From: Joseph Brunner (joe@affirmedsystems.com)
Date: Mon Aug 20 2007 - 20:15:45 ART
You just need to read the tasks carefully and fully plan out what you are
going to do before you start doing stuff. If you makes changes in your plan
along the way, consider the effects your changes will have.
For instance, if you started out configuring a stub area, but realized there
was redistribution in the stub area, (say a switch is redistributing its
loopback 0 interface via a redistribute command). Now you decide to create a
nssa. Well right now you need to remember that a stub area gets a default
route by default, where an NSSA does not. Remembering the tasked called for
a default route to be sent into the area you now, decide to make it a
nssa-totally stubby area, so you get that default route. Well the task also
said you should not see external routes, but SHOULD see inter-area routes...
How do you handle this task?
-nssa with default information originate on ABR?
-stub area with a tunnel from redistributing router, where the tunnel is in
area 0
-just a normal area, with a default originate on the abr...
Again, think quickly, but carefully and remember PLAN YOUR VERIFICATION so
you can be sure you fulfilled the task requirements...
As far as redistribution, if the task wants specific routing paths to be
achieved, believe me, they'll ask for it.
This is where you first ask yourself
-I am comparing two protocols, or two routes with in a protocol
-Do I need tags when I redistribute to deny a route from being redistributed
back into the original source protocol (prevent routing feedback)
-Do I need to modify the distance of OSPF external routes to say 171, so
that eigrp's 170 externals will be preferred?
What are my route redistribution verification steps?
Show ip protocols
Show ip route x.x.x.x/xx
Show ip ospf database external, etc
Show ip eigrp top x.x.x.x/xx
Tcl ping script and from which routers?
Macro ping script and from which routers?
Will Frame relay interface ip being unreachable from where, due to you can't
ping your own ip by default on a NBMA frame-relay interface, and the task
may not call for it.
Read the tasks carefully...
I always tell myself, DRAW out redistribution, and look for any tasks which
imply redistribution is need by don't specifically ask for it (i.e. BGP sync
issues throughout the network)
-Joe
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of NET
HE
Sent: Monday, August 20, 2007 6:41 PM
To: ccielab@groupstudy.com
Subject: suboptimal routes in routing table
Hi, there
I am wondering if I need to pay attention to suboptimal routes at CCIE lab
or not if there is nowhere mentioning to avoid suboptimal routes.
For example, there are 2 routers working as border routers between OSPF and
EIGRP domains. OSPF and EIGRP are mutually redistributed. And there are some
external routes from somewhere else (not from OSPF) in EIGRP domain. The
border routers will receive those external routes from OSPF and EIGRP
domain. Since external EIGRP routes' AD is 170, and OSPF routes' AD is 110,
those routes coming from OSPF, which are redistributed from EIGRP will enter
routing table.
How do I handle it? Do I have to consider bandwidth along the path?
Thanks.
Best Regards,
Net (Xin) He
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