1) POE -> you mean Power over Ethernet, right ?
I do not think there is such a thing as a ring-topology for PoE
a ring topology is possible for data using PoE switches but not for power
if you connect two PoE switch ports together, they will not supply power to each other!
Cisco offers some switches that can both be powered using PoE on an uplink port
and supply a smaller amount of PoE power to a downstream device on a downlink port (PoE-in PoE-out)
but here also available power decreases in each step
so the number of devices in a chain is very limited. And a ring I don't think it's possible.
PoE Pass-Through
The Catalyst 2960CPD-8PT-L and 3560CPD-8PT-S switches provide PoE pass-through.
The Catalyst 2960CPD-8PT-L is powered either through the 10/100/1000 PoE uplink ports receiving power from a PoE or PoE+
switch or through an auxiliary power adapter. The Catalyst 3560CPD-8PT-S is powered through the 10/100/1000 PoE uplink ports receiving power from a PoE+
switch or through an auxiliary power adapter. If the switch has surplus power (see Table 1-2),
it can power other PoE-capable devices such as IP phones, access points, and so on.
2) what kind of devices are you planning in this ring
are these all network switches?
or mixed switches, phones, access points, camera's..... -> this will not work in a ring
3) what do you mean with "non standard" ?
Cisco switches support PoE according to 802.3af at bt and other standards (48V or higher)
Cisco switches also support pre-standard PoE
but do not support PoE for non-standard devices bases on their own 12 or 24V PoE injectors
