User guide

Controlling and Provisioning Network Devices Port Management (non-iMAP Devices)
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AlliedView NMS Administration Guide
5.7.3 Dual End Line Testing (DELT)
5.7.3.1 Overview of DELT
DELT provides information about the quality of the link between the ADSL card and the modem by collecting upstream and
downstream values for attainable rate, line attenuation, signal attenuation, signal-to-noise margin, power spectrum density,
and aggregate transmitted power. DELT diagnostics are conducted over a low bit rate channel between the iMAP and the
CPE and can therefore be executed in extremely degraded cases where the ADSL link cannot train up.
The data collected is based on recommendations of ITU G.997.1 section 7.5.
In addition to line-level attributes, DELT tests also collect signaling information on a sub-carrier basis. For ADSL, there are
512 sub-carriers per line. The sub-carrier data can be graphically displayed to show the characteristics of the line. The
graph, in conjunction with signaling templates, can reveal the source or sources of line interference.
For provisioning, note the following:
• This feature works with the xDSL family (ADSL24A, ADSL24B, ADSL48A, ADSL48B, ADSL24SA, VDSL, PAC24A,
ADSL24AE) of cards.
• DELT results are only available if the service module and modem are configured to support one of the ADSL2 modes.
• Not all ADSL2 and ADSL2+ modems support DELT. Running DELT diagnostics on a modem that is not DELT capable
will result in a DELT test failure.Since DELT is relatively new capability, inter operability issues exist with some CPE
devices. These issues can cause DELT diagnostics to fail, or in some cases, cause DELT to report incorrect results. Allied
Telesis will publish a list of CPE (hardware and software versions) that have been verified for proper DELT operation.
Note: The ability for the iMAP to run DELT is from release 9.0, while the NMS DELT feature is for NMS release 10.0. Therefore,
this NMS feature can be run on an iMAP running a 9.0 load, although there are some additional DELT feature for iMAP 10.0.
5.7.3.2 Accessing DELT
From the Port Management application select an active ADSL port one of the supported card types. Select the ADSL
Configuration tab, then the Diagnostics tab. If the tab is not present then the port does not support DELT. Then select the
DELT tab, as shown in the following figure. If there is existing data from a previous DELT the fields are populated and the
DELT Graph tab will be active. If there was no previous DELT the DELT Graph tab will be inactive and grayed out.