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Post #67,650
by folkert
Picture of folkert
12/9/02 6:41:37 PM
Reply
New Might be interested to know...
Subnet masks 11111111.11111111.11111111.11110000 (or 255.255.255.240 or 0xFF.0xFF.0xFF.0xF0) and 11111111.11111111.11111111.00001111 (or 255.255.255.16 or 0xFF.0xFF.0xFF.0x0F) are not equal halves of a subnet. They a "16ths" of a "/24"subnet. 11111111.11111111.11111111.10000000 (or 255.255.255.128 or 0xFF.0xFF.0xFF.0x80) would be half of a 255 subnet( or "/25" is half of "/24").

255.255.255.240(which would be a "/28" subnet, being CIDR compliant) has 16 subnets 0-15, 16-31, 32-47, 48-53, 54-63, 64-79, 80-95, 96-111, 112-127, 128-143, 144-159, 160-171, 172-187, 188-203, 204-219, 220-235, 236-255. Each with a network Designate(first address IOW 192.168.0.0/28 is designate) giving us 192.168.0.1-14 usable addresses and a Network Broadcast (last address 192.168.0.15).

255.255.255.16(is not classable and is not CIDR compliant) has 16 subnets too, but are differing in length: "0,16,32,48,54,64,80,96,112,128,144,160,172,188,204,220,236" is "0" subnet, "1,17,33,49,55,65,81,97,113,129,145,161,172,189,205,221,237" is "1" subnet, etc...

It would get ALOT more screwed up then that if you used say: 11111111.11111111.11111111.10010101 (or 255.255.255.149 or 0xFF.0xFF.0xFF.0x95) it hurts my head to think that hard... but if you want answers... I'd be more than happy to guide you into solving it yourself.
[link|mailto:curley95@attbi.com|greg] - Grand-Master Artist in IT
[link|http://www.iwethey.org/ed_curry/|REMEMBER ED CURRY!!!]

Your friendly Geheime Staatspolizei reminds:
[link|http://www.wired.com/news/wireless/0,1382,56742,00.html|Wi-Fi enabled device use] comes with an all inclusive
free trip to the (county)Photographer!
Overbooking, is a problem, please be prepared for "room-ies".

Why You ask? Here is the answer to your query:
SELECT * FROM politicians WHERE iq > 40 OR \\
  WHERE ego < 1048575;
0 rows found
Post #67,688
by boxley
12/9/02 9:27:33 PM
Reply
New swotting the old CCNA books?
subneting in binary gives me a headache unless i is the easy stuff, would rather decipher ss7 ain messages.
thanx,
bill
will work for cash and other incentives [link|http://home.tampabay.rr.com/boxley/resume/Resume.html|skill set]


Opera was the television of the nineteenth century:loud, vulgar and garish with plots that could only be called infantile. "Pendergast"
Post #67,702
by folkert
Picture of folkert
12/9/02 10:34:39 PM
Reply
New No... actually Bill...
Was pulling those from memory...

If I were to pull out those old CCNA or Cisco IOS manuals or the Bay Network manuals for SiteMangler, then I'd be spouting off the OOB SNM and Variable SNM networking scenarios...

Head hurts... must stop thinking in BINARY..... Must convert to 0x(HEX)... then Octal *THEN* Decimal... ahhh better.

As teh saying goes:

There are 10 people that understand Binary, those that do, and those that don't!

Personally I like "Safe Hex" better.

[link|mailto:curley95@attbi.com|greg] - Grand-Master Artist in IT
[link|http://www.iwethey.org/ed_curry/|REMEMBER ED CURRY!!!]

Your friendly Geheime Staatspolizei reminds:
[link|http://www.wired.com/news/wireless/0,1382,56742,00.html|Wi-Fi enabled device use] comes with an all inclusive
free trip to the (county)Photographer!
Overbooking, is a problem, please be prepared for "room-ies".

Why You ask? Here is the answer to your query:
SELECT * FROM politicians WHERE iq > 40 OR \\
  WHERE ego < 1048575;
0 rows found
Post #67,707
by deSitter
Picture of deSitter
12/9/02 11:00:54 PM
12/9/02 11:05:55 PM
Reply
New Re: swotting the old CCNA books?
Fun with number representation - the factorial basis.

Consider this series:

0,1,10,11,20,21,100,101,110,111,120,121,200,201,210,211,220,221,300,301,310,311,320,321,1000,1001...

The kth digit can take on values 0...k. The last number before a turnover of digits is k.(k-1).(k-2)...321. Thus 7654321 + 1 = 10000000.

Now, it so happens that

100....00 (k zeros) is the representation of (k+1)! = (k+1)k(k-1)(k-2)..1 and by definition 0! = 1.

Thus a number in this representation can be written

A = sum(0..k) An * n!

where 0 <= An <= n.

What are the primes?

2 = 10
3 = 11
5 = 21
7 = 101
11 = 121
13 = 201
17 = 221
19 = 301
23 = 321
29 = 1021
31 = 1101
37 = 1201
41 = 1221

Here are all the primes up to 719 = 6!-1 ;

0 0 0 1 0
0 0 0 1 1
0 0 0 2 1
0 0 1 0 1
0 0 1 2 1
0 0 2 0 1
0 0 2 2 1
0 0 3 0 1
0 0 3 2 1
0 1 0 2 1
0 1 1 0 1
0 1 2 0 1
0 1 2 2 1
0 1 3 0 1
0 1 3 2 1
0 2 0 2 1
0 2 1 2 1
0 2 2 0 1
0 2 3 0 1
0 2 3 2 1
0 3 0 0 1
0 3 1 0 1
0 3 1 2 1
0 3 2 2 1
0 4 0 0 1
0 4 0 2 1
0 4 1 0 1
0 4 1 2 1
0 4 2 0 1
0 4 2 2 1
1 0 1 0 1
1 0 1 2 1
1 0 2 2 1
1 0 3 0 1
1 1 0 2 1
1 1 1 0 1
1 1 2 0 1
1 1 3 0 1
1 1 3 2 1
1 2 0 2 1
1 2 1 2 1
1 2 2 0 1
1 2 3 2 1
1 3 0 0 1
1 3 0 2 1
1 3 1 0 1
1 3 3 0 1
1 4 1 0 1
1 4 1 2 1
1 4 2 0 1
1 4 2 2 1
1 4 3 2 1
2 0 0 0 1
2 0 1 2 1
2 0 2 2 1
2 0 3 2 1
2 1 0 2 1
2 1 1 0 1
2 1 2 0 1
2 1 2 2 1
2 1 3 0 1
2 2 0 2 1
2 2 3 0 1
2 2 3 2 1
2 3 0 0 1
2 3 0 2 1
2 3 3 0 1
2 4 0 0 1
2 4 1 2 1
2 4 2 0 1
2 4 2 2 1
2 4 3 2 1
3 0 1 0 1
3 0 2 0 1
3 0 3 0 1
3 0 3 2 1
3 1 0 2 1
3 1 2 0 1
3 1 2 2 1
3 2 0 0 1
3 2 1 2 1
3 2 2 0 1
3 2 3 2 1
3 3 0 0 1
3 3 1 0 1
3 3 1 2 1
3 3 2 2 1
3 4 0 0 1
3 4 0 2 1
3 4 1 0 1
3 4 1 2 1
3 4 3 2 1
4 0 1 0 1
4 0 1 2 1
4 0 3 0 1
4 0 3 2 1
4 1 0 2 1
4 1 2 2 1
4 1 3 0 1
4 2 2 0 1
4 2 3 0 1
4 3 0 2 1
4 3 1 2 1
4 3 2 2 1
4 3 3 0 1
4 4 0 0 1
4 4 1 2 1
4 4 2 2 1
4 4 3 2 1
5 0 0 0 1
5 0 1 0 1
5 0 2 0 1
5 0 2 2 1
5 0 3 0 1
5 1 1 0 1
5 1 2 2 1
5 1 3 0 1
5 1 3 2 1
5 2 0 2 1
5 2 1 2 1
5 2 2 0 1
5 3 0 0 1
5 3 0 2 1
5 3 1 2 1
5 3 3 0 1
5 4 0 2 1
5 4 2 0 1
5 4 3 2 1

Can you see a pattern?
-drl
Expand Edited by deSitter Dec. 9, 2002, 11:05:55 PM EST
Expand All History
Post #67,695
by deSitter
Picture of deSitter
12/9/02 10:06:46 PM
Reply
New Re: Might be interested to know...
Who says subnets have to be consecutive? :)

You could even break down cases like mask = .01101001 = .105. It's just bit flipping and addition modulo the mask.
-drl
Post #67,700
by folkert
Picture of folkert
12/9/02 10:29:22 PM
Reply
New Yep... I know the whole shebang...
It's what I specialized in... I took so many freaking TCP/IP courses, read so-many books, had long talks with just about anyone in the TCP/IP design process... RFP Process, etc...

One reason why Out Of Bit Order Subnet Masking is not standard... Too many people screwed it up!

The Backbone carriers will not route an OOB SNM. mainly cause BGP and so on, work best in CIDR mode. Oh well. Too bad.

I see an awful lot of <127.0.0.0 subnets are starting to get used better now. Some of them have changed hands of late. Although, some companies like ATTBI is getting awful sloppy with re-distributing the 12.X.X.X network.
[link|mailto:curley95@attbi.com|greg] - Grand-Master Artist in IT
[link|http://www.iwethey.org/ed_curry/|REMEMBER ED CURRY!!!]

Your friendly Geheime Staatspolizei reminds:
[link|http://www.wired.com/news/wireless/0,1382,56742,00.html|Wi-Fi enabled device use] comes with an all inclusive
free trip to the (county)Photographer!
Overbooking, is a problem, please be prepared for "room-ies".

Why You ask? Here is the answer to your query:
SELECT * FROM politicians WHERE iq > 40 OR \\
  WHERE ego < 1048575;
0 rows found
     Might be interested to know... - (folkert) - (5) - Dec. 9, 2002, 06:41:37 PM EST
         swotting the old CCNA books? - (boxley) - (2) - Dec. 9, 2002, 09:27:33 PM EST
             No... actually Bill... - (folkert) - Dec. 9, 2002, 10:34:39 PM EST
             Re: swotting the old CCNA books? - (deSitter) - Dec. 9, 2002, 11:05:55 PM EST
         Re: Might be interested to know... - (deSitter) - (1) - Dec. 9, 2002, 10:06:46 PM EST
             Yep... I know the whole shebang... - (folkert) - Dec. 9, 2002, 10:29:22 PM EST

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