openstack team mailing list archive

["Sreerekha Shenoy (sresheno)" <sresheno@xxxxxxxxx>]

Hi,
We are a team attempting a PoC on Openstack with a single node deployment to start with.
It currently has Keystone, Glance and Nova enabled.

As a part of this PoC, we learnt that Openstack with Nova-network in FlatDHCP mode,
uses two subnets on the Host machine:
-              Public Subnet for floating IPs :
o             Openstack manages the mapping of floating to fixed IPs for VMs.
o             VMs are not aware of the additional public IP assigned.

-              Private Subnet for Fixed IPs:
o             Openstack boots up the VM with this IP address and VM is aware of it
o             BR100 created to manage the VMnet fabric for traffic on this subnet.

Few Queries:
----------------
-For applications on such a setup that use IP-sensitive protocols like SIP, how do we handle the scenarios?
Are we expected to have SIP ALG to do additional SIP based NAT'ng apart from what nova-network manages?

-Does this NAT'ng of Floating to Fixed IP not really pull down the performance overall?

-What if I need my VMs to be spawned on a public subnet for general accessibility
"without any NAT'ng" involved? Is there anyways Openstack can help?

Thanks,
Best Regards,
Rekha