From: Scott Morris (swm@emanon.com)
Date: Mon Jul 19 2004 - 19:26:19 GMT-3
I'm only skimming here, so forgive me if I miss a beat... (e.g. not
replying to everything you state)
However, the "why" you are missing with IS-IS happens to do with the RIBs.
You need to remember that IS-IS is NOT an IP protocol. CLNS views/viewed IP
as a "passing phase". So,it happens to carry IP. So you have two different
processes occurring. Or at least two different tables/parameters to monitor
things.
When you bring a connected interface in, you are bringing it in to the CLNS
RIB and tagging it as an IP-set. When it exists locally, it exists as a
CLNS entry locally attached. When you send it out to another router, it
exists as an IP-set entry, which is a subset table (like another RIB).
So locally, you don't view connected interfaces as part of your IP-set RIB.
Just one of those magical little nuances that keeps things exciting. :)
but it's also the history that sometimes makes things make a little more
sense!
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, CISSP,
JNCIP, et al.
IPExpert CCIE Program Manager
IPExpert Sr. Technical Instructor
swm@emanon.com/smorris@ipexpert.net
http://www.ipexpert.net
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
ccie2be
Sent: Monday, July 19, 2004 2:14 PM
To: Kenneth Wygand; john matijevic; Shibu Nair; Richard Dumoulin
Cc: James; ccielab@groupstudy.com
Subject: Re: Redistribution question
Hey Guys,
I have to admit that until I took the IE bootcamp with the 2 Brian's, I
didn't really understand what was going here. But, ... after listening to
Brian Dennis's explanation, I feel I truly understand this issue.
Here's my current understanding. (Brian, if I'm not 100% corect, please
correct me.)
With all IGP's except IS-IS, when you redist igp1 into igp 2, what's really
happening are 2 things:
a) all routes that show up in the route table listed as igp 1 are redist
into igp 2.
b) all connected routes on which igp 1 is running are redist into igp 2.
This assumes there aren't any route maps or filters affecting redist. The
above is the default behavior, again, for all igp's except ISIS.
Now, if there are 2 redist statements:
router igp 2
redist igp 1
redist conn [route-map <name>]
the 2nd redist statment overrides the default behavior. Now, either all the
connected interfaces or those explicitly referenced in the route-map will be
redist. By having the 2nd redist statement, you stop the default behavior
of IOS from automatically looking for those conencted interfaces which are
running igp 1and redist them. Now, the connected routes that are redist
depend completely on what you specify in the redist connected statement.
Now, if ISIS is the protocol being redist into igp 2, for whatever reason,
the IOS never looks to see under which interfaces ISIS is running, so
connected interfaces running ISIS are never automatically redist.
Exactly why this is, I can't say. But, I know what I described above is
true. And, I challenge anyone to prove me wrong.
HTH, Tim
----- Original Message -----
From: "Kenneth Wygand" <KWygand@customonline.com>
To: "john matijevic" <matijevi@bellsouth.net>; "Shibu Nair"
<shinair@cisco.com>; "Richard Dumoulin" <richard.dumoulin@vanco.es>
Cc: "James" <james@towardex.com>; <ccielab@groupstudy.com>
Sent: Monday, July 19, 2004 1:35 PM
Subject: RE: Redistribution question
> John,
>
> Nonetheless, you've brought up a great topic of discussion and have made
> our brains work a bit harder in thinking about these scenarios as well
> as tweaks of these scenarios. Your input and contributions to this
> group are always appreciated!
>
> Thanks!
>
> Kenneth E. Wygand
> Systems Engineer, Project Services
> CISSP #37102, CCNP, CCDP, ACSP, Cisco IPT Design Specialist, MCP, CNA,
> Network+, A+
> Custom Computer Specialists, Inc.
> "The only unattainable goal is the one not attempted."
> -Anonymous
>
> -----Original Message-----
> From: john matijevic [mailto:matijevi@bellsouth.net]
> Sent: Monday, July 19, 2004 1:14 PM
> To: 'Shibu Nair'; 'Richard Dumoulin'
> Cc: Kenneth Wygand; 'James'; ccielab@groupstudy.com
> Subject: RE: Redistribution question
>
> Hello Richard and Shibu,
> Yes you are both correct in your statements, I guess I originally
> thought of RIP behaving like IS-IS. I am glad Kenneth corrected me, I
> was able to lab out and indeed I was wrong with the rip redistribution
> statement I made earlier.
>
> Sincerely,
> John Matijevic, CCIE #13254, MCSE, CNE, CCEA
> Network Consultant
> Hablo Espanol
> 305-321-6232
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Shibu Nair
> Sent: Monday, July 19, 2004 12:44 PM
> To: Richard Dumoulin
> Cc: john matijevic; 'Kenneth Wygand'; 'James'; ccielab@groupstudy.com
> Subject: RE: Redistribution question
>
> You are right.
> Indirect redistribution is not allowed on the same router.
> for instance if you are redistributing loopback 1 on R1 in to RIP.
> Now loopback 1 ip address is part of RIP.
>
> Assuming that you are redistributing RIP in to OSPF on the same
> router. You would think that the loopback ip address which is now
> part of RIP will redistribute to OSPF. But it will NOT happen since
> you are doing both redistribution on the same router and this kind
> of indirect redistribution on the same router will not be allowed.
> Shibu
> At 05:31 PM 7/19/2004 +0100, Richard Dumoulin wrote:
> >If I remember well when you do a redistribute connected on RIP with a
> >route-map, and redistribute rip into ospf, then the directly connected
> >networks won't go from RIP to OSPF. Need testing though because I
> vaguely
> >remember,
> >
> >--Richard
> >
> >-----Original Message-----
> >From: john matijevic [mailto:matijevi@bellsouth.net]
> >Sent: lunes, 19 de julio de 2004 18:17
> >To: 'Kenneth Wygand'; 'James'; ccielab@groupstudy.com
> >Subject: RE: Redistribution question
> >
> >
> >Hello Kenneth,
> >Yes you are correct as far as redistributing the rip route, I just
> tested
> >this myself. I was thinking of another issue with RIP.
> >
> >Sincerely,
> >John Matijevic, CCIE #13254, MCSE, CNE, CCEA
> >Network Consultant
> >Hablo Espanol
> >305-321-6232
> >
> >-----Original Message-----
> >From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> >Kenneth Wygand
> >Sent: Monday, July 19, 2004 11:51 AM
> >To: john matijevic; James; ccielab@groupstudy.com
> >Subject: RE: Redistribution question
> >
> >John,
> >
> >Great post. However, you mentioned:
> >
> ><SNIP>
> >Basically, with RIP, and ISIS when you redistribute the protocols into
> >another protocol you will have to do a redistribute connected even
> through
> >you maybe advertising the networks in the routing protocol. </SNIP>
> >
> >I agree that this is the case with ISIS because the connected
> interfaces are
> >not in the ISIS database, rather the CLNS database (they don't enter
> the
> >ISIS database until advertised to the ISIS process of a neighbor).
> >
> >However, with RIP, this is not the case. If you have a loopback
> 1.1.1.1 on
> >R1, you enter this router into RIP with "network 1.0.0.0" and then
> >redistribute into OSPF which is running between R1 and R2, this _will_
> in
> >fact show up in R2 as an E2 OSPF route.
> >
> >Did you mean something else?
> >
> >Kenneth E. Wygand
> >Systems Engineer, Project Services
> >CISSP #37102, CCNP, CCDP, ACSP, Cisco IPT Design Specialist, MCP, CNA,
> >Network+, A+
> >Custom Computer Specialists, Inc.
> >"The only unattainable goal is the one not attempted." -Anonymous
> >
> >-----Original Message-----
> >From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> john
> >matijevic
> >Sent: Monday, July 19, 2004 11:02 AM
> >To: 'James'; ccielab@groupstudy.com
> >Subject: RE: Redistribution question
> >
> >Hi James,
> >There are a few more tools that you can use to tell what routes are
> being
> >advertised by what protocol. When you do a sh ip route, you see that
> there
> >are external routes which are coming in, even though you don't have
> >redistribute connected under the routing protocol process. Basically,
> if you
> >put a network under the routing process in ospf or eigrp, that network
> is
> >going to be advertised to the neighbors, even though it is a "connected
> >route". If you look at the ospf databse by using a sh ip ospf database
> >command you should see that these routes are indeed in the database and
> >being advertised via lsa. With eigrp you can use the command sh ip
> eigrp
> >topology, to look at the eigrp database. When you redistribute, from
> one
> >protocol to another; lets say for example from ospf to eigrp; if you do
> a sh
> >ip route, all the routes marked O from output, and any connected route
> which
> >you included in the routing process, which are ospf routes on the
> router
> >your doing the redistribution should be redistributed into eigrp, and
> you
> >should be able to go to remote router and see the routes as external if
> you
> >do a sh ip route on the remote router. The part that may confuse you
> with
> >connected is when you are using a routing protocol like rip and isis
> for
> >redistribution. These protocols don't behave like the others do. And
> this is
> >where I see much confusion from many posts here on groupstudy time and
> time
> >again, this issue has been documented in previous posts. Basically,
> with
> >RIP, and ISIS when you redistribute the protocols into another protocol
> you
> >will have to do a redistribute connected even through you maybe
> advertising
> >the networks in the routing protocol. I hope this helps clear up some
> >confusion, you can also can lab this out to see the results for
> yourself.
> >
> >Sincerely,
> >John Matijevic, CCIE #13254, MCSE, CNE, CCEA
> >Network Consultant
> >Hablo Espanol
> >305-321-6232
> >
> >-----Original Message-----
> >From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> >James
> >Sent: Monday, July 19, 2004 10:28 AM
> >To: ccielab@groupstudy.com
> >Subject: Redistribution question
> >
> >Hi group,
> >
> >Got a question about redist'ing between protocols.
> >It is my understanding that when redistributing between two protocols
> >directly, it does not perform the exchange through the specific
> protocol
> >databases, but rather performed by going through the RIB, which you can
> see
> >by issuing
> >'sh ip route' command.
> >
> >So.. let's take an example
> >R1--R2--<OSPF>-----------R5--------------<EIGRP>--R7--R8
> > s0/1 fa0/0
> > 192.168.10.1/24 192.168.100.1/24
> > <-- OSPF Sector EIGRP Sector -->
> >
> >R5 is redistributing between OSPF network (192.168.10.0/24) and EIGRP
> >network (192.168.100.1/24).
> >
> >However, when doing 'sh ip route', the 192.168.10.0/24 and
> 192.168.100.0/24
> >are really NOT ospf, NOR eigrp networks, even though R8 sees
> >192.168.100.0/24 as EIGRP route, and R1 sees 192.168.10.0/24 as ospf
> route.
> >However, to R5, these networks are neither ospf, nor eigrp, but they
> are
> >Connected routes.
> >
> >So redist connected is probably the needed solution on R5 to ensure
> that
> >
> >connected networks are carried out as well.. However, I did this on R5
> and
> >192.168.100.0/24 is appearing as OSPF E2 external route on R1/R2, as
> well as
> >192.168.10.0/24 appearing as EIGRP EX route on R7/R8 even though I do
> not
> >have 'redistribute connected' on R5. R5 just has redistribute ospf
> under
> >eigrp process, and redistribute eigrp under ospf process.
> >
> >Am I missing something?
> >
> >Thanks for clues!
> >-J
> >
> >--
> >James Jun TowardEX
> >Technologies, Inc.
> >Technical Lead Network Design, Consulting, IT
> >Outsourcing
> >james@towardex.com Boston-based Colocation & Bandwidth
> >Services
> >cell: 1(978)-394-2867 web: http://www.towardex.com , noc:
> >www.twdx.net
> >
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