NEC Sl2100 Networking Manual page 110

SL2100
• The cabling infrastructure can be simplified. There is no longer a need for separate cabling for the
phone system. Built into the IP phones is a 2 port 10/100 manageable data switch. The data
connection for the PC is available on the back of the IP phone. This built in data switch also
supports 802.1Q and 802.1 P VLAN tagging abilities. The data and the voice can be tagged
separately.
• Allows you to connect remote office workers with a telephone that has the look and same
functionality as the telephones connected at the office.
SIP is used for VoIP as defined by the IETF (Internet Engineering Task Force) RFC3261. The NEC
SIP MLT uses IP Multiline Station (SIP) (proprietary enhanced SIP protocol) to facilitate the
multifunction, multiline telephone.
The SIP Multiline Telephone interfaces directly to the CPU that houses the VoIPDB daughter board.
The VoIPDB provides the digital signal processors (DSPs) for IP stations and trunks.
• VoIPDB provides 128 DSPs
A DSP provides format conversion from circuit switched networks (TDM) to packet switched networks
(IP). Each voice channel from the circuit switched network is compressed and packetized for
transmission over the packet network. In the reverse direction, each packet is buffered for de-jittering,
decompressed and sent to the circuit switched network. Each DSP converts a single speech channel
from IP to TDM and vice versa.
The following are examples of DSP allocation.
• Calling from an IP phone to a TDM phone uses one DSP.
• Calling from an IP phone to another IP phone, registered to the same CPU, uses no DSPs.
• Calling from a TDM phone to another TDM phone uses no DSPs.
• Calling from a TDM phone and out an IP trunk uses one DSP.
An IP to IP call is peer-to-peer, and no DSP resource is used. When this feature is deactivated, an IP to IP
call consumes two DSP resources.
13.2 IP Addressing
When a VoIPDB daughter board is installed in an SL2100 two IP addresses, in the same network, will
be required. One IP Address will be for the VoIPDB and this address is assigned in Program 10-12-09.
This IP Address is used for IP Phones/Trunks to register and pass signaling messages. The other IP
Address is for the DSP's and this address is assigned in Program 84-26-01. This IP Address is used to
pass voice traffic.
By default when an SL2100 with a VoIPDB is installed in a customer's network, the SL2100 will try and
request IP Addressing information from the local DHCP server (DHCP Client Feature). The DHCP
server can provide the SL2100 with the following information:
• IP Address for VoIPDB (PRG 10-12-09)
• Subnet Mask for VoIPDB (PRG 10-12-10)
• Default Gateway for VoIPDB (PRG 10-12-03)
The DHCP server will NOT provide the IP address for the DSP's (PRG 84-26-01). This IP Address will
have to be manually configured.
The DHCP Client Feature can be disabled in Program 10-63-01. When this program is changed a
reset of the SL2100 is required.
When the VoIPDB is installed, in the SL2100, the CPU NIC card is no longer available. All connections
that previously were terminated to the CPU will now terminate to the VoIPDB. It is recommended when
adding the VoIPDB to change the IP Address of the CPU NIC card (PRG 10-12-01) to be 0.0.0.0.
9-12
ISSUE 1.0
IP Multiline Station (SIP)