From: ying c (bf5tgh1@xxxxxxxxx)
Date: Tue Jul 23 2002 - 16:23:47 GMT-3
Fred,
Ah, tricky question. The light finally clicked. Thanks
for the explaination. I guess I fall into the trap of
"Do not use the backup interface command." - it made
me to think I have to either use dialer watch or
floating static.
Thanks,
Chang
--- Fred Ingham <fingham@cox.net> wrote:
> Chang: Dialer watch is not required and should not
> be configured. The
> requirement is fully satisfied with OSPF demand
> circuit configured on R2.
>
> The key to deciding whether to configure OSPF demand
> circuit OR dialer watch
> is in the statement of requirements. The
> requirements state that the ISDN
> link is running OSPF, and that R2 is to call when
> routeS learned over the
> frame relay link
> disappear. If you were using dialer watch - what
> route(s) would you choose?
> If you chose one particular route and that route
> disappears but others are
> still available over the frame relay interface then
> the ISDN line would come
> up. The requirement is fully satisfied by OSPF
> demand circuit.
>
> If the requirement was for dialer watch, the routes
> to be watched would be
> stated or there would be a requirement that neither
> backup interface nor
> demand circuit could be used.
>
> HTH, Fred
>
>
>
> ----- Original Message -----
> From: "ying c" <bf5tgh1@yahoo.com>
> To: "Fred Ingham" <fingham@cox.net>;
> <ccielab@groupstudy.com>
> Sent: Monday, July 22, 2002 11:02 PM
> Subject: Re: Conflict ISDN backup requirements?
>
>
> > Fred,
> >
> > I must missing something. If ospf demand circuit
> is
> > placed in r2 and we use dialer watch to monitor
> the
> > route, when idle-timer expires at the end of 2
> > minutes, dialer watch check the route and as long
> as
> > the primary is down, it will keep the isdn link up
> > until we restore the frame relay link. So I don't
> see
> > ospf demand circuit doing anything here.
> >
> > If we placed the ospf demand circuit in r1,
> because r1
> > could not call r2 and does not have dialer watch
> to
> > stop it from bringing down the line, when dialer
> idle
> > timer hit 2 minutes, it will take down the link;
> > however, r2 is still watching the route, since the
> > primary is still down, it will call r1 and brings
> up
> > the isdn link again, the end result is we are
> going to
> > have a flapping isdn link, is this what we want?
> >
> > What am I missing here?
> >
> > Thanks,
> > Chang
> > --- Fred Ingham <fingham@cox.net> wrote:
> > > Chang: OSPF demand circuit is what is required
> > > here. In addition,
> > > consider :
> > > no peer neighbor-route - to eliminate ppp
> host
> > > routes
> > > area 33 as a virtual link if R2 has any
> OSPF
> > > areas other than 0, and 33
> > > cost for isdn link.
> > >
> > > Lately there have been counterfeit copies
> claiming
> > > to be ECP1 and ECP2 labs
> > > on eBay, some are copies of copies, some contain
> > > labs with wrong answers.
> > > All violate the copyright which is held by
> > > NetMasterClass, LLC. Recent
> > > auctions have been terminated by eBay for
> copyright
> > > infringement.
> > >
> > > Cheers, Fred
> > > ----- Original Message -----
> > > From: "ying c" <bf5tgh1@yahoo.com>
> > > To: <ccielab@groupstudy.com>
> > > Sent: Monday, July 22, 2002 9:22 AM
> > > Subject: Conflict ISDN backup requirements?
> > >
> > >
> > > > Hi,
> > > >
> > > > Below is queston 16 from ECP1's final exam
> which I
> > > > could not come up with any answer:
> > > >
> > > > "Configure dial backup so that R2 calls R1
> when
> > > routes
> > > > learned over the Frame-Relay interface
> disappear.
> > > Do
> > > > not use the backup interface command. Make
> sure
> > > the
> > > > ISDN link does not stay up indefinitely.
> (Include
> > > the
> > > > backup link in OSPF area 33)."
> > > >
> > > > The general requirement for this exam is no
> static
> > > > route unless noted otherwise, which means I
> cannot
> > > use
> > > > the floating static. That makes me to think
> the
> > > only
> > > > option I have is to use dialer watch, but that
> > > will
> > > > make the ISDN staying up until Frame-Relay
> network
> > > > comes back up. Don't bother ip ospf
> demand-circuit
> > > > with dialer watch, as when dialer idle-timeout
> > > > expires, it will check the routing table and
> keep
> > > the
> > > > line up.
> > > >
> > > > Other than backup, floating static and dialer
> > > watch,
> > > > is there other way to solve this problem?
> > > >
> > > > By the way, please include me in the copy list
> > > when
> > > > you send your reply, as I'm having troubles to
> > > receive
> > > > groupstudy emails recently.
> > > >
> > > > Thanks,
> > > > Chang
> > > >
> > > >
> > > >
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