[c-nsp] Hierarchical FIB on Cisco 7600

redscorpion69 redscorpion69 at gmail.com
Fri Apr 25 17:32:29 EDT 2014


Thank you all; so let me just see if I got this right.

If we're not loadbalancing with IGP (instead there's primary/backup uplink)
on edge, and not using H.FIB (with cef table output-chain build favor
convergence-speed) and we're running full BGP table on edge routers, anyone
with experience on how would flat FIB affect convergence without PIC Core
on 7600? In other words what would be real life effect of rewriting couple
of hundred thousand entries to point to new output interface in terms of
convergence?

If you don't mind, could you explain part with "VPNv4 requires recirc" ?
I'm not sure what does that mean in relation with PIC Core?

And if I understand, since we're already installing in CEF 'repair' path in
PIC Edge scenario, then H.FIB is not really required?

Do you utilize PIC Core and Edge to full extend in your networks?

Many regards




On Fri, Apr 25, 2014 at 10:06 PM, Pete Lumbis <alumbis at gmail.com> wrote:

> for PIC Core
> IP2IP hacks it using loadbalance adjacencies.
> VPNv4 requires recirc.
>
> PIC Edge is a different story since we are pre-installing the backup path
> like FRR
>
>
>
> On Fri, Apr 25, 2014 at 1:03 PM, Saku Ytti <saku at ytti.fi> wrote:
>
> > On (2014-04-25 10:56 -0400), Pete Lumbis wrote:
> >
> > > The difference in commands is mainly in relation to software/memory.
> This
> > > has the biggest impact on software based platforms like the 7200 but
> > you'll
> > > see an uptick in RP/SP memory usage by enabling, but only changes how
> > > routes are built in hardware.
> >
> > How does it change how routes are built in HW?
> >
> > My understanding is that 7600 won't do indirection (load-info) in
> hardware
> > TCAM regardless of your configuration.
> > I don't think the hardware is really even capable of that, outside
> > recirculation which I think is how MPLS FRR is implemented. But that'll
> > mean
> > you'll halve your PPS.
> >
> > --
> >   ++ytti
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