Rambler's Top100
Siemens AG  Сайт PKU   | ICN
---
First Page Previous Page Next Page Last Page

7.8 Least Cost Routing (LCR) (Not for U.S.)

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
Subject 
Pro 
Com 
Point 
One  
Start  
Feature available in 
x 
x 
x 
x 
x 
HW requirements 
SW requirements 
Rel. 1.0 or later 
Number of LCR classes of service 
15 
15 
15 
15 
15 

Requirements and Conditions
Subject 
Requirement or Condition 
LCR 
If all the least expensive connection paths have been seized, LCR automatically switches to defined more expensive paths. The system can signal user of this fact both visually and acoustically.  
LCR 
The dialed station number is displayed until the station number information on the other party is received. 
LCR 
If LCR is activated, the system checks for the least costly route for every trunk seizure (except when a trunk code is dialed). 
LCR 
Digits can be transmitted either singly or en-bloc, depending on the access method and the dial plan. 
LCR 
After an account code is entered, it applies to the entire connection setup. 
LCR 
The allowed and denied lists are also used for LCR. The toll restriction check then refers to the digits dialed at the station without considering the trunk group code. 
LCR class of service 
The LCR class of service determines whether a station can use the route recommended in the path table. 
Prime Line on (automatic line seizure) 
LCR is not possible when Prime Line is active. 

7.8.1 Carrier Types

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).

7.8.1.1 Mercury Communications Limited Single Stage

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
Subject 
Pro 
Com 
Point 
One  
Start  
Feature available in 
x 
x 
x 
x 
x 
HW requirements 
SW requirements 
Rel. 1.0 or later 

Requirements and Conditions
Subject 
Requirement or Condition 
MCL Single Stage 
Dialing is carried out in the D channel (with ISDN) or as normal dialing (on analog trunks). 

7.8.1.2 Mercury Communications Limited Two Stage

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
Subject 
Pro 
Com 
Point 
One  
Start  
Feature available in 
x 
x 
x 
x 
x 
HW requirements 
SW requirements 
Rel. 1.0 or later 

Requirements and Conditions
Subject 
Requirement or Condition 
MCL 
With synchronization during timeout, you must program a pause of 2 to 12 seconds. 

7.8.1.3 Dial-In Control Server (DICS)

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
Subject 
Pro 
Com 
Point 
One  
Start  
Feature available in 
x 
x 
x 
x 
x 
HW requirements 
SW requirements 
Rel. 1.0 or later 

Requirements and Conditions
Subject 
Requirement or Condition 
Station number suppression 
Temporary or permanent station number suppression cannot be activated. 
ISDN/SUB addressing 
The ISDN feature SUB must be applied for or released in the public network. 
Analog trunk 
DICS can only be used with ISDN. 

7.8.1.4 Corporate Network (CN)

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
Subject 
Pro 
Com 
Point 
One  
Start  
Feature available in 
x 
x 
x 
x 
x 
HW requirements 
SW requirements 
Rel. 1.0 or later 

7.8.1.5 Primary Carrier

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
Subject 
Pro 
Com 
Point 
One 
Start 
Feature available in 
x 
x 
x 
x 
x 
HW requirements 
SW requirements 
Rel. 1.0 or later 

7.8.2 Routing Tables

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:

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:
A: Repeat remaining fields (transmit). This letter causes all subsequent digit fields to be transmitted. The point of reference is the last field pointer before A. The combination E1A is permitted only at the beginning of a string.
D (n): Dial digit sequence (1 to 25 digits). This letter can be inserted multiple times and at any position in the string.
E (n): Repeat field from dial plan (from 1 to 10 times). This letter can be inserted multiple times and at any position in the string. E can also appear in any order with relation to (n). A specific field can be addressed multiple times, including in sequence. With the exception of E1, this letter can be surrounded by any parameter.
P (n): Pause (1 to 60 times the system-wide pause unit). This letter can be inserted multiple times and at any position in the string.
M (n): Authorization code (1 to 16). This letter must not be in the final position.
S: Switch, changes signaling methods from DP to DTMF (with CONNECT, PROGRESS or CALL PROC with PI). This letter can be inserted in the string only once and may not be in the final position. The C parameter cannot be used after S.
U: Use subaddress signaling method. This letter can be inserted in the string only once and may not be in the final position. Subsequent characters are again dialed in INFO. The S, P, and C parameters cannot be used after U.
C: Access code. This letter can be inserted in the string only once. The subsequent characters are transmitted without a dial pause and are used for single stage, two-stage, DICS (not for U.S.), BRI, and PRI carrier access.
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 *****).
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.
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.
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.
Depending on the entry in the path table, a warning can be issued to the station informing the user that the call is being routed. This warning can be signaled by a warning tone and a display message. The display shows the outdial rule name.
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.
To use all available features (such as callback) in conjunction with LCR, the trunk group code must be separated from the dialed station number by a dash (-) in the dial plan (sample dial plan entry: 0-CZ).
 
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.  

The following station number entries are valid:
0...9: Permissible digits
-: Field separator
X: Any digit from 0 to 9
N: Any digit from 2 to 9
Z: One or more digits to follow up to the end of dialing
C: Simulated dial tone (can be entered up to three times)
If Prime Line on (automatic line seizure) is active, trunk group 1 should be the default setting (in Release 2.2 [for world, excluding U.S], Release 2.0 [for U.S. only], and earlier versions).

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.

Figure 7-3 Sample LCR Flow Diagram (Not for U.S.)

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.

Figure 7-4 General LCR Flow

A system-wide flag activates LCR via Hicom Assistant T or Hicom Assistant E.
When LCR is activated, the check is performed for every trunk seizure (except when dialing a trunk code).
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.
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.
Digits can be transmitted either per digit or en-bloc, depending on the access method and the dial plan.
Once an account code is entered, it applies to the entire connection setup.
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
Subject 
Pro 
Com 
Point 
One  
(not for U.S.) 
Start  
(not for U.S.) 
Feature available in 
x 
x 
x 
x 
x 
HW requirements 
SW requirements 
Rel. 2.0 or later 
No. of path tables 
254 
254 
254 
254 
254 
Number of paths per path table 
16 
16 
16 
16 
16 
No. of time zones 
No. of outdial rules 
254 
254 
254 
254 
254 
Number of characters per outdial rule 
40 
40 
40 
40 
40 
No. of dial plans 
514 
514 
514 
514 
514 
Number of digits dialed (including trunk group code) 
32 
32 
32 
32 
32 
No. of digits evaluated 
25 
25 
25 
25 
25 

Requirements and Conditions
Subject 
Requirement or Condition 
LCR 
With per-digit dialing, the last element in the outdial rule cannot be E(n); it may be E(n)A. 
Networking 
In networking with open numbering, route optimization cannot be activated. 
Least cost routing (LCR) 
If primary carrier is entered as a type in the outdial rule, rerouting is not done in the path tables. 
If routing should be carried out when the trunk is busy or when S0 lines are disrupted, the type should be set to Single Stage

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:
Step 
Action 
1.  
Configure LCR 
2.  
35-1 => Least cost routing - LCR on/off 
3.  
35-2 => Least cost routing - Dialing mode 
4.  
35-3 => Least cost routing - Outdial rule 
5.  
35-4 => Least cost routing - PIN 
6.  
35-5 => Least cost routing - Schedule 
7.  
35-6 => Least cost routing - Access 
8.  
35-7 => Least cost routing - Path tables 
9.  
35-8 => Least cost routing - Dial plan 

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. 

Top of Page
Last Page
First Page Previous Page Next Page

---
---

Rambler's Top100