[LAC-TF] Implementar Tunnel Broker

Tue Jun 5 17:13:19 BRT 2007

Carlos,

    You could find some ipv6 ip calculators by googling for it 
(www.google.com!), seek for something like ipcalc ipv6.
    What if you feel brave?
    Ipv6 works as follow:
ab:cd:ef:gh:ij:kl:mn:op

  Each a,b,c,d,e,f,g,h... chars are one offset in hexadecimal. It contains a 
number from 0 to 255. For example, in the last field, if o has 0 and p has 
something correspondent to 120, you have an ipv6 address that ends on :120 
(ipv6 are by default shown in hexadecimal form, which would be 78 in hex --  
use some sci calculator to pass from base10(decimal) to 
base16(hexadecimal)). In this approach we can realise that only the last 
field holds 256×256 numbers, totalysing 65536 different IP addresses only on 
that field (from 0 to 65535). Now, why all that?
    When you are calculating the subnet, for each increment on the mask you 
divide the network by two. For example, if you define something like ::/0 
(which is a shortcut to 0:0:0:0:0:0:0:0/0), and then increment by one the 
netmask, you get two networks:
0::/1 and 128::/1. Then as you keep splitting the networks (i'll show it 
only for the first parts of the subnets 'tree' that is formed) you'll get 
0::/2 and 64::, and so on:
0::/0 splits into 0::/1 and 32768::/1 or 8000::/1
0::/1 splits into 0::/2 and 4000:/2
0::/2 splits into 0::/3 and 2000::/3
0::/3 splits into 0::/4 and 1000::/4
0::/4 splits into 0::/5 and 800:/5
0::/5 splits into 0::/6 and 400:/6
0::/6 splits into 0::/7 and 200:/7
0::/7 splits into 0::/8 and 100:/8
0::/8 splits into 0::/9 and 80::/9
0::/9 splits into 0::/10 and 40::/10
0::/10 splits into 0::/11 and 20::/11
0::/11 splits into 0::/12 and 10::/12
12 into 8::, 13 into 4::, 14 into 2::, and 15 into 1::, and 16... did you 
think only 0::?
No, now they recurse to the next item so,
0::/15 splits into 0::/16 and 0:8000::/16 and so the story repeats from the 
beginning, now modifying only the second field, until it is empty then third 
then...
/16 is an entire nnnn:x:x:x:x:x:x:x. With a /16 network you'll be bound only 
to the first field, the next seven are up to you to route!..
the point it reaches /128, you'll get something like
0::/127 splits into 0::/128 and 0::1/128
And this 0::/128 can't be split again It is one network containing just one 
IP.

How can you know at once which field is being modified by a /64 or a /48?
Well, for each netprefix increment of 16, we noticed it jumped to the next 
field so, 64/16=4, tis the fourth field and, as it's an exact division, it's 
exactly on one cut-point. Likewise, /48 is the third field, so, if you got a 
/48 class, they can name no more than three of the 'fields' of your ip6 
pool. For example if they say a /48 net of 2001::/48, they refer to the 
2001:0:0::/48, the remaining you can do whatever you want with it, that's 
inside that /48 net. They can also say something like 2001:2fc0:3ba2::/48. 
You can route anything as long as you keep the 2001:2fc0:3ba2 part intact.
  Well, disconsider the small error above, it indicated that /16 is a 
two-network, one with x:0000->x:7fff and other x:8000->x:ffff. No it is not. 
/17 should be that, I've calculated something wrong in the way :P. But 
anyway, the error is small (and i'm too lazy to fix it now), but the idea 
indeed is there.

hope this helps!..

----- Original Message ----- 
From: "Carlos Andres Pulgarin" <carlos1andres at yahoo.com>
To: <lactf at lac.ipv6tf.org>
Sent: Tuesday, June 05, 2007 12:59 PM
Subject: Re: [LAC-TF] Implementar Tunnel Broker

Hola Jordi

Muchas gracias por la explicación.

Eso significa que puedo hacer pruebas con IPv6 con ese
segmento /64 para incursionar y ver las
configuraciones en los clientes, ya que la idea mi o
el proyecto seria que la proxima asignacion de IPS
para el ISP sea en IPv6 y no IPv4

para la pregunta de ipcal si pero actualmente tengo
una para IPv4 me gustaria tener una para IPv6.

Saludos
--- JORDI PALET MARTINEZ <jordi.palet at consulintel.es>
escribió:

> Hola Carlos,
>
> Es facil, en un /64 tienes 2^64 direcciones. Ten en
> cuenta que el requisito
> para el diseño de IPng era de 64 bits en total, y se
> decidio adoptar otros
> 64 para las LAN, con la idea de poder utilizar
> autoconfiguracion y otras
> cosas. Por eso, la idea no es que se utilicen todas
> las posibles direcciones
> de un /64, sino que haya una muy baja posibilidad de
> colisiones (con lo que
> se gana por ejemplo frente a un posible port
> scanning que tardaria 5.3
> billones de años).
>
> El subnneting es mas sencillo si cabe que con IPv4,
> aunque parezca que sea
> mas completo porque tienes mas bits.
>
> Si un proveedor recibe un /32, y entrega a un
> cliente un /48, el cliente
> puede hacer subneting de /48 a /64 (65.535
> subredes).
>
> Lo de la calculadora supongo que te refieres al
> ipcalc ?
>
> Saludos,
> Jordi
>
>
>
>
> > De: Carlos Andres Pulgarin
> <carlos1andres at yahoo.com>
> > Responder a: <lactf at lac.ipv6tf.org>
> > Fecha: Tue, 5 Jun 2007 03:19:52 -0500 (CDT)
> > Para: <lactf at lac.ipv6tf.org>
> > Asunto: Re: [LAC-TF] Implementar Tunnel Broker
> >
> > Hola
> >
> > Me gustaria conocer si hay una tabla disponible de
> > como hacer subneting en IPv6 o una calculadora
> >
> > Y saber cuantas ips tengo disponibles en un
> segmento
> > /64.
> >
> > Gracias
> >
> > __________________________________________________
> > Correo Yahoo!
> > Espacio para todos tus mensajes, antivirus y
> antispam ¡gratis!
> > Regístrate ya - http://correo.espanol.yahoo.com/
> > _______________________________________________
> > LACTF mailing list
> > LACTF at lacnic.net
> > https://mail.lacnic.net/mailman/listinfo/lactf
>
>
>
>
> **********************************************
> The IPv6 Portal: http://www.ipv6tf.org
>
> Bye 6Bone. Hi, IPv6 !
> http://www.ipv6day.org
>
> This electronic message contains information which
> may be privileged or confidential. The information
> is intended to be for the use of the individual(s)
> named above. If you are not the intended recipient
> be aware that any disclosure, copying, distribution
> or use of the contents of this information,
> including attached files, is prohibited.
>
>
>
> _______________________________________________
> LACTF mailing list
> LACTF at lacnic.net
> https://mail.lacnic.net/mailman/listinfo/lactf
>

__________________________________________________
Correo Yahoo!
Espacio para todos tus mensajes, antivirus y antispam ¡gratis!
Regístrate ya - http://correo.espanol.yahoo.com/
_______________________________________________
LACTF mailing list
LACTF at lacnic.net
https://mail.lacnic.net/mailman/listinfo/lactf