ZyXEL Communications VMG892-B10A User Manual page 48

Chapter 5 Broadband
• 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.
IPv6 Prefix and Prefix Length
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.
IPv6 Subnet Masking
Both an IPv6 address and IPv6 subnet mask compose of 128-bit binary digits, which are divided
into eight 16-bit blocks and written in hexadecimal notation. Hexadecimal uses four bits for each
character (1 ~ 10, A ~ F). Each block's 16 bits are then represented by four hexadecimal
characters. For example, FFFF:FFFF:FFFF:FFFF:FC00:0000:0000:0000.
IPv6 Rapid Deployment
Use IPv6 Rapid Deployment (6rd) when the local network uses IPv6 and the ISP has an IPv4
network. When the Device has an IPv4 WAN address and you set IPv6/IPv4 Mode to IPv4 Only,
you can enable 6rd to encapsulate IPv6 packets in IPv4 packets to cross the ISP's IPv4 network.
The Device generates a global IPv6 prefix from its IPv4 WAN address and tunnels IPv6 traffic to the
ISP's Border Relay router (BR in the figure) to connect to the native IPv6 Internet. The local
network can also use IPv4 services. The Device uses it's configured IPv4 WAN IP to route IPv4
traffic to the IPv4 Internet.
Figure 20 IPv6 Rapid Deployment
LAN
- IPv6
- IPv4
+ IPv4
IPv6
48
WAN
- IPv4
- IPv6 in IPv4
ISP (IPv4)
IPv6 in IPv4
IPv4
IPv4 Internet
VMG8924-B10A and VMG8924-B30A Series User's Guide
BR
IPv6 Internet