<div dir="ltr">Well it's not really that Linux Bridge isn't capable of doing the basic operations used in OVS right now by service chains. Using combinations of ebtables and iptables (or just nftables), we can get the packet header rewrites required.<div><br></div><div>It's mainly an issue of lack of contributors for that type of solution. Right now the linux bridge agent pretty much just lets the bridge behave like a bridge, so we don't have the scaffolding setup for complex packet manipulation pipelines (beyond the basic anti-ARP spoofing and security groups implementation).</div><div><br></div><div>If someone really wanted support in the linux bridge agent, and they could conceivably even accomplish it with the extension points we have now. It's just going to take some dedicated effort.</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Nov 14, 2016 at 6:37 AM, CARVER, PAUL <span dir="ltr"><<a href="mailto:pc2929@att.com" target="_blank">pc2929@att.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="EN-US" link="blue" vlink="purple">
<div class="m_1332718757222374179WordSection1"><span class="">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Michael Gale [mailto:<a href="mailto:gale.michael@gmail.com" target="_blank">gale.michael@gmail.com</a><wbr>] wrote:<br>
<br>
<b><span style="color:#1f497d"><u></u><u></u></span></b></span></p>
</span><div><span class="">
<div>
<p class="MsoNormal"><span style="color:#1f497d">></span>Does anyone know if the work for Neutron Service Chains supports environments built with Linux Bridge as the Neutron ML2<span style="color:#1f497d">
</span>driver?<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
</span><div>
<p class="MsoNormal"><span style="color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">I don’t think it’s possible. I’m not aware of any document that says Linux Bridge doesn’t support modifications to its forwarding tables, but I think that’s for
the same reason that it’s unlikely that a car’s owner’s manual is unlikely to mention that you can’t seal the doors and use it for deep sea exploration. It’s not at all a use case the designers expected.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Service chaining is all about manipulating the forwarding tables in order to override the normal “forward via most direct path to destination” behavior. It relies
on the dataplane having a standard, documented and designed/intended mechanism for manipulating the forwarding tables in arbitrary (or at least fairly flexible) ways. I don’t believe Linux Bridge was designed with any intention to allow external software to
manipulate its forwarding behavior on a per packet/per destination basis.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">OvS and several other dataplanes are explicitly designed with the expectation and interface for an external controller to manipulate the forwarding in rich and
flexible ways.<u></u><u></u></span></p>
</div>
</div>
</div>
</div>
<br>______________________________<wbr>_________________<br>
Mailing list: <a href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack" rel="noreferrer" target="_blank">http://lists.openstack.org/<wbr>cgi-bin/mailman/listinfo/<wbr>openstack</a><br>
Post to : <a href="mailto:openstack@lists.openstack.org">openstack@lists.openstack.org</a><br>
Unsubscribe : <a href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack" rel="noreferrer" target="_blank">http://lists.openstack.org/<wbr>cgi-bin/mailman/listinfo/<wbr>openstack</a><br>
<br></blockquote></div><br></div>