}, error))
 
 		for _, p := range set {
-			exp := p[len(p)-1]
-			var expe error
-			switch v := exp.(type) {
-			case error:
-				expe = v
-				exp = nil
-			}
+			// Execute the funciton
 			res, err := fn(p[0], p[1])
-			if res != exp || (err != nil && expe == nil) {
-				t.Errorf("%v expected %v got %v error %v err: %v", p, exp, res, expe, err)
+
+			// expect return value
+			exp := p[2]
+			exp_err := len(p) == 4
+
+			// Check errors
+			if err != nil && !exp_err {
+				t.Errorf("%v no err expected, err: %v", p, err)
+			}
+			if err == nil && exp_err {
+				t.Errorf("%v err expected, non found", p)
+			}
+
+			// Check value
+			if res != exp {
+				// allow arrays (match on string only)
+				if fmt.Sprintf("%v", res) == fmt.Sprintf("%v", exp) {
+					continue
+				}
+				t.Errorf("%v expected %v got %v", p, exp, res)
 			}
 		}
 	}
diff --git a/templates/vr-sros/base-node.tmpl b/templates/vr-sros/base-node.tmpl
index ecd150c79..8bf29749e 100644
--- a/templates/vr-sros/base-node.tmpl
+++ b/templates/vr-sros/base-node.tmpl
@@ -1,3 +1,6 @@
+{{ expect .systemip "ip" }}
+{{ expect .sid_idx "0-1000" }}
+
 /configure system login-control idle-timeout 1440
 
 /configure apply-groups ["baseport"]
@@ -66,13 +69,13 @@
 
 /configure router
     autonomous-system {{ default .as_number "64500" }}
-    mpls-labels sr-labels start {{ default .sid_start "19000" }} end {{ default .sid_end "30000" }}
+    mpls-labels sr-labels start {{ default .sid_start 19000 }} end {{ default .sid_end 30000 }}
 
-/configure router isis {{ default .isis_iid "0" }}
-    area-address 49.0000.000{{ default .isis_iid "0" }}
+/configure router isis {{ default .isis_iid 0 }}
+    area-address 49.0000.000{{ default .isis_iid 0 }}
     level-capability 2
     level 2 wide-metrics-only
-    interface "system" ipv4-node-sid index {{ .sid_idx }}
+    interface "system" ipv4-node-sid index {{ require .sid_idx }}
     #database-export igp-identifier {{ default .isis_iid "0" }} bgp-ls-identifier value {{ default .isis_iid "0" }}
     traffic-engineering
     advertise-router-capability area