From: Brian Dennis (bdennis@internetworkexpert.com)
Date: Thu Oct 25 2007 - 03:44:27 ART
So the difference between something complex (tag using device# + AD) and
something simple (tag using only AD) is only 1 digit? Seems like a pretty
fine line you've drawn there ;-)
Brian Dennis, CCIE4 #2210 (R&S/ISP-Dial/Security/SP)
bdennis@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
>----- Original Message -----
Subject: RE: Redistribution with route tags are KILLING ME!!!`
Date: Wed, October 24, 2007 22:15
From: "Scott Morris" <smorris@ipexpert.com>
> If you have multiple routers redistributing the same routes adding the
> device number to the tag may be a necessary thing, but in a simpler rule
> does it help any? (e.g. personal choice) :)
>
> Let's not make things more thought provoking than necessary. In my
> experience watching people use tags and working through redistribution
> problems, it's easier for them to remember AD values as that has more
likely
> been ingrained in their brains for years thereby reducing the thought
> processes needed to come up with tags or watch things happen.
>
> Both obviously work perfectly fine, I simply look at it for simplicity.
>
> The tag for connected is an interesting idea.... I'd never thought of
that,
> but likely because I never worried about a routing look with connected
> interfaces before. But an interesting idea!
>
>
> Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713,
JNCIE-M
> #153, JNCIS-ER, CISSP, et al.
> CCSI/JNCI-M/JNCI-ER
> VP - Technical Training - IPexpert, Inc.
> IPexpert Sr. Technical Instructor
>
> A Cisco Learning Partner - We Accept Learning Credits!
>
> smorris@ipexpert.com
>
> Telephone: +1.810.326.1444
> Fax: +1.810.454.0130
> http://www.ipexpert.com
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Brian Dennis
> Sent: Wednesday, October 24, 2007 11:46 PM
> To: Scott Vermillion
> Cc: 'Herbert Maosa'; 'Joseph Brunner'; 'Jeffrey Biggs';
> ccielab@groupstudy.com
> Subject: Re: Redistribution with route tags are KILLING ME!!!`
>
> If you are going to tag use the device number plus the administrative
> distance of the routes being redistributed (i.e. R2 OSPF = 2110 or R6
> connected = 60).
>
> Also we have a free route redistribution vseminar on November 14th that's
> open to everyone. We'll limit this vseminar to only 300 people so sign up
> early if you are interested as the last one on Catalyst QoS pushed the
> limits of the vseminar software ;-)
>
> --
>
> Brian Dennis, CCIE4 #2210 (R&S/ISP-Dial/Security/SP)
> bdennis@internetworkexpert.com
>
> Internetwork Expert, Inc.
> http://www.InternetworkExpert.com
> Toll Free: 877-224-8987
> Direct: 775-852-3995 (Outside the US and Canada)
>
> Scott Vermillion wrote:
> > I don't know, I thought Scott Morris's idea of tagging all routes with
> their
> > "native" AD was quite brilliant. Sure makes things easy to keep straight
> > (although I confess I haven't done too much in the way of redistribution
> > labs at this juncture in my studies, so I'm certainly no expert on the
> > subject).
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> > Herbert Maosa
> > Sent: Wednesday, October 24, 2007 4:37 PM
> > To: Joseph Brunner
> > Cc: Jeffrey Biggs; ccielab@groupstudy.com
> > Subject: Re: Redistribution with route tags are KILLING ME!!!`
> >
> > Actually, I use route-tags in two cases
> >
> > - one of the protocols is already carrying external routes from
> > elsewhere
> > - one of the protocols is RIP, which has no concept of External routes
> >
> > Except for these two cases, so far I successfullly implement loop free
> > redistribution by matching internal routes ( in the case of OSPF ) or
> > matching route-type Internal ( for the case of EIGRP ).
> >
> > I think the use of route-tags is generally overused, perhaps overtrained,
> so
> > much so that you end up using it on every redistribution scenario without
> > understanding what you are trying to accomplish. Could waste quite a lot
> of
> > time at the best, and you could get it all wrong at the worst !
> >
> > .
> > Herbert.
> >
> > On 10/24/07, Joseph Brunner <joe@affirmedsystems.com> wrote:
> >> Wait slow down...
> >>
> >> You only NEED to use redistribution with route-tags when you have more
> >> than
> >> 1 router doing mutual route re-distribution. We use the tags to block
> >> route
> >> feedback. That is, if a route has been redistributed already at either
> >> router it wont be re-redistributed back to the source protocol at the
> >> other
> >> router.
> >>
> >> Here is an example... R3 and R4 are redistributing between EIGRP
& OSPF.
> >> To
> >> prevent a loop we don't allow route feedback from a protocol back into a
> >> protocol. Anything going from OSPF to EIGRP, and EIGRP to OSPF is tagged
> >> and
> >> the redistribution at other router denies routes with that tag before
> >> redistribution. The tags allow us to know WHERE that route originally
> came
> >> from.
> >>
> >> Here is the topology
> >>
> >> R1---OSPF--- R3--- EIGRP-AS-10--- R5
> >> | |
> >> R2---OSPF--- R4--- EIGRP-AS-10--- R6
> >>
> >>
> >> R3&R4
> >>
> >> Router ospf 1
> >> Redis eigrp 10 subnets route-map watch-tag
> >>
> >> Router eigrp 10
> >> Redistribute ospf 1 route-map watch-tag metric 1500 100 255 1 1500
> >>
> >> Route-map watch-tag deny 5
> >> Match tag 5
> >> Route-map watch-tag permit 10
> >> Set tag 5
> >>
> >>
> >> Try it with my topology in your dynamips...
> >>
> >>
> >> -----Original Message-----
> >> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> >> Jeffrey Biggs
> >> Sent: Wednesday, October 24, 2007 4:48 PM
> >> To: ccielab@groupstudy.com
> >> Subject: Redistribution with route tags are KILLING ME!!!`
> >>
> >> I have been trying to grasp the use of redistribution using only route
> >> tags,
> >> but I just keep getting killed by it. I can redistribute using
> >> prefix-lists
> >> and ACL's all day long, but I know I am going to see something where I
> >> need
> >> to "make sure all IP's are fully reachable without the use of
> >> ACL's/Prefix-lists" and I am going go down in flames..Is there someone
> out
> >> there that has a solution that can help me??????? I have used NMC and
> >> IPEXPERT (BOTH VERY GOOD TOOLS, NOT KNOCKING ANY OTHERS) but my brain is
> >> just not grasping the concept.
> >>
> >>
> >>
> >> HELP!!!!!!!
> >>
> >>
> >>
> >> Thanks
> >> JB
> >>
> >> _______________________________________________________________________
> >> Subscription information may be found at:
> >> http://www.groupstudy.com/list/CCIELab.html
> >>
> >> _______________________________________________________________________
> >> Subscription information may be found at:
> >> http://www.groupstudy.com/list/CCIELab.html
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Fri Nov 16 2007 - 13:11:18 ART