[CentOS] Switch to measure traffic at IP level?

Les Mikesell lesmikesell at gmail.com
Fri Oct 23 17:15:38 UTC 2009


Neil Aggarwal wrote:
> Matt:
>  
>> why not just use your current cacti setup and 
>> enable snmp on each of the hosts?  That seems like 
>> the simplest and cheapest approach.
> 
> As I understand it, I would actually have to
> enable snmp on each of the guests, not the hosts.
> 
> Am I wrong?
> 

Yes - the host would see the total traffic.  The only other way to separate it 
would be something upstream (switch/router, etc.) that knows how to do sflow 
plus a collector device.  These are typically pretty expensive.  For some small 
number of guests it might be cheaper to add NICs to your hosts and bridge the 
guests to individual NICs where you could monitor on either the host interface 
or the connected switch port.  You might be able to simulate this with some 
clever use of vlans but I'm not sure how they interact with the virtual nic bridges.

-- 
   Les Mikesell
    lesmikesell at gmail.com


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