ZyXEL Communications P-660HN-TxA, Руководство пользователя

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Chapter 6 WAN Setup
P-660HN-TxA User’s Guide
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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
packet, used within one network to a different IP address known within another
network.
6.5 Traffic Shaping
Traffic Shaping is an agreement between the carrier and the subscriber to regulate
the average rate and fluctuations of data transmission over an ATM network. This
agreement helps eliminate congestion, which is important for transmission of real
time data such as audio and video connections.
Peak Cell Rate (PCR) is the maximum rate at which the sender can send cells. This
parameter may be lower (but not higher) than the maximum line speed. 1 ATM
cell is 53 bytes (424 bits), so a maximum speed of 832Kbps gives a maximum
PCR of 1962 cells/sec. This rate is not guaranteed because it is dependent on the
line speed.