Comments within:
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of
Howard C. Berkowitz
Sent: Tuesday, July 04, 2000 7:01 PM
To: [EMAIL PROTECTED]
Subject: Dark side of the puzzle More puzzles - OSPF Network statements
Chuck,
I agree that problems like this do provide practice in masking.
Let's make very sure, however, not to give the impression that
minimizing the number of statements -- definitely OSPF network, and
arguably access lists -- is a good idea for the real world.
CL: point taken
Consider the situation when one is called in, at 3AM, to troubleshoot
a mission-critical network. And, as you look at the configuration in
the routers having problems, you find nothing but "cute" statements,
with no documentation.
CL: which is one more reason to understand what wildcards are and how they
really operate :->
Personally, I make a point of having one OSPF network statement for
each interface I want to speak OSPF. Much easier to understand, and
there is no performance advantage to having a lesser number of
statements.
CL: as stated elsewhere, my answer to the puzzle is network 0.0.0.0
255.255.255.255 area X this serves a number of purposes and none of them
bad, that I can see, in a situation where every interface on the router
belongs in the OSPF process. For one, there is no argument that the problem
lies within the network statement. In the situation where there are certain
interfaces/networks that one does NOT want included in the OSPF process,
then of course, other means should be employed
Even with access lists, I don't try to minimize except when I am
facing a real performance problem that can't be solved any other way.
The original Sprint access list that imposed their prefix length
restrictions, IIRC, was 16 pages long.
CL: I don't think I've ever written sixteen pages of anything, including
times when the requirement was a twenty page paper :->
>Gee, the recent wildcard mask puzzle was so much fun, let's do it again.
>
>The problem revolves around the OSPF network statement. Given an OSPF
>routing process, what are the fewest number of network statements that will
>incorporate the following networks into the given OSPF process?
>
>For example:
>
>router OSPF 100
>Network a.b.c.d w.x.y.z area 0.0.0.0
>Network b.c.d.e u.v.w.x area 0.0.0.0
>etc
>
>Assume that all networks are in the same area ( for simplicity sake )
>You may also assume ( for simplicity sake ) that the particular interface
on
>which each particular network resides is the first host address on that
>network. For example, on network 10.10.3.0/24, the first host address ( and
>therefore the interface address ) is 10.10.3.1
>
>Networks are as follows:
>
>10.10.3.0 /24
>10.25.17.0 /16
>10.51.100.192 /26
>172.16.0.0 /16
>172.16.100.0 /24
>172.16.210.240 /28
>172.27.32.0 /19
>192.168.0.0 /24
>192.168.1.0 /30
>192.168.207.56 /29
>
>remember - accolades go to the one who can enter all of these networks into
>a single ospf process with the fewest possible network statements.
>
>Have fun!
>
>Chuck
>
>Please check out my new footers for a new age
>1) Altruism
>http://www.thehungersite.com/cgi-bin/WebObjects/HungerSite
>Please help feed hungry people worldwide. A few seconds a day can make a
>difference to many people
>
>2) Shameless Hucksterism
>http://www.certificationzone.com
>An excellent study focal point for all levels of certification, as well as
>the attainment of internetworking expertise. Use my name when you register.
>You get good study material and I get extra time
>
>___________________________________
>UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
>FAQ, list archives, and subscription info: http://www.groupstudy.com
>Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
___________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
___________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
