RE: [nsp] OSPF not distributing 1 interface

From: Chris Davis (chris.davis@computerjobs.com)
Date: Tue May 22 2001 - 13:04:59 EDT


I took the official Cisco BSCN training course last year, covering this
topic. The instructor explained that OSPF can be a bit kooky and won't
always pick up connected networks without the redistribute statement. He
didn't offer details as to why, but apparently it's common behavior.

-----Original Message-----
From: ken lindahl [mailto:lindahl@ack.Berkeley.EDU]
Sent: Tuesday, May 22, 2001 12:30 PM
To: cisco-nsp@puck.nether.net
Subject: RE: [nsp] OSPF not distributing 1 interface

i keep wondering what i'm missing. as i read it, the original report
states that the /30 ethernet between the two routers is in the ospf
area, but the /30 route does not appear in the route table. if the
/30 is in the ospf area, the /30 should appear in the routing table
by default; no redistribute statement should be necessary. the
discussion of redistribute seems to ignore that fundamental discrepency.

i think this is what Zaheer Aziz was getting at, and in addition to
the two diagnostic statement recommended by Zaheer:
>> > > sh ip route 10.0.16.30
>> > > sh ip ospf database router <router ID of R1>,
i suggest:
   sho ip ospf neighbor

i also think it would be helpful to see more of the router configurations,
since there is clearly something critical not being revealed.

ken

On Mon, 21 May 2001, George Robbins <grr@shandakor.tharsis.com> wrote:
>Right, but the bottom line is that "connected" and/or "static"
>routes don't become known to ospf until they're redistributed
>into ospf. Routes may heard over the interface once an adjacency
>is established, but in this case neither router is feeding any
>routes into ospf, so there's nothing to pass.
>
>Other routes may exsit in the environment beyond what are explictly
>in the configuration, PPP negotation may inject a /32 for the peer
>address, OSPF may create internal routes (this isn't clear) to
>adjacent neighbors.
>
>And the usuaul reminder with OPSF, add a loopback to the configuration
>for OSPF to pick up as the router-id or specifiy a router ID so that
>OSPF does not pick one at random.
>
> George
>
>> From cisco-nsp-request@puck.nether.net Mon May 21 22:01:31 2001
>> Resent-Date: Mon, 21 May 2001 22:01:19 -0400
>> Received-Date: Mon, 21 May 2001 21:55:36 -0400
>> X-Sender: zaziz@ce-nfs-1.cisco.com
>> Date: Mon, 21 May 2001 18:54:00 -0700
>> To: Charles Sprickman <spork@inch.com>
>> From: Zaheer Aziz <zaziz@cisco.com>
>> Subject: RE: [nsp] OSPF not distributing 1 interface
>> Cc: Barry Wright <Bwright@interland.com>,
>> "'Chris Davis'" <chris.davis@computerjobs.com>,
>> "'steven.godfrey@intechnology.co.uk'"
<steven.godfrey@intechnology.co.uk>,
>> <cisco-nsp@puck.nether.net>
>> In-Reply-To: <Pine.BSF.4.33.0105211929520.17664-100000@shell.inch.com>
>> References: <4.3.2.7.2.20010521155218.02ed3708@ce-nfs-1.cisco.com>
>> Resent-From: cisco-nsp@puck.nether.net
>> X-Mailing-List: <cisco-nsp@puck.nether.net> archive/latest/6376
>> X-Loop: cisco-nsp@puck.nether.net
>> Precedence: list
>> Resent-Sender: cisco-nsp-request@puck.nether.net
>>
>> At 07:31 PM 5/21/2001 -0400, Charles Sprickman wrote:
>> >On Mon, 21 May 2001, Zaheer Aziz wrote:
>> >
>> > > Steve,
>> > >
>> > > The redistribute trick will work, but question remains why the
network
>> > > statement under ospf is
>> > > not picking up this interface.
>> >
>> >I thought that the network statement was only to describe which
interfaces
>> >would be in the ospf area. Is this incorrect?
>>
>> It is correct but in addition it does a lot more
>> e.g.
>>
>> detects ospf neighbors on that interface
>> advertise the subnet of that interface via is Router Link State
>> advertisement (LSA)
>> exchange OSPF LSAs to the neighbors on that interface
>>
>> Zaheer
>>
>>
>> >Thanks,
>> >
>> >Charles
>> >
>> > > taking a look at database and routing table may be good start
>> > >
>> > > please provide
>> > >
>> > > sh ip route 10.0.16.30
>> > > sh ip ospf database router <router ID of R1>,
>> > >
>> > > repeat for R2
>> > >
>> > > It may have been the case that OSPF did not pick this interface by
mistake,
>> > > removing the network statement and
>> > > reinsertion may trigger it
>> > >
>> > > Hope this helps
>> > > Zaheer
>> > >
>> > >
>> > >
>> > > >-----Original Message-----
>> > > >From: Chris Davis [mailto:chris.davis@computerjobs.com]
>> > > >Sent: Monday, May 21, 2001 12:45 PM
>> > > >To: 'steven.godfrey@intechnology.co.uk'; cisco-nsp@puck.nether.net
>> > > >Subject: RE: [nsp] OSPF not distributing 1 interface
>> > > >
>> > > >
>> > > >Hello,
>> > > >
>> > > >Try "redistribute static subnets" under "router ospf 10"
>> > > >
>> > > >Chris Davis
>> > > >Site Engineer
>> > > >www.ComputerJobs.com
>> > > >Upgrade Your Future
>> > > >
>> > > >
>> > > >
>> > > >-----Original Message-----
>> > > >From: Freeserve (E-mail) [mailto:steve@godus.freeserve.co.uk]
>> > > >Sent: Monday, May 21, 2001 12:26 PM
>> > > >To: cisco-nsp@puck.nether.net
>> > > >Subject: [nsp] OSPF not distributing 1 interface
>> > > >
>> > > >
>> > > >Hi,
>> > > >I have a strange problem with OSPF.
>> > > >
>> > > >The config is a very simple one area, one network statement. I have
a /30
>> > > >joining to routers over Ethernet and basically neither of the
routers is
>> > > >redistributing this connected link into OPSF?
>> > > >
>> > > >The 2 routers have other connections in the same network range and
>> > these are
>> > > >being redistributed ok to the other 10 routers on the network?
>> > > >
>> > > >If anyone has any ideas I would appreciate it.
>> > > >
>> > > >Here is the config:
>> > > >
>> > > >ROUTER 1:
>> > > >
>> > > >interface FastEthernet0/0
>> > > > description ******* HG1-PE4 ********
>> > > > ip address 10.0.16.30 255.255.255.252
>> > > > ip ospf cost 5
>> > > > duplex auto
>> > > > speed auto
>> > > > tag-switching mtu 1600
>> > > > tag-switching ip
>> > > > no cdp enable
>> > > >
>> > > >router ospf 10
>> > > > log-adjacency-changes
>> > > > network 10.0.0.0 0.255.255.255 area 0.0.0.0
>> > > >
>> > > >
>> > > >ROUTER 2:
>> > > >
>> > > >interface FastEthernet2/1
>> > > > description ****** HG1-PE5 ******
>> > > > ip address 10.0.16.29 255.255.255.252
>> > > > ip ospf cost 5
>> > > > duplex auto
>> > > > speed auto
>> > > > tag-switching mtu 1600
>> > > > tag-switching ip
>> > > >
>> > > >router ospf 10
>> > > > log-adjacency-changes
>> > > > passive-interface Serial3/0.2
>> > > > network 10.0.0.0 0.255.255.255 area 0.0.0.0
>> > > >
>> > > >Thanks in advance
>> > > >
>> > > >Steve.
>> > >
>>
>>
>
>



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