From: Andrew Lee Lissitz (alissitz@corvil.com)
Date: Thu Dec 23 2004 - 12:10:00 GMT-3
Hey Kurt!
In Sparta NJ? I live in Blairstown... just down the road. I also work in
Penn Station NYC. GS - anyone else in this area of NJ or working @ Penn
Station?
None of us can tell you what is on the real lab (I failed my first attempt)
however, all the practice labs will require some physical and subinterfaces.
It would be too easy to have all the interfaces as the same type...
With that said you will need to implement a solution that will not allow for
mis-matched interface types with ISIS and OSPF. The easy solution - use
only multipoint subinterfaces and all interfaces will be multipoint. If you
are told what type of interface to create then choose multipoint. If you
are told to create point-to-point subinterfaces, then I would say get ready
for a fun routing protocol section...
Concerning FR mappings... most of the practice labs I see do not allow you
to dynamically learn mappings. Again this would be too easy... If you are
told not to 'have' any DLCIs or mappings that are not listed in your
practice lab, then you would need to disable inverse-arp to keep you router
from learning. Because nothing will be learned dynamically, you will need
to configure the mappings yourself.
Concerning split-horizon... always a concern with multipoint interfaces. As
far as I know (someone please correct this next statement if it is
incorrect), only RIP and EIGRP require this. I think the only solution to
this is to disable split-horizon. GS gurus - any additional work around for
this?
Concerning the switch dynamically telling the router of the mappings... I
would suggest configuring FR fully on one router (the DCE and clock source
router), and only enabling FR on the interface of other router. See what
the other router learns.
Try different combinations on this other router and be sure to use the debug
commands for FR to see what is learned etc... You will also see a lot of
cool debug messages as well. Only a geek would think these debug messages
are cool... my oldest daughter says I am not cool... she right!!!
Kindest Regards all,
Andrew
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Kurt
VanDerMark
Sent: Thursday, December 23, 2004 8:39 AM
To: ccielab@groupstudy.com
Subject: Frame Relay Questions
I'm doing a little frame relay review, trying to make sure I nail down the
basics...and I have a few questions.
Please correct anything I say that's wrong...
I understand frame relay can be configured on an interface 3 ways:
- physical interface (considered multipoint)
- subinterface point-to-point
- subinterface multipoint
Say for instance I have a connection going from one router defined as a
physical interface, to another router defined via a subinterface. To avoid
routing issues such as interface mismatch with IS-IS (any other issues or is
this the only one?), I'll want to define the subinterface as multipoint.
If the other end of the connection is defined by a physical interface, why
wouldn't I always define the subinterface end as multipoint? If you aren't
worried about routing issues, is there some advantage to defining that end
as point-to-point?? Are there some split-horizon issues?
Also, as a best practice, I understand its best to disable inarp on an
interface if you plan to use map statements before bringing the interface
up. If you don't plan to use map statements, and want to use dynamic
maps, does the FR switch just notify the router about all the mappings it
knows about, or does the service provider do filtering on the switch, or how
does that work?
Sorry if these are basic questions, but I want to make sure I have this
down...
Thanks.
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