From: David Luu (wicked01@xxxxxxxxxxxxx)
Date: Thu May 09 2002 - 20:12:04 GMT-3
in OSPF, each router has a link state database so it knows of all paths and
doesnt have the need for split horizon
At 06:40 AM 5/10/2002 +0900, Jenkins, Buddy wrote:
>Read Doyle Chapter 11. Read the questions at the end of the
>chapter. RIP/IGRP use split horizon. OSPF does not. That is the only
>documented explanation I can find. Instead of saying "I think" or "I
>guess" can someone come up with some more documented references for this
>type of redistribution behavior.
>
>Buddy
>
>-----Original Message-----
>From: Kirby, Ron [mailto:Ron.Kirby@getronics.com]
>Sent: Friday, May 10, 2002 5:16 AM
>To: David Luu; Joe Higgins; ying chang
>Cc: ccielab@groupstudy.com
>Subject: RE: Redistribute ospf external route into igrp
>
>
>I had a lab setup yesterday in which I had a similar situation, but
>instead of igrp running on the router it was rip. Rip did not
>redistribute the connected. I will test some more.....
>
>Ron Kirby
>Network Engineer
>ICTC Engineering
>
>Getronics Infrastructure Solutions
>9009 West Loop South
>Houston, Texas 77096
>713-852-5567
>832-256-5403
>www.getronics.com/us
>
>
>The information transmitted is intended only for use by the addressee and
>may contain confidential and/or privileged material. Any review,
>re-transmission, dissemination or other use of it, or the taking of any
>action in reliance upon this information by persons and/or entities other
>than the intended recipient is prohibited. If you received this in error,
>please inform the sender and/or addressee immediately and delete the
>material. Thank you.
>
>
>
>-----Original Message-----
>From: David Luu [mailto:wicked01@ix.netcom.com]
>Sent: Thursday, May 09, 2002 3:06 PM
>To: Kirby, Ron; Joe Higgins; ying chang
>Cc: ccielab@groupstudy.com
>Subject: RE: Redistribute ospf external route into igrp
>
>
>igrp knows of the 2 other interfaces, so when you redistribute to ospf it
>will know the networks as well and will appear in the routing table as O E1
>or O E2 depending on which metric-type you are using
>
>At 09:32 AM 5/9/2002 -0500, Kirby, Ron wrote:
> >I have a lab from solie setup (darth reid) and I have igrp running on r1
> >and ospf configured only on the serial and dialer interface. The
> >133.10.0.0 address in igrp covers two other interfaces on that router that
> >are not in the ospf process, and they are in the route table as
> >connected. Yet, when I redistribute igrp into ospf, those connected
> >routes show up in the table of other ospf routers. I thought they would
> >not, but they are????
> >
> >Ron Kirby
> >Network Engineer
> >ICTC Engineering
> >
> >Getronics Infrastructure Solutions
> >9009 West Loop South
> >Houston, Texas 77096
> >713-852-5567
> >832-256-5403
> >www.getronics.com/us
> >
> >
> >The information transmitted is intended only for use by the addressee and
> >may contain confidential and/or privileged material. Any review,
> >re-transmission, dissemination or other use of it, or the taking of any
> >action in reliance upon this information by persons and/or entities other
> >than the intended recipient is prohibited. If you received this in error,
> >please inform the sender and/or addressee immediately and delete the
> >material. Thank you.
> >
> >
> >
> >-----Original Message-----
> >From: Joe Higgins [mailto:netsat@optonline.net]
> >Sent: Thursday, May 09, 2002 9:02 AM
> >To: ying chang
> >Cc: ccielab@groupstudy.com
> >Subject: Re: Redistribute ospf external route into igrp
> >
> >
> >The way that redistribution appears to work to me is as follows.
> >For example if you are redistributing ospf into igrp then on the
> >redistribution
> >router the IOS looks in its ip routing table and redistributes any
> routes that
> >begin with an O in front of it into the igrp process. If you are
> >redistributing
> >rip into igrp it looks in its routing table and redistributes into igrp any
> >routes with an R in front of it. The reason that connected routes in
> the ospf
> >database and the rip process do not get redistributed into igrp is because
> >they
> >have a C (connected) in front of them in the routing table on the
> >redistribution
> >router. The rule that I use is that if it has a C in front, it is not
> >going to
> >be redistributed unless you redistribute connected. I welcome any
> comments to
> >the contrary.
> >
> >ying chang wrote:
> >
> > > Sorry, found a few mistakes from my post below, but the basic concept
> > > presented is correct. In short, an external route will not get
> > redistributed
> > > if it's also an internal route or a local routing process.
> > >
> > > Chang
> > >
> > > >From: "ying chang" <ying_c@hotmail.com>
> > > >Reply-To: "ying chang" <ying_c@hotmail.com>
> > > >To: ccielab@groupstudy.com
> > > >Subject: RE: Redistribute ospf external route into igrp
> > > >Date: Thu, 09 May 2002 00:32:51 -0400
> > > >
> > > >After went through a few tests, I don't think the issue is not on
> > > >split-horizon but on whose route is more trustworthy:
> > > >
> > > >Since mutual redistribution is always causing confusion, and this
> problem
> > > >can be simulated without mutual redistribution, so I set up an
> environment
> > > >like the following:
> > > >
> > > > R4<--igrp---R3<---rip---R5--172.16.155.0/24
> > > > |
> > > > ospf
> > > > |
> > > > R1<--rip----R2--172.16.125.0/24
> > > >
> > > >and below is what I got:
> > > >
> > > >Two external routes in R3:
> > > >
> > > >r3#sio d | b -5 <<<- both 125.0/24 and 155.0/24 are in ospf external db
> > > > Type-5 AS External Link States
> > > >
> > > >Link ID ADV Router Age Seq# Checksum Tag
> > > >172.16.125.0 172.16.200.1 48 0x80000001 0xC013 12
> > > >172.16.155.0 172.16.146.1 610 0x80000002 0x8E45 35
> > > >
> > > >Only 172.16.155.0 is redistributed into igrp:
> > > >
> > > >r3#debug ip igrp tra <<<--sending 125.0/24 but not 155.0/24
> > > >IGRP protocol debugging is on
> > > >r3#
> > > >13:28:22: IGRP: sending update to 255.255.255.255 via Ethernet0
> > > >(172.16.52.3)
> > > >13:28:22: subnet 172.16.144.0, metric=501
> > > >13:28:22: subnet 172.16.145.0, metric=501
> > > >13:28:22: subnet 172.16.146.0, metric=501
> > > >13:28:22: subnet 172.16.53.0, metric=1100
> > > >13:28:22: subnet 172.16.10.0, metric=8476
> > > >13:28:22: subnet 172.16.125.0, metric=158250 <<<<----
> > > >r3#
> > > >r3#sh ip rip data <<<- r3 has 155.0/24 but not 125.0/24
> > > >172.16.0.0/16 auto-summary
> > > >172.16.145.0/24 directly connected, Loopback1
> > > >...
> > > >172.16.149.0/24
> > > > [1] via 172.16.10.1, 00:00:08, Serial0
> > > >172.16.155.0/24 <<<<------
> > > > [1] via 172.16.53.1, 00:00:09, Ethernet1
> > > >...
> > > >r3#
> > > >
> > > >I think the reason 172.16.155.0/24 was not sending to IGRP is
> because from
> > > >R3's point of view, 172.16.155.0/24 is in its rip database (know it by
> > > >first
> > > >hand), it also knows 172.16.155.0/24 is in ospf - but that's learn from
> > > >some
> > > >other protocol (second hand stuff), so the route is not cannot be
> trusted,
> > > >and that's why when you redistribute ospf into igrp, you only see
> R1's rip
> > > >routes but not R4's rip routes. 172.16.125.0/24 did not have this
> problem,
> > > >because it's not in R3's local rip database.
> > > >
> > > >The moral for this problem: when you run more than two protocols in a
> > > >router
> > > >like this, not only you have to redistribute ospf into igrp, you
> also need
> > > >to redistribute directly connected rip routes into igrp.
> > > >
> > > >Chang
> > > >
> > > >>From: "Jenkins, Buddy" <buddy.jenkins@csfb.com>
> > > >>Reply-To: "Jenkins, Buddy" <buddy.jenkins@csfb.com>
> > > >>To: ccielab@groupstudy.com
> > > >>Subject: RE: Redistribute ospf external route into igrp
> > > >>Date: Thu, 9 May 2002 07:25:00 +0900
> > > >>
> > > >>Jeff,
> > > >>
> > > >>Refer to Doyle Volume1 Chapter 11 on redistribution. In the
> questions at
> > > >>the end of the chapter there is a question (I don't have the book
> with me
> > > >>right now so I can't tell you the specific question) that has the same
> > > >>scenario that you have. Doyle says that the reason for that type of
> > > >>behaviour is because of the rule of split horizon. This makes
> sense for
> > > >>you scanario below because IGRP would use split horizon and OSPF
> does not
> > > >>use split horizon. However this is the part that still confuses
> > me. I do
> > > >>not know why split horizon is applied to a redistribution process. I
> > > >>always though split horizon was implemented to not advertise a
> route out
> > > >>an
> > > >>interface from which that route was learned. Can any of the guru's out
> > > >>there explain why split horizon is applied during mutual
> redistribution?
> > > >>
> > > >>Buddy
> > > >>
> > > >>-----Original Message-----
> > > >>From: Jeff Szeto [mailto:jytszeto@hotmail.com]
> > > >>Sent: Wednesday, May 08, 2002 5:20 PM
> > > >>To: ccielab@groupstudy.com
> > > >>Subject: Redistribute ospf external route into igrp
> > > >>
> > > >>
> > > >>Hi,
> > > >>
> > > >>A router runs IGRP, OSPF and RIP. Mutual redistribution exist between
> > > >>OSPF---RIP and OSPF---IGRP. But no redistribution between IGRP and
> RIP.
> > > >>From the debug message I found that IGRP is no advertising the RIP
> routes
> > > >>that are redistributed into OSPF while the OSPF routes are advertised
> > > >>normally.
> > > >>On the other hand, the IGRP routes are advertised into RIP through
> OSPF.
> > > >>
> > > >>Could someone explain the concept behind or point me to a document.
> > > >>
> > > >>Thanks in advance.
> > > >>
> > > >>Jeff
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 10:58:54 GMT-3