IPv6 addresses are 128 bits long, compared to 32 bits for IPv4 addresses. IPv6 addresses are represented as 8 chunks of 16 bits in hexadecimal separated by colons, compared to 4 chunks of 8 bits in decimal (dotted-quad) for IPv4.  For example, IPv4 addresses looks like:

      128.255.1.3
      209.85.225.106
      38.100.128.10

whereas IPv6 addresses looks like:

      2620:0:e50:2::1
      2001:4860:800b::67
      2001:550:1::cc01

In IPv6, leading 0s in each chunk can be omitted, & a single instance of consecutive 0s can be replaced with "::".  For example, the following IPv6 addresses are equivalent:

      2620:0000:0e50:0002:0000:0000:0000:0001
      2620:0:e50:2:0:0:0:1
      2620:0:e50:2::1

Finally, IPv6 addresses use the same prefix/length notation which is now used for IPv4 to specify blocks of address space.  The "prefix" is the base address of the block.  The "length" is the number of bits from the left which are the same for all addresses in the block.  This is often called "CIDR notation" because it was created when Classless Inter-Domain Routing was employed in the IPv4 Internet.  For example:

The IPv6 address space which will be used on most of the uiowa campus net will be the 2620:0:e50::/48 block.  We also have a "local" fd9a:2c75:7d0c::/48 block for devices which need campus connectivity but not access to the general Internet.