<div dir="ltr">Hi Marco,<div><br></div><div>At least two of your questions clearly hint at the dichotomy between subnet and network, which appear to be redundant.</div><div>A multi-homing use case on a single network is a potential use case for this, albeit a very limited one, since one might argue that in a cloud scenario instead of allocating two IPs from two different subnets on a NIC one would rather have two NICs with one IP each.</div>
<div><br></div><div>I agree that perhaps in 99% of cases there's no need for separating this two concepts. Automatically provisioning a network when a subnet with no network id is created is something which might be considered.</div>
<div>In my opinion, a reason for which the network/subnet concept are separated is for allowing either L2-only and L2/L3 use cases. For instance, with L2-only you might have Neutron provisioning your networks and then either no IP configuration at all, or some other service doing IP configuration. </div>
<div><br></div><div>On a separate note, exhaustion of the VLAN pool is very likely in cloud deployments. There is a hard limit given the 12-bit size of the VLAN identifier. Also, if switches are not trunked and VLANs are provisioned there too, there might be a further limitation on the number of VLANs which can be configured on each switch port. But please don't trust me when it comes to networking appliances, as I have a rather limited knowledge on the subject.</div>
<div><br></div><div>Salvatore</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On 14 October 2013 09:01, Yongsheng Gong <span dir="ltr"><<a href="mailto:gongysh@unitedstack.com" target="_blank">gongysh@unitedstack.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><br><div class="gmail_extra"><br><br><div class="gmail_quote"><div class="im">On Mon, Oct 14, 2013 at 2:55 PM, Marco Fornaro <span dir="ltr"><<a href="mailto:Marco.Fornaro@huawei.com" target="_blank">Marco.Fornaro@huawei.com</a>></span> wrote:<br>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Hi Gong,<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Thanks so much for your answers<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Just one more question: you wrote “</span><span lang="EN-US">You can create networks with just one subnet, but the vlan id will run out soon if
vlan is used.</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">”<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Sorry but: how can the Vlan ID “run out soon”?...is it really possible to finish them?<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> </span></p></div></div></blockquote></div><div>for example, one network is using one vlan ID if vlan is used for linux bridge plugin. If we create networks with just one subnet, we will need more vlan ids than networks with more than subnets.</div>
<div><div class="h5">
<div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="SV" link="blue" vlink="purple"><div><p class="MsoNormal"> </p></div></div></blockquote><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="SV" link="blue" vlink="purple"><div><p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Best Regards<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Marco</span><span lang="EN-US" style="color:#1f497d"><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<div style="border:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Yongsheng Gong [mailto:<a href="mailto:gongysh@unitedstack.com" target="_blank">gongysh@unitedstack.com</a>]
<br>
<b>Sent:</b> den 11 oktober 2013 10:56<br>
<b>To:</b> OpenStack Development Mailing List<br>
<b>Subject:</b> Re: [openstack-dev] Tricky questions - 1/2 Quantum Network Object<u></u><u></u></span></p>
</div><div><div>
<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><u></u> <u></u></p>
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<p class="MsoNormal">On Fri, Oct 11, 2013 at 4:41 PM, Marco Fornaro <<a href="mailto:Marco.Fornaro@huawei.com" target="_blank">Marco.Fornaro@huawei.com</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal"><span lang="EN-US">Hi All,</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">(I already posted this on openstack mail list, but perhaps it’s more a developer stuff
</span><span lang="EN-US" style="font-family:Wingdings">J</span><span lang="EN-US">)</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Some Tricky questions I ask help for (email 1 of 2):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:14.0pt">Quantum Network object</span></b><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">In the “openstack networking guide”->”Using Openstack compute with Openstack”->” Advanced VM creation” (</span><a href="http://docs.openstack.org/grizzly/openstack-network/admin/content/advanceed_vm_creation.html" target="_blank"><span lang="EN-US">http://docs.openstack.org/grizzly/openstack-network/admin/content/advanceed_vm_creation.html</span></a><span lang="EN-US">)
there are example boot a VM on one or more NETWORKs (meaning the quantum Network object): </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";color:#23302d">nova boot --image <img> --flavor <flavor> \</span><u></u><u></u></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";color:#23302d">--nic net-id=<net1-id> --nic net-id=<net2-id></span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";color:#23302d"> <vm-name></span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">BUT if you look at the description of the network object in the API abstraction it looks like a collection of subnets (meaning the quantum object), so basically
a collection of IP Addresses like <a href="http://192.168.100.0/24" target="_blank">
192.168.100.0/24</a></span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:14.0pt">SO (first question): what happens in the network where I boot the VM has more than a subnet?...I suppose the VM should have a nic
for EACH subnet of the network!</span></b><u></u><u></u></p>
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<p class="MsoNormal">You will just get a nic for each network, not for each subnet of the network. to choose the subnet, use --nic net-id=net-uuid,v4-fixed-ip=ip-addr<u></u><u></u></p>
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<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:14.0pt">THEN (second question): why do I need a network object? Shouldn’t it be more practical to have just the subnet object?..why do I need
to create a Network if it’s just a collection of subnets?</span></b><u></u><u></u></p>
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<p class="MsoNormal">under the hood, the traffic among networks are isolated by tunnel id, vlan id or something else. You can create networks with just one subnet, but the vlan id will run out soon if vlan is used.<u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
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<p class="MsoNormal">we can have many networks, and the subnets within network can have overlap IPs.<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Thanks in advance for any help</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Best Regards</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#888888"> </span><span style="color:#888888"><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#888888">Marco</span><span style="color:#888888"><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#888888"> </span><span style="color:#888888"><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#888888"> </span><span style="color:#888888"><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#888888"> </span><span style="color:#888888"><u></u><u></u></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><br>
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<p class="MsoNormal"><u></u> <u></u></p>
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