[c-nsp] multiple vlans on a port

[A.L.M.Buxey at lboro.ac.uk]

Hi,

> I realize this is impossible, at least I have read it is on an access  
> port.  So if I sent up a trunk port with the machine, does the machine  
> need to speak 802.1q as well?
>
> interface GigabitEthernet0/15
>  switchport access vlan 120
>  switchport trunk native vlan 120
>  switchport trunk allowed vlan 100,120,231,321
>  switchport mode trunk
> end
>
> The purpose of this is that the machine in a Linux machine running Xen, 
> so the cloud will decide what machines and vlans it needs to spin up at 
> what time.  Meaning this port will need access to these vlans.  This 
> being the case, will I need to configure the Linux machine for 802.1q 
> trunking as well?  I found this article that seemed to suggest, yes, but 
> I wanted a second opinion.  http://www.linuxjournal.com/article/7268

Linux very happily talks 802.1q.  yes, if you want to feed multiple
networks to the Xen host you need to send it a trunk feed... or invest
in multiple NICs and assign NICs to virtual hosts. our Xen boxes
get trunk feeds and /sbin/ifconfig lists all the pvlanXXX and xenbrXXXX
and xenbrtrunk etc.  VMWare has the virtual switch technology so currently
is _slightly_ ahead of Xen on that point...

alan