User manual

mPBX-100 User Manual
www.yeastar.com Page 55
This setting is only required when your public IP address is not static. It is
recommended that a static public IP address be used with this system. Please
contact your ISP for more information.
·External Refresh Interval
If an external host has been supplied, you may specify how often the system will
perform a DNS query on this host. This value is specified in seconds.
·Local Network Identification
Used to identify the local network using a network number/subnet mask pair
when the system is behind a NAT or firewall .
Some examples of this are as follows:
'192.168.0.0/255.255.0.0' : All RFC 1918 addresses are local networks;
'10.0.0.0/255.0.0.0' : Also RFC1918;
'172.16.0.0/12':Another RFC1918 with CIDR notation;
'169.254.0.0/255.255.0.0' : Zero conf local network.
Please refer to RFC1918 for more information.
·NAT Mode
Global NAT configuration for the system . The options for this setting are as
follows:
Yes = Use NAT. Ignore address information in the SIP/SDP headers and reply to
the sender's IP address/port.
No = Use NAT mode only according to RFC3581.
Never = Never attempt NAT mode or RFC3581 support.
Route = Use NAT but do not include rport in headers.
·Allow RTP Reinvite
By default, the system will route media steams from SIP endpoints through
itself. Enabling this option causes the system to attempt to negotiate the
endpoints to route packets to each other directly, bypassing the system. It is not
always possible for the system to negotiate endpoint-to-endpoint media
routing.
3）Codecs
A codec is a compression or decompression algorithm that used in the
transmission of voice packets over a network or the Internet.
u-law: A PSTN standard codec, used in North America, that provides very
good voice quality and consumes 64kbit/s in each direction (receiving and
transmitting) of a VoIP call.
a-law: A PSTN standard codec, used outside of North America, that
provides very good voice quality and consumes 64kbit/s in each direction
(receiving and transmitting) of a VoIP call.