Panasonic KX-TDA0490, Начало работы

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A1 VoIP Requirements
Getting Started 51
Is the card located appropriately?
Transmission delays can cause pauses and loss in VoIP communications. The more network devices
(e.g., routers and switches) there are between the communicating cards, the larger the transmission
delays, because a certain amount of delay is inevitable when packets go through each network device
(hop).
One preventative measure is to install the card so that the number of transmission hops is kept to a
minimum. In the diagram below, the card is located as close to the IP network interface as possible.
A1.3 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 taken into your evaluation.
Can the firewall pass packets from the VoIP Gateway Card?
If the VoIP network contains a firewall, the firewall must be configured appropriately to allow VoIP
packets, which are listed in the table below, to pass through the network without being blocked by
filtering.
For more information, consult your network administrator.
Protocol TCP/UDP Default Port No.
HTTP
*1 TCP 80
RTP/RTCP
*2 UDP 5004 to 5035
H.225.0 Call Signalling
*2 TCP 1720
H.245 *2 TCP 1712 to 1724
H.225.0 RAS *2 UDP 1719
QSIG Connectionless Tunnelling *1
TCP 1718
*1 For the actual setting values, refer to "2.2.1 Network Parameters" in the VoIP Gateway Card
Programming Guide.
Router
Switch
Too many hops
Switch
Hub
Router
Switch
Better
(PBX located nearest IP network access point)
Switch
Hub