Open Stack

Hi,

I'm having real trouble setting up networking with OpenStack.  I had it 
partly working a while ago, but now I don't even get an IP address.  I 
followed the main guide, but found it difficult to understand why things 
were being done - a list of instructions is all very well, but without 
explanations/background it makes debugging tough 
(http://docs.openstack.org/folsom/basic-install/content/basic-install_intro.html)

I've got a few questions I hope someone can help me with:

(1) responsibility for networking has mainly moved from nova to 
quantum.  So the new way of doing things is solely in quantum - I can 
ignore anything network related in nova EXCEPT for metadata?
(2) there is a problem with rebooting - the bridges created in the guide 
don't come up automatically?

If I manually start the bridges and restart all the services I can bring 
up a virtual machine in the web GUI and see messages in /var/log/syslog 
- pairs of DHCPDISCOVER/DHCPOFFER.  This goes on for some time until the 
VM gives up:

cloud-init-nonet waiting 120 seconds for a network device.
cloud-init-nonet gave up waiting for a network device.
ci-info: lo    : 1 127.0.0.1       255.0.0.0       .
ci-info: eth0  : 1 .               .               fa:16:3e:14:5a:69
route_info failed

The bridge setup (ovs-vsctrl show):

2df4b128-c977-48e2-aac9-596d386b7af1
     Bridge br-tun
         Port br-tun
             Interface br-tun
                 type: internal
         Port patch-int
             Interface patch-int
                 type: patch
                 options: {peer=patch-tun}
     Bridge br-int
         Port "qr-03033815-f4"
             tag: 1
             Interface "qr-03033815-f4"
                 type: internal
         Port br-int
             Interface br-int
                 type: internal
         Port patch-tun
             Interface patch-tun
                 type: patch
                 options: {peer=patch-int}
         Port "qvocd51bf09-06"
             tag: 1
             Interface "qvocd51bf09-06"
         Port "tap5ec829c5-74"
             tag: 1
             Interface "tap5ec829c5-74"
                 type: internal
     Bridge br-ex
         Port br-ex
             Interface br-ex
                 type: internal
         Port "eth1"
             Interface "eth1"
     ovs_version: "1.4.0+build0"

(3) Interfaces: the "tap" interface seems to be the network node, while 
the "qr" interface is the controller.  (Is this always the case?  I'm 
just matching IP addresses when I do "ifconfig <interface>")  The "qvoc" 
interface is the VM - I think - it has no IP address?

(4) Connectivity: all three of them are on the br-int bridge, so 
presumably they should all be able to talk to each other?  (This is the 
same as if they were all plugged into a switch, right?)

(5) Is there a way to see where things are going wrong?  It looks like 
the DHCPOFFER is never reaching the VM, which if they're all connected 
seems odd.  Can I get a trace of packets being dropped or similar?

Iain