ZyXEL Communications EMG5324-D10A User Manual

EMG5324-D10A User’s Guide

IPv6 (Internet Protocol version 6), is designed to enhance IP address size and 
features. The increase in IPv6 address size to 128 bits (from the 32-bit IPv4 
address) allows up to 3.4 x 10

38

 IP addresses. 

The 128-bit IPv6 address is written as eight 16-bit hexadecimal blocks separated 
by colons (:). This is an example IPv6 address 
2001:0db8:1a2b:0015:0000:0000:1a2f:0000

. 

IPv6 addresses can be abbreviated in two ways:

• Leading zeros in a block can be omitted. So 

2001:0db8:1a2b:0015:0000:0000:1a2f:0000

 can be written as 

2001:db8:1a2b:15:0:0:1a2f:0

. 

• Any number of consecutive blocks of zeros can be replaced by a double colon. A 

double colon can only appear once in an IPv6 address. So 
2001:0db8:0000:0000:1a2f:0000:0000:0015

 can be written as 

2001:0db8::1a2f:0000:0000:0015

, 2001:0db8:0000:0000:1a2f::0015, 

2001:db8::1a2f:0:0:15

 or 2001:db8:0:0:1a2f::15.

Similar to an IPv4 subnet mask, IPv6 uses an address prefix to represent the 
network address. An IPv6 prefix length specifies how many most significant bits 
(start from the left) in the address compose the network address. The prefix 
length is written as “/x” where x is a number. For example, 

2001:db8:1a2b:15::1a2f:0/32

means that the first 32 bits (2001:db8) is the subnet prefix.