Oh, It looks like a problem, because I see provider network mtu is 1500 and self service is 1450. It means we need both of them to be 1500 to avoid income packets dropping?

Nguyen Huu Khoi

On Tue, Apr 15, 2025 at 6:22 PM Vincent Godin <vince.mlist@gmail.com> wrote:

One of the problems encountered with OVN is the management of the MTU. On an OpenStack infrastructure, if the MTU of the self-service networks is smaller than that of the provider network for example, the incoming packets will be silently dropped by OVN. It is important to ensure that the MTU of the provider network (or public) and that of the private networks are identical. Similarly, it is important that the MTU is identical between the tenant networks otherwise the east-west traffic will encounter the same problems.

Le mar. 15 avr. 2025 à 06:09, Satish Patel <satish.txt@gmail.com> a écrit :

Biggest advantage for me to switch to OVN is not needing to run an ip namespace for l3 router services, no need to run keepalived etc.  OVN runs l3 within openflow and that simplifies deployment. Also L3 failover is very fast.  OVN does DHCP within openflow so that it reduces BUM chattiness on the network. It doesn't ACL in openflow so no need to run iptables etc.. There are many things OVN does and more to come in future. 

Downside of OVN is troubleshooting, it requires some good knowledge of openflow and its components etc. otherwise it rocks. 

On Mon, Apr 14, 2025 at 9:55 PM Nguyễn Hữu Khôi <nguyenhuukhoinw@gmail.com> wrote:

Hello.

It is very helpful for me. Thank you very much. Could you share some experiences with ovn? 

Nguyen Huu Khoi

On Mon, Apr 14, 2025 at 10:33 PM Vincent Godin <vince.mlist@gmail.com> wrote:

Hello,

You can start by looking at : https://docs.openstack.org/neutron/latest/ovn/gaps.html

You will find ovn documentation at : https://docs.ovn.org/en/latest/

For your routing questions with ovn, you'll find your response with ovn-nbctl which describes your network design and ovn-sbctl which will give you the mappings between your router ports and your physical chassis.

Vincent

Le lun. 14 avr. 2025 à 16:21, Nguyễn Hữu Khôi <nguyenhuukhoinw@gmail.com> a écrit :

Hello.

I am going to deploy an openstack network for a DC. I would like to have some advice on choosing between them.

Could you show me some pros and cons between them? About OVN, I don't see many articles about it. And How can I check traffic routes via which GW, I can check this via ha_state with OVS

Thank you very much.

Nguyen Huu Khoi