Chapter 1: Understanding ISDN and the Express L128/L128T
61202.070L1-1 Express L128/L128T User Manual 11
Small Office - Home Office (SOHO) to Corporate LAN
• Connects the small office or home office to the corporate LAN
• Routes IP and Internet Packet Exchange (IPX) traffic from multiple devices
to the corporate LAN
• Bridges all non-routed traffic (e.g., AppleTalk)
• Provides dedicated or on-demand services
• Low-cost alternative to buying a high-end router
• Compatible with popular central site LAN access devices
Figure 1-5
SOHO to Corporate LAN
The Express L128/L128T provides the following basic functions:
1. LAN Bridge: Bridging provides a point-to-point connection between two
LANs. The bridge learning function scans the source and destination me-
dia access control (MAC) addresses of all packets on its local LAN and de-
termines which packets should be transmitted over the ISDN link.
Applications include connectivity between single user or small offices to
corporate LANs. The Express L128/L128T uses the Spanning Tree Algo-
rithm (IEEE 802.1d-ISO/IEC10038), which provides a loop-free topology
and redundancy.
Router
ISDN
Server
10 BT
ISDN
1
O
ISDN
OFF
ON
2 1
EIA23210 BASE TPOWER
1 2 3 4
TO
HUB
TO
NIC
Hub
