When you create summary routes in OSPF by default it will also create summary route to null 0 interface to prevent routing loop.Now in the lab they have issued no-discard-route command on R4 so it will not create summary route to null 0 interface and so that way nasty routing loop is created in this trouble ticket.Basically discard-route is feature in ospf . Its not external or internal routes and by turning off this feature in trouble ticket they have created routing loop. Hope this will help you.... Onceyou understand this you have 2-3 different ways to resolve this TT which explained in DSG very well
Thanks. Nilesh On Sun, Apr 10, 2011 at 10:09 AM, Cedric King <[email protected]> wrote: > The lab is based off of trouble ticket # 2... > > We have lost reachability to R5 @ 150.100.42.5 ......... > > The R4 is missing one command.. discard route under the process but the > configs > doesn't state wether its for internal or external routes.. Just to need to > know > which one we are looking for ? > > > > ________________________________ > From: Roy Waterman <[email protected]> > To: Cedric King <[email protected]> > Cc: "[email protected]" <[email protected]> > Sent: Sun, April 10, 2011 10:13:27 AM > Subject: Re: [OSL | CCIE_RS] Lab 1 vl 3 > > Hi Cedric > > I don't have the lab to hand but does the lab require summarisation of > inter > area or external routes or both? > > Sent from my iPad > > On 10 Apr 2011, at 02:46, Cedric King <[email protected]> wrote: > > > Hi Gang, > > > > I'm going through Vl3 lab 1 and I noticed that the OSPF config for the R4 > >router > > > > says [no discard-route]... This command is being rejected by my routers > due to > > > the missing last entry... is it for internal or external routes ? > > > > v/r > > > > Cedric (future Shogun) > > > > > > > > _______________________________________________ > > For more information regarding industry leading CCIE Lab training, please > visit > >www.ipexpert.com > > > > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
