31. IPv6 : PART 1

HEXIDECIMAL (Review)

What about the reverse (Hex to Binary) ???

WHY IPv6?

The MAIN REASON is that there are simply not enough IPv4 addresses available
There are 2^32 IPv4 Addresses available (4,294,967,296)
When IPv4 was being designed 30 years ago, the creators had NO idea the Internet would be as large as today
VLSM, Private IPv4 ADDRESSES, and NAT have been used to conserve the use of IPv4 ADDRESS SPACE.
- These are short-term solutions, however.
The LONG -TERM solution is IPv6
IPv4 ADDRESS assignments are controlled by IANA (Internet Assigned Number Authority)
IANA distributes IPv4 ADDRESS space to various RIRs (Regional Internet Registries), which then assign them to companies that need them.

On September 24th, 2015, ARIN declared exhaustion of the ARIN IPv4 address pool
On August 21st, 2020, LACNIC announced that it had made its final IPv4 allocation

BASICS OF IPv6

SHORTENING (Abbreviating) IPv6 ADDRESSES

EXPANDING (Abbreviating) IPv6 ADDRESSES

FINDING the IPv6 PREFIX (GLOBAL UNICAST ADDRESSES)

Typically, an Enterprise requesting IPv6 ADDRESSES from their ISP will receive a /48 BLOCK
Typically, IPv6 SUBNETS use a /64 PREFIX LENGTH
That means an Enterprise has 16 bits to use to make SUBNETS
The remaining 64 bits can be used for HOSTS

(Each digit is 4 bits / each 4 digit block is 16 bits)

REMEMBER : You can only remove the LEADING ZEROS !!!

2001 : 0DB8 : 8B00 : 0001 : FB89 : 017B : 0020 : 0011 /93

Because 93 lands in the middle of a 4 bit number, we need to convert the last digit to binary and borrow a “bit” from the first binary digit.

:: 017 [B] :: B = 0d11 = 0b1011 = 0b1000 (the first digit is borrowed, the remainder become 0)

CONFIGURING IPv6 ADDRESSES

This allows the ROUTER to perform IPv6 ROUTING

💡 R1(config) #ipv6 unicast-routing

Configuring an INTERFACE with an IPv6 Address

💡 R1(config) #int g0/0 R1(config-if) #ipv6 address 2001:db8:0:0::1/64 R1(config) #no shutdown

You can also type out the full address (if necessary)

NOTE ABBREVIATED IPv6 ADDRESSES SHOWN

LINK-LOCAL ADDRESSES are automatically added when creating an IPv6 INTERFACE (Covered in IPv6 - PART 2 Lecture)

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