User guide

System Administrator’s Guide – Release 7.5
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Toll Free 1-866-ALLWORX • 585-421-3850 • www.allworx.com
Revised: April 9, 2013
Page 119
13.5.1 Port Expander Options
Clicking on the port expander’s Description opens its View Configuration page. Use
this page to show and modify the options for that port expander. To change the
configuration, click the Modify link. Other options are identical to those on the Port
Expanders page.
Options Description
MAC Address Hardware identifier for the port expander. It cannot be
changed.
IP Address Network address for the port expander. Clicking on it will
open the port expander’s web admin page in another browser
window or tab. The IP address cannot be changed
Description Name given to the port expander. During plug-and-play
installation, the Description is set to the port expander’s MAC
address. Changing it to something more meaningful to the
site or configuration is recommended
Codec Preference Order Set the preferred codec order for the port expander. The
codec is the method of encoding/decoding the audio sent and
received. The two possible codec’s are G.711 and G.729A.
G.711 preserves voice quality but takes more bandwidth.
G.729A takes less bandwidth but reduces voice quality
Note: This setting defines the order of codec selection. Not
all codec’s are supported for all call types (for example,
accessing the server Auto Attendant requires G.711). The
port expander will attempt to use the first choice but will use
whichever codec is required to support calls.
RTP Media Range (Port to
Port)
Specifies the range of UDP ports used for Real Time Packet
communications. Using a maximum range of values makes
the port expander the most secured from snooping and denial
of service activities. However, when remote port expanders
are placed behind 3rd-party firewalls, under certain conditions
the UDP port range may need to be restricted so that
mapping rules can be created for each port expander behind
the firewall. See Chapter 17, Remote Allworx Phones and
Port Expanders, for more information.
SIP NAT Keep-alive Interval Some NAT firewalls will automatically time out and close
connections to devices they protect. If a remote port
expander is behind such a firewall, then this setting prevents
the timeout. Messages called keep-alive packets are sent
from the port expander to the Allworx server at the frequency
specified. The value should be set to an interval that is
shorter than the firewall timeout
SIP Port UDP port number used for the SIP protocol by the port
expander. The default value of 5060 should be used unless
the port expander is behind a 3rd-party firewall and the
network requires a different value.