From: ccie2be (ccie2be@nyc.rr.com)
Date: Fri Jan 14 2005 - 18:41:08 GMT-3
Hey Scott,
I'd be happy to go with a different analogy but I don't recall ever hearing
one, so that left me no choice
but to make one up myself.
In any case, you're right. With an acl, it can be very broad or very
specific or anything inbetween.
But, I use "retail" because when creating the required acl, one needs to be
very careful to make sure
that every route that should be included is included and likewise for those
routes that should be excluded.
And, therefore, in the lab, you might need to consider many of the routes in
your domain.
While, if you can use the "wholesale" version of the distance command, you
can probably save yourself alot of time
because you're thinking in terms of a whole class of routes all at once.
Anyway, thanks for pointing out that isis detail. That just might be one of
the reasons I need to take the lab again.
Tim
----- Original Message -----
From: "Scott Morris" <swm@emanon.com>
To: "'ccie2be'" <ccie2be@nyc.rr.com>; "'Group Study'"
<ccielab@groupstudy.com>
Sent: Friday, January 14, 2005 3:59 PM
Subject: RE: Distance vs Distance
> That's an interesting analogy for it all. :)
>
> When you use the retail version, you can have a broad ACL apply to any
> neighbor and therefore affect the same change as the wholesale version.
>
> Which do you use? Well, here you lose the analogy. You should be as
> specific as possible. Just because you should stay 500 feet back from a
> firetruck (per its sign) doesn't mean that you apply that to every vehicle
> you are near. Perhaps you do. Like AD, it's your own decision and
doesn't
> really affect anyone else, but may lead you to make some less-than-optimal
> decisions.
>
> As for ISIS, yes there are multiple versions. If you aren't careful, when
> you enter "distance isis" and go back to look at your config, you will
find
> you are only changing distance on isis CLNS routes. There is also
"distance
> isis ip" which is likely more what you want. But otherwise, there are no
> further delineations.
>
> HTH,
>
>
> Scott Morris, MCSE, CCDP, CCIE4 (R&S/ISP-Dial/Security/Service Provider)
> #4713, JNCIP, CCNA-WAN Switching, CCSP, Cable Communications Specialist,
IP
> Telephony Support Specialist, IP Telephony Design Specialist, CISSP
> CCSI #21903
> swm@emanon.com
>
>
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> ccie2be
> Sent: Friday, January 14, 2005 3:42 PM
> To: Group Study
> Subject: Distance vs Distance
>
> Hi guys,
>
> Have any of you had difficulty learning when to use the different versions
> of this command.
>
> I have but now I think I got it and want to confirm with the pool of GS
> brain power.
>
> Several protocols support a version of distance that specific to that
> protocol.
>
> For example, distance eigrp, distance ospf, and distance bgp. (Rip and
isis
> don't seem to have an equivalent)
>
> In addition, there's the plain or IP version of distance <AD#> <ip addr
> mask> [acl] command.
>
> The way I think about these now is that the distance <protocol> version of
> the command is sort of "wholesale".
>
> It will change the AD for all routes in the route table that match that
> protocol (or class) within that protocol.
>
> While the distance <AD#> version of the command is more like "retail". It
> will affect those routes that that are either
>
> from a certain neighbor(s) or match the optional acl at the end of the
> command.
>
> Q1: Do people agree with this conceptualization?
>
> Q2: Can the same thing be done with ip version of the command that can be
> done with the protocol specific version
>
> as long as the neighbors and acl are properly defined?
>
> Q3: Has anyone come up with a simple way of knowing when using the ip
> version of the command which ip address to use
>
> when defining the source of the routes? I recall that sometimes it's the
> router ID of the neighbor but sometimes the physical
>
> address but can never remember which.
>
> All your thoughts and insights are appreciated.
>
> TIA, Tim
>
> _______________________________________________________________________
> 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 : Wed Feb 02 2005 - 22:10:23 GMT-3