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The following table describes the labels in this screen.
Table 13 Network Setting > Broadband > Advanced
LABEL
DESCRIPTION
DSL Capabilities
PhyR US
Enable or disable PhyR US (upstream) for upstream transmission to the WAN. PhyR US
should be enabled if data being transmitted upstream is sensitive to noise. However,
enabling PhyR US can decrease the US line rate. Enabling or disabling PhyR will require the
CPE to retrain. For PhyR to function, the DSLAM must also support PhyR and have it
enabled.
PhyR DS
Enable or disable PhyR DS (downstream) for downstream transmission from the WAN.
PhyR DS should be enabled if data being transmitted downstream is sensitive to noise.
However, enabling PhyR DS can decrease the DS line rate. Enabling or disabling PhyR will
require the CPE to retrain. For PhyR to function, the DSLAM must also support PhyR and
have it enabled.
Bitswap
Select Enable to allow the VMG to adapt to line changes when you are using G.dmt.
Bit-swapping is a way of keeping the line more stable by constantly monitoring and
redistributing bits between channels.
SRA
Enable or disable Seamless Rate Adaption (SRA). Select Enable to have the VMG
automatically adjust the connection's data rate according to line conditions without
interrupting service.
ADSL Modulation
PTM over ADSL
Select Enable to use PTM over ADSL. Since PTM has less overhead than ATM, some ISPs
use this for better performance.
G.Dmt
ITU G.992.1 (better known as G.dmt) is an ITU standard for ADSL using discrete multitone
modulation. G.dmt full-rate ADSL expands the usable bandwidth of existing copper
telephone lines, delivering high-speed data communications at rates up to 8 Mbit/s
downstream and 1.3 Mbit/s upstream.
G.lite
ITU G.992.2 (better known as G.lite) is an ITU standard for ADSL using discrete multitone
modulation. G.lite does not strictly require the use of DSL filters, but like all variants of
ADSL generally functions better with splitters.
T1.413
ANSI T1.413 is a technical standard that defines the requirements for the single asymmetric
digital subscriber line (ADSL) for the interface between the telecommunications network and
the customer installation in terms of their interaction and electrical characteristics.
ADSL2
It optionally extends the capability of basic ADSL in data rates to 12 Mbit/s downstream
and, depending on Annex version, up to 3.5 Mbit/s upstream (with a mandatory capability
of ADSL2 transceivers of 8 Mbit/s downstream and 800 kbit/s upstream).
AnnexL
Annex L is an optional specification in the ITU-T ADSL2 recommendation G.992.3 titled
Specific requirements for a Reach Extended ADSL2 (READSL2) system operating in the
frequency band above POTS, therefore it is often referred to as Reach Extended ADSL2 or
READSL2.The main difference between this specification and commonly deployed Annex A is
the maximum distance that can be used. The power of the lower frequencies used for
transmitting data is boosted up to increase the reach of this signal up to 7 kilometers
(23,000 ft).
ADSL2+
ADSL2+ extends the capability of basic ADSL by doubling the number of downstream
channels. The data rates can be as high as 24 Mbit/s downstream and up to 1.4 Mbit/s
upstream depending on the distance from the DSLAM to the customer's premises.
Annex M
Annex M is an optional specification in ITU-T recommendations G.992.3 (ADSL2) and
G.992.5 (ADSL2+), also referred to as ADSL2 M and ADSL2+ M. This specification extends
the capability of commonly deployed Annex A by more than doubling the number of
upstream bits. The data rates can be as high as 12 or 24 Mbit/s downstream and 3 Mbit/s
upstream depending on the distance from the DSLAM to the customer's premises.
VDSL Profile
VDSL2 profiles differ in the width of the frequency band used to transmit the broadband signal. Profiles that
use a wider frequency band can deliver higher maximum speeds.
Chapter 6 Broadband
VMG1312-Bx0D User's Guide
78
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