US Robotics ADSL Ethernet Modem Overview page 6

Note: After you click OK, you will be prompted to save your settings.
Click Save to save the changes you have made.
Configuring the Service Provider Settings
The ADSL modem supports four Service Provider WAN services:
•
RFC1483 Bridged Mode (To be used as an Ethernet bridge)
•
RFC1483 Routed Mode
•
PPP over ATM (PPPoA) Mode
•
PPP over Ethernet (PPPoE) Mode
A more detailed description of each connection mode follows.
Configure RFC1483 Bridged Mode
Select RFC1483 Bridged to use RFC1483 Bridged mode. Bridging is a
standardized layer 2 technology. It is typically used in corporate networks
to extend the physical reach of a single LAN segment and increase the
number of stations on the common LAN without compromising
performance. Bridged data is encapsulated using the RFC1483 protocol
to enable data transport.
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One important characteristic of bridging is the number of bridge ports.
The ADSL modem has eight remote virtual ports on the ADSL interface
and one local port (Ethernet) on the user interface.
The ports on the ADSL interface are described as virtual because they
are associated with the ATM virtual connections that are configured on
the ADSL line. To establish a connection from any of the remote
destinations to the bridge port, PVCs must be configured end-to-end
through the network. Your DSL service provider will provide you with the
VPI/VCI values to use after you subscribe to the service.
The bridged mode comes with the following parameters:
Parameters Description
VPI Virtual path identifier
VCI Virtual circuit identifier
Logical Link Control allows multiple protocol
LLC
running over one virtual circuit with a little bit more
overhead.
Virtual Circuit Multiplexer (null encapsulation)
VCMUX
allows only one protocol running per virtual circuit
with less overhead.
Enable This option is only for a routed connection and
NAPT cannot be used in bridged or PPPoE mode.
VPI/VCI
The ATM connection is identified by the two following indicators: virtual
path identifiers (VPI) and virtual circuit identifiers (VCI). Each connection
must have a unique pair of <VPI, VCI> settings.
RFC 1483 Bridged Setup
Create a new RFC1483 Bridged Connection
1. Enter the correct numbers in the VPI and VCI fields.
2. Select the appropriate encapsulation - LLC or VCMUX.
3. Click Add. This will create a new VPI/VCI connection. Up to 8
VPI/VCI connections can be set.
4. Click OK to save the settings.*
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