Re: [Xen-devel] Netback & NetFront Driver

[Mats Petersson <mats@xxxxxxxxxxxxxxxxx>]

At 16:12 08/07/2007, TEJ wrote:
> On 7/8/07, TEJ <tejparkash.d@xxxxxxxxx> wrote:
> > On 7/8/07, Mats Petersson <mats@xxxxxxxxxxxxxxxxx> wrote:
> > > At 08:03 2007-07-08, you wrote:
> > > >hi
> > > >
> > > >i am new to the xen development list. I am just curious about the
> > > >networking architecture of the XEN.
> > > >
> > > >there are two separate things i have read.
> > > >
> > > >first is the Network driver architecture is a spilt driver (Netfront
> > > >and NetBack)...
> > > >Second is while domu is coming up it creates the virtual interfaces
> > > >like (vif<id>.0 <--> (v)eth0).
> > > >
> > > >I am unable to relate these two concept. As far as my understanding
> > > >say that, for all the (v)eth0, eth1, eth2 interface in domu is managed
> > > >by Netfront Driver. So IP layer in domu talks to Netfront Driver and
> > > >uses one of the veth and then pass packet through that channel i.e.
> > > >corresponding vif through hypervisor.
> > >
> > > That is correct - the packet is sent by netfront (acting on behalf of
> > > "eth%d" in DomU) to netback.
> > >
> > >
> > > >All the vif<id>.x interfaces in the dom0 will be managed by NetBack
> > > >Driver. Since all the vif's are grouped with bridge which actaully
> > > >forward the packet to the actual driver of correspinding vif
> > > >interface.
> > >
> > > The netback receives the packet from the frontend driver, and passes
> > > it to the listener for "vif%d.%d". This ends up in the bridge (or
> > > route) component, which forwards the packet to the correct hardware
> > > port. This part is no different from the normal bridge/route
> > > behaviour (taking a network packet on one device and sending it out
> > > on the other device, e.g. linking eth0 to eth1 - of course, when
> > > doing this, usually there are rules about which packets go where,
> > > e.g. for routing, you only send packets intended for the other
> > > network across).
> just i am curious to know that why it there is like IP forwarding and
> MAC forwarding. because as i understand, MAC forwarding is sufficient
> to forward the packet. and it is performance hit if the IP forwarding
> is implemented in the DOMU.
>
> Can you give a link to the page saying this - or some other 
> reference to what you're on about, since I don't quite know what you 
> mean (and I may not be able to answer the question, but with a link 
> I may understand it better and determine if I actually do know how 
> it works or not).

--
Mats



> > >
> > thanks for your confirmation Mat,
> >
> > > --
> > > Mats
> > >
> > >
> > > >I just want somebody confirmation on that or somebody want to add
> > > >something over this will be helpful to me
> > > >
> > > >i have attached one doc if some is interested can through some 
> > light on that..
> > > >
> > > >i am sorry if it is totally a crap.
> > > >
> > > >thanks
> > > >TEJ
> > > >
> > > >
> > > >Content-Type: application/msword; name=networking.doc
> > > >X-Attachment-Id: f_f3v6ewmc
> > > >Content-Disposition: attachment; filename="networking.doc"
> > > >
> > > >_______________________________________________
> > > >Xen-devel mailing list
> > > >Xen-devel@xxxxxxxxxxxxxxxxxxx
> > > >http://lists.xensource.com/xen-devel
> > >
> > >

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