From: alsontra@hotmail.com
Date: Tue Feb 24 2004 - 12:50:13 GMT-3
Chirs,
I "labed up" all of the possible scenarios to really understand
what enabling manual distribution does to a routing protocol. I now find
that I try not redistribute connected interfaces. That is, if its not
required. If you have both options available which method would you use?
Redistribute connected
Advertising into a protocol using net statements
Using redistribute connected seems to be problematic.
Alsontra
----- Original Message -----
From: "christopher snow" <cbsnow31@yahoo.com>
To: "Karim" <karim_ccie@hotmail.com>
Cc: <ccielab@groupstudy.com>
Sent: Tuesday, February 24, 2004 5:18 AM
Subject: Re: Redistrbute Connected breaks other igp connected routes on the
same router
> That is correct. The only protocol that behaves
> differently is ISIS. ISIS will not advertise a
> connected network unless told to do so. BGP does not
> route per say like OSPF. It simply advertises
> reachability and does not have a default behavior like
> an interior routing protocol.
>
> Chris
>
>
> --- Karim <karim_ccie@hotmail.com> wrote:
> > Hi all,
> >
> > From the posts that was sent about this issue from
> > Michael, Chris and
> > Alsontra, I can get the following but I need you to
> > correct me if I am
> > wrong:
> > - When redistributing from RIP into OSPF, both the
> > existing RIP routes in
> > the routing table and connected interface with RIP
> > network command will be
> > redistributed into OSPF.
> > - Whenever I add a redistribute connected with a
> > route map to the OSPF
> > process, this will stop redistributing the RIP
> > connected interfaces into
> > OSPF.
> > - To have these interfaces (connected interfaces)
> > redistributed again into
> > OSPF, I have use redistribute connected and don't
> > rely on the RIP into OSPF
> > redistribution.
> >
> > I have seen this behavior with RIP to OSPF
> > redistribution but does this
> > behavior implies to the other way (OSPF to RIP) and
> > will it be the same for
> > all routing protocols (IGPs and BGP) ??
> >
> > Many thanks in advance for your help,
> > Karim.
> >
> >
> > ----- Original Message -----
> > From: <alsontra@hotmail.com>
> > To: "christopher snow" <cbsnow31@yahoo.com>
> > Cc: <ccielab@groupstudy.com>
> > Sent: Sunday, February 22, 2004 7:11 PM
> > Subject: Re: Redistrbute Connected breaks other igp
> > connected routes on the
> > same router
> >
> >
> > > Brilliant! I never would have figured that out on
> > my own. So let me get
> > > this straight, if your using the redistribute
> > (protocol) command and you
> > > start to specify individual interfaces you
> > effectively remove all
> > previously
> > > specified interfaces. You are now doing manual
> > distribution by virtue of
> > > the fact that are explicitly pointing out
> > individual interface using
> > > route-maps?
> > >
> > >
> > > Alsontra
> > >
> > > GroupStudy Rocks!
> > >
> > >
> > > ----- Original Message -----
> > > From: "christopher snow" <cbsnow31@yahoo.com>
> > > To: <alsontra@hotmail.com>
> > > Cc: <ccielab@groupstudy.com>
> > > Sent: Sunday, February 22, 2004 2:25 AM
> > > Subject: Re: Redistrbute Connected breaks other
> > igp connected routes on
> > the
> > > same router
> > >
> > >
> > > > Think about the default behavior of the router
> > when
> > > > you redistribute from one protocol into another.
> > For
> > > > instance, if one tells the router to
> > redistribute rip
> > > > into ospf the router will do two steps. First,
> > it
> > > > will take all the rip routes in the routing
> > table
> > > > (unless filtering). Second, it will take all of
> > the
> > > > interfaces that rip is running on by default.
> > What
> > > > happens later, and is somewhat of a trap, is
> > that one
> > > > may be told to redistribute a loopback address
> > into
> > > > OSPF later in the scenrio. When one does a
> > > > redistribute connected under OSPF with a
> > route-map
> > > > that references the loopback, the default
> > behavior
> > > > (second step above) has now been manually
> > overridden.
> > > > By manually specifing the loopback address
> > alone, one
> > > > has now inadvertantly removed the
> > interfaces/subnets
> > > > that were once being used by default (second
> > step
> > > > above). You must now manually add those
> > > > subnets/interfaces to the connected route-map.
> > Lab it
> > > > up and check it out :)
> > > >
> > > > HTH,
> > > >
> > > > Chris Snow
> > > >
> > > >
> > > > --- alsontra@hotmail.com wrote:
> > > > > Are you saying that ospf removed a connected
> > > > > interface from its LSA database
> > > > > when you used the redistribute connected
> > command on
> > > > > another interface?
> > > > >
> > > > > Alsontra
> > > > >
> > > > >
> > > > > I noticed this behavior a few days ago, after
> > the
> > > > > fact. This time I
> > > > > caught it red handed. What a nightmare in the
> > lab
> > > > > this could be.
> > > > > Here's what I was doing, the local isis
> > interface
> > > > > didn't get
> > > > > redistributed, which is normal.
> > > > > I use tags, so I included the local interface
> > (s0.24
> > > > > 136.10.24.0/29)
> > > > > with the proper tag for isis into ospf, fixing
> > what
> > > > > isis should have
> > > > > done. (step 1)
> > > > > Immediately my rip (s1 136.10.12.0/24)
> > connected
> > > > > route which was
> > > > > perfectly stable dropped out of ospf. (step 2)
> > > > > I did nothing to effect the redistribution
> > between
> > > > > rip and ospf! It has
> > > > > to be some logic being turned off by a
> > specific
> > > > > redistribute connected
> > > > > cmd being present in the ospf config.
> > > > > To fix it, I added another statement to my
> > route-map
> > > > > using the right tag
> > > > > for rip, and the route came back. (step 3)
> > > > > Remote router watching ospf routes
> > > > > Step 1) -
> > > > > RT: add 136.10.24.0/29 via 136.10.56.5, ospf
> > metric
> > > > > [110/1065]
> > > > > Step 2)
> > > > > RT: del 136.10.12.0/24 via 136.10.56.5, ospf
> > metric
> > > > > [110/1065]
> > > > > RT: delete subnet route to 136.10.12.0/24
> > > > > Step 3)
> > > > > RT: add 136.10.12.0/24 via 136.10.56.5, ospf
> > metric
> > > > > [110/1065]
> > > > >
> > > >
> >
> ------------------------------------------------------------------------
> > > > > ----
> > > > > Step 1)
> > > > > redistribute connected metric 1000 metric-type
> > 1
> > > > > subnets route-map
> > > > > connectedisis
> > > > > route-map connectedisis permit 10
> > > > > match interface Serial0.24
> > > > > set tag 444
> > > > > Step 3)
> > > > > route-map connectedisis permit 15
> > > > > match interface Serial1
> > > > > set tag 111
> > > > >
> > > >
> >
> ------------------------------------------------------------------------
> > > > > ----
> > > > > Is this normal? Maybe a bug in my ios? I
> > hadn't
> > > > > noticed it before, but
> > > > > I notice a lot more now than I used to.
> > > > >
> > > >
> >
> _______________________________________________________________________
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> === message truncated ===
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