Should it not also advertise that routing assumes that either spanning
tree is running or that the physical topology contains no loops to
function correctly.
Martin Casado wrote:
Ah, I'm starting to understand what is going on. Routing has no notion
of subnets, vlans etc. It doesn't operate like a standard ipv4 router
(perhaps the name should be changed to avoid confusion).
Routing operates as follows:
- It pulls in the authenticator component which tracks MAC addresses and
the switch ports they are bound to
- For each packet in which the destination MAC address has been
discovered, a point to point route is calculated and a flow entry is
added to each switch along path.
- If the destination MAC has not been discovered, the packet is flooded
It doesn't, however, have an ARP stack. So if you're host is configered
with the first switch as the next hop, the ARP packet will be flooded,
to no effect.
This is a roundabout way of saying that, "yes" in order to operate
correctly, all hosts must be on the same subnet.
hope this all makes sense,
.martin
The switch application does not work under my vlan configuration, and
it should not as each the two end hosts reside in different subnets.
It seems that the routing module expects all datapaths to be within
the same openflow vlan instance. Basically this means that if H1 is in
one vlan instance and H2 is in the other, then these hosts will never
be able to communicate. I do not know if this issue is specific to
hardware openflow implementations, but I believe so.
The solution that I have found so far is to put all datapaths in the
same vlan. This seems to solve the problem, and the routing module
picks up routes.
Let me know if I have missed something.
Cheers.
Martin Casado wrote:
What I don't understand is why I don't see packets sent to Nox in the
debugging output you sent out. I would expect some output from
authenticator or routing. My suspicion is that the switch is not
forwarding packets to Nox under the VLAN configuration you're testing.
Does the switch application work under your VLAN configuration?
Hi Martin,
If I put the two end hosts in the same vlan and ping them it works
fine. But when they are in different vlans the arp requests are not
resolved, the only flow which is added is the one I quoted in my
original email. So I am positive that the packets are making it to
nox. What is the scenario in which the routing module works best?
Could you give me some pointers as to how the routing module works?
Thanks for your help,
On Oct 13, 2009, at 9:30 PM, Martin Casado wrote:
All I see are the LLDP packets being received. Are you sure that
packets from the end hosts are making it to Nox? If not, perhaps
there is a switch mis-configuration.
What happens if you run "switch" instead of routing? If this
doesn't work as well, then it is almost certainly a switch issue.
.martin
--
Ali Al-Shabibi
Doctoral Student
PH-ATD
CERN - European Organization for Nuclear Research
Office: 513 R-018
ali.al-shab...@cern.ch
Tel : +41 22 767 86 46
Mob : +41 78 609 04 84
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