NEC SL1100, Networking Manual

Page: 157 / 292

NEC SL1100 Issue 6.0
Networking Manual 9 - 23
Conditions

Encryption is not supported on DR700 series phones that are connected
via NAPT.

If the encryption feature is enabled in terminal programming but not
licensed, the terminal displays “Invalid server” and will not function.
13.4 General IP Configuration
The voice quality of VoIP depends on variables such as available bandwidth,
network latency, and quality of service initiatives (QOS). These variables are
controlled by the network and Internet service providers. Because these
variables are not in NEC control, NEC cannot guarantee the performance of
the users IP based voice solution. NEC recommends connecting the VoIP
equipment through a local area network using private IP addresses.
To ensure a network meets the specific requirements for VoIP
implementation, an IP ready check and a site survey must be completed at
each site before VoIP implementation.

One way delay must not exceed 100ms.

Round trip delay must not exceed 200ms.

Packet loss must not exceed 1%.

Data switches must be manageable.

Routers must provide QOS.

There must be adequate bandwidth for estimated VoIP traffic. Refer to
Section
13.7 Bandwidth on page 9-40 .
Depending on how QOS policies are built in the network, assignments may be
needed in both the CPU and IP terminal. The NEC SL1100 supports the
flagging of packets at layer 2 (VLAN tagging 802.1Q/802.1P) and at layer 3
levels.
13.5 VLANs
A VLAN is used to logically break up the network and minimize broadcast
domains. Without VLANS, the network must be physically segmented to break
up broadcast domains. Each network segment is then connected through a
routing device adding latency and cost. Latency is a delay in the transmission
of data and is caused by routing packets from one LAN to another. In a VoIP
environment latency must be kept to a minimum.