[libvirt-users] Fwd: Re: [libvirt] how did libvirt manage Virtual Network?

Wayne Xia xiawenc at linux.vnet.ibm.com
Tue Sep 13 05:53:57 UTC 2011

Thank u very much, it helps a lot.

于 2011-9-13 10:22, Lei Li 写道:
> -------- Original Message --------
> Subject: 	Re: [libvirt] how did libvirt manage Virtual Network?
> Date: 	Fri, 09 Sep 2011 12:28:38 -0400
> From: 	Laine Stump <laine at laine.org> <mailto:laine at laine.org>
> To: 	libvirt-users at redhat.com <mailto:libvirt-users at redhat.com>
> CC: 	libvir-list at redhat.com <mailto:libvir-list at redhat.com>
> (This seems more appropriate for the libvirt-users mailing list)
> On 09/08/2011 10:16 PM, Wayne Xia wrote:
>>      Working at the network management, I am a bit confused about the
>>  VLAN model in libvirt.
>>      in the xml definition, there is a section as following:
>>  <devices>
>>  <interface type='network'>
>>  <source network='default'/>
>>  </interface>
>>      ...
>>  <interface type='network'>
>>  <source network='default'  portgroup='engineering'/>
>>  <target dev='vnet7'/>
>>  <mac address="00:11:22:33:44:55"/>
>>  <virtualport type='802.1Qbg'>
>>  <parameters managerid='11'  typeid='1193047'  typeidversion='2'
>>  instanceid='09b11c53-8b5c-4eeb-8f00-d84eaa0aaa4f'/>
>>  </virtualport>
>>  </interface>
>>  </devices>
>>      What is the really meaning of its related parameters of
>>  "virtualport"? I want to discover informations such as VLAN id,
>>  the switch type( software switch or hardware switch), connecting
>>  relationship, but from the xml I can only found"managerid". I am not
>>  sure how to map these xml information to those I needed, could I
>>  consider managerid as VLAN id, and a portgroup as a specified VLAN group?
>>      By the way to use virtualport, what components should I install on
>>  Linux?
> <virtualport>  is used only when configuring guests that connect directly
> to a VEPA or VNLINK (i.e. 802.1Q) capable switch. Unless you have one of
> these switches, you will not use it. If you do have one of these
> switches, you will also have information included with them that
> explains the meaning of the virtualport parameters and how they are used
> (they're opaque to libvirt - it just passes them on to the switch
> without assigning any meaning to them).
> portgroup is a tag used to select certain bits of config out of
> <portgroup>  sections in the<network>  definition being used for the
> interface. Currently the things that can be configured in the
> <portgroup>  sections are 1)<bandwidth>  info, and 2)<virtualport>
> parameters. Again, it has nothing to do with VLAN groups.<portgroup>  is
> very new, btw - it has only been in libvirt since 0.9.4, so if you're
> using an older version don't expect it to do anything.
> Down to the real basic question of which VLAN a particular guest is
> using - that can either be determined by the guest itself, or if the
> guest has no VLAN id setting, it could be determined by the
> switch/bridge the guest is connected to; in other words, wherever it is
> done, it's outside of libvirt (well, I guess if your platform has
> support for the iface-* commands, you could define a bridge that uses a
> vlan interface as its connection to the physical network - then traffic
> from any guest connected to that bridge would end up going onto the
> physical network with the given vlan id).
> --
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> libvir-list at redhat.com  <mailto:libvir-list at redhat.com>
> https://www.redhat.com/mailman/listinfo/libvir-list

Best Regards

Wayne Xia
mail:xiawenc at linux.vnet.ibm.com

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