[Day 11] 6. IPv6

Address Size:
IPv6 addresses are 128 bits long (16 bytes), compared to IPv4 addresses, which are only 32 bits (4 bytes). This provides a much larger address space.
Representation:
IPv6 addresses are written in hexadecimal (base-16) format, making it easier to represent the longer addresses in a compact way.

Full Notation:
```
003A:2B1C:0000:0000:0009:0101:0000:007C /64
```
(All groups of zeros are written explicitly.)
Compressed Notation:
```
3A:2B1C:0:0:9:101:0:7C /64
```
(Leading zeros in each group can be removed.)
Using Double Colon (::):
```
3A:2B1C::9:101:0:7C /64
```
(The
```
::
```
replaces consecutive groups of zeros to shorten the address.)
Another Variation:
```
3A:2B1C:0:0:9:101::7C /64
```
(The
```
::
```
can only be used once per address to avoid confusion.)

Network Part (First 64 Bits):
- This part identifies the specific network.
- Example: In
```
3A:2B1C::/64
```
  , the
  3A:2B1C
  is the network prefix.
Host Part (Last 64 Bits):
- This part identifies individual devices (hosts) within the network.
- Example: In
```
3A:2B1C:0:0:9:101:0:7C
```
  , the
  0:0:9:101:0:7C
  is the host portion.

The Double Colon (::) simplifies addresses by replacing consecutive zeros.
- Example:
```
3A:2B1C:0:0:0:0:0:1
```
  can be written as
```
3A:2B1C::1
```
  .
Limitation: The
```
::
```
can be used only once in a single IPv6 address to avoid ambiguity.

Massive Address Space: IPv6 supports a vast number of addresses, solving IPv4's exhaustion problem.
Simplified Network Management: Its structure makes it easier to identify and manage networks.

Enable IPv6 Routing:
- Command:
```
ipv6 unicast-routing
```
Access the Interface:
- Command:
```
int g0/0
```
  (Enter configuration mode for the Gigabit Ethernet interface 0/0.)
Assign an IPv6 Address Using EUI-64:
- Command:
```
ipv6 address 3A:2B1C::/64 eui-64
```
  (Generates the address automatically based on the interface’s MAC address.)
Manually Assign a Specific IPv6 Address:
- Command:
```
ipv6 address 3A:2B1C::1/64
```
  (Manually assigns the first IP in the network to the interface.)