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With transmission over a noisy line, the ability to recover encoded bits is significantly improved by using a
Trellis Coder/Decoder. The Trellis Coder for ADSL can achieve a better coding gain. Trellis coding can be
optionally used only for Multimode. The DSLAM and Netopia 4741 negotiate if Trellis Coding is enabled
during part of their initialization.
The default is enabled, so you probably do not need to change it unless your provider specifically tells you
to do so.
Select Cell Format and from the pop-up menu select either Scrambled (the default) or Unscrambled. This
setting must match the format used by your service provider. Scrambled is the most common, so you
probably do not need to change it unless your provider specifically tells you to do so.
Select Unused Cell Format and from the pop-up menu select either Idle (the default) or Empty. This setting
must match the format used by your service provider. Idle is the most common, so you probably do not
need to change it unless your provider specifically tells you to do so.
Select Data Link Encapsulation and from the pop-up menu choose your DLE. The DLE choices are PPP or
RFC 1483 (the default).
If you selected RFC1483, the next pop-up menu RFC1483 Mode offers the choice of Bridged 1483 or
Routed 1483. If you select Bridged 1483, a new option PPP over Ethernet (PPPoE) appears. You can
then toggle PPPoE On or Off. Choosing Routed 1483 hides the PPPoE option.
If you selected PPP, the next pop-up menu PPP Mode offers the choice of VC Multiplexed or LLC SNAP.
Select Display/Change Circuit, and from the pop-up menu choose the circuit to use for this connection.
The default circuit is called Circuit 1, and uses the default values for data traffic and the WAN Default
Profile for the connection. See
Add Circuit and Delete Circuit allow you to create or delete circuit settings "on the fly." This is useful if you
want to manage sets of circuit values without deleting a previous set or delete sets that no longer apply.
For more information on VPIs and VCIs, see
The Netopia 4741 supports up to eight permanent virtual circuits.
On cell-based DSL WAN interfaces, the ATM connection between the device and the central office equipment
(DSLAM) is divided logically into one or more virtual circuits (VCs). A virtual circuit may be either a permanent
virtual circuit (PVC) or a switched virtual circuit (SVC). Netopia devices support PVCs.
VCs are identified by a Virtual Path Identifier (VPI) and Virtual Channel Identifier (VCI). A VPI is an 8-bit value
between 0 and 255, inclusive, while a VCI is a 16-bit value between 0 and 65535, inclusive.
Circuits now support attributes in addition to their VPI and VCI values. When configuring a circuit, you can
specify an optional circuit name of up to 14 characters. The circuit name is used only to identify the circuit
for management purposes as a convenience to aid in selecting circuits from lists. The default circuit name
is "Circuit <n>", where <n> is some number between one and eight corresponding to the circuit's position
in the list of up to eight circuits.
You can also individually enable or disable a circuit without deleting it. This is useful for temporarily
"The WAN Default Profile" on page 8-14
"Multiple ATM Permanent Virtual Circuit Support"
WAN and System Configuration 8-3
for more information.
below.
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