ZyXEL Communications P-660RU-T1 v3, User Manual, Page: 60 / 230

Chapter 7 Internet Setup
P-660RU-Tx v3 User’s Guide
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ADSL Terms
A Permanent Virtual Circuit (PVC) is the connection for your device to the ISP. You need a
Virtual Path Identifier (VPI) and a Virtual Channel Identifier (VCI) to identify a PVC.
Multiplexing is a way of carrying protocols on a PVC. Your ISP should supply you with all
this information.
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) (and a gateway IP address if you use the Ethernet or ENET
ENCAP encapsulation method).
ATM QoS
Asynchronous Transfer Mode (ATM) is a LAN and 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. QoS is a service agreement
that guarantees certain speed even when the network is congested. ATM QoS is defined by the
Peak Cell Rate (PCR), Sustain Cell Rate (SCR) and Maximum Burst Size (MBS).
NAT
NAT (Network Address Translation - NAT, RFC 1631) is the translation of the IP address of a
host in a packet, for example, the source address of an outgoing packet, used within one
network to a different IP address known within another network.
Multicast
Traditionally, IP packets are transmitted in one of either two ways - Unicast (1 sender - 1
recipient) or Broadcast (1 sender - everybody on the network). Multicast delivers IP packets to
a group of hosts on the network - not everybody and not just one.
IGMP
Internet Group Multicast Protocol (IGMP) is a network-layer protocol used to establish
membership in a Multicast group - it is not used to carry user data. There are three versions of
IGMP. IGMP version 2 is an improvement over version 1, but IGMP version 1 is still in wide
use. IGMP version 3 supports source filtering, reporting or ignoring traffic from specific
source address to a particular host on the network.
Finding Out More
See Section 7.3 on page 69 for technical background information on WAN.
7.1.3 Before You Begin
You need to know your Internet access settings such as encapsulation and WAN IP address.
Get this information from your ISP.