[openstack-dev] Tricky questions - 1/2 Quantum Network Object

Yongsheng Gong gongysh at unitedstack.com
Mon Oct 14 07:01:06 UTC 2013


On Mon, Oct 14, 2013 at 2:55 PM, Marco Fornaro <Marco.Fornaro at huawei.com>wrote:

>  Hi Gong,****
>
> ** **
>
> Thanks so much for your answers****
>
> ** **
>
> Just one more question: you wrote “You can create networks with just one
> subnet, but the vlan id will run out soon if vlan is used.”****
>
> Sorry but: how can the Vlan ID “run out soon”?...is it really possible to
> finish them?****
>
> **
>
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.


>
**
>
> Best Regards****
>
> ** **
>
> Marco****
>
> ** **
>
> ** **
>
> *From:* Yongsheng Gong [mailto:gongysh at unitedstack.com]
> *Sent:* den 11 oktober 2013 10:56
> *To:* OpenStack Development Mailing List
> *Subject:* Re: [openstack-dev] Tricky questions - 1/2 Quantum Network
> Object****
>
> ** **
>
> ** **
>
> ** **
>
> On Fri, Oct 11, 2013 at 4:41 PM, Marco Fornaro <Marco.Fornaro at huawei.com>
> wrote:****
>
> Hi All,****
>
>  ****
>
> (I already posted this on openstack mail list, but perhaps it’s more a
> developer stuff J)****
>
> Some Tricky questions I ask help for (email 1 of 2):****
>
>  ****
>
>  ****
>
> *Quantum Network object*****
>
> In the “openstack networking guide”->”Using Openstack compute with
> Openstack”->” Advanced VM creation” (
> http://docs.openstack.org/grizzly/openstack-network/admin/content/advanceed_vm_creation.html)
> there are example boot a VM on one or more NETWORKs (meaning the quantum
> Network object):  ****
>
> nova boot --image <img> --flavor <flavor> \****
>
> *--nic net-id=<net1-id> --nic net-id=<net2-id>* <vm-name>****
>
>  ****
>
> 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 192.168.100.0/24**
> **
>
>  ****
>
> *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!*****
>
> 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****
>
>   ****
>
> *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?*****
>
>  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.****
>
> ** **
>
> we can have many networks, and the subnets within network can have overlap
> IPs.****
>
> ** **
>
>   ****
>
> Thanks in advance for any help****
>
>  ****
>
> Best Regards****
>
>  ****
>
> Marco****
>
>  ****
>
>  ****
>
>  ****
>
>
> _______________________________________________
> OpenStack-dev mailing list
> OpenStack-dev at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev****
>
>  ** **
>
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