Power Priority Mechanism - Avaya g700 Installation And Upgrades

Telephones and adjunct systems
All PoE Switches comply with the IEEE 802.3af standard.
Switch
C363T-PWR
C364T-PWR
C460
P333T-PWR
PoE is carried over the signal leads, providing remote -48V power feeds on all 10/100 ports in
the switch/module (except on an expansion module in P333T-PWR). This allows the PD
(Powered Device) to be up to 100m away from the switch. Each port performs a standard
compatibility detection process before power is supplied to the Ethernet lines. If the PD is
removed or the link is interrupted, the port polling mechanism detects this, and power is cut off
to the port while the detection process is applied again.
The PoE switch applies power to the port only after it detects that a PD is actually connected to
the port. Each PD has a resistance range known as a "signature." The switch knows what
power has to be supplied to the device according to the signature.
Load detection is performed every 240 ms. All ports are checked for the resistance signature on
a port-by-port basis. Only non-powered ports participate in the periodic load detection. Once
power is provided to a port, it is checked periodically to see if a PD is still connected. If a PD is
disconnected from a powered port, then power is denied to the port. Disconnected ports then
automatically join the periodic load detection cycle. Each port of the switch is protected against
channel overload, short circuit, and reversed polarity that might be caused by faulty connection
between two feeding channels or by a crossed cable connection.

Power priority mechanism

The priority mechanism is implemented in order to handle cases where the power requested by
the PDs exceeds the switch PoE capacity. This priority mechanism determines the order in
which ports will be powered on after boot, and powered off if the power resources of the module
are exhausted. Three user-configurable port power priority levels are available: low, high &
critical. Within each priority level the lower the port number, the higher the priority (by default all
the ports have low priority).
Disconnected power will be automatically reconnected to the PDs based on their priority,
whenever there is an available power budget. Immediately after the PoE has booted up, it starts
to supply power to the ports where a load is detected. Ports are powered up one after another,
based on the port priority, until the limit is reached. Power calculation is based on the actual
power consumption of the PD. After this, no more ports are powered up until the total power
consumption drops lower than the limit. The limit is 18 Watts below the maximum PoE capacity.
The remaining 18W are reserve power for a change in the power draw of PDs.
350 Installation and Upgrades for Avaya G700 Media Gateway and Avaya S8300 Media Server
Maximum PoE Power (W)
305
520
2,400 (with three PSUs)
200
Number of Powered Ports in Switch
24
48
192
24