User's Manual

Chapter 6 WAN Setup
P-660HW-Tx v3 Series User’s Guide
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and for the VCI is 32 to 65535 (0 to 31 is reserved for local management of ATM
traffic). Please see the appendix for more information.
6.4.4 IP Address Assignment
A static IP is a fixed IP that your ISP gives you. A dynamic IP is not fixed; the ISP
assigns you a different one each time. The Single User Account feature can be
enabled or disabled if you have either a dynamic or static IP. However the
encapsulation method assigned influences your choices for IP address and ENET
ENCAP gateway.
IP Assignment with PPPoA or PPPoE Encapsulation
If you have a dynamic IP, then the IP Address and Gateway IP Address fields
are not applicable (N/A). If you have a static IP, then you only need to fill in the IP
Address field and not the Gateway IP Address field.
IP Assignment with RFC 1483 Encapsulation
In this case the IP address assignment must be static.
IP Assignment with ENET ENCAP Encapsulation
In this case you can have either a static or dynamic IP. For a static IP you must fill
in all the IP Address and Gateway IP Address fields as supplied by your ISP.
However for a dynamic IP, the ZyXEL Device acts as a DHCP client on the WAN
port and so the IP Address and Gateway IP Address fields are not applicable
(N/A) as the DHCP server assigns them to the ZyXEL Device.
6.4.5 Nailed-Up Connection (PPP)
A nailed-up connection is a dial-up line where the connection is always up
regardless of traffic demand. The ZyXEL Device does two things when you specify
a nailed-up connection. The first is that idle timeout is disabled. The second is that
the ZyXEL Device will try to bring up the connection when turned on and
whenever the connection is down. A nailed-up connection can be very expensive
for obvious reasons.
Do not specify a nailed-up connection unless your telephone company offers flat-
rate service or you need a constant connection and the cost is of no concern.
6.4.6 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