38 messages in net.nether.puck.cisco-nsp[c-nsp] VLSM
FromSent OnAttachments
ShaunJan 10, 2005 4:53 pm 
Gert DoeringJan 10, 2005 5:26 pm 
Stephen J. WilcoxJan 10, 2005 5:27 pm 
matthew zeierJan 10, 2005 5:46 pm 
ShaunJan 10, 2005 6:19 pm 
Michael SmithJan 10, 2005 6:26 pm 
Stephen J. WilcoxJan 10, 2005 6:28 pm 
lis...@hojmark.orgJan 10, 2005 6:55 pm 
Brant I. StevensJan 10, 2005 11:25 pm 
Gert DoeringJan 11, 2005 2:33 am 
Stephen J. WilcoxJan 11, 2005 6:11 am 
Mark PersikoJan 11, 2005 10:49 am 
Gert DoeringJan 11, 2005 11:22 am 
Hudson Delbert J Contr 61 CS/SCBNJan 11, 2005 12:11 pm 
Brant I. StevensJan 11, 2005 12:45 pm 
Pete TemplinJan 11, 2005 12:52 pm 
Stephen J. WilcoxJan 11, 2005 1:30 pm 
Stephen J. WilcoxJan 11, 2005 1:39 pm 
Pete TemplinJan 11, 2005 2:09 pm 
Gert DoeringJan 11, 2005 2:47 pm 
Gert DoeringJan 11, 2005 2:48 pm 
matthew zeierJan 11, 2005 3:09 pm 
lis...@hojmark.orgJan 11, 2005 5:22 pm 
Anson RinesmithJan 11, 2005 5:47 pm 
Michael LoftisJan 11, 2005 5:57 pm 
Stephen J. WilcoxJan 11, 2005 7:23 pm 
Stephen J. WilcoxJan 11, 2005 7:37 pm 
ShaunJan 11, 2005 8:31 pm 
Jon LewisJan 11, 2005 9:48 pm 
Majid FaridJan 12, 2005 12:24 am 
matthew zeierJan 12, 2005 1:23 am 
Ted MittelstaedtJan 12, 2005 1:41 am 
Ted MittelstaedtJan 12, 2005 1:44 am 
Ted MittelstaedtJan 12, 2005 1:51 am 
lis...@hojmark.orgJan 12, 2005 1:18 pm 
lis...@hojmark.orgJan 12, 2005 1:30 pm 
ShaunJan 13, 2005 4:05 am 
Ted MittelstaedtJan 14, 2005 12:29 am 
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Subject:[c-nsp] VLSMActions...
From:Stephen J. Wilcox (ste@telecomplete.co.uk)
Date:Jan 11, 2005 7:37:24 pm
List:net.nether.puck.cisco-nsp

no no no no it absolutely is not! read rfc1812

<rant> to be a Class B,

1) our routers must be operating in classful mode (no ip classless) which changes the behaviour of routing

2) the first two bits of the ip address must be 1-0

i may be given the netblock 172.13.14.0/24... the first two bits are 1-0 therefore by rfc796 it must be class b network 172.13.0.0 using a subnet of 255.255.255.0 creating 256x 172.13.x.y networks - clearly not true

alternatively i may have 195.0.0.0/16 .. as it is a /16 it must be class B, but class B must start 1-0 and this starts 1-1 .. in fact according to rfc796 it is in class C space so i must be talking about 256x Class Cs - this is actually what you say below. but this is also untrue because i have taken the /16 and i have split it into 4x /18s each of which is a single lan subnet eg 195.0.64.0/255.255.192.0 with default gateway 195.0.127.254 .. in fact i may wish to assign my computer the ip 195.0.100.255/18 -- something which is reserved according to rfc796 as a broadcast address

do you see how none of this can work when we start mixing the logic of classful network and classful behaviour with classless?

Steve

On Tue, 11 Jan 2005, Anson Rinesmith wrote:

Actually according to the RFC, Class B and /16 (16-bit local address) are the same thing...

"The second type (or class b) of address has a 14-bit network number and a 16-bit local address."

If you have a /16 (or class b), and give me anyone 1 IP in that range, I can tell you the beginning and ending IP of that range, otherwise it is just a group of Class C's.

-----Original Message----- From: cisc@puck.nether.net [mailto:cisco-nsp- boun@puck.nether.net] On Behalf Of lis@hojmark.org Sent: Tuesday, January 11, 2005 4:25 PM To: 'Hudson Delbert J Contr 61 CS/SCBN'; 'matthew zeier'; 'Gert Doering'; 'Shaun' Cc: cisc@puck.nether.net Subject: RE: [c-nsp] VLSM

since when is a /16 size chunk of addresses not a class 'b' space.

It's only class B if the first two bits are 10, otherwise it's a just block of addresses the same size as an old class b. Check out http://rfc.sunsite.dk/rfc/rfc796.html

... But why not simply call it "a /16", since that's what it is?

i think what manner in which the size of a space is called as long as one understands what it speak of. much ado about nothing methinks.

OK. I'll just call you Peter then, though that's not your name. It doesn't really matter as long as people know I mean you ;-)

-A

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