> Subject: Re: [PATCH] macvlan: add tap device backend > > On Fri, 7 Aug 2009 12:10:07 -0700 > "Paul Congdon \(UC Davis\)" <ptcongdon@xxxxxxxxxxx> wrote: > > > Responding to Daniel's questions... > > > > > I have some general questions about the intended use and benefits > of > > > VEPA, from an IT perspective: > > > > > > In which virtual machine setups and technologies do you forsee this > > > interface being used? > > > > The benefit of VEPA is the coordination and unification with the > external network switch. So, in environments where you are > needing/wanting your feature rich, wire speed, external network device > (firewall/switch/IPS/content-filter) to provide consistent policy > enforcement, and you want your VMs traffic to be subject to that > enforcement, you will want their traffic directed externally. Perhaps > you have some VMs that are on a DMZ or clustering an application or > implementing a multi-tier application where you would normally place a > firewall in-between the tiers. > > I do have to raise the point that Linux is perfectly capable of keeping > up without > the need of an external switch. Whether you want policy external or > internal is > a architecture decision that should not be driven by mis-information > about performance. VEPA is not only about enabling faster packet processing (like firewall/switch/IPS/content-filter etc) by doing this on the external switch. Due to rather low performance of software-based I/O virtualization approaches a lot of effort has recently been going into hardware-based implementations of virtual network interfaces like SRIOV NICs provide. Without VEPA, such a NIC would have to implement sophisticated virtual switching capabilities. VEPA however is very simple and therefore perfectly suited for a hardware-based implementation. So in the future, it will give you direct I/O like performance and all the capabilities your adjacent switch provides. Anna _______________________________________________ Bridge mailing list Bridge@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/bridge
