Nortel DMS-100 Metallic Test Access Minibar Driver Table (MTAMDRVE)

Table Name

Metallic Test Access Minibar Driver Table

Functional Description of Table MTAMDRVE

The Metallic Test Access (MTA) is a matrix of vertical and horizontal crosspoints (comparable to a minibar) which can connect specified verticals to horizontals within the MTA.  It connects test equipment to a circuit that requires testing in cases where the test equipment is connected to a horizontal, and the circuit that requires testing is connected to a vertical.

A MTA of the required size is constructed through the interconnection of a number of smaller minibar circuits.  The DMS-100 switch has three circuit elements that can be used as building block components in the construction of a MTA.  These elements, which are referred to as MTA Minibar Drivers (MTAM), are described by Product Engineering Code (PEC) in the following table:

----------------------------------------------------------------------------------------------
MTA Minibar Drivers

Model (PEC)   Function           Description
----------------------------------------------------------------------------------------------
NT2X50AB      Minibar Driver     This is a 20 vertical by 16 horizontal circuit that has two
                                 components: cards NT2X46 and NT2X50AB.

                                 NT2X46 is the physical minibar.  Located in a miscellaneous
				 frame, it receives crosspoint connection requirements from 
				 he NT2X50AB control card and makes the corresponding 
				 connections.

				 The NT2X50AB is a single package card that requires one slot 
				 in a Peripheral Module (PM) shelf.  The MTA uses the control 
				 card to request crosspoint connections or disconnections on 
				 the minibar.
----------------------------------------------------------------------------------------------
NT3X09AA      Remote Metallic    This is a four vertical by eight horizontal (see note) circuit 
              Test Access        hat allows MTA access on Remote Line Concentrating Devices 
	                         (RLCDs).  Relays on this circuit card handle the crosspoint 
				 connections.  The NT3X09AA is a single card package that 
				 requires one slot in the PM shelf.

                                 Note: Although software uses this circuit as a four vertical 
				 by eight horizontal minibar, the physical wiring (hardware 
				 design) is eight verticals by four horizontals.

NT3X09BA      8x8 Remote         This is an eight vertical by eight horizontal circuit. 
              Metallic Test      The physical package is similar to the 3X09AA.  Relays on
	      Access             this circuit card handle the crosspoint connections.
----------------------------------------------------------------------------------------------

The minibar components are interconnected to construct a MTA using the Main Distribution Frame (MDF).  The MDF has connections to all circuits and Peripheral Module (PM) in a switch and connects the various circuits together.  This type of connection is known as a cross-connect.

In the case of MTAMs, each vertical and horizontal is wired to the MDF and cross-connects are made between various MTAMs.  These MTAMs are datafilled as being part of the MTA.  A large MTA can be constructed using this approach.


Figure 1: Basic MTA Matrix

Building the MTA Structure

The MTA requires three tables to define all the connections involved.  The use of these tables is described the following table and Figure 2.

----------------------------------------------------------------------------------------------
MTA Table Structure

Table Name   Description
----------------------------------------------------------------------------------------------
MTAMDRVE     Datafilled to locate a MTAM driver in the MTA structure.
MTAVERT      Datafilled to define the physical vertical connections on the MTA.
MTAHORIZ     Datafilled to define the physical horizontal connections on the MTA.
----------------------------------------------------------------------------------------------


Figure 2: Basic System and MTA Table Relationship

Horizontal Groups

The horizontal group provides a method of assigning different test equipment (horizontal agents) on the same MTA horizontal.  A horizontal group can involve only one horizontal agent, but is cross-connected (multipled) at the MDF on one or more MTAM driver horizontals, as shown in the Figure 3 and Figure 4.














In Figure 3, each horizontal agent relates as a horizontal group on the MTA.  This figure is the same as remote usage.


Figure 3: MTA Horizontal Groups

The following example MAP displays shows sample datafill for the previous diagram (not including table MTAVERT).


MTAMEM    VERT    HORIZ    TMTYPE    TMNO    TMCKTNO     MTACARD
________________________________________________________________
     0       0        0       MTM       0          0     2X50AB
     1      20        0       MTM       0          0     2X50AB
     5      40        0       RMM       0          0     3X09AA
     9      44        0       RMM       0          0     3X09BA





HORIZ    HORIZGRP    HORIZAGT     MTAGRP
__________________________________________
    0           0    L LTU 0 Y    ( 1 0) $
    0           0    L LTU 1 Y    ( 5 0) $
    0           0    L LTU 2 Y    ( 9 0) $















Figure 4 also shows the cross-connections of horizontal groups.


Figure 4: MTA Horizontal Group Cross-Connections

Extended MTA

The main use of the Extended MTA (EMTA) is for No-Test Trunks (NTT or NOTEST).  These trunks are used for local test cabinet, line test desk, repair and verification access, and Mechanized Loop Test (MLT) access.  The interface is similar in all cases and works in the following manner:

There are two reasons for using the extended MTA capabilities to make the metallic MTA connection between the no-test trunk and the line.  These are as follows:

In both cases, connectivity issues must be addressed if a large MTA structure is required due to a large number of lines.  The extended MTA overcomes some of the connectivity issues.  See the Large MTA Configuration section in this table description.

If a vertical is either a host or remote vertical, the extended MTA connection connects the vertical to a horizontal as a horizontal agent at host.

Only one EMTA connection at a time is allowed between a horizontal agent and a vertical.  An EMTA horizontal and line test equipment (Line Test Units [LTU] and Multi-line Test Units [MTU]) cannot make extended MTA connections to get a metallic connection.


Figure 5: MTA Horizontal Group Multipled Over MTAMs

Vertical at Remote and Host

Figure 6 and Figure 7 shows the verticals served by the remote and the host verticals.

In Figure 6, MTAM 0 and 1 has MTAM 10 directly adjacent.


Figure 6: Verticals Served by Remote and Host











In Figure 7, verticals 20 through 23 are not used.


Figure 7: Verticals Served by Remote and Host

Many Remotes in a MTA

A MTA can support up to a maximum of 509 remotes, by adding up to four horizontal rows with an offset of two verticals.  This configuration works with either NT3X09AA or NT3X09BA MTAMDRVE cards.  See Figure 8.


Figure 8: Example Configuration for a MTA with Many Remotes

The following MAP display example shows table MTAMDRVE datafill for the previous example.


MTAMEM    VERT    HORIZ    TMTYPE    TMNO    TMCKTNO    MTACARD
_______________________________________________________________
   146     402        0       RMM      50         18    3X09BA
   147     404        8       RMM      51         18    3X09BA
   148     406       16       RMM      52         18    3X09BA
   149     408       24       RMM      53         18    3X09BA


The following MAP display example shows table MTAHORIZ datafill for the previous example.


HORIZ    HORIZGRP    HORIZAGT       MTAGRP
_____________________________________________
    0           5    L MTU 50 Y     (146 0) $
    8           5    L MTU 51 Y     (147 0) $
   16           5    L MTU 52 Y     (148 0) $
   24           5    L MTU 53 Y     (149 0) $


The following MAP display example shows table MTAVERT datafill for the previous example.


VERT             VERTCONN
_____________________________
402              S L RM50 0 0
404              S L RM51 0 0
406              S L RM52 0 0
408              S L RM53 0 0


Large MTA Configuration

The size of a MTA depends on the size of an office and the number of verticals required to serve the Line Concentrating Devices (LCD).  If dealing with large MTA configurations, there are two issues that require consideration:

The first consideration is of primary importance because it imposes a physical hardware constraint.  This constraint makes it necessary to engineer on a switch basis to satisfy MTA requirements that are different for each switch.

Connection Considerations

An individual crosspoint has multiple connections to all vertical and horizontal MTA drivers associated with the crosspoint vertical and horizontal.

When determining the physical hardware constraints, all vertical MTA drivers, horizontal MTA drivers and the interconnecting cabling require consideration, as shown in Figure 9.


Figure 9: Crosspoint Connections





























If EMTA connections are involved, extended connections also require consideration, as shown in Figure 10.


Figure 10: Extended Crosspoint Connections

All vertical MTA drivers, horizontal MTA drivers and interconnecting cables must be taken into account for both the EMTA vertical connections and the EMTA horizontal connections.

Horizontal Agent Considerations

Line Test Equipment (LTE) that is a horizontal agent (such as a LTE, LTU, or MTU) requires access to a limited number of verticals of the MTA matrix.

This limit depends on the connection considerations of the MTA.  If the LTE has too many connections, measurements on loops are incorrect or inaccurate.  The recommended equipment for an office is one LTE for every 5,120 lines and one extra rover LTE for every 20,000 lines.  LTEs must be equipped in accordance with operating company requirements and the setup of the MTA matrix in the switch.


Other types of horizontal agents (such as the test access or verification trunk) require the capability of connecting to all LCDs that are located at the same site.  In cases where agents such as these are used and the number of verticals and MTA driver limits can be met, rearrangement of the MTA is required.  The rearrangement uses the extended MTA capabilities of the MTA matrix.

Example

The following example illustrates the interconnection of MTAs to meet the requirements of an application.

A switch has 155 LCMs and 3X09BA MTA drivers.  The 155 LCMs require 310 of the MTA matrix verticals (two verticals for each LCM).  39 MTA drivers are required to serve the 310 verticals.  Table MTAHORIZ allows the datafilling of up to 32 MTA drivers for a given horizontal agent.

Four test access trunks require connection capability to the 155 LCMs (all HOST site).  There is a physical cabling constraint that prevents more than 15 MTA drivers from being multipled in this office.

Based on the above information, the following approach can be taken:

Because of the 15 MTA driver cabling constraint, three groups of multipled MTA drivers are needed in order to meet the 39 MTA driver requirement.  These groups are referred to in this example as LCD groups A, B, and C.

Each LCD group requires connection capability to the test access trunks.  Extended MTA capabilities can be used to meet this requirement.  Three LCD groups times four test access trunks equals 12 additional verticals for the EMTA verticals.  Two MTA drivers are needed.

As the EMTA vertical uses two MTA drivers and the office only allows 15 MTA drivers to be multipled, 13 drivers for each of the groups A, B, and C are allowed.  This group of 13 drivers has the corresponding EMTA horizontal.

Each LCD group (A, B, and C) of 13 MTA drivers is shown in Figure 11.


Figure 11: LCD Group




An area in the MTA matrix must be dedicated for the EMTA and test access trunk connections, as shown in Figure 12.


Figure 12: MTA Matrix Area for EMTA and Test Access Trunk Connections

For better access reliability, distribute the EMTA verticals so that they are not concentrated on a particular MTA driver.  In the event that a MTA driver is unavailable, access using the other driver or drivers is possible.  See Figure 13.


Figure 13: Distributed Approach for Better Access Reliability

Figure 14 shows how the LCD group MTA drivers, the EMTA connections, and the MTA drivers interconnect.


Figure 14: LCD Connections to EMTA

If there are a large number of test access trunks, the previous solution could result in a large number of MTA drivers being needed for the EMTA set up.  Breaking the EMTA up into groups reduces the number of MTA drivers required.  See Figure 15.


Figure 15: MTA Driver Reduction Through Grouping

By grouping the EMTAs, the number of MTA drivers involved in multiple connections is reduced also.

Further consideration must also be given to reducing the number of MTA drivers required for the LCD groups.  If all test access trunks are required to have complete access to the LCD groups, the number of MTA drivers cannot be reduced.  For example, if complete access requires EMTA and MTA connections for 16 test access trunks to interconnect with 16 verticals of a single LCD group, then 16 EMTA verticals and EMTA horizontals are needed for each LCD group.

Reducing the number of MTA drivers in the LCD groups entails calculating the expected access required to verticals (lines) in the LCD group.  For example, if 16 test access trunks are allowed access to eight EMTA verticals and EMTA horizontals in LCD group A, the remaining eight can have access to LCD groups B and C.  The eight EMTA verticals and EMTA horizontals connected to LCD group A represent the percentage of the total lines in the office that are in LCD group A.

Functional Description

Table MTAMDRVE specifies the type of the minibar driver assigned to the minibar switch and the physical location of this driver.  The NT2X50AB driver is part of NT2X46 minibar switch, while the NT3X09 driver (whose relays are on the card itself) does not require an associated minibar switch.  Each minibar switch is identified by its horizontal and vertical location in the grid.

The MTAM drivers can be located anywhere within the MTA matrix.  Using MTA matrix vertical and horizontal start points, the MTAM driver is located in the matrix using its 0,0 crosspoint.  The number of MTA verticals or horizontals that the driver is associated with depends on its size.




The following restrictions exist when datafilling MTAM drivers in table MTAMDRVE:


Figure 16: MTA MTAM Overlapping Not Allowed


Figure 17: MTAM Driver Outside MTA Matrix







Datafill Sequence and Implications

The following tables must be datafilled before table MTAMDRVE:

Table Size

0 to 512 tuples

Table MTAMDRVE is extended by changing the value in field TRKGRSIZ specified in table CLLI for the pseudo-CLLI code MTADRIVER.  A restart is not required for this extension.

Datafill

The following table lists datafill for table MTAMDRVE.

----------------------------------------------------------------------------------------------
Table MTAMDRVE Field Descriptions

Field       Subfield       Entry               Explanation and Action
----------------------------------------------------------------------------------------------
MTAMEM                     See subfield        Metallic Test Access Minibar Driver Member
                                               This field consists of subfield MTAMEM.
					       This is the key to the table.

            MTAMEM         0 to 511            Metallic Test Access Minibar Driver Member
	                                       Enter the Metallic Test Access Minibar (MTAM) 
					       driver member number.
----------------------------------------------------------------------------------------------
VERT                       0 to 1023           MTAM Driver Vertical Start Location
                                               Enter the vertical start location for the MTAM 
					       driver.  The MTAM driver is located using its 
					       0,0 crosspoint.  See the "Datafill Example" 
					       section in this description.
----------------------------------------------------------------------------------------------
HORIZ                      0 to 127            MTAM Driver Horizontal Start Location
                                               Enter the horizontal start location for the MTAM 
					       driver.  The MTAM driver is located using its 
					       0,0 crosspoint.  See the "Datafill Example" 
					       section in this description.
----------------------------------------------------------------------------------------------
TMTYPE                     MTM, PTM,           Trunk Module Type
                           RMM, RSM            Enter the type of trunk module on which the 
			                       minibar driver is mounted:

				               * If the minibar switch is located at the host 
					         and mounted on a maintenance trunk module, 
						 enter "MTM".

					       * If the minibar switch is located at a 
					         cabinetized Meridian SL-100 and mounted on a 
						 packaged trunk module, enter "PTM".

					       * If the minibar switch is located at a RLCM 
					         location and mounted on a remote maintenance 
						 module, enter "RMM". 
						 (Only used if the MTA driver is 3X09AA or BA)

					       * If the minibar switch is located at a RLM 
					         location and mounted on a remote service
						 module, enter "RSM".

					       Any entry outside the range indicated for this 
					       field is invalid.
----------------------------------------------------------------------------------------------
TMNO                       0 to 2047           Trunk Module Number
                                               Enter the number assigned to the MTM, PTM, RMM, 
					       or RSM on which the minibar driver is mounted.
----------------------------------------------------------------------------------------------
TMCKTNO                    0 to 28             Trunk Module Circuit Number
                           (even numbers       Enter the trunk module circuit number on the MTM, 
			   only)               PTM, RMM, or RSM to which the minibar driver is 
			                       assigned.  Only even numbers within the specified 
					       range can be entered.

                                               Any entry outside the range indicated for this 
					       field is invalid.
----------------------------------------------------------------------------------------------
MTACARD                    2X50AB              Metallic Test Access Minibar Driver Card
                           3X09AA              Enter the card code of the MTAM driver card.
			   3X09BA              
			                       Any entry outside the range indicated for this 
					       field is invalid.
----------------------------------------------------------------------------------------------
-End-

Datafill Example

The following example MAP display shows sample datafill for table MTAMDRVE.

The example lists the physical locations of the four minibar drivers, as shown in Figure 18.  The example shows the positioning of the MTAM driver on the vertical and horizontal locations.


MTAMEM    VERT    HORIZ    TMTYPE    TMNO    TMCKTNO    MTACARD
_______________________________________________________________
     0       0        0       MTM       4          9    2X50AA
     1      20        0       MTM       2         18    3X09AA
     2      20        8       MTM       1         16    3X09BA
     3      24        0       MTM      10         22    3X09AA



Figure 18: Physical Locations of Four Minibar Drivers