Chapter 1: Understanding ISDN and the Express L128/L128T
Network Address Translation Mode
NAT is a special mode of operation in which the Express L128/L128T obtains a dynamically assigned IP address from the peer router (typically an Internet Service Provider). This allows a network of computers to benefit from Ether- net to ISDN speeds while still appearing to the Internet Service Provider (or central site router) as a single IP address, which is typical of PC based serial
A call is initiated to the ISP using the Dial menu or demand for a Connection List profile that has the IP parameter NAT set to Yes. The network computer’s IP stack may use DHCP to request an IP address, default gateway address, and domain name server addresses from the Express L128/L128T.
Front Panel
Figure 1-6 on page 17 shows the front panel of the Express L128/L128T. The indicators are divided into LAN functions, WAN functions, and Test func- tions.
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 L128/L128T and the Hub/NIC card. |
16 | Express L128/L128T User Manual |
