Network Requirements - NEC SL2100 Quick Install Manual

NEC SL2100 Communication System

Network Requirements

SLNet should be deployed on networks connected by some form of Point-to-Point connection such as a VPN,
MPLS, or other Point-to-Point circuit.
The voice quality of VoIP depends on variables such as available bandwidth, network latency, and
quality of service initiatives (QoS), all of which are controlled by the network and internet service
providers. Because these variables are not within NEC's control, the performance of the user's IP based
voice solution cannot be guaranteed. Therefore, NEC recommends connecting the VoIP
equipment through a fully managed data network with Quality of Service (QOS) implemented.
For a network to be suitable for VoIP it must pass specific requirements.
The requirements are:
• One way delay must not exceed 150 ms
• Round trip delay must not exceed 300 ms
• Packet loss must not exceed 1 %
• Data switches must be manageable
• No half-duplex equipment may be present in the network
• Routers must provide QOS
Depending upon how the QOS policies are built in the network, assignments may be needed in the CPU
(PRG 84-10).
• Adequate bandwidth for the estimated VoIP traffic must be available
See below chart for bandwidth calculations.
Below is a chart that shows the average bandwidth per VoIP call over Ethernet
Codec Packet size
G.711 10 mS
G.711 20 mS
G.711 30 mS
G.711 40 mS
G.722 10 mS
G.722 20 mS
G.722 30 mS
G.722 40 mS
As an example, if one site plans on making a maximum of 16 calls across the network using G.729 with
a 30 ms packet size, there must be a minimum of 376 kbps available for voice traffic. The QOS policy
for this network should allow for 376 kbps to be set aside for voice prioritization.
Quick Install Guide – SL2100 SLNet rev1.0
Bandwidth used Codec
110.4 kbps G.729
87.2 kbps G.729
79.5 kbps G.729
75.6 kbps G.729
110.4 kbps G.729
87.2 kbps G.729
79.5 kbps G.723
75.6 kbps G.723
8
Packet size Bandwidth used
10 mS 54.4 kbps
20 mS 31.2 kbps
30 mS 23.5 kbps
40 mS 19.6 kbps
50 mS 17.3 kbps
60 mS 15.7 kbps
30 mS 20.8 kbps
60 mS 13.2 kbps