diff --git a/daemon/core/emulator/session.py b/daemon/core/emulator/session.py
index dffaff04..4118bd78 100644
--- a/daemon/core/emulator/session.py
+++ b/daemon/core/emulator/session.py
@@ -361,6 +361,18 @@ class Session(object):
                             self.delete_node(net_one.id)
                         node_one.delnetif(interface_one.netindex)
                         node_two.delnetif(interface_two.netindex)
+                elif node_one and net_one:
+                    interface = node_one.netif(interface_one_id)
+                    logging.info("deleting link node(%s):interface(%s) node(%s)",
+                                 node_one.name, interface.name, net_one.name)
+                    interface.detachnet()
+                    node_one.delnetif(interface.netindex)
+                elif node_two and net_one:
+                    interface = node_two.netif(interface_two_id)
+                    logging.info("deleting link node(%s):interface(%s) node(%s)",
+                                 node_two.name, interface.name, net_one.name)
+                    interface.detachnet()
+                    node_two.delnetif(interface.netindex)
         finally:
             if node_one:
                 node_one.lock.release()
diff --git a/daemon/tests/conftest.py b/daemon/tests/conftest.py
index cf82993e..76be943a 100644
--- a/daemon/tests/conftest.py
+++ b/daemon/tests/conftest.py
@@ -40,6 +40,14 @@ class CoreServerTest(object):
         self.session = None
         self.request_handler = None
 
+    def setup_handler(self):
+        self.session = self.server.coreemu.create_session(1)
+        request_mock = MagicMock()
+        request_mock.fileno = MagicMock(return_value=1)
+        self.request_handler = CoreHandler(request_mock, "", self.server)
+        self.request_handler.session = self.session
+        self.request_handler.add_session_handlers()
+
     def setup(self, distributed_address):
         # validate address
         assert distributed_address, "distributed server address was not provided"
@@ -154,6 +162,20 @@ def cored():
     ServiceManager.services.clear()
 
 
+@pytest.fixture()
+def coreserver():
+    # create and return server
+    server = CoreServerTest()
+    server.setup_handler()
+    yield server
+
+    # cleanup
+    server.shutdown()
+
+    # cleanup services
+    ServiceManager.services.clear()
+
+
 def ping(from_node, to_node, ip_prefixes, count=3):
     address = ip_prefixes.ip4_address(to_node)
     return from_node.cmd(["ping", "-c", str(count), address])
diff --git a/daemon/tests/test_gui.py b/daemon/tests/test_gui.py
index 3083ea2d..ab8169c0 100644
--- a/daemon/tests/test_gui.py
+++ b/daemon/tests/test_gui.py
@@ -2,19 +2,18 @@
 Unit tests for testing with a CORE switch.
 """
 
-import threading
+import pytest
 
-from core.api.tlv import coreapi, dataconversion
+from core.api.tlv import coreapi
 from core.api.tlv.coreapi import CoreExecuteTlv
-from core.emulator.enumerations import CORE_API_PORT, NodeTypes
 from core.emulator.enumerations import EventTlvs
-from core.emulator.enumerations import EventTypes
 from core.emulator.enumerations import ExecuteTlvs
 from core.emulator.enumerations import LinkTlvs
 from core.emulator.enumerations import LinkTypes
 from core.emulator.enumerations import MessageFlags
 from core.emulator.enumerations import MessageTypes
-from core.nodes import ipaddress
+from core.emulator.enumerations import NodeTypes, NodeTlvs
+from core.nodes.ipaddress import Ipv4Prefix
 
 
 def command_message(node, command):
@@ -101,74 +100,212 @@ def run_cmd(node, exec_cmd):
 
 
 class TestGui:
-    def test_broker(self, cored):
-        """
-        Test session broker creation.
+    @pytest.mark.parametrize("node_type, model", [
+        (NodeTypes.DEFAULT, "PC"),
+        (NodeTypes.EMANE, None),
+        (NodeTypes.HUB, None),
+        (NodeTypes.SWITCH, None),
+        (NodeTypes.WIRELESS_LAN, None),
+        (NodeTypes.TUNNEL, None),
+        (NodeTypes.RJ45, None),
+    ])
+    def test_node_add(self, coreserver, node_type, model):
+        node_id = 1
+        message = coreapi.CoreNodeMessage.create(MessageFlags.ADD.value, [
+            (NodeTlvs.NUMBER, node_id),
+            (NodeTlvs.TYPE, node_type.value),
+            (NodeTlvs.NAME, "n1"),
+            (NodeTlvs.X_POSITION, 0),
+            (NodeTlvs.Y_POSITION, 0),
+            (NodeTlvs.MODEL, model),
+        ])
 
-        :param core.emulator.coreemu.EmuSession session: session for test
-        :param cored: cored daemon server to test with
-        """
+        coreserver.request_handler.handle_message(message)
 
-        # set core daemon to run in the background
-        thread = threading.Thread(target=cored.server.serve_forever)
-        thread.daemon = True
-        thread.start()
+        assert coreserver.session.get_node(node_id) is not None
 
-        # ip prefix for nodes
-        prefix = ipaddress.Ipv4Prefix("10.83.0.0/16")
-        daemon = "localhost"
+    def test_node_update(self, coreserver):
+        node_id = 1
+        coreserver.session.add_node(_id=node_id)
+        x = 50
+        y = 100
+        message = coreapi.CoreNodeMessage.create(0, [
+            (NodeTlvs.NUMBER, node_id),
+            (NodeTlvs.X_POSITION, x),
+            (NodeTlvs.Y_POSITION, y),
+        ])
 
-        # add server
-        session = cored.server.coreemu.create_session()
-        session.broker.addserver(daemon, "127.0.0.1", CORE_API_PORT)
+        coreserver.request_handler.handle_message(message)
 
-        # setup server
-        session.broker.setupserver(daemon)
+        node = coreserver.session.get_node(node_id)
+        assert node is not None
+        assert node.position.x == x
+        assert node.position.y == y
 
-        # do not want the recvloop running as we will deal ourselves
-        session.broker.dorecvloop = False
+    def test_node_delete(self, coreserver):
+        node_id = 1
+        coreserver.session.add_node(_id=node_id)
+        message = coreapi.CoreNodeMessage.create(MessageFlags.DELETE.value, [
+            (NodeTlvs.NUMBER, node_id),
+        ])
 
-        # have broker handle a configuration state change
-        session.set_state(EventTypes.CONFIGURATION_STATE)
-        event_message = state_message(EventTypes.CONFIGURATION_STATE)
-        session.broker.handlerawmsg(event_message)
+        coreserver.request_handler.handle_message(message)
 
-        # create a switch node
-        switch = session.add_node(_type=NodeTypes.SWITCH)
-        switch.setposition(x=80, y=50)
-        switch.server = daemon
+        with pytest.raises(KeyError):
+            coreserver.session.get_node(node_id)
 
-        # retrieve switch data representation, create a switch message for broker to handle
-        switch_data = switch.data(MessageFlags.ADD.value)
-        switch_message = dataconversion.convert_node(switch_data)
-        session.broker.handlerawmsg(switch_message)
+    def test_link_add(self, coreserver):
+        node_one = 1
+        coreserver.session.add_node(_id=node_one)
+        switch = 2
+        coreserver.session.add_node(_id=switch, _type=NodeTypes.SWITCH)
+        ip_prefix = Ipv4Prefix("10.0.0.0/24")
+        interface_one = ip_prefix.addr(node_one)
+        coreserver.session.add_link(node_one, switch, interface_one)
+        message = coreapi.CoreLinkMessage.create(MessageFlags.ADD.value, [
+            (LinkTlvs.N1_NUMBER, node_one),
+            (LinkTlvs.N2_NUMBER, switch),
+            (LinkTlvs.INTERFACE1_NUMBER, 0),
+            (LinkTlvs.INTERFACE1_IP4, interface_one),
+            (LinkTlvs.INTERFACE1_IP4_MASK, 24),
+        ])
 
-        # create node one
-        node_one = session.add_node()
-        node_one.server = daemon
+        coreserver.request_handler.handle_message(message)
 
-        # create node two
-        node_two = session.add_node()
-        node_two.server = daemon
+        switch_node = coreserver.session.get_node(switch)
+        all_links = switch_node.all_link_data(0)
+        assert len(all_links) == 1
 
-        # create node messages for the broker to handle
-        for node in [node_one, node_two]:
-            node_data = node.data(MessageFlags.ADD.value)
-            node_message = dataconversion.convert_node(node_data)
-            session.broker.handlerawmsg(node_message)
+    def test_link_update(self, coreserver):
+        node_one = 1
+        coreserver.session.add_node(_id=node_one)
+        switch = 2
+        coreserver.session.add_node(_id=switch, _type=NodeTypes.SWITCH)
+        ip_prefix = Ipv4Prefix("10.0.0.0/24")
+        interface_one = ip_prefix.addr(node_one)
+        message = coreapi.CoreLinkMessage.create(MessageFlags.ADD.value, [
+            (LinkTlvs.N1_NUMBER, node_one),
+            (LinkTlvs.N2_NUMBER, switch),
+            (LinkTlvs.INTERFACE1_NUMBER, 0),
+            (LinkTlvs.INTERFACE1_IP4, interface_one),
+            (LinkTlvs.INTERFACE1_IP4_MASK, 24),
+        ])
+        coreserver.request_handler.handle_message(message)
+        switch_node = coreserver.session.get_node(switch)
+        all_links = switch_node.all_link_data(0)
+        assert len(all_links) == 1
+        link = all_links[0]
+        assert link.bandwidth is None
 
-        # create links to switch from nodes for broker to handle
-        for index, node in enumerate([node_one, node_two], start=1):
-            ip4_address = prefix.addr(index)
-            link_message = switch_link_message(switch, node, ip4_address, prefix.prefixlen)
-            session.broker.handlerawmsg(link_message)
+        bandwidth = 50000
+        message = coreapi.CoreLinkMessage.create(0, [
+            (LinkTlvs.N1_NUMBER, node_one),
+            (LinkTlvs.N2_NUMBER, switch),
+            (LinkTlvs.INTERFACE1_NUMBER, 0),
+            (LinkTlvs.BANDWIDTH, bandwidth),
+        ])
+        coreserver.request_handler.handle_message(message)
 
-        # change session to instantiation state
-        event_message = state_message(EventTypes.INSTANTIATION_STATE)
-        session.broker.handlerawmsg(event_message)
+        switch_node = coreserver.session.get_node(switch)
+        all_links = switch_node.all_link_data(0)
+        assert len(all_links) == 1
+        link = all_links[0]
+        assert link.bandwidth == bandwidth
 
-        # Get the ip or last node and ping it from the first
-        output, status = run_cmd(node_one, "ip -4 -o addr show dev eth0")
-        pingip = output.split()[3].split("/")[0]
-        output, status = run_cmd(node_two, "ping -c 5 " + pingip)
-        assert not status
+    def test_link_delete_node_to_node(self, coreserver):
+        node_one = 1
+        coreserver.session.add_node(_id=node_one)
+        node_two = 2
+        coreserver.session.add_node(_id=node_two)
+        ip_prefix = Ipv4Prefix("10.0.0.0/24")
+        interface_one = ip_prefix.addr(node_one)
+        interface_two = ip_prefix.addr(node_two)
+        message = coreapi.CoreLinkMessage.create(MessageFlags.ADD.value, [
+            (LinkTlvs.N1_NUMBER, node_one),
+            (LinkTlvs.N2_NUMBER, node_two),
+            (LinkTlvs.INTERFACE1_NUMBER, 0),
+            (LinkTlvs.INTERFACE1_IP4, interface_one),
+            (LinkTlvs.INTERFACE1_IP4_MASK, 24),
+            (LinkTlvs.INTERFACE2_IP4, interface_two),
+            (LinkTlvs.INTERFACE2_IP4_MASK, 24),
+        ])
+        coreserver.request_handler.handle_message(message)
+        all_links = []
+        for node_id in coreserver.session.nodes:
+            node = coreserver.session.nodes[node_id]
+            all_links += node.all_link_data(0)
+        assert len(all_links) == 1
+
+        message = coreapi.CoreLinkMessage.create(MessageFlags.DELETE.value, [
+            (LinkTlvs.N1_NUMBER, node_one),
+            (LinkTlvs.N2_NUMBER, node_two),
+            (LinkTlvs.INTERFACE1_NUMBER, 0),
+            (LinkTlvs.INTERFACE2_NUMBER, 0),
+        ])
+        coreserver.request_handler.handle_message(message)
+
+        all_links = []
+        for node_id in coreserver.session.nodes:
+            node = coreserver.session.nodes[node_id]
+            all_links += node.all_link_data(0)
+        assert len(all_links) == 0
+
+    def test_link_delete_node_to_net(self, coreserver):
+        node_one = 1
+        coreserver.session.add_node(_id=node_one)
+        switch = 2
+        coreserver.session.add_node(_id=switch, _type=NodeTypes.SWITCH)
+        ip_prefix = Ipv4Prefix("10.0.0.0/24")
+        interface_one = ip_prefix.addr(node_one)
+        message = coreapi.CoreLinkMessage.create(MessageFlags.ADD.value, [
+            (LinkTlvs.N1_NUMBER, node_one),
+            (LinkTlvs.N2_NUMBER, switch),
+            (LinkTlvs.INTERFACE1_NUMBER, 0),
+            (LinkTlvs.INTERFACE1_IP4, interface_one),
+            (LinkTlvs.INTERFACE1_IP4_MASK, 24),
+        ])
+        coreserver.request_handler.handle_message(message)
+        switch_node = coreserver.session.get_node(switch)
+        all_links = switch_node.all_link_data(0)
+        assert len(all_links) == 1
+
+        message = coreapi.CoreLinkMessage.create(MessageFlags.DELETE.value, [
+            (LinkTlvs.N1_NUMBER, node_one),
+            (LinkTlvs.N2_NUMBER, switch),
+            (LinkTlvs.INTERFACE1_NUMBER, 0),
+        ])
+        coreserver.request_handler.handle_message(message)
+
+        switch_node = coreserver.session.get_node(switch)
+        all_links = switch_node.all_link_data(0)
+        assert len(all_links) == 0
+
+    def test_link_delete_net_to_node(self, coreserver):
+        node_one = 1
+        coreserver.session.add_node(_id=node_one)
+        switch = 2
+        coreserver.session.add_node(_id=switch, _type=NodeTypes.SWITCH)
+        ip_prefix = Ipv4Prefix("10.0.0.0/24")
+        interface_one = ip_prefix.addr(node_one)
+        message = coreapi.CoreLinkMessage.create(MessageFlags.ADD.value, [
+            (LinkTlvs.N1_NUMBER, node_one),
+            (LinkTlvs.N2_NUMBER, switch),
+            (LinkTlvs.INTERFACE1_NUMBER, 0),
+            (LinkTlvs.INTERFACE1_IP4, interface_one),
+            (LinkTlvs.INTERFACE1_IP4_MASK, 24),
+        ])
+        coreserver.request_handler.handle_message(message)
+        switch_node = coreserver.session.get_node(switch)
+        all_links = switch_node.all_link_data(0)
+        assert len(all_links) == 1
+
+        message = coreapi.CoreLinkMessage.create(MessageFlags.DELETE.value, [
+            (LinkTlvs.N1_NUMBER, switch),
+            (LinkTlvs.N2_NUMBER, node_one),
+            (LinkTlvs.INTERFACE2_NUMBER, 0),
+        ])
+        coreserver.request_handler.handle_message(message)
+
+        switch_node = coreserver.session.get_node(switch)
+        all_links = switch_node.all_link_data(0)
+        assert len(all_links) == 0