From: Tony Schaffran (groupstudy@cconlinelabs.com)
Date: Fri May 19 2006 - 10:36:15 ART
You can break it up into /28, /29, and /30 subnets, you just need to stay
within your bit boundries.
The best way to illustrate this is like this:
First, create your /28's
192.168.0.0/28
192.168.0.16/28
192.168.0.32/28
192.168.0.48/28
192.168.0.64/28
And so on.....
Then you can take one of those /28's and break it up into smaller /29
subnets.
192.168.0.0/29
192.168.0.8/29
Then you can take on of the /29's you just created and break it down
further.
192.168.0.0/30
192.168.0.4/30
Another thing to keep in mind, is if you are going to use one of the smaller
subnets, it voids the use of the larger subnet it was created from. For
example, if you decide to deploy 192.168.0.4/30 then you cannot use the
192.168.0.0/28
Did I clear anything up or just confuse things further?
Tony Schaffran
Network Analyst
CCIE #11071
CCNP, CCNA, CCDA,
NNCDS, NNCSS, CNE, MCSE
www.cconlinelabs.com
Your #1 choice for online Cisco rack rentals.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Radioactive Frog
Sent: Friday, May 19, 2006 6:16 AM
To: alexeim@orcsoftware.com
Cc: Jai Prakash; ccielab@groupstudy.com
Subject: Re: Subneting - Basic Question but doubt full
HI Alexei,
I am within the subnet boundary. I am only talking about subneting the
192.168.1.0. my first subnet would be /30, second subnet would be /29 third
could be /28, remember its still under the /24 boundary. Why can't I subnet
this IP block like this ?
Frog!
Jumping on the wall
On 5/19/06, Alexei Monastyrnyi <alexeim@orcsoftware.com> wrote:
>
> No, you cannot do like this.. since /30+/30=/29 you have to assign one
> more /30 network after 192.168.1.0/30 to be able to change from /30 to
> /29 , etc /29+/29=/28..
> i.e. you cannot allocate smaller subnet from any place of /24 network,
> you have to consider bit boundaries. in your example you cannot allocate
> /27 subnet from 192.168.1.4...
>
> If I am not missing something here.... :-) pls do correct me otherwise
>
> A.
>
>
>
> on 19/05/2006 02:58 Radioactive Frog wrote:
> > Hi Jaiprakash,
> > thanks for answering to my query:
> >
> > Can't we subnet 192.168.1.0 to as below :
> >
> > a) first subnet 192.168.1.0/30 --> valid host 192.168.1.1 to
> > 192.168.1.2broadcast IP
> > 192.168.1.3
> >
> > b) Second subnet 192.168.1.4/27 --> valid host 192.168.1.5 to
> 192.168.1.34 ?
> >
> > and next subnet /28 and next subnet /30 ??????????
> >
> >
> > OR
> >
> > It has to be either 192.168.1.0/26 or /27 or 38, I mean the whole subnet
> > ?????
> >
> > REgards,
> >
> > Frog
> >
> > Ans of 2nd Qusetion ) Subnet mask for /25 will be 255.255.255.128 (
> Here U
> > can use 2
> > valid Network subnets with 126 valid
> host
> > IPs in each subnet)
> > Subnet mask for /26 will be
> > 255.255.255.192( Here U can use 4
> > valid Network subnets with 62 valid
> > host IPs in each subnet)
> > Subnet mask for /27 will be
> > 255.255.255.224 (Here
> > U can use 8
> > valid Network subnets with 30 valid
> host
> > IPs in each subnet)
> >
> >
> >
> >
> > On 5/19/06, Jai Prakash <jpjsr06@gmail.com> wrote:
> >
> >> Hi Frog
> >>
> >> As per my understanding, when u take calss C as a major network and
> >> divides into subnets, it takes all available subnets with valid hosts.
> >>
> >> In your case, if you divide 192.168.1.0/24 into subnets of 30 block
> host
> >> IP.........you will get 8 valid subnet blocks with each having 30 valid
> >> hosts IP. You can use any subnet from these 8 subnets block.
> >>
> >> The theory says.....don't use 1st IP and the Last IP of the subnets
> >> because, they represent Network IP and Broadcast IP accordangliy for
> that
> >> particular subnet.I never seen that books says don't use 1st subnet and
> >> last subnet, when you divide Major Network into subnets.
> >>
> >> The whole discussion outcome is :
> >>
> >> Ans of 1st Qusetion ) U can use 1st and Last subnet of Major Network
> >>
> >> Ans of 2nd Qusetion ) Subnet mask for /25 will be 255.255.255.128 (
> Here
> >> U can use 2
> >> valid Network subnets with 126 valid
> host
> >> IPs in each subnet)
> >> Subnet mask for /26 will be
> >> 255.255.255.192 ( Here U can use 4
> >> valid Network subnets with 62 valid
> >> host IPs in each subnet)
> >> Subnet mask for /27 will be
> >> 255.255.255.224 (Here U can use 8
> >> valid Network subnets with 30 valid
> host
> >> IPs in each subnet)
> >>
> >> Correct me , if I m wrong................
> >>
> >> Best Regards,
> >> Jai
> >>
> >>
> >>
> >> On 5/18/06, Radioactive Frog <pbhatkoti@gmail.com> wrote:
> >>
> >>> Hi Guys,
> >>>
> >>> Very basic question but lots of doubt.
> >>>
> >>> 1) First question:
> >>>
> >>> If class C subnet 192.168.1.0 is routed to ISP-B (small) by ISP-A (BIG
> >>> ISP).
> >>> When ISP B starts subneting the 192.168.1.0 IP block for different
> >>> customer
> >>> why do he starts distributing from the first subnet from
> 192.168.1.0/24
> >>> (which sholdn't be used)???????????
> >>> The books and theory says first and last subnet shouldn't be used (as
> >>> network and broadcast subnets), hence we shouldn't use the
> >>> 192.168.1.0/24(first <http://192.168.1.0/24%28first> subnet)
> >>>
> >>> Means the ISP should start distributing from second subnets e.g.
> >>> 192.168.1.32 (see below).
> >>>
> >>> ---------------------------------------------------------
> >>> Subnet , Valid Hosts , Broadcast
> >>> 192.168.1.0 , 192.168.1.1 to 192.168.1.30 ,
> 192.168.1.31
> >>> 192.168.1.32 , 192.168.1.33 to 192.168.1.62 , 192.168.1.63
> >>> 192.168.1.64 , 192.168.1.65 to 192.168.1.94 , 192.168.1.95
> >>> 192.168.1.96 , 192.168.1.97 to 192.168.1.126 ,
> 192.168.1.127
> >>> 192.168.1.128 , 192.168.1.129 to 192.168.1.158 ,
> 192.168.1.159
> >>> 192.168.1.160 , 192.168.1.161 to 192.168.1.190 ,
> 192.168.1.191
> >>> 192.168.1.192 , 192.168.1.193 to 192.168.1.222 ,
> 192.168.1.223
> >>> 192.168.1.224 , 192.168.1.225 to 192.168.1.254 ,
> 192.168.1.255
> >>>
> >>>
> >>>
> >>> 1) Second question:
> >>>
> >>> What if ISP starts distributing /25 /26 /27 IP blocks from
> >>> 192.168.1.0/24 IP
> >>> block to the customers ? In this case what subnet mask shouldn't be
> used
> >>> (still first and the last in 192.168.1.0/24 blocks) ?
> >>>
> >>> Appreciate your answers to this basic topic!
> >>>
> >>> Frog!
> >>>
> >>>
> _______________________________________________________________________
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> >>> http://www.groupstudy.com/list/CCIELab.html
> >>>
> >
> > _______________________________________________________________________
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This archive was generated by hypermail 2.1.4 : Thu Jun 01 2006 - 06:33:22 ART