From: Jim Graves (jtg@xxxxxxxxxx)
Date: Mon Apr 30 2001 - 10:35:39 GMT-3
What? Do things the wy they're intended to be used? That doesn't sound
very relevant to the CCIE test. :)
I'm curious, though, how you'd get the OSPF network into the IGRP process
in this configuration:
r1
|
| 172.16.12.0/24 - IGRP
|
r2
|
| 172.16.23.0/27 - OSPF area 0
|
r3
How do you make r1 see the 172.16.23.0 network?
At 07:41 AM 4/30/2001 -0500, jim.fitzpatrick@verizon.com wrote:
>I have just been reading this thread and it appears to me that you may be
>trying to use the OSPF 'summary-address' command in the wrong context. This
>command is for summarizing routes as they go IN to OSPF. If you are trying to
>summarize routes for redistribution this should be done on an ABR not the
>ASBR. To get the OSPF routes into IGRP summarize them to a classfull boundary
>on an ABR and then redistribute into IGRP on the ASBR.
>
>Jim
>---------- Original Text ----------
>
>From: "Mas Kato" <tealp729@home.com>, on 4/30/2001 2:00 AM:
>
>Russ,
>
>Thanks, I took it for granted that mutual redistribution was part of the
>deal. What's got me in stitches after reading about your findings is
>I -couldn't- get it to work with my directly connected OSPF subnet.
>
>All my summary would ever look like is this one from your OSPF process
>200:
>
>170.10.13.0/255.255.255.128 Metric 16777215, Type 0, Tag 0
>
>...with that peculiar metric; The only difference being I was trying to
>summarize a directly-connected OSPF /28 route into an IGRP /24 AS. 'show
>ip protocols' would indicate that address summarization was taking place
>in my OSPF process, but the field that would indicate "for which
>networks" would be blank.
>
>The only way I ever got the OSPF 'summary-address' command to work was
>by employing it exactly as it is documented. I redistributed a /30 from
>an EIGRP AS on the other side of the network. One philosophy, I'm told,
>is to preserve the specificity of the route as long as possible, so I
>tried to summarize the route at the OSPF/IGRP ASBR. Nope. I had to place
>the command exactly where the docs say to place it--at the ASBR
>redistributing the route in.
>
>I've long since moved on to other topics, uneasily writing this one off
>as bug that may be exploited perhaps in earlier or different builds of
>the IOS (I'm running 12.1(7)). I'm just going to have to find a way to
>work-around it and defend my tactics if I get dealt a situation that
>calls for it in the lab. My uneasiness has only grown after wrestling
>with glitches in other areas as well--like the whole DDR mess,
>NLSP-to-IPX EIGRP aggregate route redistribution, DLSW filtering logic,
>etc.--because of things like this, I'm grateful this group exists!!
>
>Mas
>
>-----Original Message-----
>From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
>Russell Lusignan
>Sent: Sunday, April 29, 2001 8:16 PM
>To: 'ccielab@groupstudy.com'
>Subject: RE: OSPF summar-address into IGRP
>
>
>Mas,
>
>This one is worrying me quite a bit to.. I have done quite a bit of
>fooling
>around since I got it working.. Here is some of the stuff I have
>figured
>out. Feel free to make comments on it (everyone):
>
>- The summary-address command wasn't giving me null0 routes in the ospf
>routing table until I did a "redistribute.. " command in the ospf
>process.
>So basically, unless I did mutual redistribution between ospf/igrp, the
>summary-address trick of getting routes into IGRP didn't work.
>
>- It appeard that only directly connected subnets summarized by the
>summary-address command on the ASBR were being redistributed
>successfully
>into IGRP, again only if mutual redist was configured.
>
>- So, mutual redistribute, what would happen if I did mutual
>redistribution
>between a separate OSPF process and IGRP? I added another ospf process,
>here
>is the basic config:
>
>route ospf 100
> router-id 170.12.1.1
> area 0 authentication message-digest
> network 170.10.1.0 0.0.0.255 area 0
> network 170.10.12.0 0.0.0.15 area 0
>!
>router ospf 200
> summary-address 170.10.24.0 255.255.255.128
> summary-address 170.10.12.0 255.255.255.128
> summary-address 170.10.13.0 255.255.255.128
> summary-address 170.10.16.0 255.255.255.128
> summary-address 170.10.17.0 255.255.255.128
> summary-address 170.10.18.0 255.255.255.128
> summary-address 170.10.19.0 255.255.255.128
> summary-address 170.10.24.128 255.255.255.128
> redist ospf 100 subnets
> passive-interface ethernet0
> passive-interface serial0
>!
>router igrp 50
> redistribute ospf 200
> network 170.10.0.0
> default-metric 10000 1000 255 1 1500
>
>The idea behind this config is to redistribute routes learned through
>OSPF
>100 into OSPF 200. OSPF 200 summarizes all of the routes to /25 which
>is
>the mask used on the IGRP interfaces. Now, from everything I have read
>in
>the list and on Cisco's site and talked about with others, the
>summary-addresses should summarize all of the routes learned from OSPF
>100
>into /25 which should then redistribute succesfully into IGRP. Only 4
>of
>the routes summarized appeared in IGRP, so I figured that it must be a
>metric/metric-type thing.. maybe that only inter-area routes were being
>successfully redistributed into IGRP, so I checked the summary-address
>table
>on ospf process 200.. Here is what it looked like:
>
>R1#sh ip ospf 200 summary-address
>
>OSPF Process 200, Summary-address
>
>170.10.24.0/255.255.255.128 Metric 138, Type 2, Tag 0
>170.10.12.0/255.255.255.128 Metric 20, Type 2, Tag 0
>170.10.13.0/255.255.255.128 Metric 16777215, Type 0, Tag 0
>170.10.16.0/255.255.255.128 Metric 148, Type 2, Tag 0
>170.10.17.0/255.255.255.128 Metric 148, Type 2, Tag 0
>170.10.18.0/255.255.255.128 Metric 148, Type 2, Tag 0
>170.10.19.0/255.255.255.128 Metric 148, Type 2, Tag 0
>170.10.24.128/255.255.255.128 Metric 129, Type 2, Tag 0
>
>The freaky thing is that only 170.10.24.0/25, 170.10.24.128/25, and
>170.10.12.0/25 appeared in the IGRP routing table on R8. I can't figure
>out
>what the common thing is with only those routes.
>
>I have tried this many ways.. not once have I felt comfortable that
>this
>will work if I do it from scratch, or if I reboot the router. So
>basically
>if I get this sort of problem in my lab (which I probably will), I will
>cross my fingers and hope it works.
>
>There is no technical explanation that I can find or make that explains
>the
>behaviour of IGRP. And the kicker is, if I just add null0 routes on the
>ASBR with a /25 mask it redistributes no problem. I hate IGRP.
>
>-Russ
>
> > -----Original Message-----
> > From: Mas Kato [mailto:tealp729@home.com]
> > Sent: Sunday, April 29, 2001 9:07 PM
> > To: 'Russell Lusignan'; ccielab@groupstudy.com
> > Subject: RE: OSPF summar-address into IGRP
> >
> >
> > Russ,
> >
> > Allow me to kick the corpse a little... I have not been able
> > to get this
> > scenario to work, at least with 12.x. I could never get a
> > null0 route to
> > install on its own when the summary's major network was the same as my
> > OSPF network and where its mask matched my interface leading out of
> > OSPF. 'show ip ospf summary' would show the summary with a very high
> > metric--apparently unreachable.
> >
> > I'm sure your research has revealed that the documentation doesn't
> > support this scenario and that the, uh, "official" way to do
> > this is to
> > either install a static summary route to null0 or source a default
> > route.
> >
> > I'm so concerned with the possibility of having to defend situations
> > like this during the lab exam, I recently wrote to the CCIE program
> > about it. I asked point blank whether we could be asked to exploit
> > undocumented "features" of IOS behavior. We all know how porous the
> > documentation is--we'll see...
> >
> > So how on Earth did you finally get it to work? Does it
> > survive reboots
> > and such?
> >
> > Regards,
> >
> > Mas Kato
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> > Russell Lusignan
> > Sent: Sunday, April 29, 2001 3:48 PM
> > To: 'ccielab@groupstudy.com'
> > Subject: RE: OSPF summar-address into IGRP
> >
> >
> > Ummm... I spent a few days trying to figure this one out to no avail,
> > as
> > soon as I post to this list my problem, it works. So, by adding the
> > "summary-address 170.10.12.0 255.255.255.128" to R1, that subnet now
> > shows
> > up on R8. Weird. So for anyone reading my previous post about this
> > problem, don't worry about it :)
> >
> > Too bad we don't have the ability to post to this list while doing the
> > actual lab :)
> >
> > sorry
> > -Russ
> >
> >
> >
> > > -----Original Message-----
> > > From: Russell Lusignan [mailto:rlusignan@birdonawire.com]
> > > Sent: Sunday, April 29, 2001 5:08 PM
> > > To: 'ccielab@groupstudy.com'
> > > Subject: OSPF summar-address into IGRP
> > >
> > >
> > > Hey group,
> > >
> > > This topic has been beaten to death, but I haven't be able to
> > > find anything
> > > in the archives on what is happening.
> > >
> > > OSPF IGRP
> > > ------------------R1-------------------R8
> > > 170.10.12.0/28 170.10.20.0/25
> > >
> > > I want the /28 to redistribute into IGRP, I know R1 won't
> > advertise it
> > > because it's not a /25. I have ready many posts about
> > people using a
> > > summary-address on R1 to summarize the /28 into a /25. This
> > > does not work
> > > for me. On R1, if I do "summary-address 170.10.12.0
> > 255.255.255.128"
> > > shouldn't that be enough to get that /28 into IGRP as a /25?
> > > This works if
> > > I place a null0 route on R1 with a /25 manually, and I have
> > > managed to get a
> > > default-network to R8, but if these are not permitted on the
> > > lab, I am not
> > > sure how else to do it.
> > >
> > > I recall reading a post a while back where someone mentioned
> > > that when you
> > > create a summary-address in ospf it should automatically
> > > create a null0
> > > route to that subnet, I know EIGRP does this, but wasn't
> > > aware that ospf did
> > > it. When I do create a summary-address there is no null0
> > > route created with
> > > OSPF...
> > >
> > > -Russ
> > > **Please read:http://www.groupstudy.com/list/posting.html
> > **Please read:http://www.groupstudy.com/list/posting.html
>**Please read:http://www.groupstudy.com/list/posting.html
>**Please read:http://www.groupstudy.com/list/posting.html
>**Please read:http://www.groupstudy.com/list/posting.html
**Please read:http://www.groupstudy.com/list/posting.html
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 10:30:02 GMT-3