Network Devices - Panasonic KX-NCP500 Networking Manual

2.1.3 Network Devices

Are the network devices located appropriately for effective VoIP
communications?
Transmission delays can cause pauses and loss in VoIP communications. The more network devices (e.g.,
routers and switching hubs) there are between the PBX and IP telephones or the IP network interface, the
longer the transmission delays. This is because a certain amount of delay is inevitable when packets go through
each network device.
To prevent unnecessary delays, it is recommended to connect the PBX as close to the IP telephones and the
IP network interface as possible so that the number of the network devices is kept to a minimum.
Router
Switching
Hub
2.1.3 Network Devices
You must evaluate the network devices that are used in the existing network to see if a VoIP network can be
implemented. Below are the points that should be evaluated.
Can the firewall pass packets appropriately?
If the VoIP network contains a firewall, the firewall must be configured appropriately to allow VoIP packets,
listed in the table below, to pass through the network without being blocked by filtering.
For more information, consult your network administrator.
[IP Packets from MPR/IP-EXT16 Card and IP Telephones]
Protocol
RTP (IP telephone
connected to MPR)
RTP (IP-PT connected to
IP-EXT16)
Maintenance (MPR)
Maintenance (IP-EXT16)
Maintenance (IP
telephone)
MGCP (MPR/IP-EXT16)
MGCP (IP telephone)
20 IP Networking Guide
IP Network
Router
Switching
Hub
Switching
Hub
Description
Real-time Transport Protocol.
Used for voice data transmission.
Panasonic proprietary protocol.
Used for communication parameter
negotiation with the PBX, download of
country/area data, confirmation of
connection with the PBX, and
notification of error messages and
statistical information to the PBX.
Media Gateway Control Protocol.
Used for call control command data and
LCD/LED data transmission.
TCP/UDP Default Port No.
UDP 12000 to 12255
UDP 8000 to 8063
TCP 35300
UDP 9300
UDP 9301
UDP 2727
UDP 2427
Document Version 2010-08