diff --git a/IPython/frontend/html/notebook/kernelmanager.py b/IPython/frontend/html/notebook/kernelmanager.py
index 9a94f2c..48f61a0 100644
--- a/IPython/frontend/html/notebook/kernelmanager.py
+++ b/IPython/frontend/html/notebook/kernelmanager.py
@@ -1,11 +1,14 @@
 import signal
 import sys
-import uuid
 
 from IPython.zmq.ipkernel import launch_kernel
 from session import SessionManager
 
 
+class DuplicateKernelError(Exception):
+    pass
+
+
 class KernelManager(object):
 
     ip = '127.0.0.1'
@@ -27,8 +30,9 @@ class KernelManager(object):
         else:
             return False
 
-    def start_kernel(self):
-        kid = str(uuid.uuid4())
+    def start_kernel(self, kernel_id):
+        if kernel_id in self._kernels:
+            raise DuplicateKernelError("Kernel already exists: %s" % kernel_id)
         (process, shell_port, iopub_port, stdin_port, hb_port) = launch_kernel()
         d = dict(
             process = process,
@@ -36,10 +40,10 @@ class KernelManager(object):
             iopub_port = iopub_port,
             shell_port = shell_port,
             hb_port = hb_port,
-            session_manager = SessionManager(self, kid, self.context)
+            session_manager = SessionManager(self, kernel_id, self.context)
         )
-        self._kernels[kid] = d
-        return kid
+        self._kernels[kernel_id] = d
+        return kernel_id
 
     def kill_kernel(self, kernel_id):
         kernel_process = self.get_kernel_process(kernel_id)
diff --git a/IPython/frontend/html/notebook/notebook.py b/IPython/frontend/html/notebook/notebook.py
index d03545b..7d3f554 100644
--- a/IPython/frontend/html/notebook/notebook.py
+++ b/IPython/frontend/html/notebook/notebook.py
@@ -1,13 +1,11 @@
 import json
 import logging
 import os
-import uuid
 
 import zmq
 
 # Install the pyzmq ioloop. This has to be done before anything else from
 # tornado is imported.
-from zmq.eventloop.zmqstream import ZMQStream
 from zmq.eventloop import ioloop
 import tornado.ioloop
 tornado.ioloop = ioloop
@@ -21,8 +19,8 @@ from kernelmanager import KernelManager
 
 options.define("port", default=8888, help="run on the given port", type=int)
 
-_kernel_id_regex = r"(?P<kernel_id>\w+-\w+-\w+-\w+-\w+)"
-_session_id_regex = r"(?P<session_id>\w+)"
+_session_id_regex = r"(?P<session_id>\w+-\w+-\w+-\w+-\w+)"
+_kernel_id_regex = r"(?P<kernel_id>\w+)"
 
 
 class MainHandler(web.RequestHandler):
@@ -30,30 +28,44 @@ class MainHandler(web.RequestHandler):
         self.render('notebook.html')
 
 
-class KernelHandler(web.RequestHandler):
+class BaseKernelHandler(object):
+
+    def get_kernel(self):
+        return self.application.kernel_manager
+
+    def get_session(self, kernel_id):
+        km = self.get_kernel()
+        sm = km.get_session_manager(kernel_id)
+        return sm
+
+
+class KernelHandler(web.RequestHandler, BaseKernelHandler):
 
     def get(self):
-        self.write(json.dumps(self.application.kernel_manager.kernel_ids))
+        self.write(json.dumps(self.get_kernel().kernel_ids))
+
+    def post(self, *args, **kwargs):
+        kernel_id = kwargs['kernel_id']
+        self.get_kernel().start_kernel(kernel_id)
+        logging.info("Starting kernel: %s" % kernel_id)
+        self.write(json.dumps(kernel_id))
 
-    def post(self):
-        kid = self.application.kernel_manager.start_kernel()
-        logging.info("Starting kernel: %s" % kid)
-        self.write(json.dumps(kid))
 
+class SessionHandler(web.RequestHandler, BaseKernelHandler):
 
-class SessionHandler(web.RequestHandler):
+    def get(self, *args, **kwargs):
+        kernel_id = kwargs['kernel_id']
+        self.write(json.dumps(self.get_session(kernel_id).session_ids))
 
     def post(self, *args, **kwargs):
         kernel_id = kwargs['kernel_id']
-        session_id = kwargs['session_id']
-        logging.info("Starting session: %s, %s" % (kernel_id,session_id))
-        km = self.application.kernel_manager
-        sm = km.get_session_manager(kernel_id)
-        sm.start_session(session_id)
-        self.finish()
+        sm = self.get_session(kernel_id)
+        session_id = sm.start_session()
+        logging.info("Starting session: %s, %s" % (kernel_id, session_id))
+        self.write(json.dumps(session_id))
 
 
-class ZMQStreamHandler(websocket.WebSocketHandler):
+class ZMQStreamHandler(websocket.WebSocketHandler, BaseKernelHandler):
 
     stream_name = ''
 
@@ -61,20 +73,17 @@ class ZMQStreamHandler(websocket.WebSocketHandler):
         kernel_id = kwargs['kernel_id']
         session_id = kwargs['session_id']
         logging.info("Connection open: %s, %s" % (kernel_id,session_id))
-        sm = self.application.kernel_manager.get_session_manager(kernel_id)
+        sm = self.get_session(kernel_id)
         method_name = "get_%s_stream" % self.stream_name
         method = getattr(sm, method_name)
         self.zmq_stream = method(session_id)
         self.zmq_stream.on_recv(self._on_zmq_reply)
-        self.session_manager = sm
-        self.session_id = session_id
 
     def on_message(self, msg):
         logging.info("Message received: %r" % msg)
-        self.zmq_stream.send(msg)
+        self.zmq_stream.send_unicode(msg)
 
     def on_close(self):
-        logging.info("Connection closed: %s, %s" % (kernel_id,session_id))
         self.zmq_stream.close()
 
     def _on_zmq_reply(self, msg):
@@ -97,8 +106,8 @@ class NotebookApplication(web.Application):
     def __init__(self):
         handlers = [
             (r"/", MainHandler),
-            (r"/kernels", KernelHandler),
-            (r"/kernels/%s/sessions/%s" % (_kernel_id_regex,_session_id_regex), SessionHandler),
+            (r"/kernels/%s" % (_kernel_id_regex,), KernelHandler),
+            (r"/kernels/%s/sessions" % (_kernel_id_regex,), SessionHandler),
             (r"/kernels/%s/sessions/%s/iopub" % (_kernel_id_regex,_session_id_regex), IOPubStreamHandler),
             (r"/kernels/%s/sessions/%s/shell" % (_kernel_id_regex,_session_id_regex), ShellStreamHandler),
         ]
diff --git a/IPython/frontend/html/notebook/session.py b/IPython/frontend/html/notebook/session.py
index bf7df13..5fe5160 100644
--- a/IPython/frontend/html/notebook/session.py
+++ b/IPython/frontend/html/notebook/session.py
@@ -1,4 +1,5 @@
 import logging
+import uuid
 
 import zmq
 from zmq.eventloop.zmqstream import ZMQStream
@@ -15,7 +16,21 @@ class SessionManager(object):
     def __del__(self):
         self.stop_all()
 
-    def start_session(self, session_id):
+    @property
+    def session_ids(self):
+        return self._session.keys()
+
+    def __len__(self):
+        return len(self.session_ids)
+
+    def __contains__(self, session_id):
+        if session_id in self.session_ids:
+            return True
+        else:
+            return False
+
+    def start_session(self):
+        session_id = str(uuid.uuid4())
         ports = self.kernel_manager.get_kernel_ports(self.kernel_id)
         iopub_stream = self.create_connected_stream(ports['iopub_port'], zmq.SUB)
         shell_stream = self.create_connected_stream(ports['shell_port'], zmq.XREQ)
@@ -23,6 +38,7 @@ class SessionManager(object):
             iopub_stream = iopub_stream,
             shell_stream = shell_stream
         )
+        return session_id
 
     def stop_session(self, session_id):
         session_dict = self._sessions.get(session_id)
diff --git a/IPython/frontend/html/notebook/zmqws.py b/IPython/frontend/html/notebook/zmqws.py
deleted file mode 100644
index e2eab10..0000000
--- a/IPython/frontend/html/notebook/zmqws.py
+++ /dev/null
@@ -1,23 +0,0 @@
-"""A simple WebSocket to ZMQ forwarder."""
-
-from tornado import websocket
-
-class ZMQWebSocketBridge(websocket.WebSocketHandler):
-    """A handler to forward between a WebSocket at ZMQ socket."""
-
-    def open(self):
-        self.stream
-
-    @property
-    def stream(self):
-        raise NotImplementedError("stream property must be implemented in a subclass")
-
-    def on_message(self, message):
-        self.stream.send(message)
-
-    def on_zmq_reply(self, reply_list):
-        for part in reply_list:
-            self.write_message(part)
-
-    def on_close(self):
-        print "WebSocket closed"