Neutron tagging

Slawomir Kaplonski skaplons at
Thu Jan 17 21:57:53 UTC 2019


> Wiadomość napisana przez cmnfths <cmnfths at> w dniu 16.01.2019, o godz. 09:04:
> Hi everyone!
> Recently I've encountered a neutron issue related to port tagging mechanism, and wonder if anyone else ever did. The initial source of the issue was, as it seems, identical numeration of external VLANs' tags and OVS (exactly br-int) port tags. The VLAN tagged 222 was added to bridge br-ex and everything worked, but at some point firewall reported unusual traffic. Thus I'd found that there was a loop and 2 qr-* ports with the same tag 222 attached to br-int. After that I deleted them and the loop was gone.

Were those qr- ports from same network?

> So the question is what exactly these tags are? The same ethernet frame bits as 802.1Q tags? Where is a pool or something they're taken from? Is there any possibility to form such pool via configs or patches? Has anyone ever encountered such situation?

Tags on ports in br-int are local tags used to separate traffic from different Neutron networks on one host. Those tags can be different for ports from same network on different host.

> Thanks,
> Andrew Th.

Slawek Kaplonski
Senior software engineer
Red Hat

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