This question comes after watching Episode 101 of CCENT "Introduction to Routing", but is a general IPv6 question so hopefully it was OK to put it here in the general discussion section.

I ask this not to correct what was said in the episode, but to make sure I understand this properly...

When discussing the IANA IPv6 ranges, specifically the 2000::/3, Don says "This covers anything starting with 20". But, being a /3 range, doesn't that mean this covers anything starting with 2 or 3?

First four bits in binary represent the first hexadecimal digit:

0010 = 2

If the mask is /3, only the first three binary bits are "fixed", therefore the first hexadecimal digit could also be:

0011 = 3

This would also mean that only the first hexadecimal digit is restricted to 2 or 3, the remaining 31 hexadecimal digits (124 bits) could be anything 0 - F, so a network in this range could start 21, 22 ... 3e, 3f, right?

Is this correct, or am I missing something? ]]>

This question comes after watching Episode 101 of CCENT "Introduction to Routing", but is a general IPv6 question so hopefully it was OK to put it here in the general discussion section.

I ask this not to correct what was said in the episode, but to make sure I understand this properly...

When discussing the IANA IPv6 ranges, specifically the 2000::/3, Don says "This covers anything starting with 20". But, being a /3 range, doesn't that mean this covers anything starting with 2 or 3?

First four bits in binary represent the first hexadecimal digit:

0010 = 2

If the mask is /3, only the first three binary bits are "fixed", therefore the first hexadecimal digit could also be:

0011 = 3

This would also mean that only the first hexadecimal digit is restricted to 2 or 3, the remaining 31 hexadecimal digits (124 bits) could be anything 0 - F, so a network in this range could start 21, 22 ... 3e, 3f, right?

Is this correct, or am I missing something? ]]>

Thanks again,

Don Pezet

Host, ITProTV ]]>