2.4.2  
Gateway Channels (DSP Channels) 
 

Connections from IP workpoint clients/lines to TDM workpoint clients/lines  
Gateway connections are required for connections from IP to TDM workpoint clients and lines. A gateway channel is required on the HG 1500 board for each gateway connection.
TDM workpoint clients/lines are:
 •   UP0/E stations (optiPoint 500)
 •   CMI stations
 •   analog stations
 •   ISDN stations
 •   trunk and tie lines (MSI, S0, S2M)
Examples for assigning a gateway channel on the HG 1500:
 •   A consultation call to a TDM workpoint client is set up during an existing connection between two IP workpoint clients.
 •   An IP workpoint client seizes a trunk.

Connections between TDM workpoint clients/lines  
Connections between TDM workpoint clients/lines do not require DSP channels. The communication system automatically detects that no DSP channels are required.

Conferences  
In the case of conferences, the number of gateway channels seized corresponds to the number of stations and IP workpoint clients involved.

Channels required for gateway connections  
The following table shows the number of gateway channels (HG 1500 boards) necessary based on the existing IP workpoint clients.
The calculation of the values is based on the following assumptions:
 •   A station spends 10 % of its working time in call status.
 •   The average time per call is three minutes.
 •   The availability loss is limited to 1.2 %.
Provisions should be made for more gateway channels (HG 1500 boards) in high traffic volume environments (for example, call centers).

 Table 2-9   Number of Required Gateway Channels (HG 1500 Boards)
 IP workpoint clients in the system  
 Required number of gateway channels  
 0 - 3  
 2  
 4 - 12  
 4  
 13 - 16  
 6  
 17 - 38  
 8  
 39 - 54  
 10  
 55 - 70  
 12  
 71 - 86  
 14  
 87 - 96  
 15  
 97 - 101  
 16  
 102 - 136  
 20  
 137 - 172  
 24  
 173 - 210  
 28  
 211 - 247  
 32  
 248 - 324  
 40  
 325 - 402  
 48  
 403 - 481  
 56  
 482 - 562  
 64  
 563 - 726  
 80  
 727 - 890  
 96  
 891 - 1000  
 112  
In a straightforward IP network, the number of gateway channels must be greater than or equal to the number of TDM lines.
The required number of HG 1500 boards for VoIP is determined by the sum of the gateway channels, MOH channels, and conference channels.

IP/IP e2e payload via enterprise proxy  
HiPath 3000/5000 as of V7 R2 supports "IP/IP e2e payload switching via enterprise proxy" for Internet (DSL) telephony (enterprise proxy: also RTP proxy). This means that, for Internet (DSL) telephony, data packets do not need to be processed by the digital signal processors of the system. Instead, the calls (i.e. payload data) are directed from the telephone over the LAN and via routers to the Internet Telephony Service Provider (ITSP), and back again.   As a result, no gateway channels (DSP channels) are needed for ITSP connections. The maximum number of simultaneous calls depends on the selected codec and the available bandwidth of the Internet (DSL) service.
In order to enable "IP/IP e2e payload switching via enterprise proxy", the "Use RTP Proxy" flag must be activated in the WBM of the HG 1500.

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