CentOS virt - Sep 2015 - Using STP in kvm bridges

Hi all,

  Reading docs about using bridges in a KVM environment, I have a doubt 
about activating STP or not in a KVM host.

  What advantages and disadvantages have??  If I will want to install 
some kvm guests that use multicast address for certain services, is it 
recommended to enable STP?

Thanks.

On 09/16/2015 03:02 PM, C.L. Martinez wrote:
>   What advantages and disadvantages have??  If I will want to install
> some kvm guests that use multicast address for certain services, is it
> recommended to enable STP?
STP has nothing to do with multicast as it's an Ethernet protocol.
It's developed to provide loop-free redundancy links to Ethernet-based 
networks.

I can't imagine any legitimate use of STP within virtualized environment 
except when BOTH a) you don't trust the person who manages VM's (like in
VPS providing) AND b) you provide more then one network interface to the 
virtual machine.

Otherwise STP can be used to prevent traffic storm because of malicious 
bridging of vNIC's inside VM.

Best regards,
	Dmitry Mikhailov

On 09/16/2015 10:15 AM, Dmitry E. Mikhailov wrote:
> On 09/16/2015 03:02 PM, C.L. Martinez wrote:
>>   What advantages and disadvantages have??  If I will want to install
>> some kvm guests that use multicast address for certain services, is it
>> recommended to enable STP?
> STP has nothing to do with multicast as it's an Ethernet protocol.
> It's developed to provide loop-free redundancy links to Ethernet-based
> networks.
>
> I can't imagine any legitimate use of STP within virtualized
environment
> except when BOTH a) you don't trust the person who manages VM's
(like in
> VPS providing) AND b) you provide more then one network interface to the
> virtual machine.
>
> Otherwise STP can be used to prevent traffic storm because of malicious
> bridging of vNIC's inside VM.
>
> Best regards,
>      Dmitry Mikhailov
Thanks Dmitry... Uhmm, but my case is: "b) you provide more then one 
network interface to the virtual machine". I have several kvm guests 
with 3 or more network interfaces ... In this case, do you recommends to 
enable STP??