Understanding IPv6 routing

Understanding Why IPv6 was Created 

• Limitations of IPv4
• IPv4 has been in use since 1981
• introduced and detailed in RFC 791 
• no substantial updates/improvements
• Exhaustion of IPv4 Address Space
• Explosive growth of the commercial internet
• proliferation of IP-enables devices (smartphones, tablets, etc)
• short-term solutions
• CIDR Classless Interdomain Routing
• NAT Network Address Translation 
• Private Addressing
• Integrated Security
• Original IPv4 specification did not indentify any security mechanisms
• IPsec was a later addition to IP 
• Scalability
• even with CIDR a typical BGP routing table is enormous 
• AT&T route server lists around 373,800 prefixes
• governments are mandating IPv6 adoption
• Benefits of IPv6 Improvements
• Vast Address Space
• 128 bit addressing (as opposed to 32 bit)
• addressing space is about 340 trillion addresses
• Address Assignment
• ability of a device to detect/create its own address
• advanced DHCP and auto-configuration features 
• Global Address Aggregation
• Hierarchical structure