# IPv6
**IPv4 has several problems:**
- Scarce IPv4 address.
- IPv4 header contains fields that are not used by every packet (should be optional)
- IPv4 imposes extra processes on routers, the network can become slower (such as fragmentation and checksum calculations)
- IPv4 does not provide any security measurement at network layer.

**IPv6 Format:**
![[IPV6-format.png]]