Chapter 6 Broadband
EX5501-B0 / AX7501-B0 / PX7501-B0 User’s Guide
77
WAN IP Address
The WAN IP address is an IP address for the Zyxel Device, which makes it accessible from an outside
network. It is used by the Zyxel Device to communicate with other devices in other networks. It can be
static (fixed) or dynamically assigned by the ISP each time the Zyxel Device tries to access the Internet.
If your ISP assigns you a static WAN IP address, they should also assign you the subnet mask and DNS
server IP address(es).
ATM
Asynchronous Transfer Mode (ATM) is a WAN networking technology that provides high-speed data
transfer. ATM uses fixed-size packets of information called cells. With ATM, a high QoS (Quality of Service)
can be guaranteed. ATM uses a connection-oriented model and establishes a virtual circuit (VC).
PTM
Packet Transfer Mode (PTM) is packet-oriented and supported by the VDSL2 standard. In PTM, packets
are encapsulated directly in the High-level Data Link Control (HDLC) frames. It is designed to provide a
low-overhead, transparent way of transporting packets over DSL links, as an alternative to ATM.
IPv6 Introduction
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 Zyxel
Device can use IPv4/IPv6 dual stack to connect to IPv4 and IPv6 networks, and supports IPv6 rapid
deployment (6RD).
IPv6 Addressing
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
.
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.
