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TANDBERG Gateway
Appendices
Appendix 3: Capacity
Gateway capacity - calculation
The total capacity in the gateway is defined by the following rules:
1)
A maximum of 8 video calls and 8 telephone calls.
2)
Software version defines maximum ISDN bandwidth:
2 Mbps -> Maximum ISDN bandwidth is 1920 kbps (30x64 kbps).
4 Mbps -> Maximum ISDN bandwidth is 3840 kbps (60x64 kbps).
3)
In addition, each call has a weight depending on bandwidth/encryption:
Bandwidth
Teleph.
64
128
192
256
320
384
512
768
1152
1472
1920
Non-encr.
22
74
80
82
84
88
92
108
124
160
176
220
Encrypted
N/A
106
118
120
122
136
146
168
222
N/A
N/A
N/A
The sum of the call weights cannot exceed 845 and max. bandwidth. Users will be prevented from setting up calls that
exceeds these limits.
Example (4 Mbps version):
If the gateway has made 3 calls at 768, 2 calls at 384, and 2 encrypted calls at 192 the calculation will be:
3x124 + 2x92 + 2x120 = 372 + 184 + 240 = 796. Since 796 is less than 845 and the total bandwidth 3456 kbps, do not
exceed the maximum bandwidth limit, this will be possible.
Gateway capacity – typical scenarios (4 Mbps version)
Below some typical capacity scenarios are listed. They can be derived by the calculation above:
Bandwidth
Non-encrypted
Encrypted
128 kbps
8+8*
7+0
256 kbps
8+7
6+5**
384 kbps
8+4
5+5
512 kbps
7+4
5+0
768 kbps
5+0
3+8
1472 kbps (1.5 Mbps)
2+8
N/A
1920 kbps (2 Mbps)
2+0
N/A
* 8+8 indicates 8 video calls and 8 telephone calls.
** 6+5 indicates 6 encrypted video calls and 5 unencrypted telephone calls.
