Chapter 1. Understanding ISDN and the Express 4100/4110
1-10 Express 4100/4110 User Manual 61200176L2-1
Network Address Translation Mode
NAT is a special mode of operation in which the Express 4100/4110
obtains a dynamically assigned IP address from the peer router ( t ypically
an Internet Service Pro vide r). This allows a ne two rk of com puters to ben-
efit fro m Ethernet to ISDN speeds while still appearing to the Internet Se r-
vice Provider (or central site router) as a single IP address, which is
typical of PC based serial dial-up solutions.
A call is initiated to the ISP using the Dial menu or demand for a Connec-
tion List profile that has the IP parameter NAT set to Yes. The network
computer’s IP stack may use DHCP to request an IP addr ess, default gate-
way address, and domain name server addresses from the Express 4100/
4110.
Front Panel
“Express 4100/4110 LEDs” on page 1-11 shows the front panel of the
Express 41 00/4110. The indicato rs are divided in to L AN functions, WAN
functions, and Test functions.
LAN Indicators
TX/RX Flashes green when transmitting data onto the 10BaseT
connector.
Flashes yellow when receiving data from the 10BaseT
connector.
LI Link integrity. Illuminates when there is a good connection between
the Express 4100/4110 and the Hub/NIC card.
WAN Indicators
PWR Flashes when the link is ina c tive; solid when th e link is active.
1 Flashes green when the link is being negotiated; off when the link is
active. After the link is active, 1 flashes green when a call on POTS line
1 is in progress; solid green when a call is connected.
2 Flashes green when the link is being negotiated; off when the link is
active. After the link is active, 2 flashes green when a call on POTS line
2 is in progress; solid green when a call is connected.
Test Indicators
1/2 A slow amber flash indicates test in progress; a fast amber flash indi-
cates test has f ailed.