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Definition
Least cost routing provides Hicom 150 E Office with automatic control over the path of an outgoing call. This path can be one of various public-network carriers or a private network. Based on routing tables, the system seeks the least expensive connection path for the outgoing call.
The system seizes a trunk only after it has scanned the routing tables. The system sends dial tone as a function of the dial plan so that the station is informed of the ready-to-dial condition. The signals dialed are buffered until the routing tables have been scanned. Only then does the system make the connection.
Model-Specific Data
Requirements and Conditions
Since in many cases individual carriers provide specific connections and conditions at different tariffs (sometimes with different signaling methods), least cost routing can be used to automatically select the most economical connection or most economical carrier for each outgoing phone call.
The following carrier types and networks are available for implementing least cost routing (LCR).
Definition
With this type of LCR, a prefix is used to dial the desired network carrier and the station number is subsequently dialed.
Model-Specific Data
Requirements and Conditions
Definition
With this type of least cost routing, the system initially selects the carrier using a configurable access code (as with single stage). Afterwards, the system also waits for a connect (synchronization during timeout).
After the connect, the system transmits an authorization code and the destination station number as DTMF signals in the B channel.
Model-Specific Data
Requirements and Conditions
Definition
With this type of least cost routing, the system uses the routing table to determine whether the call should be made via the DICS or the public network. If the DICS is used, the system dials the DICS using a configurable access code and an authorization code and transmits the station number dialed by the station in the SUB address (on the D channel). The DICS checks the authorization based on the CLIP information and the transmitted authorization code.
If the DICS is not present during the first connection setup, the system reroutes the connection to the public network. This alternative access must be configured.
Model-Specific Data
Requirements and Conditions
Definition
A corporate network is an alternative network, such as a company-owned network, that is connected directly to the Hicom 150 E.
The LCR function determines the corresponding trunk group based on the station number dialed and then routes the call either via the trunk group in the public exchange or via the trunk group in the corporate network.
If necessary, the system translates the station number.
Model-Specific Data
Definition
When a trunk is seized by the primary carrier, simplified dialing is performed by en-bloc dialing or by dialing individual digits into the public network.
If primary carrier was the method selected in the outdial rule table, forwarding in the trunk group table is not performed for entries after the route configured as a primary carrier.
Model-Specific Data
Definition
The routing tables evaluate the digits dialed by the user and determine the station number that the system should dial. In the process, the digits are modified as necessary. This modification can mean that digits are repeated, suppressed, added, or reordered. It is also possible to add a dial pause and change the signaling method. A distinction is made between the following types of routing tables:
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Outdial rule table: This table determines how the digits dialed by the user will be converted and dialed by the system. The following special characters can be defined: |
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Authorization code: The authorization code is divided into the carrier ID and customer ID. The carrier ID is entered as one entry in the authorization code table and the customer ID is entered as another entry in the authorization code table. The authorization code entry in the outdial rule then consists of the two authorization codes. Only a protected authorization code is supported (represented by *****). |
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Class of service: Each station is assigned a class of service (COS). A station can then seize a path only if its COS is greater than or equal to the COS in the path table; for example, a station with a COS 7 cannot seize a path with COS 8. |
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Schedule: Up to eight time zones per day can be configured for each day of the week to control LCR. A search is performed based on the schedule ID entered in the path table to determine whether the current time matches the value entered in the schedule. If it does and if the correct class of service is present, dialing is performed as per the outdial rule entered in the path table. |
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Path table: Up to 254 path tables (Rel. 2.0 or later) with 16 paths each can be created. Each path in a path table is described by a combination of the trunk group, outdial rule, toll restriction, schedule, and an option for warning against a more expensive route. The table is scanned from top to bottom. The system checks to determine whether the trunk group is free and the station has the requisite class of service. If so, the system dials per the outdial rule and schedule entered in the path table. |
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Dial plan: Each station number dialed for external traffic is checked against the dial plan for up to 30 positions (including field separator and trunk group code). If the number dialed matches an entry in the dial plan, LCR is handled in accordance with the path table in the dial plan. |
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The first entry in a dial plan does not have to be a trunk group code; it can also be a station number in a networked system. |
To block incoming external calls, enter a dash (-) in the Routing table field of the dial plan.
Example:
Dialed Digits (Code + Station Number) |
Path Table |
Explanation |
---|---|---|
9C1-900-XXX-XXX |
- |
The dash (-) blocks all 900 numbers. |
9C1-976-123-3456 |
- |
The dash (-) blocks only the number 976-123-3456. |
Do not confuse the hyphen (-) in the Dialed digits field, which separates the digit blocks in the number, with the dash in the Path table field, which blocks the numbers.
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The dialed call number is used as the criterion for the connection path to be used. The system can evaluate up to 24 digits of the digit sequence plus up to 9 field separators. The digit sequence that can be dialed can consist of up to 32 digits. The evaluation can be carried out both destination dependently and time dependently and in dependence on the station's LCR class of service (COS).
The system contains 254 route tables with 16 routes each. The LCR class-of-service is evaluated hierarchically for LCR.
The outdial rule is described in the Assistant by its name, which consists of not more than 16 characters, and in the System Administration by its index.
The station can cancel automatic selection by seizing a line directly (Carrier Select Override - CSO). The LCR class-of-service cannot be transferred between CorNet-N networked systems.
General Operating Principle
The system analyzes the number dialed to determine if the digits input are valid. If the digits are recognized, a reference route table is scanned for Route group choices. Once the Route group is selected, the availability of the route is checked against the time schedule. If the Route group is available, the LCR COS requirement assigned to the route group is compared to the LCR COS associated with the dialing device. If the LCR COS associated with the dialing station is equal to or greater than the route group COS, the Toll Restriction tables are checked for additional screening information. This process is repeated for every call using the system LCR application.
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A system-wide flag activates LCR via Hicom Assistant T or Hicom Assistant E. |
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When LCR is activated, the check is performed for every trunk seizure (except when dialing a trunk code). |
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If all the least expensive connection paths have been seized, LCR automatically switches to defined more expensive paths. The user can be signaled of this fact both visually and acoustically. |
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In the case of outgoing calls on the ISDN network, the dialed number continues to be displayed until the destination number information on the other party is received. |
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Digits can be transmitted either per digit or en-bloc, depending on the access method and the dial plan. |
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Once an account code is entered, it applies to the entire connection setup. |
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The allowed and denied lists are also used for LCR. The toll restriction check then refers to the digits dialed on the station without the trunk group code. |
Model-Specific Data
Requirements and Conditions
Configuration Options
This feature can be configured using Hicom Assistant T or Hicom Assistant E Office.
Configuring the Feature Using Hicom Assistant T
Configure the feature using Hicom Assistant T as follows:
Configuring the Feature Using Hicom Assistant E Office
Configure the feature using Hicom Assistant E Office as follows:
Step |
Action |
---|---|
1. |
Configure LCR Options |
2. |
Least Cost Routing |
Testing the Feature
Check the feature for error-free functioning as follows:
Step |
Action |
---|---|
1. |
Configure LCR. |
2. |
Place an outgoing call. |
3. |
The call is routed according to the setting. |
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Hicom 150 H V1.0 - Hicom 150 E Office Rel.2.0-3.0 Service Manual | Siemens Part No.: P31003-M1550-X403-3-7620 | Conversion Date: 2000-08-24 |
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Contact: E-Doku-Team | © Siemens AG 2001 |