From: Gary Duncanson (gary.duncanson@googlemail.com)
Date: Wed Aug 22 2007 - 10:31:31 ART
Hey Michael,
I'm sorry to hear you have decided to call it a day. There is more to life
than the CCIE but it sounds like the process certainly was of benefit. Good
luck as a physicist!
Regards
Gary
----- Original Message -----
From: "Michael Snyder" <msnyder@revolutioncomputer.com>
To: <ccielab@groupstudy.com>
Sent: Wednesday, August 22, 2007 1:47 PM
Subject: So Long, and Thanks for All the Fish
> Hey Guys,
>
> Been putting off setting this message to the groupstudy board. Around
> 2001
> I started studying for my CCIE. Took the test five times, with my highest
> score being 80%.
>
> So, when I was thinking of taking the test the sixth time, I looked at all
> my finances and said gee, I could have gotten a college degree with the
> all
> money I spend on the racks, remote classes, and my study rack!
>
> So instead of the taking the test the sixth time, I went to college!
>
> Long story short, it is now 2007, I'm 20 credit hours away from getting an
> undergrad degree in physics. I have found it's easier to pass a quantum
> mechanics class than passing the ccie test!
>
> My classmates turn about a bit green during our three hour physics finals,
> and I'm just sitting there smiling, thinking gee, a least it isn't an 8
> hour
> ccie test!
>
> Looking back at my old emails, I did come up with a method on how to use
> windows calc to do bit based route summarization. Found out later that it
> is the same method computers use, its called bit based erosion in my
> present
> math classes. My version of the method is reposted below.
>
> Also, while in college I've been filming the magnetic field, here's a
> video
> and an undergrad paper of my present work.
>
> http://www.youtube.com/watch?v=2MHIncd1rSY
>
>
> http://www.esnips.com/doc/2e05744f-aa5d-40b3-937b-73c22d6eaa6f/Magnetic-Cont
> ours
>
> I've been putting off unjoining the list, but I need to move on, and those
> 40,000 messages from groupstudy is starting to freak out my outlook email.
> So sadly, please remove me from the list.
>
> I thank you guys and the groupstudy host for everything, it turned out to
> be
> a really good thing learning how to study and work together. My five
> failed
> tests were not wasted, they taught me how to study and I now use those
> skills daily!
>
> I encourage you guys, keep going on your studies; but please remember you
> can change the game if the rules ain't working for you.
>
> Michael Snyder
>
> --------------------------
>
> Using the windows calc to do summarization. The reason that it works is
> that logical operations work in any number base. Of course you should
> know
> how to do it in binary, but speed is what we need in the lab; not to
> mention
> less mistakes.
>
> The method is as follows:
>
> Assuming you have networks you want to summarize in octet columns
>
> a1.b1.c1.d1
> a2.b2.c2.d2
>
> You do the logical operations in columns, of example all the a`s then the
> b`s then the c`s, etc. Of course it only applies to the octets you wish
> to
> summarize. If all the a`s and b`s and d`s are the same, you only have to
> do
> is the c'`s. Wildcard zeros will do an exact match, Wildcard 255 is a any
> match.
>
> `and` all the c`s and call it result-1
>
> `or` all the c`s and call it result-2
>
> The finished access list will use the results in this way
>
> Access-list 1 permit a.b.(result-1).d 0.0.(result-1 xor result-2).255
>
> So the wildcard octet is really result-1 xor result-2 = wildcard
>
> It's not as complex as it looks; I'll do some examples with real network
> numbers.
>
> -------------------------
>
> Let's deny the odd subnets of 192.168.x.x/32
>
> R2#show ip route 192.168.0.0 255.255.0.0 longer-prefixes
>
> 192.168.9.0/32 is subnetted, 1 subnets
>
> O E1 192.168.9.9 [110/1128] via 172.16.56.6, 1d16h, Serial0.56
>
> 192.168.4.0/32 is subnetted, 1 subnets
>
> D 192.168.4.4 [90/2297856] via 172.16.24.2, 1d16h, Serial0.24
>
> 192.168.5.0/32 is subnetted, 1 subnets
>
> O IA 192.168.5.5 [110/65] via 172.16.56.5, 1d16h, Serial0.56
>
> 192.168.6.0/32 is subnetted, 1 subnets
>
> O IA 192.168.6.6 [110/65] via 172.16.56.6, 1d16h, Serial0.56
>
> 192.168.7.0/32 is subnetted, 1 subnets
>
> O 192.168.7.7 [110/75] via 172.16.56.6, 1d16h, Serial0.56
>
> [110/75] via 172.16.56.5, 1d16h, Serial0.56
>
> 192.168.1.0/32 is subnetted, 1 subnets
>
> R 192.168.1.1 [120/1] via 172.16.12.1, 00:00:22, Serial1
>
> 192.168.2.0/32 is subnetted, 1 subnets
>
> C 192.168.2.2 is directly connected, Loopback0
>
> R2#
>
> 192.168.1.1
>
> 192.168.5.5
>
> 192.168.7.7
>
> 192.168.9.9
>
>
> So, the third and fourth octets are same, let`s just do one of them.
>
> First `and` the values
>
>
> (1&5&7&9) = 1
>
>
> 'or' the values
>
> (1|5|7|9) = 15
>
>
> `xor` the results
>
> 1 xor 15 = 14
>
>
> Answer in permit format (the show `ip route list` list command didn't like
> my deny format)
>
> access-list 12 permit 192.168.1.1 0.0.14.14
>
> Let`s try it on the router.
>
> R2#show ip route list 12
>
> O E1 192.168.9.9 [110/1128] via 172.16.56.6, 1d17h, Serial0.56
>
> O IA 192.168.5.5 [110/65] via 172.16.56.5, 1d17h, Serial0.56
>
> O 192.168.7.7 [110/75] via 172.16.56.6, 1d17h, Serial0.56
>
> [110/75] via 172.16.56.5, 1d17h, Serial0.56
>
> R 192.168.1.1 [120/1] via 172.16.12.1, 00:00:17, Serial1
>
> The final form would be
>
> acess-list 12 deny 192.168.1.1 0.0.14.14
> acess-list 12 permit any
>
> Ok, some notes. The math works, but think about the answer it's giving
> you.
> Permit 10.0.0.0 128.255.255.255 isn't much better than a default route.
> If
> the single line answer has too much scope, try a multiline answer. I've
> included a more complex example from a previous email below.
>
> --------------------------
>
> Summarize the following list:
>
> 133.6.11.0
>
> 135.16.171.0
>
> 172.60.51.0
>
> 121.15.120.0
>
> 112.59.9.0
>
> Now using windows calc in decimal mode, lets do some octet equations.
>
> First will check the first octet for a common network. If there isn't a
> common network, then granddaddy of all summaries is the single line
> answer.
> 0.0.0.0/0
>
> 133&135&172&121&112=0, which means there's no common network for a one
> line
> answer, other than a default network.
>
> There's only 5 networks, so lets check pairs for common networks.
>
> 133&135 = 133, there's common network.
>
> Just checking against the others, 133&172=132, another common network.
>
>
> Note that we're using the result of the preceding common network check to
> check against the next network.
>
> Using 132&121=0; no good.
>
> Checking 132&112=0; also no good.
>
> Maybe 121&112 are common to each other. 121&112=112, which means we can
> have a two line solution. The first three networks, then the next two.
>
>
> A summary is defined as the networks `and` together for the common
> network,
> then the values `or` together. Then take the two results and `xor` for
> the
> wildcard mask.
>
> You do one octet column at a time.
>
> 133.6.11.0
>
> 135.16.171.0
>
> 172.60.51.0
>
> (133&135&172) xor (133|135|172)
>
> answer 132, 132 xor 175
>
> answer network 132 wildcard 43
>
> Next octet,
>
> (6&16&60) xor (6|16|60)
>
> Network 0, 0 xor 62
>
> Answer network 0 wildcard 62
>
> Third octet
>
> (11&171&51) xor (11|171|51)
>
> Network 3, wildcard 184
>
> Putting the answers together,
>
> 132.0.3.0 43.62.184.255
>
> Applying the same treatment to
>
> 121.15.120.0
>
> 112.59.9.0
>
> results as
>
> 112.11.8.0 9.52.113.255
>
> My final answer
>
> access-list 10 permit 132.0.3.0 43.62.184.255
>
> access-list 10 permit 112.11.8.0 9.52.113.255
>
> -----------------------------------
>
> Good Luck and thanks for the Fish!
>
> _______________________________________________________________________
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> http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Sat Sep 01 2007 - 11:32:12 ART