From: Ludwig A. Morales (morales_l@xxxxxxxxxxx)
Date: Sun May 19 2002 - 10:34:14 GMT-3
Unless all my router has bugs on the IOS the summary address command *DOES
NOTHING* to summarize outgoing advertisements, if any one have a working
config with these pleases post it to prove-test this.
Now, how would I use a second ospf process? do I create a second process
and redistribute my original ospf, use summary address here and redistribute
this one to igrp, or do I run the network I want to summarize in a second
process, summarize it under my original process. please post an example if
anyone have it.
Regards,
Ludwig----- Original Message -----
From: "David Luu" <wicked01@ix.netcom.com>
To: "Jonathan Hays" <jhays@jtan.com>; <ccielab@groupstudy.com>
Sent: Sunday, May 19, 2002 3:50 AM
Subject: RE: FATKID 502 Expert Redistribution
> i did some testing out of curiosity, and the summary-address will be
> advertised out of ospf with or without the 2nd ospf process...so i retract
> the statement below...however i couldnt get it to ping across, buts its
> probably some human error on my end...i will do some more testing to get
> the ping to work...
>
> learning something new everyday
>
> At 11:51 PM 5/18/2002 -0700, David Luu wrote:
> >summary-address summarizes going into ospf, not out
> >
> >if you looked at his config, the 135.1.20.0/22 subnet originated in ospf,
> >so the summary-address would not be advertised to igrp
> >
> >since R4 is an ASBR, you need to summarize to a /24 by creating a second
> >ospf process and redistributing it into and using the summary-address
> >command on the first process
> >
> >
> >At 11:13 PM 5/18/2002 -0700, Jonathan Hays wrote:
> >>Yes - I know what you are thinking - this:
> >>
> >>http://www.cisco.com/warp/public/104/3.html#12.0
> >>
> >>"External Route Summarization
> >>
> >>External route summarization is specific to external routes that are
> >>injected into OSPF via redistribution. Also, make sure that external
> >>ranges that are being summarized are contiguous. Summarization
> >>overlapping ranges from two different routers could cause packets to be
> >>sent to the wrong destination. Summarization is done via the following
> >>router ospf subcommand:
> >>
> >> summary-address ip-address mask
> >>
> >>This command is effective only on ASBRs doing redistribution into OSPF."
> >>---
> >>The above CCO verbiage WOULD seem to indicate that the command is
> >>effective only one way. However, don't forget, this is an ASBR which
> >>also has the duty to tell external networks about what routes are
> >>available in the OSPF cloud.
> >>
> >>The configuration you gave is only the part where IGRP is redistributed
> >>into OSPF:
> >>
> >>router ospf 100
> >> router-id 4.4.4.4
> >> log-adjacency-changes
> >> summary-address 135.1.20.0 255.255.255.0
> >> redistribute igrp 100 subnets
> >>
> >>I haven't seen the write-up in question, but you are correct that the
> >>above configuration by itself does nothing to redistribute routes into
> >>IGRP. To do that statements like the ones below are needed:
> >>
> >>router igrp
> >> redistribute ospf 100 metric 10000 2000 255 1 1500 subnets
> >>
> >>And the trick here, is that since the 135.1.20.0/22 network has been
> >>summarized in OSPF as a /24, then *that* /24 is what gets redistributed
> >>into IGRP. This "trick" is necessary because IGRP won't understand the
> >>classless subnets. Essentially, you are using the OSPF ASBR's summary
> >>network statement to "adjust" the mask of OSPF classless networks to
> >>something that IGRP will understand.
> >>
> >>HTH,
> >>
> >>Jonathan
> >>
> >>
> >>-----Original Message-----
> >>From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> >>Todd Spencer
> >>Sent: Saturday, May 18, 2002 4:54 PM
> >>To: ccielab@groupstudy.com
> >>Subject: FATKID 502 Expert Redistribution
> >>
> >>
> >>I am trying to do the FatKid 502 Expert Redistribution
> >>Lab, and I don't understand the solution provided. I
> >>will try to briefly explain.
> >>
> >>The problem has to do with the classic VLSM to FLSM
> >>problem (IGRP/OSPF). The lab requires that OSPF area
> >>4 be configured with a /22 subnet, and the IGRP domain
> >>be configured with a /24. OSPF area 4 is using the
> >>following subnet 135.1.20.x/22 and the IGRP domain is
> >>using 135.1.1.x/24. The OSPF configuration below is
> >>taken from the solution:
> >>
> >>router ospf 1
> >> summary-address 135.1.20.0 255.255.255.0
> >> redistribute igrp 1 subnets
> >> network 135.1.14.0 0.0.0.255 area 4
> >> network 135.1.20.0 0.0.3.255 area 4
> >>
> >>I am unsure what the summary-address command is doing
> >>in this configuration. How is it able to summarize a
> >>/22 into a /24? How is the /22 subnet getting into
> >>the IGRP domain? If anyone has done this lab and can
> >>provide assistance, it would be greatly appreciated.
> >>
> >>-Todd
> >>
> >>
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