<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Aug 18, 2016 at 6:57 PM, Alexis HAUSER <span dir="ltr"><<a href="mailto:alexis.hauser@telecom-bretagne.eu" target="_blank">alexis.hauser@telecom-bretagne.eu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">hi,<br>
<br>
I'd like to know what happens when you create a new network, tagged with VLAN for example 25 and using em2 :<br></blockquote><div><br></div><div>Assuming that by 'tag' you mean the 4 byte added to the ethernet header, then see answers below.<br></div><div>Note that you can verify this by simply running tcpdump or any other sniffer.<br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
- the packets outgoing from em2.25 are tagged, right ?<br></blockquote><div><br>Frames seen by this virtual interface are stripped of the vlan tag.<br></div><div>The purpose of this interface is to abstract the vlan from upper levels.</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
- the packets outgoing from em2 are tagged or not ?<br></blockquote><div><br>If it originated from em2.25 (from the network you defined), then they will be tagged with vlan ID 25.<br></div><div>If they originated from em2 (itself), then no tag will exist. (Usually this occurs when you create a non-vlan network attached to em2)<br></div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
- the result is packets inside ovirt are tagged, but when you go out of it and reach something from em2, are the packets still tagged ?<br></blockquote><div><br>If you created a VLAN network, then the following flow will exist: (assumed a VM network)<br></div><div>[external network]---[em2]----[em2.25]---[bridge]---[vm vnic]<br></div><div>[tag25]-------------------[tag25]--[no tag]-----[no tag]--[no tag]<br><br></div><div></div><div>This is true for both ingress and egress traffic.<br><br></div><div>For a non-vlan network, the linux bridge is connected directly to em2, and if a tag exists or not depends on the ingress and egress traffic,<br>there is no stripping or adding of tags on the way.<br></div></div><br></div><div class="gmail_extra">Thanks,<br></div><div class="gmail_extra">Edy.<br><br></div></div>