Re: OSPF ADV Router is not-reachable

Yes LSAs with DNA bit set wont age out in the database. Like the one with
the Virtual Links or else in the Demand Circuit where u usually dont need
the hellos to be sent within the interval but still u need the databases to
be synced

It wont show the ADV router is not reachable in the database if DNA bit is
set. But i would test this once and let u know
about it more.

On Sat, Dec 15, 2012 at 5:47 PM, Antoine Monnier <mrantoinemonnier_at_gmail.com
> wrote:

> What would happen if those LSAs had the Do Not Age bit set ? Would
> those LSAs stay in the database forever ??
>
>
>
> On Thu, Dec 13, 2012 at 5:38 PM, Brian McGahan <bmcgahan_at_ine.com> wrote:
> > That's normal. This is a convergence optimization of OSPF in which it
> retains old LSAs until the MAXAGE is reached. The idea is that if the
> neighbor temporarily flaps, once they come back and they send a database
> descriptor you will realize that you already have their LSAs in the
> database from before, and the only thing you need to do is update the
> neighbor as reachable and reset the age & checksum. Otherwise OSPF would
> have to go through full flooding every time there is a neighbor flap. If
> you wait an hour (MAXAGE) you will see the LSA eventually disappear.
> Normally only the originator of the LSA can prematurely flush the LSA out
> of the database by reflooding with MAXAGE, and if that router is cut off
> from the entire OSPF network it cannot flood, hence your case.
> >
> >
> > HTH,
> >
> > Brian McGahan, CCIE #8593 (R&S/SP/Security)
> > bmcgahan_at_INE.com
> >
> > Internetwork Expert, Inc.
> > http://www.INE.com
> >
> > -----Original Message-----
> > From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
> ccie99999
> > Sent: Thursday, December 13, 2012 5:56 AM
> > To: Cisco certification
> > Subject: OSPF ADV Router is not-reachable
> >
> > Hello friends,
> >
> > I'm working on OSPF in these days and I don't undertand this thing:
> >
> > I've a stable topology and I've one router (R3) that is my exit point
> for my nssa area..
> > R3 indeed is configured as nssa no-summary.
> > And in the routers in this area (it's area2) get him as only summary
> LSAs.
> >
> > Summary Net Link States (Area 2)
> >
> > Link ID ADV Router Age Seq# Checksum
> > 0.0.0.0 150.1.3.3 1091 0x80000001 0x00BED9
> >
> > If now I decide to kill R3 (shut all interfaces) and even do a clear of
> ospf process, I still see the summary in the ospf database.
> >
> > If then I check the LSA1 on in it I see ADV Router is not-reachable.
> >
> > Rack1SW1#show ip ospf database router 150.1.3.3
> >
> > Adv Router is not-reachable
> > LS age: 2292
> >
> > I don't understand the reason it's still there. Should't be flushed? and
> why by design it's not?
> >
> > thank you
> >
> >
> > --
> > @ccie99999
> >
> >
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-- 
Regards
Routing Freak CCIE#35889 (SPv3)
Blogs and organic groups at http://www.ccie.net