Re: [Xen-users] veth0 is from netback and vifu.0 is from thebridge-utils?

[Ramiro Brito Willmersdorf <ramiro@xxxxxxxxxxxxxxxx>]

That's great, except when you need *two* bridges, for two independent
subnets, and there is no, as far as I can see, peth1.

Em Wednesday 14 September 2005 16:30, John Wilson escreveu:
> Yo,
>
> I had big problems with this myself, but now as far as I can tell, veth0
> (renamed to eth0 in the v recent releases) is the virtual nic for dom0
> which corresponds to the virtual eth0 nics in the domU's (the physical nic
> itself has been renamed to peth0).
>
> The vifU.N's are the dom0 links to the virtual nics ethN in domU, and
> aren't to be treated as proper network interfaces in thier own right. If
> you assign an IP address to, say, vif1.0 and attempt to communicate with
> eth0 in dom1, you can ping between them and such, but ssh nor vnc wont
> work, complaining for the most part about bad checksums.
>
> The vif0.0 interface in dom0 is linked to dom0's virtual nic, veth0 (or
> eth0 in the recent builds).
>
> Now... The correct way to interface the cards and provide connectivity
> between the domains and the outside world is to attach all the vifU.N
> interfaces to a bridge in dom0 (normally xen-br0) together with the
> physical nic, eth0 (or peth0 recently). IP addresses are then assigned to
> the eth0 links and inter-domain sshing, vncing and communication with the
> outside world all result.
>
> Here's a badly drawn diagram to illustrate...
>
>   ____________________________         _____________________
>
> |dom0                        |       |dom1                 |
> |  _______                   |       |       ________      |
> |
> | |eth0   |                  |       |      |eth0    |     |
> | |IP_____|   +--------------+-------+------|IP______|     |
> |
> | ____|_______|_____________ |       |                     |
> |
> || ___|___ ___|___ _______  ||       |                     |
> ||
> |||vif0.0 |vif1.0 |peth0  | ||       |                     |
> |||_______|_______|_______| ||       |                     |
> ||
> ||xen-br0_____________|_____||       |                     |
> |
> |_____________________|______|       |_____________________|
>
> ______________________|_____________________>>LAN>>>
>
>
> I've used eth0 as the virtual nics and peth0 as the physical nic.
> IP has been used to denote devices with an IP address. All the interfaces
> there are automatically generated by Xen, and I used ifconfig to
> statically set IP addresses (because I was having trouble with our lab
> DHCP server, although it was assigning addresses to the correct cards),
> and brctl addif xen-br0 vif1.0 etc. to add the vifs to the bridge, because
> for some reason Xen wasn't...
>
> Well thats my contribution for this evening.
>
>
>
> John
>
>
>
> P.S. Official documentation/Howto/wiki is a little on the sparse side for
> this Ian.
>
> Quoting Anthony.Golia@xxxxxxxxxxxxxxxxx:
> > On Thu, 8 Sep 2005, Ian Pratt wrote:
> >> > Hi.  what creates veth0 and vifu.0, when?  what's the
> >> > underlying architecture behind them?  Just trying to
> >> > understand the internals.
> >>
> >> netback/loopback.c creates them.
> >>
> >> It's effectively a point to point link, allowing domain 0 to connect on
> >> to the bridge in the same manner that other domains do. (before, packets
> >> to domain 0 were short-cutted and came off the bridge directly, which
> >> could lead to traffic from other domains being stalled if a lot of
> >> traffic was destined to user space in dom0.
> >
> > thx.  what's the diff betwn the two (veth0 and vifu.0) ?
> >
> >> Best,
> >> Ian
> >>
> >> )
> >
> > Cheers,
> > Anthony
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
>
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-- 
Ramiro Brito Willmersdorf  Dep. Engenharia Mecânica/UFPE
ramiro@xxxxxxxxxxxxxxxx        tel: +55 81 2126-8231e239          

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