diff --git a/gns3server/modules/dynamips/backends/atmsw.py b/gns3server/modules/dynamips/backends/atmsw.py
index 4c5c2644..b775c191 100644
--- a/gns3server/modules/dynamips/backends/atmsw.py
+++ b/gns3server/modules/dynamips/backends/atmsw.py
@@ -38,7 +38,7 @@ class ATMSW(object):
         """
         Creates a new ATM switch.
 
-        Optional request parameters:
+        Mandatory request parameters:
         - name (switch name)
 
         Response parameters:
@@ -52,10 +52,8 @@ class ATMSW(object):
         if request and not self.validate_request(request, ATMSW_CREATE_SCHEMA):
             return
 
-        name = None
-        if request and "name" in request:
-            name = request["name"]
 
+        name = request["name"]
         try:
             if not self._hypervisor_manager:
                 self.start_hypervisor_manager()
diff --git a/gns3server/modules/dynamips/backends/ethhub.py b/gns3server/modules/dynamips/backends/ethhub.py
index 28678bf0..9939cb71 100644
--- a/gns3server/modules/dynamips/backends/ethhub.py
+++ b/gns3server/modules/dynamips/backends/ethhub.py
@@ -37,7 +37,7 @@ class ETHHUB(object):
         """
         Creates a new Ethernet hub.
 
-        Optional request parameters:
+        Mandatory request parameters:
         - name (hub name)
 
         Response parameters:
@@ -51,10 +51,7 @@ class ETHHUB(object):
         if request and not self.validate_request(request, ETHHUB_CREATE_SCHEMA):
             return
 
-        name = None
-        if request and "name" in request:
-            name = request["name"]
-
+        name = request["name"]
         try:
             if not self._hypervisor_manager:
                 self.start_hypervisor_manager()
diff --git a/gns3server/modules/dynamips/backends/ethsw.py b/gns3server/modules/dynamips/backends/ethsw.py
index cf8369f4..cb06f927 100644
--- a/gns3server/modules/dynamips/backends/ethsw.py
+++ b/gns3server/modules/dynamips/backends/ethsw.py
@@ -37,7 +37,7 @@ class ETHSW(object):
         """
         Creates a new Ethernet switch.
 
-        Optional request parameters:
+        Mandatory request parameters:
         - name (switch name)
 
         Response parameters:
@@ -51,10 +51,7 @@ class ETHSW(object):
         if request and not self.validate_request(request, ETHSW_CREATE_SCHEMA):
             return
 
-        name = None
-        if request and "name" in request:
-            name = request["name"]
-
+        name = request["name"]
         try:
             if not self._hypervisor_manager:
                 self.start_hypervisor_manager()
diff --git a/gns3server/modules/dynamips/backends/frsw.py b/gns3server/modules/dynamips/backends/frsw.py
index 5bbf72a2..34042332 100644
--- a/gns3server/modules/dynamips/backends/frsw.py
+++ b/gns3server/modules/dynamips/backends/frsw.py
@@ -37,7 +37,7 @@ class FRSW(object):
         """
         Creates a new Frame-Relay switch.
 
-        Optional request parameters:
+        Mandatory request parameters:
         - name (switch name)
 
         Response parameters:
@@ -51,10 +51,7 @@ class FRSW(object):
         if request and not self.validate_request(request, FRSW_CREATE_SCHEMA):
             return
 
-        name = None
-        if request and "name" in request:
-            name = request["name"]
-
+        name = request["name"]
         try:
             if not self._hypervisor_manager:
                 self.start_hypervisor_manager()
diff --git a/gns3server/modules/dynamips/backends/vm.py b/gns3server/modules/dynamips/backends/vm.py
index 99fa0f87..56274d9f 100644
--- a/gns3server/modules/dynamips/backends/vm.py
+++ b/gns3server/modules/dynamips/backends/vm.py
@@ -105,12 +105,12 @@ class VM(object):
         Creates a new VM (router).
 
         Mandatory request parameters:
+        - name (vm name)
         - platform (platform name e.g. c7200)
         - image (path to IOS image)
         - ram (amount of RAM in MB)
 
         Optional request parameters:
-        - name (vm name)
         - console (console port number)
         - aux (auxiliary console port number)
         - mac_addr (MAC address)
@@ -127,9 +127,7 @@ class VM(object):
         if not self.validate_request(request, VM_CREATE_SCHEMA):
             return
 
-        name = None
-        if "name" in request:
-            name = request["name"]
+        name = request["name"]
         platform = request["platform"]
         image = request["image"]
         ram = request["ram"]
diff --git a/gns3server/modules/dynamips/nodes/atm_switch.py b/gns3server/modules/dynamips/nodes/atm_switch.py
index eecd9544..7dfcbbbe 100644
--- a/gns3server/modules/dynamips/nodes/atm_switch.py
+++ b/gns3server/modules/dynamips/nodes/atm_switch.py
@@ -37,22 +37,16 @@ class ATMSwitch(object):
     _allocated_names = []
     _instance_count = 1
 
-    def __init__(self, hypervisor, name=None):
+    def __init__(self, hypervisor, name):
+
+        # check if the name is already taken
+        if name in self._allocated_names:
+            raise DynamipsError('Name "{}" is already used by another ATM switch'.format(name))
 
         # create an unique ID
         self._id = ATMSwitch._instance_count
         ATMSwitch._instance_count += 1
 
-        # let's create a unique name if none has been chosen
-        if not name:
-            name_id = self._id
-            while True:
-                name = "ATM" + str(name_id)
-                # check if the name has already been allocated to another switch
-                if name not in self._allocated_names:
-                    break
-                name_id += 1
-
         self._allocated_names.append(name)
         self._hypervisor = hypervisor
         self._name = '"' + name + '"'  # put name into quotes to protect spaces
@@ -102,6 +96,10 @@ class ATMSwitch(object):
         :param new_name: New name for this switch
         """
 
+        # check if the name is already taken
+        if new_name in self._allocated_names:
+            raise DynamipsError('Name "{}" is already used by another ATM switch'.format(new_name))
+
         new_name_no_quotes = new_name
         new_name = '"' + new_name + '"'  # put the new name into quotes to protect spaces
         self._hypervisor.send("atmsw rename {name} {new_name}".format(name=self._name,
diff --git a/gns3server/modules/dynamips/nodes/bridge.py b/gns3server/modules/dynamips/nodes/bridge.py
index a47bf654..d0f194d6 100644
--- a/gns3server/modules/dynamips/nodes/bridge.py
+++ b/gns3server/modules/dynamips/nodes/bridge.py
@@ -20,6 +20,8 @@ Interface for Dynamips NIO bridge module ("nio_bridge").
 http://github.com/GNS3/dynamips/blob/master/README.hypervisor#L538
 """
 
+from ..dynamips_error import DynamipsError
+
 
 class Bridge(object):
     """
@@ -58,6 +60,10 @@ class Bridge(object):
         :param new_name: New name for this bridge
         """
 
+        # check if the name is already taken
+        if new_name in self._allocated_names:
+            raise DynamipsError('Name "{}" is already used by another bridge'.format(new_name))
+
         new_name_no_quotes = new_name
         new_name = '"' + new_name + '"'  # put the new name into quotes to protect spaces
         self._hypervisor.send("nio_bridge rename {name} {new_name}".format(name=self._name,
diff --git a/gns3server/modules/dynamips/nodes/c1700.py b/gns3server/modules/dynamips/nodes/c1700.py
index 51318790..09d75d31 100644
--- a/gns3server/modules/dynamips/nodes/c1700.py
+++ b/gns3server/modules/dynamips/nodes/c1700.py
@@ -39,7 +39,7 @@ class C1700(Router):
     1710 is not supported.
     """
 
-    def __init__(self, hypervisor, name=None, chassis="1720"):
+    def __init__(self, hypervisor, name, chassis="1720"):
         Router.__init__(self, hypervisor, name, platform="c1700")
 
         # Set default values for this platform
diff --git a/gns3server/modules/dynamips/nodes/c2600.py b/gns3server/modules/dynamips/nodes/c2600.py
index e7f5b61a..ff0fb0c0 100644
--- a/gns3server/modules/dynamips/nodes/c2600.py
+++ b/gns3server/modules/dynamips/nodes/c2600.py
@@ -54,7 +54,7 @@ class C2600(Router):
                            "2650XM": C2600_MB_1FE,
                            "2651XM": C2600_MB_2FE}
 
-    def __init__(self, hypervisor, name=None, chassis="2610"):
+    def __init__(self, hypervisor, name, chassis="2610"):
         Router.__init__(self, hypervisor, name, platform="c2600")
 
         # Set default values for this platform
diff --git a/gns3server/modules/dynamips/nodes/c2691.py b/gns3server/modules/dynamips/nodes/c2691.py
index 9ba7e396..baec82de 100644
--- a/gns3server/modules/dynamips/nodes/c2691.py
+++ b/gns3server/modules/dynamips/nodes/c2691.py
@@ -35,7 +35,7 @@ class C2691(Router):
     :param name: name for this router
     """
 
-    def __init__(self, hypervisor, name=None):
+    def __init__(self, hypervisor, name):
         Router.__init__(self, hypervisor, name, platform="c2691")
 
         # Set default values for this platform
diff --git a/gns3server/modules/dynamips/nodes/c3600.py b/gns3server/modules/dynamips/nodes/c3600.py
index ccbd565c..fd9790d4 100644
--- a/gns3server/modules/dynamips/nodes/c3600.py
+++ b/gns3server/modules/dynamips/nodes/c3600.py
@@ -37,7 +37,7 @@ class C3600(Router):
     3620, 3640 or 3660 (default = 3640).
     """
 
-    def __init__(self, hypervisor, name=None, chassis="3640"):
+    def __init__(self, hypervisor, name, chassis="3640"):
         Router.__init__(self, hypervisor, name, platform="c3600")
 
         # Set default values for this platform
diff --git a/gns3server/modules/dynamips/nodes/c3725.py b/gns3server/modules/dynamips/nodes/c3725.py
index d32fab1b..455575ce 100644
--- a/gns3server/modules/dynamips/nodes/c3725.py
+++ b/gns3server/modules/dynamips/nodes/c3725.py
@@ -35,7 +35,7 @@ class C3725(Router):
     :param name: name for this router
     """
 
-    def __init__(self, hypervisor, name=None):
+    def __init__(self, hypervisor, name):
         Router.__init__(self, hypervisor, name, platform="c3725")
 
         # Set default values for this platform
diff --git a/gns3server/modules/dynamips/nodes/c3745.py b/gns3server/modules/dynamips/nodes/c3745.py
index 5c0ea13c..5c914fee 100644
--- a/gns3server/modules/dynamips/nodes/c3745.py
+++ b/gns3server/modules/dynamips/nodes/c3745.py
@@ -35,7 +35,7 @@ class C3745(Router):
     :param name: name for this router
     """
 
-    def __init__(self, hypervisor, name=None):
+    def __init__(self, hypervisor, name):
         Router.__init__(self, hypervisor, name, platform="c3745")
 
         # Set default values for this platform
diff --git a/gns3server/modules/dynamips/nodes/c7200.py b/gns3server/modules/dynamips/nodes/c7200.py
index 0307eedc..ce63e726 100644
--- a/gns3server/modules/dynamips/nodes/c7200.py
+++ b/gns3server/modules/dynamips/nodes/c7200.py
@@ -38,7 +38,7 @@ class C7200(Router):
     :param npe: default NPE
     """
 
-    def __init__(self, hypervisor, name=None, npe="npe-400"):
+    def __init__(self, hypervisor, name, npe="npe-400"):
         Router.__init__(self, hypervisor, name, platform="c7200")
 
         # Set default values for this platform
diff --git a/gns3server/modules/dynamips/nodes/ethernet_switch.py b/gns3server/modules/dynamips/nodes/ethernet_switch.py
index 83ddf080..99794f4a 100644
--- a/gns3server/modules/dynamips/nodes/ethernet_switch.py
+++ b/gns3server/modules/dynamips/nodes/ethernet_switch.py
@@ -37,22 +37,16 @@ class EthernetSwitch(object):
     _allocated_names = []
     _instance_count = 1
 
-    def __init__(self, hypervisor, name=None):
+    def __init__(self, hypervisor, name):
+
+        # check if the name is already taken
+        if name in self._allocated_names:
+            raise DynamipsError('Name "{}" is already used by another Ethernet switch'.format(name))
 
         # create an unique ID
         self._id = EthernetSwitch._instance_count
         EthernetSwitch._instance_count += 1
 
-        # let's create a unique name if none has been chosen
-        if not name:
-            name_id = self._id
-            while True:
-                name = "SW" + str(name_id)
-                # check if the name has already been allocated to another switch
-                if name not in self._allocated_names:
-                    break
-                name_id += 1
-
         self._allocated_names.append(name)
         self._hypervisor = hypervisor
         self._name = '"' + name + '"'  # put name into quotes to protect spaces
@@ -102,6 +96,9 @@ class EthernetSwitch(object):
         :param new_name: New name for this switch
         """
 
+        if new_name in self._allocated_names:
+            raise DynamipsError('Name "{}" is already used by another Ethernet switch'.format(new_name))
+
         new_name_no_quotes = new_name
         new_name = '"' + new_name + '"'  # put the new name into quotes to protect spaces
         self._hypervisor.send("ethsw rename {name} {new_name}".format(name=self._name,
diff --git a/gns3server/modules/dynamips/nodes/frame_relay_switch.py b/gns3server/modules/dynamips/nodes/frame_relay_switch.py
index 8a1eec31..1cd5f3a0 100644
--- a/gns3server/modules/dynamips/nodes/frame_relay_switch.py
+++ b/gns3server/modules/dynamips/nodes/frame_relay_switch.py
@@ -37,22 +37,16 @@ class FrameRelaySwitch(object):
     _allocated_names = []
     _instance_count = 1
 
-    def __init__(self, hypervisor, name=None):
+    def __init__(self, hypervisor, name):
+
+        # check if the name is already taken
+        if name in self._allocated_names:
+            raise DynamipsError('Name "{}" is already used by another Frame Relay switch'.format(name))
 
         # create an unique ID
         self._id = FrameRelaySwitch._instance_count
         FrameRelaySwitch._instance_count += 1
 
-        # let's create a unique name if none has been chosen
-        if not name:
-            name_id = self._id
-            while True:
-                name = "FR" + str(name_id)
-                # check if the name has already been allocated to another switch
-                if name not in self._allocated_names:
-                    break
-                name_id += 1
-
         self._allocated_names.append(name)
         self._hypervisor = hypervisor
         self._name = '"' + name + '"'  # put name into quotes to protect spaces
@@ -102,6 +96,9 @@ class FrameRelaySwitch(object):
         :param new_name: New name for this switch
         """
 
+        if new_name in self._allocated_names:
+            raise DynamipsError('Name "{}" is already used by another Frame Relay switch'.format(new_name))
+
         new_name_no_quotes = new_name
         new_name = '"' + new_name + '"'  # put the new name into quotes to protect spaces
         self._hypervisor.send("frsw rename {name} {new_name}".format(name=self._name,
diff --git a/gns3server/modules/dynamips/nodes/hub.py b/gns3server/modules/dynamips/nodes/hub.py
index b66a5488..2ee8274b 100644
--- a/gns3server/modules/dynamips/nodes/hub.py
+++ b/gns3server/modules/dynamips/nodes/hub.py
@@ -38,20 +38,14 @@ class Hub(Bridge):
 
     def __init__(self, hypervisor, name):
 
+        # check if the name is already taken
+        if name in self._allocated_names:
+            raise DynamipsError('Name "{}" is already used by another Ethernet hub'.format(name))
+
         # create an unique ID
         self._id = Hub._instance_count
         Hub._instance_count += 1
 
-        # let's create a unique name if none has been chosen
-        if not name:
-            name_id = self._id
-            while True:
-                name = "Hub" + str(name_id)
-                # check if the name has already been allocated to another switch
-                if name not in self._allocated_names:
-                    break
-                name_id += 1
-
         self._mapping = {}
         Bridge.__init__(self, hypervisor, name)
 
diff --git a/gns3server/modules/dynamips/nodes/router.py b/gns3server/modules/dynamips/nodes/router.py
index 554cd729..931573f3 100644
--- a/gns3server/modules/dynamips/nodes/router.py
+++ b/gns3server/modules/dynamips/nodes/router.py
@@ -50,22 +50,18 @@ class Router(object):
                2: "running",
                3: "suspended"}
 
-    def __init__(self, hypervisor, name=None, platform="c7200", ghost_flag=False):
+    def __init__(self, hypervisor, name, platform="c7200", ghost_flag=False):
 
         if not ghost_flag:
+
+            # check if the name is already taken
+            if name in self._allocated_names:
+                raise DynamipsError('Name "{}" is already used by another router'.format(name))
+
             # create an unique ID
             self._id = Router._instance_count
             Router._instance_count += 1
 
-            # let's create a unique name if none has been chosen
-            if not name:
-                name_id = self._id
-                while True:
-                    name = "R" + str(name_id)
-                    # check if the name has already been allocated to another router
-                    if name not in self._allocated_names:
-                        break
-                    name_id += 1
         else:
             log.info("creating a new ghost IOS file")
             self._id = 0
@@ -581,10 +577,10 @@ class Router(object):
             reply = self._hypervisor.send("vm extract_config {}".format(self._name))[0].rsplit(' ', 2)[-2:]
         except IOError:
             #for some reason Dynamips gets frozen when it does not find the magic number in the NVRAM file.
-            return (None, None)
+            return None, None
         startup_config = reply[0][1:-1]  # get statup-config and remove single quotes
         private_config = reply[1][1:-1]  # get private-config and remove single quotes
-        return (startup_config, private_config)
+        return startup_config, private_config
 
     def push_config(self, startup_config, private_config='(keep)'):
         """
@@ -727,7 +723,7 @@ class Router(object):
         else:
             flag = 0
         self._hypervisor.send("vm set_sparse_mem {name} {sparsemem}".format(name=self._name,
-                                                                     sparsemem=flag))
+                                                                            sparsemem=flag))
 
         if sparsemem:
             log.info("router {name} [id={id}]: sparse memory enabled".format(name=self._name,
diff --git a/gns3server/modules/dynamips/schemas/atmsw.py b/gns3server/modules/dynamips/schemas/atmsw.py
index b545880b..2041299b 100644
--- a/gns3server/modules/dynamips/schemas/atmsw.py
+++ b/gns3server/modules/dynamips/schemas/atmsw.py
@@ -27,6 +27,7 @@ ATMSW_CREATE_SCHEMA = {
         },
     },
     "additionalProperties": False,
+    "required": ["name"]
 }
 
 ATMSW_DELETE_SCHEMA = {
diff --git a/gns3server/modules/dynamips/schemas/ethhub.py b/gns3server/modules/dynamips/schemas/ethhub.py
index efea271c..6db1b796 100644
--- a/gns3server/modules/dynamips/schemas/ethhub.py
+++ b/gns3server/modules/dynamips/schemas/ethhub.py
@@ -27,6 +27,7 @@ ETHHUB_CREATE_SCHEMA = {
         },
     },
     "additionalProperties": False,
+    "required": ["name"]
 }
 
 ETHHUB_DELETE_SCHEMA = {
diff --git a/gns3server/modules/dynamips/schemas/ethsw.py b/gns3server/modules/dynamips/schemas/ethsw.py
index 0c8b8074..a33a98b8 100644
--- a/gns3server/modules/dynamips/schemas/ethsw.py
+++ b/gns3server/modules/dynamips/schemas/ethsw.py
@@ -27,6 +27,7 @@ ETHSW_CREATE_SCHEMA = {
         },
     },
     "additionalProperties": False,
+    "required": ["name"]
 }
 
 ETHSW_DELETE_SCHEMA = {
diff --git a/gns3server/modules/dynamips/schemas/frsw.py b/gns3server/modules/dynamips/schemas/frsw.py
index 72272782..5dd5e5bb 100644
--- a/gns3server/modules/dynamips/schemas/frsw.py
+++ b/gns3server/modules/dynamips/schemas/frsw.py
@@ -27,6 +27,7 @@ FRSW_CREATE_SCHEMA = {
         },
     },
     "additionalProperties": False,
+    "required": ["name"]
 }
 
 FRSW_DELETE_SCHEMA = {
diff --git a/gns3server/modules/dynamips/schemas/vm.py b/gns3server/modules/dynamips/schemas/vm.py
index 581a4d65..47bcb75b 100644
--- a/gns3server/modules/dynamips/schemas/vm.py
+++ b/gns3server/modules/dynamips/schemas/vm.py
@@ -66,7 +66,7 @@ VM_CREATE_SCHEMA = {
         }
     },
     "additionalProperties": False,
-    "required": ["platform", "image", "ram"]
+    "required": ["name", "platform", "image", "ram"]
 }
 
 VM_DELETE_SCHEMA = {