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Hi Xuhan,</div>
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<div>What I saw is that GARP is sent to the gateway port and also to the router ports, from a neutron router. I’m not sure why it’s sent to the router ports (internal network). My understanding for arping to the gateway port is that it is needed for proper
NAT operation. Since we are not planning to support ipv6 NAT, so this is not required/needed for ipv6 any more?</div>
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<div>I agree that this is no longer necessary.</div>
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<div>There is an abandoned patch that disabled the arping for ipv6 gateway port: <a href="https://review.openstack.org/#/c/77471/3/neutron/agent/l3_agent.py">https://review.openstack.org/#/c/77471/3/neutron/agent/l3_agent.py</a></div>
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<div>thanks,</div>
<div>Robert</div>
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<div>On 8/27/14, 1:03 AM, "Xuhan Peng" <<a href="mailto:pengxuhan@gmail.com">pengxuhan@gmail.com</a>> wrote:</div>
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<div dir="ltr">As a follow-up action of yesterday's IPv6 sub-team meeting, I would like to start a discussion about how to support l3 agent HA when IP version is IPv6.
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<div style="">This problem is triggered by bug [1] where sending gratuitous arp packet for HA doesn't work for IPv6 subnet gateways. This is because neighbor discovery instead of ARP should be used for IPv6.</div>
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<div style="">My thought to solve this problem turns into how to send out<font color="#000000" face="sans-serif"> neighbor advertisement for IPv6 routers just like sending ARP reply for IPv4 routers after reading the comments on code review [2].</font></div>
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<div style=""><font color="#000000" face="sans-serif">I searched for utilities which can do this and only find a utility called ndsend [3] as part of vzctl </font><span style="color:rgb(0,0,0);font-family:sans-serif">on ubuntu. I could not find similar tools
on other linux distributions. </span></div>
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<div style="">There are comments in yesterday's meeting that it's the new router's job to send out RA and there is no need for neighbor discovery. But we didn't get enough time to finish the discussion. </div>
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<div>Because OpenStack runs the l3 agent, it is the router. Instead of needing to do gratuitous ARP to alert all clients of the new MAC, a simple RA from the new router for the same prefix would accomplish the same, without having to resort to a special package
to generate unsolicited NA packets. RAs must be generated from the l3 agent anyway if it’s the gateway, and we’re doing that via radvd now. The HA failover simply needs to start the proper radvd process on the secondary gateway and resume normal operation.</div>
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<div style="">Can you comment your thoughts about how to solve this problem in this thread, please?</div>
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<div style="">[1] <a href="https://bugs.launchpad.net/neutron/+bug/1357068">https://bugs.launchpad.net/neutron/+bug/1357068</a></div>
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<div style="">[2] <a href="https://review.openstack.org/#/c/114437/">https://review.openstack.org/#/c/114437/</a></div>
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<div style="">[3] <a href="http://manpages.ubuntu.com/manpages/oneiric/man8/ndsend.8.html">
http://manpages.ubuntu.com/manpages/oneiric/man8/ndsend.8.html</a></div>
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<div style="">Thanks,</div>
<div style="">Xu Han </div>
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<div>-Anthony</div>
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