[ovs-discuss] Connection problem regarding OvS server and client (switches)

[Justin Pettit]

On Apr 21, 2010, at 3:10 PM, Sean Law wrote:

> Our team has successfully build Open vSwitches on three computers, now we are testing the connection among different OvSs (we have install OvS on the three computers). Our topology is shown in the attached file. Our aim is to make our system successfully communicate between host 2 & 3 via server (host) 1.
> 
> Server's command we used: sudo ovsdb-server /usr/local/etc/ovs-vswitchd.conf.db --remote=ptcp:4444:<server's IP>;
> Client (switch)'s command we used: sudo ovs-vswitchd tcp:<server's IP>:4444
> 
> Problem: host 1 being as a server, host 2 & 3 being as a switch, the server's log is as follows:
> ...
> 
> through the experiment, we found that the switches' connections to the server would be dropped in a few second (we did nothing else but waiting), and then the two clients could not connect to the Internet. Only after they two clients build a self-server and a self-switch by using command "punix & unix" on its local machine, respectively, and connect the self-server & self-switch, which is guided by the Building and installation instructions (start-up).
> 
> Would you please tell me what is wrong and how to address this issue?

I'm not sure I completely understand your setup, but it sounds like you're maybe trying to use a single ovsdb-server to which all ovs-vswitchd instances connect.  The ovsdb-server is only meant to be used for local configuration, so each ovs-vswitchd should be connecting to an ovsdb-server on the same box.  The tcp/ssl options are meant to connect to a centralized configuration manager--this is different from ovsdb-server--and you probably don't need anything like that at the moment.  Connecting with the "unix" and "punix" is probably the way to go.  To reiterate: you will need a separate ovsdb-server running for each ovs-vswitchd.

> Another problem is that: we want to build a switch on the server side, but if the server side build a self-server and self-switch, how can we connect the clients to the server?

As should be clear from above, your clients' ovs-vswitchds will not connect to your server's ovsdb-server; they will have their own.  OVS does not ship with the software that will coordinate configuration or manipulating the flow table in any interesting way.  You need to look at something like NOX (noxrepo.org) to do that.

--Justin