Internet Protocol version 6 (IPv6) expands the number of network address bits from 32 bits (in IPv4) to 128 bits, which provides more than enough globally unique IP addresses for every networked device on the planet. Feature Information for IPv6 Addressing and Basic Connectivity.Example: Hostname-to-Address Mappings Configuration.Example: Dual-Protocol Stack Configuration.Example: IPv6 Addressing and IPv6 Routing Configuration.Configuration Examples for IPv6 Addressing and Basic Connectivity.Configuring an Interface to Support the IPv4 and IPv6 Protocol Stacks.Configuring IPv6 Addressing and Enabling IPv6 Routing.How to Configure IPv6 Addressing and Basic Connectivity.IPv6 on BVI Interfaces for Bridging and Routing.

IPv6 for Cisco Software Support for Wide-Area Networking Technologies.

Cisco Discovery Protocol IPv6 Address Support.

Large IPv6 Address Space for Unique Addresses.

Information About IPv6 Addressing and Basic Connectivity.

Restrictions for IPv6 Addressing and Basic Connectivity.

Just be sure to NEVER compress trailing zeros, and NEVER EVER compress more than one instance of neighboring all-zero blocks in any one address using the double colon (::).

Multiple all-zero blocks can be compressed down to a single 0.Īny and all of these IPv6 compression techniques can be employed on any legal IPv6 address.

Leading zeros in any/all blocks of an address can be dropped to compress further.

It would be impossible to reliably decompress the address. There would be absolutely no way of knowing how the 5 compressed blocks are allocated between the two gaps. If there are two gaps to fill, it is anyone’s guess as to how many compressed blocks belong to each gap.Ġ143:0000:0000:FF2A:0000:0000:0000:0231 down to Rebuilding the address relies upon filling in the remaining number of blocks in the :: gap with zeros, with the knowledge that each address contains 8 blocks.

It becomes obvious why consecutive all-zero blocks can only be compressed one time in any given address. Any single group of neighboring blocks with all zeros in an address can be compressed using a double colon (::).IPv6 addresses are comprised of 8 “quartets” or “blocks” of 4 hex digits.

Topics covered include address format, two ways of compressing all-zero blocks, and compressing leading-zeros. This is fundamental to working with IPv6, so pay attention and make sure you understand it. Here are some quick bullet points about the formatting and compression techniques used in IPv6.

Two rules of ipv6 compression