Ericsson EDN312 Betriebsanweisung PDF herunterladen (Seite 17)

Function Description

4/1553-HSC 901 101/2 Uen B 2009-02-27

3.2 EDN312

The IP DSLAM is able to provide high speed IP access to all the

subscribers simultaneously. Service activation of ADSL is done individually

per subscriber line through the EDA Management System (Public Ethernet

Manager – PEM).

The IP DSLAM has built-in Gas Discharge Tube (GDT) for Over Voltage

Protection and secondary protection on all subscriber lines. The GDT

conforms to ITU-T K.20 and K.21.

On the local loop each subscriber has up to eight ATM Permanent Virtual

Circuits (PVCs), however at most there can be 72 PVCs in one IP DSLAM.

Each can be configured with:

• ATM cell rate: Peak and Sustainable cell rate, Max burst size

• ATM service class: UBR, CBR, VBR-rt or VBR-nrt

The IP DSLAM maps traffic from the EDA Ethernet network to the End-

user, using different schemes, which are configurable from PEM. For more

information about the different mapping possibilities, please refer to the

System Description.

The IP DSLAM is also able to perform two tests:

• Single Ended Line Test (SELT) - estimates the ADSL connection

properties. The SELT can be performed when the IP DSLAM is

installed. No CPE is required for the SELT execution.

• Loop Diagnostics – defined in ADSL2 standard (G.992.3). The Loop

diagnostics measures the line properties, from both sides (Central

Office and Customer premises). The Loop Diagnostics require an

active CPE modem that supports ADSL2 or higher.

The IP DSLAM HW and SW supports various ADSL transmission modes

including ADSL, ADSL2 and ADSL2+ (G.992.1, G.992.3, G.992.5

respectively) with multi annexes, meaning that both base band services

POTS (Annex A), and ISDN (Annex B) are supported.

Furthermore, the ADSL2 (G.992.3) "symmetrical" service for higher

upstream bandwidths (Annex M) is supported. Also a special version of the

ADSL2 Annex M is supported with underlying POTS service. The IP

DSLAM also supports G.Lite (G992.2) with the same SW.

The ADSL (1, the first ADSL standard) downstream line rate is limited to

approximately 8 Mbit/s, but according to the G.992.1 this can be

increased by use of the optional S=½ feature. Increasing the downstream

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Ericsson EDN312 Betriebsanweisung Seite 17