Ciscos, BGP, L2TPV3 pseudowires and loopback Ips

nanog at nanog at
Thu Nov 11 15:32:35 CST 2010


it works perfectly well with

pseudowire-class tortellini
 encapsulation l2tpv3
 ip local interface Vlan2

where vlan2 is the wan interface on an 1812, for example.

You want to transport the real physical ports (fas0 or fas1 on the 1812)
to be able to transport vlan-tags, spanning-tree-bpd's, etc...
thru your l2tpv3 pseudowire, 
so you will use one of the switch-ports for your "internet" Connection .

So there is no need to re-configure your working WAN connection.

Juergen Marenda.

> -----Original Message-----
> From: David Freedman [mailto:david.freedman at] 
> Sent: Thursday, November 11, 2010 1:35 AM
> To: nanog at
> Subject: Re: Ciscos, BGP, L2TPV3 pseudowires and loopback Ips
> >>  interface WAN1 (actually a gigether)
> >>   ip unnumbered loopback0  (or no ip addr?)
> >>
> >That's not correct.
> Actually, was fixating on the fact that he has ethernet WAN and last I
> checked IOS doesn't have unnumbered-to-ethernet capability 
> (well not true,
> recently they introduced unnumbered SVI support, don't know 
> if it actually
> works on anything else)
> Dave.

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