[ovs-discuss] GRE tunneling questions

JC Martin jch.martin at gmail.com
Wed Nov 2 17:09:33 UTC 2011


I am new to openvswitch, and while experimenting, I built a mixed setup :
  - two xenserver (XCP 1.1.0) with openvswitch : xcp-1 and xcp-2
  - one ubuntu 10.04 with openvswitch (1.2.2) : bm-1
I was able to build two networks on xenserver and connect them through a GRE tunnel
I cannot add the ubuntu machine to the same network.

My goal is to build something like :
  xcp-1 <----gre----> xcp-2 <-----gre------> bm-1

xcp-1, xcp-2, and bm-1 are all on 172.16.228.x.
I would like to create a private network on 192.168.200.x between VMs in xcp-1, xcp-2 and the bm-1 server

Here are my questions :
  -in the following setup, how (why) are incoming GRE packets directed to the xapi2 bridge ?
   on xcp-1 :
   xenbr0 is administrative interface with an IP (
        [root at xcp-1 xen-vms]# ovs-vsctl list-ports xenbr0 
   xapi2 is the VM bridge with the tunnel
       [root at xcp-1 xen-vms]# ovs-vsctl list-ports xapi2
  tunnel was created through the command :
  ovs-vsctl add-port xapi2 gre0 -- set interface gre0 type=gre options:remote_ip=
  corresponding tunnel was created on xcp-1 with :
  ovs-vsctl add-port xapi1 gre0 -- set interface gre0 type=gre options:remote_ip=

  - what is the right setup to add bm-1 to the same network ?
  I tried to tunnel between xapi1 on xcp-2 and bm-1:
  [root at xcp-2 ~]# ovs-vsctl list-ports xapi1 

  gre1 was built with the following command:
  [root at xcp-2 ~]# ovs-vsctl add-port xapi1 gre1 -- set interface gre1 type=gre options:remote_ip=

  I tried to replicate the xenserver setup on bm-1 by adding a bridge with eth0 as a port, adding another bridge with the tunnel and an interface, but it has not been successful (i tried also with only one bridge with the tunnel and an interface). Ideally, on bm-1 I would like to have two interfaces, one on 172.16.188.x and one on my private network (192.168.200.x)

Thanks in advance,


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