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2.2. MARCO TEÓRICO REFERENCIAL
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The dial plan configuration file is an ASCII text file that implements the dial plan and specifies pretranslation (digit manipulation). The system is shipped with several default dial plan configuration files, typically, a 3-digit and a 4-digit file for each supported country.
The dial plan configuration file includes several tables:
■ Internal — Must be table ID 1 ■ Incoming — Must be table ID 2
■ Least Cost Routing — Must be table ID 3 ■ Routes
■ Pretranslators
You can create additional tables if necessary.
Each dial plan table consists of a series of entries, each of which includes a sequence of digits and the action to be performed by the NBX system in response to sending or receiving those digits. For more information on the Internal, Incoming, and Least Cost Routing dial plan tables, see “Dial Plan Tables” on page 35.
Usually, you access the dial plan configuration file and manage dial plan operations, tables, pretranslators, and extension lists through the NBX NetSet administration utility. If your dial plan is larger than 32,000 characters, however, you cannot edit the dial plan using the NBX NetSet utility. You must export the dial plan, edit it, and then import it.
Before you configure the dial plan, please be sure that you understand these concepts:
■ Call Process Flow (page 31)
■ Inbound and Outbound Call Processing (page 31) ■ NBX System Database (page 32)
■ NBX System Dial Plan (page 32) ■ Pretranslation (page 33)
■ Routing (page 33)
In addition, be sure to understand how the dial plan configuration file can affect other parts of the NBX system. See “System Features Affected by the Dial Plan Configuration” on page 34.
Dial Plan Concepts and Overview 31
Call Process Flow The dial plan configuration file is a key component of inbound and outbound call processing. The dial plan tables in the configuration file process incoming calls in this order:
1 Incoming Dial Plan Table 2 Pretranslator Table
The dial plan tables process outgoing calls in this order: 1 Internal Dial Plan Table
2 Least Cost Routing Table
After pretranslation (if performed), the final translation process routes the call to the destination.
Inbound and Outbound Call Processing
The system routes all inbound and outbound calls through the dial plan. Inbound Call Processing
The system processes inbound calls using the Incoming table. The system can also use pretranslators to perform digit manipulations on incoming calls before it uses the Incoming table.
Each pretranslator operation performs a digit manipulation operation on the dialed digits. For incoming calls, if the DID/DDI range matches the internal extensions, the dial plan requires no pretranslator. However, you can use pretranslators to map nonmatching dialed numbers on an incoming DID/DDI channel to desired internal extensions. See the
example in Customer Requirement 1 in “Sample Solutions Using Dial Plan Configuration File Commands” on page 124.
Outbound Call Processing
The system processes outbound calls using the Internal dial plan table or the Least Cost Routing table. You can add entries to the Internal dial plan table to match the system to your service. See Customer Requirement 2 in “Sample Solutions Using Dial Plan Configuration File Commands” on
page 124.
If you have entries in both the Least Cost table and the Internal table for the same purpose, the behavior of the dial plan can be confusing. 3Com recommends that you accomplish least cost routing using Internal Table entries. For more information, see TimedRoute Create, TimedRouteEntry Create, and TimedRouteOperation Create later in this chapter.
NBX System Database The NBX system database contains a default dial plan that is initially loaded at the factory and is reloaded if you purge the database.
■ NBX V3000 system — default 4-digit plan ■ SuperStack 3 NBX system — default 4-digit plan ■ NBX 100 — default 3-digit plan
Changes that you make to any system settings, including changes made by importing a modified dial plan configuration file, are stored in the database. When you reboot the system, it loads the database with any changes that you have made. The NBX system database includes all of the settings necessary for system operation.
NBX System Dial Plan You can import a dial plan configuration file to provide the system with a set of operating instructions for managing the telephone system.
Alternatively, if you have made changes to the currently loaded
instructions through the NBX NetSet utility, you can export the dial plan configuration file to save it. You can also make changes by editing the configuration file off-system, using any ASCII editor, and then importing the modified file. You can easily reuse a given configuration file on many systems. For more information, see “Importing and Exporting Dial Plan Configuration Files” on page 47.
The system is shipped with several default dial plan configuration files, typically, a 3-digit and a 4-digit file for each country that is supported. In addition, the file samples.txt contains several examples that illustrate how you can configure the dial plan configuration file to control how the system manages incoming and outgoing calls.
Normally, you completely configure a dial plan before you start to use the system to control the telephones. Although you can make changes later, major changes in the dial plan can disrupt the system.
Decide whether you want to use a 3-digit or 4-digit dial plan before you create the dial plan, autodiscover, or manually add telephones or other devices to the NBX system.
When you import a dial plan, some parameters of the system change immediately. Others change only when you reboot the NBX system. 3Com recommends that you reboot the NBX system each time that you change the dial plan.
Dial Plan Concepts and Overview 33
Rebooting the system disrupts service to the telephones. Plan to reboot at a time that does not inconvenience telephone users.
Pretranslation Pretranslation is the process of translating (or manipulating) dialed digits before they are passed to the appropriate dial plan table for subsequent routing. You can set the dial plan to perform pretranslation on incoming or outgoing calls. For more information, see “Dial Plan Pretranslators” on
page 42.
Routing Routing specifies how a call reaches a destination. You define the routes for the system to use in the Routes section of the dial plan configuration file.
When you define call routing, you can also instruct the system to perform pretranslations (digit manipulations). Both destination routes and timed routes have digit manipulation operations (append, prepend, replace, stripLead, or stripTrail).
The system passes dialed digits first through the device’s Least Cost Routing table (if there is one). If the system finds no entry there, it then uses the Normal dial plan table. If it does find an entry in the Least Cost Routing table, it attempts to use that entry and, even if the attempt is unsuccessful, it does not use the Normal table.
You can route incoming calls to the Auto Attendant port, and you can instruct the Auto Attendant to route these calls to any internal or external number.
CAUTION: If you configure the Auto Attendant so that it can access any external number, you risk the possibility of toll fraud. You can reduce the possibility of toll fraud by explicitly putting specific external numbers into the outgoing dial plan table. This precaution prevents outside callers from dialing any external number except the ones that you define.
There are two types of routes:
■ Destination routes — Specify the extension of a destination device.
They can also perform digit manipulation operations on the dialed digits that resulted in the selection of this route before those digits are dialed on the destination device.
■ Timed routes — Specify time of day and day of week criteria which,
CAUTION: If you operate the NBX system in Keyset Mode, routes are not applicable.
For more information, see “DestinationRoute Create”on page 112,
“TimedRoute Create”page 120, and related entries under “Dial Plan Configuration File Commands” on page 110.
System Features Affected by the Dial Plan Configuration
The dial plan configuration affects several system features:
■ Keyset Mode Operation Using the Dial Plan ■ Hybrid Mode Operation Using the Dial Plan ■ Off-Site Notification
Keyset Mode Operation Using the Dial Plan
If you map any telephone buttons that have LEDs to specific Analog Line Card ports, you enable Keyset mode in the NBX system. Instead of dialing a single digit (typically 8, 9, or 0) before placing an outside call, the user presses a button to select an available Analog Line Card port. The user defines the routing (that is, the selection of a destination device) by pressing the button to select the Analog Line Card port; however the NBX system controls the call using the dial plan.
You cannot map a digital line extension in Keyset mode.
The NBX system applies any Class of Service restrictions that are associated with the user's telephone to determine whether to make a call. The system also uses any pretranslator that a device uses and performs any required digit manipulation operations before it actually transmits the digits on the Analog Line Card or Digital Line Card port. Hybrid Mode Operation Using the Dial Plan
If you map telephone buttons for some telephones but not others, you enable Hybrid mode (a mixture of standard and Keyset behaviors). The system provides a system-wide External Prefix setting, which allows the administrator to establish a prefix.
Off-Site Notification
The NBX system uses off-site notification to notify users when new voice mail messages arrive. You can define notification devices and assign them in the Internal dial plan as well as through the NBX NetSet utility.
Dial Plan Tables 35
Example: When voice mail arrives, the NBX system dials the telephone number of the user’s pager. Typically, you use a system-wide prefix to designate the device or devices you want to use for outdialing purposes, including off-site notification calls.
Example: If the user’s pager number is 800-555-3751, and the system-wide prefix digit is 9, the system dials 98005553751 to send a call to the user’s pager.
To tell the system to dial a single Line Card port or a restricted number of Line Card ports, create a suitable pool of Line Card ports for that purpose, and then use an existing set of dial plan table entries (such as the entries that begin with 8) or create a new set of entries to allow the dial plan devices to route calls via the selected line card ports.
Example: You set up one 4-port card to handle all off-site notification calls. You create a set of entries in the Internal dial plan table that each start with the digit 8. You define a route to the 4-port card for all of these dial plan entries so that whenever the system acts on one of these entries, it uses one of the 4 ports on that card to dial out and notify the user. To apply different off-site CoS restrictions to different users, you need multiple dial plan entries. If you are not trying to apply the CoS restrictions, then a single dial plan entry is sufficient.
Dial Plan Tables
Dial plan tables contain information that controls how the system routes calls. Each dial plan configuration file consists of at least three dial plan tables. This section discusses these topics:■ Dial Plan Command Format
■ Internal Dial Plan Table — Must be table ID 1 ■ Incoming Dial Plan Table — Must be table ID 2
■ Least Cost Routing Dial Plan Table — Must be table ID 3 ■ Adding New Dial Plan Tables
CAUTION: Tables 1, 2, and 3 must exist. Do not delete them. You may create additional dial plan tables if necessary, but they must be numbered 4 or higher.
If the Least Cost Routing table exists, it takes precedence over the Internal table. If the system cannot find a Least Cost Routing table, it attempts to find a corresponding entry in the Internal table. If you have entries for the same purpose in both the Least Cost and Internal tables, the behavior of the dial plan can be confusing.
See “Dial Plan Command Format” next for a description of dial plan command syntax and structure. For a complete list and description of dial plan commands, including command arguments and examples, see “Dial Plan Configuration File Commands” on page 110.
Dial Plan Command Format
Each dial plan table contains a sequence of commands. These commands collectively determine how calls are handled.
Most of the dial plan commands have a very similar format, as shown in
Dial Plan Tables 37
Figure 2 Dial Plan Command Format
Table 6 describes each field of a dial plan command.
Table Create 1 Internal
/ Id Entry Digits Min Max Class Prio Route /
TableEntry Create 1 1 0 1 1 Internal 0 4 TableEntry Create 1 2 1 3 3 Internal 0 0
TableEntry Create 1 3 2 3 3 Internal 0 0
Table Create 2 Incoming
/ Id Entry Digits Min Max Class Prio Route /
TableEntry Create 2 1 0 1 1 Internal 0 4
TableEntry Create 2 2 1 3 3 Internal 0 0
Table Create 3 Least Cost Routing
/ Id Entry Digits Min Max Class Prio Route Command
Table ID Number Leading Digits to Collect Table Entry ID Number
Call Classification — Used with Class of Service
Priority (Not Used) Table Name
Number of the route (dial tone facility) from Routing Tables Maximum and Minimum
Characters to Collect
Table 6 Dial Plan Command Fields Field Description
Command Command name. For example, TableEntry Create is the command that makes Class of Service and call routing decisions based on the correspondence of dialed digits and table entry digits. See “Dial Plan Configuration File Commands” later in this chapter for a description of each command.
Table ID Number Table ID number. This is always 1 for the Internal dial plan table, 2 for the Incoming dial plan table, and 3 for the Least Cost Routing Table.
If a new entry in the Internal table appears not to work, it is possible that the system is using an entry from the Least Cost table instead. To avoid such conflicts, you can accomplish least cost routing using only the Internal table. 3Com strongly recommends that, to keep the dial plan as simple as possible, you use only the Internal table for least cost routing. For more information on how to use the dial plan configuration file, see “Managing the Dial Plan Configuration File” on page 46. Basic Dial Plan Table Examples
These examples describe the basic operation of a dial plan table. Example: If you are using a 4-digit dial plan and the telephone
extensions start with 2, then the table entry with 2 in the Digits column typically has 4 in the Min column. Before making a decision, the system
Table Entry ID Number
Table entry number (a unique number for each entry in the table). These numbers are usually in ascending order in the table, but you can change the order. For example, you might want to place a new item near other items of the same type (that begin with the same digit) in order to help you when you troubleshoot the configuration file.
Digits One or more digits that begin the dial sequence. Either single or multiple entries can start with the same digit. The system uses this field in conjunction with Min and Max to determine when to make the call routing decision.
Most sample tables have a single entry for digit 0 (zero) to specify how the system handles a telephone number which has zero as the first digit.
If you want the system to handle calls differently, depending on whether they start with 90 or 91, you must have one entry in the table for each of these 2-digit sequences.
Min Minimum number of digits that the system collects before routing the call. Max Maximum number of digits the system collects before routing a call.
Class Class of Service (CoS). The system uses this information to decide whether a caller is allowed to make this specific type of call. The possible classifications are:
Internal, Local, LongDistance, International, WAN, Toll- Free, Emergency, COCode, Wireless, Toll, Operator, AlternateLong, TrunkToTrunk, Diagnostics, NotAllowed, Other Each of these values corresponds to a selection in the NBX NetSet utility.
Priority Priority number. This field is not used at this time, but must be present and should always be 0 (zero).
Route Route number. This identifies an entry in the Routes section of the dial plan. Zero is a typical value for internal calls, and indicates that this call uses no route, in which case, digits are transmitted as soon as they are dialed.
Table 6 Dial Plan Command Fields (continued) Field Description
Dial Plan Tables 39
would collect all 4 digits of the extension. If the caller dials fewer than the Min number of digits, the system times out in 20 seconds.
Example: If Digits = 2, Min = 4, and Max = 4, the system knows that if the first digit is 2, it must collect no less than 4 and no more than 4 digits before making the call routing decision.
If the caller dials at least the minimum number of digits and not more than the maximum number of digits, the system waits 5 seconds and then routes the call based on the digits dialed.If the caller dials more than the maximum number of digits, the system attempts to place the call. Often, Max value and the Min value are identical, because you want the system to collect a specific number of digits, no more and no less. Example: For internal extensions, you want the system to collect exactly 3 digits (4 in a 4-digit dial plan) before making a decision, so you would set both Min and Max to 3 (4 in a 4-digit dial plan).
The two columns may be different if the table entry applies to more than one situation.
Example: In the United States, the Min value for the 90 entry is 2, because 90 allows an internal caller to reach a telephone company operator (9 to get an outside line, and then 0 to get the operator). The Max value is 64, because the caller can continue to dial after the zero, entering a number to call, plus a telephone credit card number, and possibly an identification code number.
If the caller dials only 90 (which satisfies the minimum of two digits) and stops dialing, the system waits for 5 seconds. If no other digits are entered, the system connects the caller to the operator.
If other digits are dialed, the system accepts them up to the limit of 64. If the caller stops after dialing fewer than 64 digits, the system again waits 5 seconds before acting on the dialed sequence of digits.
Example: You can assign a new employee to the Default User Group. You can then set the permissions for that group so that group members have permission to make LongDistance calls when the system mode is Open or Lunch, but not when the system mode is Closed or Other.
Example: You can assign the company’s Vice President of Finance to a group that you name the All Privileges Group. You can set the