Extreme Networks EPICenter 6.0, Reference Manual

Page: 557 / 580

QoS Settings for a VoIP VLAN
EPICenter Reference Guide
557
Default Configuration Attributes
The default configuration settings are used in the calculation of the minimum bandwidth for the VLAN,
and can also be used to configure all switches in the VLAN automatically. As an alternative, you can
you specify settings for individual switches in the VLAN and configure the devices individually. The
default configuration settings are saved in the EPICenter database; individual switch settings are not.
The Default Configuration Attributes display shows the following information:
●
Max # of Phones : This shows the number of ports that are available for use as IP phone ports. This
number is calculated as the total number of ports in the VLAN minus the number used as egress
ports.
●
Compression Algorithm : This specifies the speech encoding/decoding algorithm that is being used
by the IP phone sets you have connected to this VLAN. You can select from the following
algorithms:
Select the setting that matches the configuration of your IP phones. The setting you select does not
actually affect the compression algorithm used, since this is done in the IP phone itself, but is used
to compute the minimum bandwidth for the QoS profile settings for this VLAN.
You can modify this setting for individual switches using the manual QoS configuration process.
You may need to do this if you have several types of IP phones that use different compression
algorithms. If the setting you select does not match the algorithm actually used to encode speech by
your phone, the computed QoS bandwidth settings may not be accurate.
NOTE
VoIP configuration attributes are set on a switch-by-switch basis, meaning that all IP phones connected to an
individual switch are assumed to use the same compression algorithm. Settings cannot currently be configured
for individual ports.
●
Priority : This specifies the priority of the VoIP traffic on this VLAN. You can select any of the eight
priority settings (from low to highHi). The default is highHi. Typically the priority for VoIP traffic
should be high relative to other traffic. Again, you can also set this parameter individually for
switches in the VLAN using the manual QoS configuration process.
If you specify an unsupported priority for a non- i -series device, the EPICenter VoIP server will
automatically map the unsupported priority to a supported priority when it does the QoS
configuration on the device. This process maps priority lowHi to low, normalHi to normal,
mediumHi to medium, and highHi to high.
●
Profile : This specifies the QoS profile that will be used by default for this VLAN on each switch in
the VLAN. The default is QP8. Note that non- i -series switches (Summit switches running
ExtremeWare 4.x) only support four QoS profiles (QP1 through QP4) so for a non- i -series switch,
you must change the profile using the manual configuration process.
NOTE
Each of these setting (except for maximum number of phones) can be modified for individual switches in this
VLAN on a switch-by-switch basis. You can do this using the manual QoS configuration process.
G.729 Encodes speech at 8 Kbps.
G.711 Encodes speech at 64 Kbps (uncompressed). This is the default.
G.723.1 Encodes speech at 6.4 Kbps.
Other If you select this, you must set a compression rate in the Configure VoIP Parameters
dialog.