[c-nsp] MPLS VPN with PE over GRE tunnels

Gert Doering gert at greenie.muc.de
Tue Sep 20 16:13:20 EDT 2011


Hi,

On Tue, Sep 20, 2011 at 12:32:13PM -0400, Ross Halliday wrote:
> Thank you Gert and Cristophe, I will give that a test tonight. Does the 
> same sort of gotcha exist on the 7200 platform? 

As it doesn't have hardware forwarding to circulate packets through, no.

> I moved the interfaces over to that router, which also runs MPLS,
> and before I corrected the VPNv4 iBGP relationships the traffic
> worked fine when the 7204 sent packets out labeled for that default
> route (which caused them to be sent back via OSPF into an SVI).
> Once I fixed the BGP peering so that the 7204 learned the far VPNv4
> route properly it exhibited the same problem as the 6509. The 7204
> is a dinky ol' NPE-225 running 12.4(22)T.

In that case, it would be "something else", though I have no idea what
it could be.

> Reading that page that Cristophe linked, I'm curious why this
> isn't default behavior. Is it just some magic knob to stump people
> on a CCIE exam or is there some performance impact or other side
> effects?

recirculation reduces forwarding performance, as (some) packets are
using twice as many cycles...

gert
-- 
USENET is *not* the non-clickable part of WWW!
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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
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