From: Richardson, Cheryl (cheryl.richardson@xxxxxxxx)
Date: Sun Dec 12 1999 - 22:48:33 GMT-3
Yes, that would work. But, as usual, statics are not allowed in this
scenario.
Thanks --
Cheryl
> -----Original Message-----
> From: Cesar Obediente [SMTP:cobedien@yahoo.com]
> Sent: Sunday, December 12, 1999 8:36 PM
> To: Richardson, Cheryl; 'ccielab@groupstudy.com';
> 'cisco-cert@cciecert.com'
> Subject: RE: [sc] Classic FLSM -> VLSM issue
>
> If you are redistributing from VLSM to FLSM the way to
> do it is to redistribute static. For example
>
> Ospf is 28 and Rip is 24 You need to create do this:
> ip route x.x.x.x / 24 Null 0
> and then redistribute static
>
> You need / 24 since that is your network (RIP or IGRP)
> which don't understand VLSM.
>
> Let me know if you have any more questions
>
> Cesar
>
>
> --- "Richardson, Cheryl" <cheryl.richardson@lmco.com>
> wrote:
> > Right after my last note, I tried a "just to see"
> > reboot and then "summary
> > address" out of desperation. And
> > even though it was against everything I have read
> > and was taught, it worked.
> >
> > I took Caslow's ECP1 course back a few months ago
> > and we studied the OSPF to
> > IGRP topic. I learned
> > four things:
> > 1) "area range" went on ABRs to summarize within
> > OSPF between areas
> > 2) "summary address" went on ASBR to summarize
> > routes from other protocols
> > upon
> > redistribution INTO OSPF.
> > 3) The only other way to fix the VLSM issue was to
> > use "ip default-network".
> >
> > 4) If "summary address" worked on a redistribution
> > FROM OSPF into another
> > protocol, it was a fluke.
> >
> > Caslow's BRS book example actually shows
> > redistributing from IGRP into OSPF.
> > And, the Cisco documentation
> > explicitely states about the "summary address"
> > command..
> >
> > "For OSPF, this command summarizes only routes from
> > other routing protocols
> > that are being redistributed
> > into OSPF"
> >
> > Obviously, #4 worked for me. So, during the exam, I
> > suppose you should just
> > go for the one that seems to
> > work? I still have doubts. Anyone care to comment?
> >
> > Also, I do not have the Little Black book that was
> > referenced. Could you
> > provide a quote regarding the subject?
> >
> > Thanks --
> >
> > > -----Original Message-----
> > > From: pkm@calweb.com [SMTP:pkm@calweb.com]
> > > Sent: Sunday, December 12, 1999 4:55 PM
> > > To: Richardson, Cheryl
> > > Subject: Re: [sc] Classic FLSM -> VLSM issue
> > >
> > > No problem. Use on the OSPF ASBR router, the
> > command summary-address. This
> > > will
> > > summarize your vlsm to whatever subnet mask you
> > are using inside your IGRP
> > > domain. The other command area range is a good
> > command but does not apply
> > > to
> > > this kind of scenario. By the way, avoid routing
> > loops by using a
> > > distribute-list command in the ospf routing
> > domain.
> > >
> > > Reference used: Calsow book and specifically Cisco
> > Routers for IP Routing
> > > (Little Black Book) by Innokenty Rudenko, CCIE
> > page 340-341. Here is the
> > > config:
> > >
> > > interface loopback0
> > > ip add 10.10.0.2 255.255.255.255.255
> > >
> > > int ethernet0
> > > ip add 10.10.2.1 255.255.255.
> > >
> > > int serial 0
> > > ip add 10.204.0.1 255.255.10 255.255.255.252
> > >
> > > router ospf 10
> > > summary-address 10.10.0.0 255.255.0.0
> > > redistribute igrp 10 metric 10 subnets
> > > network 10.10.0.0 0.0.0255.255 area 10
> > > distribute-list 10 out igrp 10
> > >
> > > router igrp 10
> > > redistribute ospf 10 metric 10000 1 255 1 1500
> > > pass-int ethernet0
> > > pass-int loopback0
> > > pass-int serial1
> > > network 10.0.0.0
> > >
> > > ip classless
> > >
> > > access-list 10 deny 10.10.0.0 0.0.255.255
> > > access-list 10 permy any
> > >
> > > Here is another good link for RIP and OSPF redist.
> > >
> > > Have fun.
> > >
> > > Phillip Moulay
> > > Future CCIE (Lab. in Dec. 16 an Dec. 17)
> > >
> > > "Richardson, Cheryl" wrote:
> > >
> > > > I know it is hard to see without seeing the
> > configs. Actually, "ip
> > > > classless" is one of the first things
> > > > I configure, in addition to "no ip
> > domain-lookup", etc. Everything
> > > works
> > > > fine with a default route and
> > > > subnets that are not in my routing table but
> > part of the class of
> > > network
> > > > that I know of still take the
> > > > default route. (normal "ip classless" behavior).
> > But, when I configure
> > > an
> > > > aggregate address under
> > > > BGP, I end up with a supernet route to null0.
> > Now subnets that are not
> > > in
> > > > my routing table but
> > > > part of the supernet route go to null0. I
> > consider this normal
> > > behavior,
> > > > just the wrong approach on
> > > > my part.
> > > >
> > > > This is what makes me think that I should have
> > taken the area-range
> > > > approach. But I still can't
> > > > get VLSM routes to summarize within the backbone
> > area 0.
> > > >
> > > > I also tried Brian's approach of placing the
> > area range commands on each
> > > > router within area 0
> > > > (even though I thought the command only applied
> > to the ABRs) and it
> > > still
> > > > didn't work for me.
> > > > Has anyone actually seen this work, and possibly
> > have working configs?
> > > >
> > > > Thanks --
> > > > Cheryl Richardson
> > > >
> > > > > -----Original Message-----
> > > > > From: Mark Adams [SMTP:adamsmw@earthlink.net]
> > > > > Sent: Sunday, December 12, 1999 1:37 PM
> > > > > To: Richardson, Cheryl
> > > > > Subject: Re: [sc] Classic FLSM -> VLSM
> > issue
> > > > >
> > > > > Now, my route table has a supernet and
> > sends all pings for the
> > > > > "unknown" VLSM subnets to the bit bucket
> > (instead of taking my default
> > > > > route). This would imply that I made the
> > wrong choice.
> > > > >
> > > > > I'm not an expert at this, but this sounds
> > like a side effect of a <no
> > > IP
> > > > > Classless> configuration. The default setting
> > of IP Classless depends
> > > on
> > > > > IOS version, so I'd start here.
> > > > >
> > > > >
> > > > > "Richardson, Cheryl" wrote:
> > > > >
> > > > > Has anyone run into the following:
> > > > >
> > > > > OSPF with VLSM subnets with mutual
> > redistribution to IGRP. How
> > > do
> > > > > you get
> > > > > the IGRP router to
> > > > > recognize the VLSM subnets?
> > > > >
> > > > > My thoughts were that there were two
> > choices:
> > > > > 1) Either "area range" the VLSM nets so
> > that they are /24 when
> > > they
> > > > > hit
> > > > > IGRP.. or
> > > > > 2) Do the "ip default-network" thing
> > > > >
> > > > > Since I had /28 subnets in area 0 (which
> > is where the redist
> > > occurs)
> > > > > and did
> > > > > not feel that area 0 routes could be
> > > > > summarized and effect IGRP (I know that
> > the summaries could
> > > apply to
> >
> === message truncated ===
>
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