ZyXEL Communications P-861H-G1, Руководство пользователя, Страница: 73 / 341

Prestige 861H Series User’s Guide
Chapter 5 WAN Setup 72
5.1.4.3 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 ENET ENCAP Gateway fields as supplied by your ISP. However for a
dynamic IP, the Prestige acts as a DHCP client on the WAN port and so the IP Address and
ENET ENCAP Gateway fields are not applicable (N/A) as the DHCP server assigns them to
the Prestige.
5.1.5 Nailed-Up Connection (PPP)
A nailed-up connection is a dial-up line where the connection is always up regardless of traffic
demand. The Prestige does two things when you specify a nailed-up connection. The first is
that idle timeout is disabled. The second is that the Prestige 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
5.1.6 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 packet, used within one
network to a different IP address known within another network.
5.2 PPPoE Encapsulation
The Prestige supports PPPoE (Point-to-Point Protocol over Ethernet). PPPoE is an IETF Draft
standard (RFC 2516) specifying how a personal computer (PC) interacts with a broadband
modem (DSL, cable, wireless, etc.) connection. The
PPPoE
option is for a dial-up connection
using PPPoE.
For the service provider, PPPoE offers an access and authentication method that works with
existing access control systems (for example Radius). PPPoE provides a login and
authentication method that the existing Microsoft Dial-Up Networking software can activate,
and therefore requires no new learning or procedures for Windows users.
One of the benefits of PPPoE is the ability to let you access one of multiple network services,
a function known as dynamic service selection. This enables the service provider to easily
create and offer new IP services for individuals.
Operationally, PPPoE saves significant effort for both you and the ISP or carrier, as it requires
no specific configuration of the broadband modem at the customer site.
By implementing PPPoE directly on the Prestige (rather than individual computers), the
computers on the LAN do not need PPPoE software installed, since the Prestige does that part
of the task. Furthermore, with NAT, all of the LANs’ computers will have access.