Apr 9th, 2010

Hi all,

I was studying for cisco exam and there is question if this address is valid IPv6 or not

thanks

mahesh

Hello Mahesh,

Each hex digits represents 4 binary digits  = 1 hex = 4 bits

the usual hex dotted representation groups 4 hex and separate these groups using a ':'

So an IPv6 address is made of 8 4hex groups divided by :

the notation allows to represent one of more 4 hex consecutive groups made of all zeroes with a ::

This can appear only once in the number.

Here we see only 6 4-hex groups, no :: appears in the middle to represent all zero groups so it is too short.

an IPv6 prefix is represented with a final ::/prefix length

this is not a valid IPv6 address because it is too short, it could be an IPv6 prefix if written as:

see

Hope to help

Giuseppe

Overall Rating: 5 (1 ratings)

## Replies

Giuseppe Larosa Fri, 04/09/2010 - 11:36
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Hello Mahesh,

Each hex digits represents 4 binary digits  = 1 hex = 4 bits

the usual hex dotted representation groups 4 hex and separate these groups using a ':'

So an IPv6 address is made of 8 4hex groups divided by :

the notation allows to represent one of more 4 hex consecutive groups made of all zeroes with a ::

This can appear only once in the number.

Here we see only 6 4-hex groups, no :: appears in the middle to represent all zero groups so it is too short.

an IPv6 prefix is represented with a final ::/prefix length

this is not a valid IPv6 address because it is too short, it could be an IPv6 prefix if written as:

see

Hope to help

Giuseppe

mahesh18 Fri, 04/09/2010 - 13:28

Hi giuslar,