From: Chris Lewis \(chrlewis\) (chrlewis@cisco.com)
Date: Sun Jul 17 2005 - 16:57:51 GMT-3
Hi,
I'd not recommend generalizaions on this topic. I was referring to a
specific case of having two routing domains joined at two points with
mutual redistribution on both points. In the simple diagram below, this
means mutual redistribution between RP1 and RP2 on R1 and R2. Many
routing loops can be fixed with AD manipulation, however the real danger
is in generalizing. There is no substitute for understanding why the
routing decisions are being made and deciding to change things to get
desired behavior. If you want to explore this further, put together a
few scenarios for discussion. Talking about specific cases is more
meaningful for this topic IMHO.
Routing protocol 1
| |
R1-------R2
| |
Routing protocol 2
For that EIGRP works well, as it has the high external metric concept,
you can make OSPF similar by using distance ospf external, so
restricting the case to the one I'm referring to, some more responses
in-line below:
-----Original Message-----
From: cacca mucca [mailto:caccamucca@hotmail.com]
Sent: Sunday, July 17, 2005 12:16 PM
To: jjrinehart@hotmail.com; Chris Lewis (chrlewis);
ccielab@groupstudy.com
Subject: Re: LAB study guide
Okay, question is regarding redistribution,
OSPF <-> EIGRP (no filtering required per Chris)
For the specific case I mention, yes
OSPF <-> ISIS (my guess is you need something on the ISIS side?)
CL: If you put distance ospf external 180 on both redistribution points
for my case described above, that is all that is necessary
OSPF <-> RIP (my guess is you need something on the RIP side?)
CL: again for the specific case of 2 mutual redistribution points
between two domains, you can get away with distance ospf external 180 on
both routers
EIGRP <-> RIP (my guess is you need something on the RIP side?)
CL: with this pair, the EIGRP external concepts takes care of things so
nothing additional is necessary
EIGRP <-> ISIS (my guess is you need something on the ISIS side?)
CL: again the EIGRP external metric values takes care of things.
CL: The only difficult one is ISIS to RIP. That requires route
filtering.
Without using extensive filtering on the subnets, how does one prevent
route feedbacks?
Thanks
>From: "Joe Rinehart" <jjrinehart@hotmail.com>
>To: "cacca mucca"
><caccamucca@hotmail.com>,<chrlewis@cisco.com>,<ccielab@groupstudy.com>
>Subject: Re: LAB study guide
>Date: Sat, 16 Jul 2005 15:00:59 -0700
>
>Can you give me the scenario? There are several ways to go about that
>and I would need a context....
>
>Joe Rinehart
>CCIE #14256, CCNP, CCDP
>Data Network Consultant
>AT&T Pacific Northwest Enterprise Markets
>----- Original Message -----
>From: "cacca mucca" <caccamucca@hotmail.com>
>To: <jjrinehart@hotmail.com>; <chrlewis@cisco.com>;
><ccielab@groupstudy.com>
>Sent: Friday, July 15, 2005 7:27 PM
>Subject: Re: LAB study guide
>
>
> > Can you provide us with an example of the "distance ospf external to
>stop
> > routes feeding back" ?
> >
> > Thanks
> >
> > >From: "Joe Rinehart" <jjrinehart@hotmail.com>
> > >Reply-To: "Joe Rinehart" <jjrinehart@hotmail.com>
> > >To: "Chris Lewis (chrlewis)" <chrlewis@cisco.com>,
><ccielab@groupstudy.com>
> > >Subject: Re: LAB study guide
> > >Date: Fri, 15 Jul 2005 08:45:08 -0700
> > >
> > >Agreed on the redistribution answers. There are several ways to
> > >answer something, especially since the real test was whether or not
> > >ot
>achieved
> > >the
> > >desired result.....
> > >
> > >----- Original Message -----
> > >From: "Chris Lewis (chrlewis)" <chrlewis@cisco.com>
> > >To: "Joe Rinehart" <jjrinehart@hotmail.com>;
> > ><ccielab@groupstudy.com>
> > >Sent: Friday, July 15, 2005 8:38 AM
> > >Subject: RE: LAB study guide
> > >
> > >
> > >My opinion, FWIW is that they both have a lot of value to offer,
> > >DoiT more for the routing scenarios, Internetworkexpert more for
> > >the
>security
> > >and services side.
> > >
> > >I would add though that I often created simpler solutions to the
> > >NMC answer keys, particularly regarding the redistribution
> > >scenarios. I found it easier to use things like distance ospf
> > >external to stop
>routes
> > >feeding back, rather than setting up lots of specific route
filters.
> > >
> > >-----Original Message-----
> > >From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
> > >Behalf Of Joe Rinehart
> > >Sent: Friday, July 15, 2005 10:27 AM
> > >To: ccielab@groupstudy.com
> > >Subject: Re: LAB study guide
> > >
> > >Well I used the DoIT lab workbook and had great results, what
> > >exactly was out in left field? The thing that drove me crazy was
> > >redistribution, DoIT would have at least three to four
> > >redistribution points on each lab and you had to be really really
> > >careful about how
>you
> > >filtered....
> > >
> > >Joe Rinehart
> > >CCIE #14256, CCNP, CCDP
> > >Data Network Consultant
> > >AT&T Pacific Northwest Enterprise Markets
> > >----- Original Message -----
> > > > On 7/14/05, cacca mucca <caccamucca@hotmail.com> wrote:
> > > > > I'm using the DOiT lab and it is out in the left field. I
> > > > > should have
> > >bought
> > > > > the InterNetwork Expert. I even had an upgrade coming, but
> > > > > went
>with
> > >DOiT.
> > > > > Kicking myself now.
> > > > >
> > > > > Just my 2 cents
> > > > >
> > > > > >From: "Hooman Parta" <hooman@voipsol.com>
> > > > > >Reply-To: "Hooman Parta" <hooman@voipsol.com>
> > > > > >To: <ccielab@groupstudy.com>
> > > > > >Subject: LAB study guide
> > > > > >Date: Thu, 14 Jul 2005 10:22:12 -0500
> > > > > >
> > > > > >Hi,
> > > > > >
> > > > > >I just started my LAB preparation and got my LAB already.
> > > > > >Does
>any
> > > > > >one recommend any of the LAB preparation materials. There are
> > > > > >several
> > >compaies
> > > > > >with differnt options. NLI, IPEXPERT, IE, InterNetwork expert
> > > > > >and much more.
> > > > > >
> > > > > >I know I should look for updated material which reflects the
> > > > > >IPv6 and
> > >12.2T
> > > > > >but which one do you think is better to start?
> > > > > >
> > > > > >Thanks,
> > > > > >Hooman Parta
> > > > > >
> > > > >
> >___________________________________________________________________
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> > > > >
> > > > >
>____________________________________________________________________
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> > > >
> > > >
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