Chapter 2 General Information; Section 1 Voice Over Ip - NEC Sl2100 Networking Manual

General Information
S 1 VOICE OVER IP
ECTION
Voice over IP (VoIP) is a technology that converts speech into data packets and transmits these
packets over TCP/IP networks. The technology also facilitates compression and silence suppression
to reduce network bandwidth demands.
As most organizations already have existing data networks in place, considerable cost savings can be
achieved by utilizing spare bandwidth on these networks for voice traffic.
NEC SL2100 supports the use of IP Phones. These telephones provide the same functionality as a
multiline telephone but use the data network rather then the traditional telecoms infrastructure. This
can reduce costs and allow the use of NEC SL2100 telephones in locations that would not normally be
supported by multiline telephones.
Table 2-1 Table 2-1 VoIP Specifications on page 2-1
NEC SL2100 VoIP system.
Category
IP Address
QoS
Maintenance
VLAN
VoCoder
Jitter Buffer Size
RTP Length
Echo Canceller Tail Size
Level Adjustment
IP Phone
SIP Trunk
*1. DHCP Server and DHCP Client cannot be used at the same time. When the DHCP Server is enabled the
DHCP Client function cannot be activated.
When the VoIPDB is installed, the CPU-C1 is no longer active, all IP connections go through the VoIPDB.
Networking Manual
lists the specifications for various aspects of
Table 2-1 VoIP Specifications
Feature
DHCP Server
*1
DHCP Client *1
802.1p/1q
L3 QoS (ToS)
HTTP Server
Tag and port-based VLAN
G.711 µ-law/A-law
G.729a
G.722
G.726
Set by system programming
Set by system programming
Set by system programming
Set by system programming
SIP Phone
SIP Trunk
Notes
CPU-C1/VoIPDB
VoIPDB/IP Phone
CPU-C1
Diffserv/IP Precedence
CPU-C1/VoIPDB
SIP Phone
Maximum 128 Trunks
2
2-1