diff --git a/discovery/Host.go b/discovery/Host.go
index b837489..f56ae0e 100644
--- a/discovery/Host.go
+++ b/discovery/Host.go
@@ -5,6 +5,13 @@ import (
 	"git.loafle.net/overflow/model/util"
 )
 
+const (
+	DefaultOsType     = "UNKNOWN"
+	DefaultHostType   = "HOST"
+	DefaultHostVendor = "UNKNOWN"
+	DefaultHostModel  = "UNKNOWN"
+)
+
 type Host struct {
 	MetaIPType *meta.MetaIPType `json:"metaIPType,omitempty"`
 	Name       string           `json:"name,omitempty"`
@@ -13,9 +20,9 @@ type Host struct {
 
 	OsType string `json:"osType,omitempty"`
 
-	DeviceType   string `json:"deviceType,omitempty"`
-	DeviceVendor string `json:"deviceVendor,omitempty"`
-	DeviceModel  string `json:"deviceModel,omitempty"`
+	HostType   string `json:"hostType,omitempty"`
+	HostVendor string `json:"hostVendor,omitempty"`
+	HostModel  string `json:"hostModel,omitempty"`
 
 	Meta           map[string]map[string]string `json:"meta,omitempty"`
 	DiscoveredBy   []string                     `json:"discoveredBy,omitempty"`
@@ -24,3 +31,15 @@ type Host struct {
 	Zone     *Zone   `json:"zone,omitempty"`
 	PortList []*Port `json:"portList,omitempty"`
 }
+
+func NewHost(zone *Zone, metaIPType *meta.MetaIPType, address string) *Host {
+	return &Host{
+		Zone:       zone,
+		MetaIPType: metaIPType,
+		Address:    address,
+		OsType:     DefaultOsType,
+		HostType:   DefaultHostType,
+		HostVendor: DefaultHostVendor,
+		HostModel:  DefaultHostModel,
+	}
+}
diff --git a/discovery/Port.go b/discovery/Port.go
index 323f69b..338274c 100644
--- a/discovery/Port.go
+++ b/discovery/Port.go
@@ -2,6 +2,7 @@ package discovery
 
 import (
 	"encoding/json"
+	"strconv"
 
 	"git.loafle.net/overflow/model/meta"
 	"git.loafle.net/overflow/model/util"
@@ -20,3 +21,11 @@ type Port struct {
 	ServiceList []*Service     `json:"serviceList,omitempty"`
 	UDPLayer    gopacket.Layer `json:"-"`
 }
+
+func NewPort(host *Host, metaPortType *meta.MetaPortType, portNumber int) *Port {
+	return &Port{
+		Host:         host,
+		MetaPortType: metaPortType,
+		PortNumber:   json.Number(strconv.Itoa(portNumber)),
+	}
+}
diff --git a/discovery/Service.go b/discovery/Service.go
index e242257..205b694 100644
--- a/discovery/Service.go
+++ b/discovery/Service.go
@@ -5,15 +5,36 @@ import (
 	"git.loafle.net/overflow/model/util"
 )
 
+const (
+	DefaultServiceType    = "ETC"
+	DefaultServiceVendor  = "UNKNOWN"
+	DefaultServiceVersion = "UNKNOWN"
+)
+
 type Service struct {
 	MetaCryptoType *meta.MetaCryptoType `json:"metaCryptoType,omitempty"`
 	Key            string               `json:"key,omitempty"`
 	Name           string               `json:"name,omitempty"`
 	Description    string               `json:"description,omitempty"`
 
+	ServiceType    string `json:"serviceType,omitempty"`
+	ServiceVendor  string `json:"serviceVendor,omitempty"`
+	ServiceVersion string `json:"serviceVersion,omitempty"`
+
 	Meta           map[string]map[string]string `json:"meta,omitempty"`
 	DiscoveredBy   []string                     `json:"discoveredBy,omitempty"`
 	DiscoveredDate *util.Timestamp              `json:"discoveredDate,omitempty"`
 
 	Port *Port `json:"port,omitempty"`
 }
+
+func NewService(port *Port, metaCryptoType *meta.MetaCryptoType, key string) *Service {
+	return &Service{
+		Port:           port,
+		MetaCryptoType: metaCryptoType,
+		Key:            key,
+		ServiceType:    DefaultServiceType,
+		ServiceVendor:  DefaultServiceVendor,
+		ServiceVersion: DefaultServiceVersion,
+	}
+}
diff --git a/discovery/Zone.go b/discovery/Zone.go
index 3b44e8b..6be8545 100644
--- a/discovery/Zone.go
+++ b/discovery/Zone.go
@@ -8,9 +8,9 @@ import (
 )
 
 type Zone struct {
+	MetaIPType *meta.MetaIPType `json:"metaIPType,omitempty"`
 	Network    string           `json:"network,omitempty"`
 	Iface      string           `json:"iface,omitempty"`
-	MetaIPType *meta.MetaIPType `json:"metaIPType,omitempty"`
 	Address    string           `json:"address,omitempty"`
 	Mac        string           `json:"mac,omitempty"`
 
@@ -20,3 +20,12 @@ type Zone struct {
 
 	mtx sync.RWMutex `json:"-"`
 }
+
+func NewZone(metaIPType *meta.MetaIPType, network string, iface string, address string) *Zone {
+	return &Zone{
+		MetaIPType: metaIPType,
+		Network:    network,
+		Iface:      iface,
+		Address:    address,
+	}
+}