2.5.2  
Thumb Rule for HiPath 3000/5000 V8 
 

2.5.2.1  
Procedural Principles 
The thumb rule presented below for calculating the dynamic load for HiPath switches is based on the principle of considering every interface (telephones and trunks) in light of its (incoming and outgoing) seizure intensity. In the case of an external seizure, for example, the CPU load is split between the telephone and the trunk.
The thumb rule for determining the manageable load takes multiple factors into account. This includes not only several parameters, whose values can be determined from the current configuration of the switch being examined, but also a variety of interfaces and performance characteristics. These interfaces are each assigned a specific weight in accordance with their share of the load to be managed. The basis for this is the average overhead for an Anate seizure (60% internal-, 20% outgoing external-, and 20% incoming external seizure). This enables all values to be normalized to Anate seizures. The planned switch configurations are then permissible if the sum of all seizures - normalized to Anate seizures - does not exceed a maximum value depending on the current switch variant and the computing hardware being used.
The goal is to detect critical switch configurations early in the planning stage and to then perform a more precise analysis. The appropriate project planning tools for this purpose are still maintained by SEN ESY HS PDT 4 or SEN ESY SME MP 42 and provided to the usual project planning locations:
 •   NERT (Network Engineering & Routing Tool for Private Networks) for network planning
http://intranet.mch4.siemens.de/syseng/perfeng/tools/nert/index_en.htm
and
 •   Project Planning Tools for HiPath Systems
http://intranet.mch4.siemens.de/syseng/perfeng/tools/hpt/index_en.htm
An electronic version of the thumb rule in which all the following calculations are implemented will also be made available there.

2.5.2.2  
Planning Load for HiPath Systems 
This section describes a dimensioning method for the various systems. In order to provide for sufficient reserves to handle load fluctuations during operations, a so-called planning load is defined the systems. This planning load consists of 70 % of the capacity available for call processing (switching) transactions (see Figure below).
 Figure 2-7   Planning Load for HiPath 3000/5000 Systems
 
The planning load values described here are taken into account in the following table as the "maximum permissible points".

2.5.2.3  
Maximum Permissible Values for HiPath 3000/5000 V8 
For version V8, the following maximum permissible point totals are used as a basis for the thumb rule (Norm BHCA):

 Table 2-14   HiPath 3000/5000 V8 Expansion Levels and their Maximum Points
 HiPath 3000  
 Maximum Points  
 HiPath 3300/3350/3500/3550  
 2,880  
 HiPath 3800  
 22,600  

2.5.2.4  
Additional Parameters 
In order to calculate the number of points for a specific system, several additional parameters are usually required. These parameters are described below.
 •   Factor FTln (subscriber traffic factor):
As in Guideline 12TR3 for 700 ports or more, this rule of thumb assumes a station traffic value PTln = 0.15 Erl and four outgoing seizures per device during busy traffic hours. The factor FTln is used to achieve some flexibility in the underlying station traffic values and seizures. In the case of international systems, in particular, a factor greater than 1 may be appropriate in some circumstances (e.g. PTln = 0.20 erl results in FTln = 1.33). In general, the following applies:
   
    If the seizure value per terminal is not directly specified, FTln can be determined via the relationship to the 4 outgoing seizures indicated above (e.g., 3 seizures produce a value of FTln = 0.75).
 •   Factor FLtg (trunk traffic factor) for traffic volume on trunks:
As in Guideline 12TR3, this rule of thumb assumes a line traffic value PLtg = 0.8 Erl and 12.5 incoming seizures per B channel during busy traffic hours. The factor FLine is used to achieve some flexibility in the underlying traffic values and seizures. A factor of less than 1 (for example, PLtg = 0.5 Erl gives FLtg = 0.63) may be appropriate in some cases, especially for systems that were over-dimensioned to create a virtually blockage-free system. In general, the following applies:
   
 •   Factor FVPL (AC traffic factor) for traffic volume of an attendant console:
This rule of thumb assumes a traffic value at an active attendant PVPL = 0.8 Erl and 144 seizures during busy traffic hours. The factor FVPL is used to achieve some flexibility in the underlying station traffic values and seizures. A factor of less than 1 may be appropriate, especially for systems in which the attendant consoles were over-dimensioned. In general, the following applies:
   
 •   Factor C for ACD utilization:
For ACD agents, the intensity of the utilization of this feature must also be taken into account. By default, it is assumed that an ACD agent handles 16 ACD calls per hour. If applications need to be configured with values that significantly exceed or fall below this default, the factor C can be used to specify the corresponding multiple of the value 16. For example, TV advertising campaigns may incur values of up to ten times the norm.
 •   Factor g for mobility within a CMI node:
This thumb rule formula is based on the assumption of the mobility level of mobile subscribers. The factor g determines the probability that a station is not located at its home board when visiting the radio area of it home system. In the case of homogeneous allocation, the factor g can be calculated from the number of SLC boards in the system:
   
 •   Factor G for mobility within the CMI network:
This thumb rule formula is based on the assumption of the mobility level of mobile subscribers. The factor G determines the probability, that a subscriber resides outside the cordless area of his home system. In branch networks where subscribers rarely reside in other nodes, G is relatively small (e.g. G  = 0.1). A homogeneous allocation can be assumed, if a location is overlapped from several cordless areas of different nodes. In this case, the factor G can be calculated from the number of CMI nodes:
   

2.5.2.5  
Current Thumb Rule Values 
The following tables list the interfaces considered in the thumb rule formula with their respective meanings and corresponding weights in points (normalized to Anate seizures).
 •   Table 2-15: Points for Devices
 •   Table 2-16: Points for Mobile Handsets
 •   Table 2-17: Points for Special Devices
 •   Table 2-18: Points for Trunks
 •   Table 2-19: Additional Overhead for Controlling Process Flows at Devices via CTI Applications
 •   Table 2-20: Points for Groups

Terminal Devices  

 Table 2-15   Points for Devices
 System Interface  
 Meaning  
 Weight  
 Analog  
Number of devices connected via T/R wires.  
 3.3 · FTln  
 UP0/E devices  
Number of devices connected via UP0/E (for example, optiPoint 500, OpenStage TDM), including adapters for data traffic characterized by long call durations.  
 7.7 · FTln  
 IP phones  
Number of terminal devices (e.g.  OpenStage (CorNet-IP [HFA]), connected via IP with HFA functionality.  
Note: HG 1500 performance must be considered separately.  
 7.6 · FTln  
 SIP phones  
Number of terminal devices (e.g. optiPoint 410 S, optiPoint 420 S) connected via SIP.  
Note: HG 1500 performance must be considered separately.  
 3.6 · FTln  
 Data  
Number of devices for data services (for example, data terminals).  
  4.7 · FTln  
 ISDN port  
Number of ISDN connections; the B channels are used for voice and data traffic characterized by relatively short call durations (e.g. S0 bus with several terminal devices but no Xpression ports).  
  12.8 · FTln  

Mobile Stations  

 Table 2-16   Points for Mobile Handsets
 System Interface  
 Meaning  
 Weight  
 Cordless Devices  
Number of CMI handsets if only one system in the network is operated in CMI mode and only one SLC16 is used.  
 6.8 · FTln  
   
Number of CMI handsets if only one system in the network is operated in CMI mode.  
 (6.8 + 23.0 · g) · FTln  
   
Number of CMI handsets, if network wide CMI mode is operated.  
 (6.8 + 23.0 · g·(1-G) + 44.4 · G) · FTln  

Special Devices  

 Table 2-17   Points for Special Devices
 System Interface  
 Meaning  
 Weight  
 UCD Agent  
 (HPCC, OSCC)  
Number of active UCD agents1controlled by the OSCC application.  
 59 · C  
 ACD Agent  
 (e.g., HPCO)  
Number of active ACD agents1, where the display of each agent is refreshed every T seconds.  
 179 / T + 65 · C  
 ACD group  
Number of ACD groups.  
 4.8  
 AC  
Number of active attendant consoles  
 252 · FVPL  
 Automatic AC
(IVM)  
Number of analog trunks or digital B channels which are routed from CO to the automatic attendant at IVM.  
 21.9 · FLtg  
1The associated devices must no longer be considered separately; the same applies to the incoming trunks provided for the ACD group (at least one B channel per agent)

Trunk Interfaces  

 Table 2-18   Points for Trunks
 System Interface  
 Meaning  
 Weight  
 Trunk  
Number of analog trunks or digital B channels to CO  
24.6 · FLtg  
 ITSP trunks  
Possible number of simultaneous voice channels to the ITSPs  
23.9 · FLtg  
 Networking trunk
(TDM CorNet-N)  
Number of digital B channels to other nodes or to Xpressions via TDM with CorNet-N  
23.4 · FLtg  
 Networking trunk
(TDM CorNet-NQ)  
Number of digital B channels to other nodes or to Xpressions via TDM with CorNet-NQ  
27.1 · FLtg  
 Networking trunk
(IP)  
Number of digital B channels to other nodes or to Xpressions via IP  
Note: HG 1500 performance must be considered separately.  
23.9 · FLtg  

Additional Overhead for Features  
The additional overhead values listed below are based on the assumption that the corresponding basic overhead for each terminal device involved has already been recorded in Table 2-15 .

 Table 2-19   Additional Overhead for Controlling Process Flows at Devices via CTI Applications
 System Interface  
 Meaning  
 Weight  
 CTI-control via CSTA  
Number of devices operated by means of CTI-controlled connection procedures via CSTA commands  
  1.7 · FTln  

 Table 2-20   Points for Groups
 System Interface  
 Meaning  
 Weight  
 Call pickup group  
Overhead per call pickup group with N members, where Opt refers to digital devices.  
(0.06 · (N-1)·N + 0.48 · (N-1)·Opt)·FTln  
 Group call  
Overhead per call pickup group with N members, where Opt refers to digital devices.  
(0.91 · (N-1)·N + 0.66 · (N-1)·Opt)·FTln  

HiPath 3000/5000 V8, Service Documentation, Issue 10   up Top
Disclaimer & Copyright   ID: P31003H3580S100017620   2011-01-24