<div dir="ltr">Dear George<div><br></div><div>Thank you for the reply. </div><div><br></div><div>I'm a little confused about your reply. </div><div><br></div><div>Can be the same tag number assigned to different tenant? For example, I assume the situation where a subnet 1 assigned tag number 1 and it belongs to tenant A, and a subnet b is also assigned tag number 1 and it belongs to tenant B. Or, should be the tag number different even if subnets belong to different tenant?</div><div><br></div><div>If the later case, the tag number seems much more strictly limited, because a tenant can have many subnet. If a subnet has 10 subnets, which means 10 tag numbers must be assigned, the openstack only create about 400 tenants.</div><div><br></div><div>Is the VXLAN network type in OpenStack really scalable comparing with VLAN or GRE? Or does the current OpenStack just provide functionality to handle VXLAN header?</div><div><br></div><div>Please let me know good example about VXLAN usage, which can provide scalability for multi-tenant on OpenStack. I'd like to know whether more than 100000 tenants could be handled by VXLAN on the latest OpenStack implementation or not.</div><div><br></div><div>Best regards</div><div><br></div><div>Byeong-Gi KIM</div></div><div class="gmail_extra"><br><div class="gmail_quote">2014-09-18 11:20 GMT+09:00 George Mihaiescu <span dir="ltr"><<a href="mailto:George.Mihaiescu@q9.com" target="_blank">George.Mihaiescu@q9.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><font color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial;color:navy">The internal VLAD ID is indeed limited to
4096 but this internal tag number is used to isolate different neutron subnets,
not tenants. <u></u><u></u></span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial;color:navy">A tenant could create 10 neutron networks
each with its own subnet and then start 10 instances each attached to a
separate net/subnet. If these instances would be scheduled on the same compute
node then they would all use different internal VLAN IDs (locally unique to
that node).<u></u><u></u></span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial;color:navy"><u></u> <u></u></span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial;color:navy">Basically, you’re right that there
is a built-in limitation of 4096 instances attached to 4096 different Neutron
net/subnets on a compute node, but it’s not realistic to actually start
that many instances on a compute node.<u></u><u></u></span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial;color:navy"><u></u> <u></u></span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial;color:navy">George<u></u><u></u></span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial;color:navy"><u></u> <u></u></span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial;color:navy"><u></u> <u></u></span></font></p>
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<p class="MsoNormal"><b><font face="Tahoma"><span style="font-size:10.0pt;font-family:Tahoma;font-weight:bold">From:</span></font></b><font face="Tahoma"><span style="font-size:10.0pt;font-family:Tahoma"> BYEONG-GI KIM
[mailto:<a href="mailto:kimbyeonggi@gmail.com" target="_blank">kimbyeonggi@gmail.com</a>] <br>
<b><span style="font-weight:bold">Sent:</span></b> Wednesday, September 17,
2014 8:47 PM<br>
<b><span style="font-weight:bold">To:</span></b> <a href="mailto:openstack@lists.openstack.org" target="_blank">openstack@lists.openstack.org</a><br>
<b><span style="font-weight:bold">Subject:</span></b> [Openstack] Question
about VXLAN support</span></font><u></u><u></u></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"><u></u> <u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">Hello.<u></u><u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"><u></u> <u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">I have a question about the VXLAN support on OpenStack.<u></u><u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"><u></u> <u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">As far as I know, the OVS operates like the below:<u></u><u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"><u></u> <u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">1. A tag number is created to identify each tenant, and it is used
between br-int and br-tun. Furthermore the tag number is identified as a VLAN
ID (I checked it via tcpdump).<u></u><u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"><u></u> <u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">2. After the packet arrived at br-tun, it is encapsulated and VNI
(VXLAN Network Identifier) is attached. The binding information between the
VLAN ID (tag number) and the VNI is stored in OVSDB. <u></u><u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"><u></u> <u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">If the operation is correct, it seems that the number of tenants which
can be created is still limited to about 4000, which is the supported range of
VLAN, because the tag number is used to identify each tenant at the inside of
br-int regardless of the supported range of VNI. <u></u><u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"><u></u> <u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">If more than 5000 tenants are created in a Compute Node, how could be
these identified after the packet arrived at br-int? In the theory, the 4500th
tenant should have 4500 tag number but the tag number is presented as VLAN ID
so that it cannot be assigned over 4096.<u></u><u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"><u></u> <u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">Any advice and comment would really be appreciated.<u></u><u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"><u></u> <u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">Best regards<u></u><u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"><u></u> <u></u></span></font></p>
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<p class="MsoNormal"><font size="3" face="Times New Roman"><span style="font-size:12.0pt">Byeong-Gi KIM<u></u><u></u></span></font></p>
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