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System Processes and Performance with a Digital Off-Hook Configuration

System Processes and Performance with a Digital Off-Hook Configuration

This chapter describes basic system processes and the performance metrics that are captured as a result of these system processes in a Digital Off-Hook configuration.

This chapter includes the following sections:

Digital Off-Hook Operation

The following process occurs when a Cisco 6100 Series system initiates a connection request to the customer premises equipment (CPE) product:

The ADSL Connection Process

The Carrierless Amplitude and Phase Modulation (CAP) rate-adaptive DSL (RADSL) transceivers that are used in Cisco ATU-Cs and ATU-Rs can train at several discrete settings within each of three baud rate ranges. The upstream and downstream data paths are transmitted in different frequencies; therefore these paths train independently.

The Cisco CAP RADSL implementation supports several ADSL training options that you can use to control subscriber traffic. The following sections describe the training option processes including bit error rate and noise margin, payload transmission rates, and modification of noise margins.

Bit Error Rate and Noise Margin

Bit error rate and noise margin are primary factors in achieving subscriber-designated parameters. SDSL and ADSL transceivers seek an upstream and downstream data rate that can be maintained as long as the amount of line noise does not cause a bit error rate (BER) in excess of 1 x 10-7. Line noise is a function of reach and disturbers. As reach or noise in the loop increases, upstream and downstream payload rates decrease. Also, the thinner the copper wire, the more susceptible it is to noise. Line noise is not constant, and a certain amount of line noise fluctuation does not significantly affect the trained rates. Line noise fluctuation is known as the noise margin. The noise margin must be supplied to the transceivers when you use the multiband method of training.

Payload Transmission Rates

Payload data represents transmitted information that is useful to the customer, but may also include additional information such as user-requested network management and accounting information. Upstream and downstream payloads transmit in different frequency ranges; therefore, the two payload rates are established independently. Layer 2 protocol data units (PDUs) are encoded into Layer 1 (xDSL) transmission frequencies through baud rates (also known as symbol rates) and constellations. You can set different baud rates to achieve different payload rates.

CAP RADSL transceivers support one baud rate to establish the upstream payload rate (136 kilobaud), and three baud rates to establish the downstream payload rate (340, 680, and 952 kilobaud). These baud rates enable CAP RADSL implementations to support the following rates:

Noise Margin Modification

You can modify the noise margins for a subscriber line. If you set a new noise margin, a line that was training successfully might not train after you set a new margin. ViewRunner alerts you to use caution when you change the margin.

Cisco recommends that you set the margin for 6 dB upstream and 3 dB downstream to provide optimal performance. The default values for noise margin are 0 upstream and 0 downstream.

As an example, if you train a unit that is provisioned with a 3 dB downstream margin and a 6 dB upstream margin against 24-ISDN near-end cross talk (NEXT) set to the 0 dB reference level (-52.6 dBm), you can increase the noise to -49.6 dBm at the CPE and -46.6 dBm at the CO, and still maintain a bit error rate less than 1 bit in error for each 10 million sent (10-7). Within each baud rate, transceivers use constellations to encode data into a frequency spectrum, and subsequently enable the discrete payload options. This concept is described in the following section, and the constellation combinations are listed in Table 7-1.

CAP RADSL Upstream and Downstream Constellation Combinations

The concept of constellation combinations refers to the way discrete subscriber line chip sets communicate with each other. Different constellations provide different levels of data transmission accuracy.

Valid CAP RADSL constellations include 256 UC, 256, 128, 64, 32, 16, 8, and 8 extended range. The 128, 32, 8, and 8 extended range constellations are not supported with downstream baud rates of 952 and 680. Because of this, some upstream-downstream payload combinations cannot be achieved.

Table 7-1 shows valid upstream and downstream constellation combinations.


Table 7-1: CAP RADSL Upstream and Downstream Constellation Combinations
Upstream

Kilobaud

136

136

136

136

136

136

136

136

Constellation

256UC

256

128

64

32

16

8

8er1

Kilobaud

Const

Payload

1088

952

816

680

544

408

272

91

952

256UC

7168

X

X

X

X

D o w n s t r e a m

952

256

6272

X

X

X

X

952

64

4480

X

X

X

X

952

16

2688

X

X

X

X

680

256UC

5120

X

X

X

X

680

256

4480

X

X

X

X

680

64

3200

X

X

X

X

680

16

1920

X

X

X

X

340

256UC

2560

X

X

X

X

X

X

X

X

340

256

2240

X

X

X

X

X

X

X

X

340

128

1920

X

X

X

X

X

X

X

X

340

64

1600

X

X

X

X

X

X

X

X

340

32

1280

X

X

X

X

X

X

X

X

340

16

960

X

X

X

X

X

X

X

X

340

8

640

X

X

X

X

X

X

X

X

136

256UC

1024

X

X

X

X

X

X

X

136

256

896

X

X

X

X

X

X

X

136

128

768

X

X

X

X

X

X

X

136

64

640

X

X

X

X

X

X

X

136

32

512

X

X

X

X

X

X

X

136

16

384

X

X

X

X

X

X

X

136

8

256

X

X

X

X

X

X

X

1er = extended range

Two entries In Table 7-1 represent the downstream rate for a payload of 4480 kbps:

The 680 kilobaud rate with a 256 constellation is the Cisco 6100 Series system and Cisco 675 default for achieving a payload rate of 4480 kbps. This rate combination supports a slightly better reach, according to 24 ISDN NEXT disturbers.

Table 7-1 also includes two entries that represent the downstream rate for a payload of 1920 kbps:

The 340 kilobaud with a 128 constellation is the Cisco 6100 Series system and Cisco 675 default for achieving the payload rate of 1920 kbps. This rate combination is compatible with any of the upstream data rate selections. The 680 kilobaud option is limited to the 1088, 952, 680, or 408 kbps upstream payload.

CAP modules support 136-kilobaud training rates, which can be allowed or disallowed when the system controller module software supports this feature and the subscriber is locked.

If the system controller module supports per-subscriber provisionable 136 kilobaud or does not support ATUCPARMS, the Allow 136K Baud checkbox on the 6100 Properties dialog box Configuration tab is disabled. If the system controller module supports ATUCPARMS, but does not support per-subscriber 136 kilobaud, the toggle is enabled.

Table 7-2 lists valid rate combinations for upstream and downstream data.


Table 7-2: Valid Rate Combinations for Upstream and Downstream Data
Upstream Rate (kbps)
Downstream Rate (kbps) 1088 952 816 680 544 408 272 91

7168

X1

X

X

X

6272

X

X

X

X

5120

X

X

X

X

4480

X

X

X

X

3200

X

X

X

X

2688

X

X

X

X

2560

X

X

X

X

X

X

X

X

2240

X

X

X

X

X

X

X

X

1920

X

X

X

X

X

X

X

X

1600

X

X

X

X

X

X

X

X

1280

X

X

X

X

X

X

X

X

1024

X

X

X

X

X

X

X

960

X

X

X

X

X

X

X

X

896

X

X

X

X

X

X

X

768

X

X

X

X

X

X

X

640

X

X

X

X

X

X

X

X

512

X

X

X

X

X

X

X

384

X

X

X

X

X

X

X

256

X

X

X

X

X

X

X

1x = valid, empty cell = invalid

The actual training procedure is a function of transceiver-controlled parameter exchange and algorithms designed by Cisco to place parameters around valid data rate selections from Table 7-2.

Training Process

The following guidelines apply to the training sequence:

This setting means that control of the downstream data rate is relinquished to the CAP ATU-C (the ATU-C controls the upstream data rate setting by default).

By using the preceding guidelines, the CAP ATU-C has complete control over upstream and downstream data rate selection. You can choose valid upstream and downstream data rate combinations on the ViewRunner GUI. ViewRunner communicates these rates to the CAP ATU-C through the following process:


Figure 7-1: Service Provisioning Dialog Box



Figure 7-2: Module Properties Dialog Box


Note If you modify the ATU-R upstream and downstream data rates from the preset maximum settings, the modem can train independently. Independent training depends on how you set the data rates in ViewRunner.
Note The CO side sets the rates at which the CPE trains. The CPE cannot change this rate.

CAP ATU-C Train Parameters

This section describes receive signal quality, receiver gain, and transmit power, where transmit power applies to noise margins on the Cisco 6100 Series systems. Each of these trained-line attributes displays in ViewRunner on the CAP ATU-C Module Port Properties dialog box Status tab.

You can change the noise margin (upstream and downstream) for each subscriber line. Increasing this margin could prevent a line that trained previously from training after you change the margin value. When you attempt to increase the noise margins, ViewRunner issues an alert that is similar to the following message:

Warning: Increasing noise margin could reduce the reach for a given data rate, or reduce the achievable data rate for a given reach. In some cases, it may prevent the line from training at all. Please consult product documentation for more information.

Figure 7-3 shows the Port Status tab of a CAP ATU-C Module Properties dialog box for a session in progress. The various train parameters are identified in the CAP ATU-C Module Properties dialog box showing a the Service State field as In Service.


Figure 7-3: CAP ATU-C Module Properties Dialog Box---In Service


Transmit Power

Transmit power is a measure of the downstream power spectral density (PSD) mask. T1E1/97-104R2a states that the PSD for the downstream channel should have an upper limit of -40 dBm/Hz in the nominal passband region with no variation exceeding -37 dBm/Hz.

Caution Cisco advises you to set the transmit power to -40 dBm/Hz. To avoid data transmission errors, do not change the PSD from -40 dBm/Hz downstream and -38 dBm/Hz downstream.

Each network provider chooses the maximum transmit power. As power is boosted, you can extend reach for a given data rate. At the same time, however, the boosted signal can disturb other services.

Although not currently displayed on the ViewRunner GUI, T1E1/97-104R2a also specifies that the PSD for the upstream channel must have an upper limit of -38 dBm/Hz nominal with no variation exceeding -35 dBm/Hz.

Beginning with Cisco 6100 Series Release 2.1.1, you can control transmit power. Controlling transmit power is helpful when the network provider wants to boost or reduce the power of a given loop.

The ATU-R transceiver determines its transmit power during the training process as it tries to fulfill the upstream data rate request. The transceiver tries to support the requested data rate at the lowest possible transmit power to minimize the NEXT in the Cisco 6100 Series system.

Understanding Performance Train Counters

The Cisco 6100 Series system has a variety of connection counters, train counters, and threshold counters that capture DOH system performance statistics. The following counter types are available:

Connection counters:

Train counters:

Threshold counters:

Counters display individual subscriber, LIM port, and CAP ATU-C modem port statistics.

If the CAP ATU-C modem and ATU-R modem train, a successful train counter increments for the CAP ATU-C modem. If the CAP ATU-C modem and ATU-R modem fail to train, a failed train counter increments for the CAP ATU-C modem. You can view train counter statistics on the Performance Management dialog box.

Connection Counters

Once you have successfully connected a LIM port and CAP ATU-C modem, a successful connection counter increments for both the logical pool and the line. At that point, the modem training sequence begins.

If all of the modems within the logical pool are busy, the system controller module sends a busy tone to the ATU-R modem and increments the logical pool blocked-connection and line blocked-connection counters.

Train Counters

After the connection between the LIM port and CAP ATU-C modem is established, the training sequence begins.

If the CAP ATU-C modem and ATU-R modem train, a successful train counter increments for the CAP ATU-C modem. If the CAP ATU-C modem and ATU-R modem fail to train, a failed train counter increments for the CAP ATU-C modem.

Threshold Counters

Two threshold counters are available for each logical pool, 80 percent and 100 percent modem usage. These two threshold counters provide the following statistics:

The sum of the these statistics is equal to the total connection requests that the logical pool handles.

Note Counters continue to increment unless you reset the system controller module.

In addition to the integer connection counters, connection activity is also represented in terms of percentage connections in each category.

Getting Feedback from the Performance Management Dialog Box

You can get feedback from the Performance Management dialog box on the current performance of each pool in a DOH system. You can choose a particular physical pool on the dialog box and view the following performance statistics for that selection. These statistics are reflected on the tabs that are described in the following sections:

To access any of these views, right-click the chassis rim and choose 6100 Performance from the Chassis menu. The Pool tabs display the following pool information:

The Performance Management dialog box also has a Cell Counts tab that contains a PVC tab and an ATM tab for monitoring performance of PVC and ATM activity. These tabs are described in the following sections:

Each Performance Management dialog box has its own set of associated counters. ViewRunner resets these counters under certain conditions. The specific counters and the conditions in which a counter is or is not reset are described in the following sections.

Counters do not reset if you take any of following actions:

Performance Management---Pool Summary Tab

The Pool Summary tab provides detailed information about successful and blocked connections, and successful and failed CAP ATU-C trains (see Figure 7-4). Summary statistics that indicate the number of trains at or below 80 percent logical pool use, over 80 percent, and blocked requests for each logical pool are also provided on this tab.


Figure 7-4: Performance Management Dialog Box---Pool Summary Tab


The Cisco 6100 Series system maintains pool summary counters in each defined pool in the Pool Summary tab fields, as described in Table 7-3.


Table 7-3: Pool Summary Fields
Field Description
Digital Off-Hook Connection Statistics:

Pool Time

Displays the number of minutes that the modem pool has been in existence (or since the last reset).

Block Time

Displays the percentage of time (in minutes) during which one or more subscribers were refused modem port assignments in response to DOH connection requests.

Number of In Service xTU-C Ports

Displays the number of in-service modem ports.

80% Threshold of In Service xTU-C Ports

Displays the number of successful connections while modems are 80 percent used (modems assigned).

Successful Connections < 80%

Displays the number of successful cross-connections (modem assigned) below the 80 percent threshold.

Successful Connections >80%

Displays the number of successful cross-connections (modem assigned) above the 80 percent threshold.

Blocked Connections

Displays the number of blocked cross-connections (modem unavailable).

Total Connection Requests

Displays the total number of requests for connection.

xTU-C Port Training Statistics:

Successful Trains

Number of times 100 percent modem use is reached (modems assigned).

Failed Trains

Number of failed trains.

Total Trains Initiated

Sum of successful trains and failed trains.

xTU-C Ports Failing to Train

Number of xTU-C ports that have attempted to train and failed.

Line Ports Connected to xTU-C Ports Failing to Train

Number of line ports that are connected to xTU-C ports that have attempted to train and failed.

ViewRunner resets the Pool Summary tab counters in the following situations:

Performance Management---Subscriber Tab

The Subscriber tab lists data about all successful and blocked-connection activity by a specific subscriber. In addition, summary statistics indicate the number of connections at, below, or over 80 percent logical pool use. Summary statistics also display blocked requests for each logical pool.

You can access the Subscriber tab as follows: place your cursor over the outside edge or rim of the chassis, right-click, and choose 6100 Performance. The Subscriber tab is shown in Figure 7-5.


Figure 7-5: Performance Management Dialog Box---Subscriber Tab


Table 7-4 describes the columns on the Subscriber tab. The statistics display at the bottom of the dialog box.


Table 7-4: Performance Management Dialog Box---Subscriber Tab Columns
Column Description

Subscriber ID

The unique identifier by which the subscriber is known.

Successful XConn

The number of successful cross connections that have been achieved for that subscriber ID since the last time ViewRunner reset the counter.

Blocked XConn

The number of blocked cross connections that have been realized for that subscriber ID since the last timeViewRunner reset the counter.

CPE Signature Rejects

The number of rejected CPE units listed by signature.

Subscriber Statistics

The current counts of the following statistics display at the bottom of the tab:

  • Subscribers

  • Successful connections

  • Blocked connections

  • CPE signature rejects

The Cisco 6100 Series system maintains the following subscriber counters:

ViewRunner resets Subscriber counters if you take any of the following actions:

Performance Management---Line Port Tab

The Line Port tab lists data about all successful and failed xTU-C trains by line port. The first column to the left identifies the line port. The Line Port tab is shown in Figure 7-6.


Figure 7-6: Performance Management Dialog Box---Line Port Tab


Table 7-5 describes the columns on the Line Port tab. The statistics display at the bottom of the dialog box.


Table 7-5: Performance Management Dialog Box---Line Port Tab Fields
Column Description

Line Port

The line port location by chassis, slot, and line port number.

Successful Trains

The number of successful trains that have been achieved for that line port since the last time ViewRunner reset the counter.

Failed Trains

The number of failed trains that have been realized for that line port since the last time ViewRunner reset the counter.

Non-timer Failed Trains

The number of failed trains that are non-timer related.

Line Statistics

The current counts of the following statistics display at the bottom of the tab:

  • Line ports

  • Successful trains

  • Failed trains

  • Nontimer failed trains

  • Line ports connected to xTU-C ports failing to train

The Cisco 6100 Series system maintains the following statistics for each line port counter:

ViewRunner resets Subscriber counters if you take any of the following actions:

Performance Management---xTU-C Ports Tab

The xTU-C Ports tab lists data about all successful and failed xTU-C port trains by modem port. The xTU-C Ports tab is shown in Figure 7-7.


Figure 7-7: Performance Management Dialog Box---xTU-C Ports Tab


Table 7-6 describes the columns on the xTU-C Ports tab. The statistics display at the bottom of the dialog box.


Table 7-6: Performance Management Dialog Box---xTU-C Ports Tab Fields
Column Description

xTU-C

xTU-C modem port location by chassis, slot, and line port number.

Successful Trains

Number of successful trains that have been achieved for that xTU-C modem port since the last time ViewRunner reset the counter.

Failed Trains

Number of failed trains that have been realized for that xTU-C modem port since the last time ViewRunner reset the counter.

The Cisco 6100 Series system maintains the following counters in each xTU-C port:

The xTU-C port counters are reset if you take any of the following actions:

Performance Management---Cell Counts PVC Tab

You can monitor the performance of PVCs on the Cell Counts PVC tab, shown in Figure 7-8.


Figure 7-8: Performance Management Dialog Box---Cell Counts PVC Tab


Table Figure 7-8 describes the fields and buttons on this dialog box.


Table 7-7: Cell Counts PVC Tab Field Descriptions

All PVCs group box

Lists the PVCs that are set up on the node. Displays the Subscriber ID, Subscriber VPI/VCI, and Network VPI/VCI assignments for each PVC.

Monitored PVCs group box

Lists the PVCs that are being monitored. Displays the Subscriber ID and the PVC, Subscriber Ingress, Subscriber Egress, Network Ingress, and Network Egress for each PVC. PVCs that are listed here do not show up in the All PVCs group box.

Add >> button

Use this button to move one PVC at a time to the Monitored PVCs group box when you want to monitor the performance of that PVC.

<< Del button

Use this button to delete a PVC from the Monitored PVCs group box. Doing this does not delete the PVC. It only removes that PVC from the performance monitoring area.

All >> button

Use this button to move all of the subscribers that are listed in the Subscriber ID column to the Monitored PVCs group box where you can monitor their performance.

<< All button

Use this button to move all of the PVCs in the Monitored PVCs group box out of that group box and returns them to the All PVCs group box.

Transit PVCs checkbox

Select this field to include transit PVCs.

Time since reset

Displays the approximate time in seconds (00:00:00) since the last counter reset.

Reset Counters button

Click this button to reset all counters in the Monitored PVCs group box to zero (0).

Refresh Counters button

Click this button to update line data after you click Reset Counters.

Steps for Monitoring PVC Performance

To check the PVC performance status for a subscriber line, you need to move that PVC from the All PVCs group box to the Monitored PVCs group box. Follow these steps:

Step 1 Click the Cell Counts tab and then click the PVC tab on the Performance Management dialog box.

Doing this opens the Cell Counts PVC tab, shown in Figure 7-8.

Step 2 Select the PVC whose performance you want to monitor; be sure to place your cursor on the Subscriber or Network VPI/VCI column.

Note If you click a PVC with your cursor in the Subscriber ID column, the Subscriber Properties dialog box for that subscriber opens. Therefore, click the PVC from either the Subscriber VPI/VCI column or the Network VPI/VCI column to move that PVC to the monitoring area.

Step 3 After you have clicked the PVC that you want to monitor, click Add >>.

Doing this moves that PVC to the Monitored PVCs list. Under the Monitor PVCs group box columns, you can monitor subscriber-side and network-side channel transmissions to identify bottlenecks.

Initially, when you move a PVC to the Monitored PVCs list, the counters display a hyphen.

Step 4 Click Reset Counters to begin monitoring the performance of that PVC.

Doing this sets the base time and displays 00:00:00 in the Time since reset field. The counters are set to zero (0). When you click Reset Counters, the Refresh Counters button is enabled.

Step 5 Click Refresh Counters to display the difference in value since the time you reset the counters. The time displays in the Time since reset field.

Step 6 To monitor the PVC performance of all PVCs, click All >>.

Step 7 To remove a PVC from the Monitored PVCs list, highlight that PVC and click << Del.

Step 8 To remove all of the PVCs from the Monitored PVCs list, click << All.

Performance Management---Cell Counts ATM Tab

To check the port status for subscribers who are using ATM, click the Cell Counts tab and then click the ATM tab on the Performance Management dialog box of an xTU-C module. Doing this opens the Cell Counts ATM tab, shown in Figure 7-9.


Figure 7-9: Performance Management Dialog Box---Cell Counts ATM Tab


Note Use the Reset Counters and Refresh Counters buttons as you use them on the Cell Counts PVC tab.

Table 7-8 describes the fields on the Cell Counts ATM tab.


Table 7-8: Performance Management Cell Count ATM Tab Fields
Field Description

Port Index

Displays the chassis slot number for the port whose performance management you are accessing.

Received Cell Count

Displays the number of cells being received.

Transmitted Cell Count

Displays the number of cells being transmitted.

Header Control Errors

Displays the number of errors accumulated in the header control.

Section Bit Interleave Parity

Displays interleave parity counts by section bits.

Line Far End Block Error

Displays far end block errors from the subscriber line.

Line Bit Interleaved Parity

Displays interleave parity counts by line bit.

Path Far End Block Error

Displays counts of far end block errors.

Path Bit Interleaved Parity

Displays interleaved parity by path bit.

Time since reset

Displays the time in seconds (00:00:00) since the last counter reset.

Reset Counters button

Click this button to reset all counters to zero (0).

Refresh Counters button

Click this button to update data after you click Reset Counters.

ViewRunner includes two methods for displaying the status of current subscriber connections:

Usage State Group Box

For CAP ATU-Cs or LIMs in a pooled Digital Off-Hook configuration, the Status tab on the Module Properties dialog box displays a Usage State group box (Figure 7-10).


Figure 7-10: Module Properties Dialog Box---Usage State Group Box


Fields on the Usage State group box identify the specific LIM and CAP ATU-C ports that are currently interconnected. You can click the LIM Properties button to open the Module Properties tab of the opposing port.

Note These fields are dimmed when the port Usage state is Idle.

Active Connections Dialog Box

The Active Connections dialog box lists data about all currently active connections in the Cisco 6100 Series system. To open the Active Connections dialog box, right-click the chassis GUI and choose Active Connections from the Chassis menu. The Active Connections dialog box, shown in Figure 7-11, Figure 7-12, and Figure 7-13 appears. Because there are several columns on this dialog box, these three figures present the Active Connections dialog box first in the far-left position, then scrolling right for the last two figures.


Figure 7-11: Active Connections Dialog Box---Left Side



Figure 7-12: Active Connections Dialog Box---Center



Figure 7-13: Active Connections Dialog Box---Right Side


Note You can use the logical service-oriented navigation to go directly to the desired entity by clicking on any blue, underlined hyperlink in the dialog box.

Table 7-9 describes the columns in the Active Connections dialog box.


Table 7-9: Active Connections Dialog Box Columns
Column Description

Pool

Lists the names of the physical and logical pools.

Active Connections

Lists the number of active connections that are associated with a physical or logical pool.

In Service Modems

Lists the number of in-service modems that you have assigned to a logical pool and whose modules and ports are unlocked.

% Usage

Displays the percentage that represents the value in the Active Connections column divided by the value in the In Service Modems column.

Subscriber ID

Displays the identifier by which the subscriber is known.

Line Port

Displays the chassis, slot number, and port number to which the subscriber ID is associated.

CAP ATU-C Port

Displays the chassis, slot number, and port number with which the line port is connected.

Modem Status

Displays whether the modem is trained, training, or not trained.

Pool

Displays the physical or logical pool of which the line port and CAP ATU-C modem port are members.

Actual Up

Displays the actual upstream train rate at which the subscriber is training. This rate can never be higher than the value in the Provisioned Up column.

Actual Down

Displays the actual downstream train rate at which the subscriber is training. This rate can never be higher than the value in the Provisioned Down column.

Rx SNR

Signal-to-noise ratio for ADSL upstream (receive side) data channel.

Provisioned Up

Displays the upstream rate set by the CO, which is the maximum upstream rate at which the subscriber can train.

Provisioned Down

Displays the downstream rate set by the CO, which is the maximum downstream rate at which the subscriber can train.

Provisioned Down Margin

Displays the downstream noise margin that you have provisioned for the subscriber.

Provisioned Up Margin

Displays the upstream noise margin that you have provisioned for the subscriber.

Actual Up Margin

Displays the upstream noise margin that actually occurs within the margin that you have provisioned for the subscriber.

Actual Down Margin

Displays the downstream noise margin that actually occurs within the margin that you have provisioned for the subscriber.

The Active Connections dialog box includes the fields that you have provisioned for upstream and downstream bit rates, actual trained upstream and downstream bit rates, and the received signal-to-noise ratio. In addition, the dialog box includes totals of active connections by pool and the current usage level of each pool.


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Posted: Wed Feb 23 12:02:26 PST 2000
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