CCNP - IPv6

Address Format
Example IPv6 Address: 2001:0050:0000:0000:0000:0AB4:1E2B:98AA 2001:0050::0AB4:1E2B:98AA 2001:50::AB4:1E2B:98AA
 * Divided into 8 sections of 4 hexadecimal characters.
 * Groups of consecutive zeros can be shortened to a ::.
 * Leading zeros are dropped.

Headers

 * Have 8 sections:
 * Version
 * Traffic Class (for QoS)
 * Flow Label
 * Payload Length
 * Next Header
 * Hop Limit
 * Source IP
 * Destination IP
 * IPv6 headers support "header extensions".

Communication and Address Types

 * Three types of messages:
 * Unicast
 * Multicast
 * Anycast
 * Three types of addresses:
 * Link-Local: layer 2 domain, typically auto-generated
 * Unique/Site-Local: private range, no longer used
 * Global Scope: for the Internet

Link-Local Addresses

 * Automatically generated when an IPv6 host comes online.
 * Scope is local to the network only.
 * Format:
 * First 64 bits = FE80
 * Last 64 bits = MAC address with FFFE in the middle.
 * FE80::C202:12FF:FEDC:0

Global Scope Address

 * Used in Internet communication.

Subnetting

 * 1) An ISP assigns the prefix 2320:1111:AAAA::/48 to a company.
 * 2) The network engineer borrows 16 host bits for subnets (mask of /64).
 * 3) This leaves 64 host bits, totalling 2^16 subnets (65,536) and 2^64 hosts.