Re: Class "A" prefix-list

Hammer,

Q1:

I did that for illustration purpose ONLY. I was trying to show how you match
class A networks that are NOT subnetted, and i was also trying to setup the
grounds for the second item that i was showing.
Q2:

If the question does not state any details, i would recommend doing it for
all class A major networks and subnetted class A networks.
On Wed, Jun 1, 2011 at 2:56 PM, Hammer cisco <cisco.iers_at_gmail.com> wrote:

> Hi Narbrik,
>
> thanks for your illustrations , but i have 2 comments :
>
> 1- i think 0.0.0.0/1 ge 8 is enough instead of saying "ge 8 le 32 " as
> mentioned in your example below
>
> 2- if the the required in a certain routing protocol to deny all Class A
> network address routes :
> what do u recommend ?
>
>
>
> On 2 June 2011 00:21, Narbik Kocharians <narbikk_at_gmail.com> wrote:
>
>> *
>>
>> Class A networks that are NOT subnetted:
>>
>>
>>
>> R2(config)#ip prefix-list Class-A seq 5 permit 0.0.0.0/1 ge 8 le 8
>>
>>
>>
>> Class A networks are identified as follows:
>>
>>
>>
>> Where n identifies the network bits and h identifies the host bits.
>>
>> 0nnnnnnn hhhhhhhh hhhhhhhh hhhhhhhh
>>
>> 7 First bit is set to 0; Therefore there
>> are 7 network bits; 24 host bits
>>
>> 7 First octet: 0 - 127
>>
>> 7 126 Class As exist (0 and 127 are
>> reserved)
>>
>> 7 16,777,214 hosts on each Class A
>>
>> Note the most significant bit of the first octet is set to a binary 0,
>> the rest of the bits in the first octet can be zeros or ones, therefore,
if
>> the most significant bit of the first octet is 0 it must be class A. The
>> prefix-list picks on the first bit by using a /1 prefix-length.
>>
>>
>>
>> Class A networks that are or are not subnetted:
>>
>>
>>
>> R2(config)#ip prefix-list Class-A seq 5 permit 0.0.0.0/1 ge 8 le 32
>>
>>
>>
>> Note in this case the prefix-list picks on class A, with a prefix-length
>> of greater than or equal 8 and less than or equal 32, which means that all
>> major class A networks, plus all class A networks that are subnetted.
>>
>>
>>
>> *
>> On Wed, Jun 1, 2011 at 1:45 PM, Hammer cisco <cisco.iers_at_gmail.com>wrote:
>>
>>> thanks danel ,
>>>
>>> but still i need to know exactly what's the difference between
0.0.0.0/1ge
>>> 8 and 0.0.0.0/1 le 32
>>>
>>> as i think all class A networks starting from mask 8 and greater , i have
>>> not seen a network with mask less 8
>>>
>>> On 1 June 2011 23:35, Daniel Kutchin <daniel_at_kutchin.com> wrote:
>>>
>>> > If you just want to match Class A's with 8 bit masks, Class B's with 16
>>> bit
>>> > masks, and class C's with 24 bit masks.
>>> >
>>> > 0.0.0.0/1 ge 8 le 8
>>> > 128.0.0.0/2 ge 16 le 16
>>> > 192.0.0.0/3 ge 24 le 24
>>> >
>>> > If you want to match anything in the individual address spaces for
>>> class
>>> > A,B, C
>>> > 0.0.0.0/1 le 32
>>> > 128.0.0.0/2 le 32
>>> > 192.0.0.0/3 le 32
>>> >
>>> >
>>> > Class A- binary first bit 0.
>>> > Class B - binary first two bits 10.
>>> > Class C - binary first three bits 110.
>>> >
>>> > -
>>> > Daniel
>>> >
>>> >
>>> > -----Original Message-----
>>> > From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf
>>> Of
>>> > Hammer cisco
>>> > Sent: Mittwoch, 1. Juni 2011 21:38
>>> > To: ccielab_at_groupstudy.com
>>> > Subject: Class "A" prefix-list
>>> >
>>> > Hi experts,
>>> >
>>> > i am a little bit confused about the exact prefix-list we can use to
>>> match
>>> > all class A network address routes :
>>> >
>>> > ip prefix-list 0.0.0.0/1 ge 8
>>> >
>>> > or
>>> >
>>> > ip prefix-list 0.0.0.0/1 le 32
>>> >
>>> >
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>>>
>>>
>>>
>>>
>>>
>>
>>
>> --
>> *Narbik Kocharians
>> *CCSI#30832, CCIE# 12410 (R&S, SP, Security)
>> www.MicronicsTraining.com <http://www.micronicstraining.com/>
>> Sr. Technical Instructor
>> *Ask about our FREE Lab Voucher with our Boot Camps*
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>>
>>
>

--
*Narbik Kocharians
*CCSI#30832, CCIE# 12410 (R&S, SP, Security)
www.MicronicsTraining.com <http://www.micronicstraining.com/>
Sr. Technical Instructor
*Ask about our FREE Lab Voucher with our Boot Camps*
YES! We take Cisco Learning Credits!
Training & Remote Racks available
Blogs and organic groups at http://www.ccie.net