Howard,
I both agree with you and not...
I agree with your statement about how difficult the access list is to read
if it's the first time you see it, or if you have been away from it for a
while. An example is shown at the end of this e-mail where I have made to
Pascal programs that does the same, but where the first is hard to read
compared to the second one.
BUT, I am not sure I agree with you about the performance issue. If a host
with address a.b.c.25 is trying to get through, it is a question about
jumping through only one or four access lines, which I believe would make a
difference (maybe not measuable to the human eye).
Here are the two source codes:
--(1)------------------------
Program Dec2Hex1;
Var
DecVal,H,L : Byte;
HexStr : String;
Begin
DecVal:=185; H:=DecVal div 16; L:=DecVal mod 16;
HexStr:=Chr(H+48+((H div 10)*7))+Chr(L+48+((L div 10)*7));
Writeln(HexStr);
End.
--(2)------------------------
Program Dec2Hex2;
Var
DecVal : Byte;
H,L : Byte;
HexStr : String;
Function DecChar2HexChar ( B : Byte ) : Char;
{----------------------------------------}
{-- Converts a four bit integer to a --}
{-- ascii character hex value. --}
{----------------------------------------}
{-- 3 = 48('0') + 3 = ascii 51('3') --}
{-- 14 = 55('7') + 14 = ascii 69('E') --}
{----------------------------------------}
Begin
Case B of
0..9 : DecChar2HexChar := Chr(48+B);
10..15 : DecChar2HexChar := Chr(55+B);
End;
End;
Begin
DecVal := 185;
H := DecVal div 16;
L := DecVal mod 16;
HexStr := DecChar2HexChar(H) + DecChar2HexChar(L);
Writeln(HexStr);
End.
---------------------------
Take care,
Ole
~~~~~~~~~~~~~~~~~~~~~~~~~~
Ole Drews Jensen
Systems Network Manager
CCNA, MCSE, MCP+I
RWR Enterprises, Inc.
[EMAIL PROTECTED]
~~~~~~~~~~~~~~~~~~~~~~~~~~
-----Original Message-----
From: Howard C. Berkowitz [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, July 04, 2000 9:01 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.
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.
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.
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.
>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
>
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>An excellent study focal point for all levels of certification, as well as
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>
>___________________________________
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