From: Marc La Porte (marc.a.laporte@gmail.com)
Date: Thu Feb 28 2008 - 13:54:08 ARST
Yes, so as there are multiple DLCIs available on the main interface, and
only one of those is used on the p2p sub-interface (which by default doesn't
do I-ARP), it would make sense to use the "no frame inv" on the main
interface to ensure no dynamic mapping between R1 and R6 is created via
Inverse-ARP. You could also do this by moving all the non-used DLCIs to an
unused multipoint sub-interface...
Indeed, the Virtual-Interface as such has no influence on the InverseARP
process.
HTH.
Marc
On Thu, Feb 28, 2008 at 4:43 PM, Andy <and123and@googlemail.com> wrote:
> For those that have the book, the question and diag are on p77. Lab 2.
>
> For those that dont: Hub and spoke with R4 as the hub.
>
> R1 has DLCI 101 and 110
> R4 has DLCI 100 and 102
> R6 has DLCI 104 and 103
>
> Mappings are
> 101 - 100
> 110 - 104
> 103 - 102
>
> I hope you can follow this, the question is:
>
> - Config the FR portion of the network as shown in figure x and ensure
> that DLCIs 110 and 104 between R1 and R6 are not used.
> - Use p2p subinterfaces
>
> The solution shows IP address on p2p and "no fram inverse-arp" on the main
> interface.
>
> The eventual solution uses PPP on the p2p interfaces with a virtual
> interface but I mention it here only as reference, I do not think it matters
> as to why we are using "no fr inv-arp" on main interface.
>
>
>
>
>
>
>
> R1 (ser0/1 DLCI 101) to R4 (ser0/0 DLCI 100)
> R1 (ser0/1 DLCI 110) to R6 (ser5/0 DLCI 104)
> R6 (ser5/0 DLCI 103) to R4 (ser0/0 DLCI
>
>
> On 28/02/2008, Marc La Porte <marc.a.laporte@gmail.com> wrote:
> >
> > Andy,
> >
> > Are both DLCIs 104 and 110 on both R1 and R6? And the p2p sub-interface
> > is for instance using DLCI 104 on both sides? Then the "no frame inv" makes
> > sense on the main interface, because all DLCIs coming in from the FR switch
> > on that main interface are automatically assigned to the main interface, so
> > if you're using DLCI 104 (for instance) on your p2p sub-interface that still
> > leaves you with DLCI 110 "assigned" to the main interface. Granted, as long
> > as there is no IP address on the main interface there is no I-ARP going on
> > (I listen to the Brian's too --- or should I say "the Brains"), but if you
> > want to be sure then that's the way to go...
> >
> > If you could gives us a copy of the config that would help to (like you
> > said) something subtle...
> >
> > Marc
> >
> > On Thu, Feb 28, 2008 at 3:43 PM, Andy <and123and@googlemail.com> wrote:
> >
> > > Hi
> > >
> > > On pages 92 and 93 of CCIE Routing and Switching LAB Practice labs by
> > > Cisco
> > > it gives a solution which uses "no frame relay inverse-arp" after
> > > asking the
> > > question "ensure that DLCIs 110 and 104 between R1 and R6 are not
> > > used. The "no fr inverse-arp" is configed on a main interface and a
> > > sub-interface used for p2p connection (with the IP going on the
> > > sub-interface).
> > >
> > > Now I know that "no frame relay inverse-arp" on an interface without
> > > an IP
> > > address does nothing (coz I have read the mails from Brian Dennis ;-)
> > > But
> > > then why does the Cisco Press book award one point for this??? In a
> > > lab
> > > scenario I would not config the command where an IP address does not
> > > exist
> > > as I would view this as overconfiguration. Am I missing something
> > > subtle
> > > here?
> > >
> > > -A
> > >
> > >
> > > _______________________________________________________________________
> > > Subscription information may be found at:
> > > http://www.groupstudy.com/list/CCIELab.html
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