Техническая Спецификация для ZyXEL VMG1312-B10A VMG1312-B10A-EU01V1F

Chapter 6 Broadband

VMG1312-B10A User’s Guide

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.