Cisco ESW-520-24 Faq page 5

© 2009 Cisco Systems, Inc. All rights reserved. This document is Cisco Public Information.
Q.
How many devices can the Cisco ESW 500 Series PoE switches power?
A.
The number of devices supported depends on the power requirements for each device and the
switch model in question. The ESW-520-24P-K9 can deliver the necessary power to support
24 ports at 7.5W, 12 ports at 15.4W and any combination in between. The ESW-520-48P-K9
can deliver the necessary power to support 48 ports at 7.5W, 24 ports at 15.4W and any
combination in between. The ESW-540-24P-K9 can deliver the necessary power to support 24
ports at 7.5W, 18 ports at 15.4W and any combination in between. To help understand this
better, the below table reviews the recommended number of POE devices for 3 different
scenarios:
Scenario 1: Assumes the PoE devices connected to the switch are all IEEE 802.3af Class 2
●
devices which draw less than 7.5W per device
Scenario 2: Assumes the PoE devices connected to the switch are a mix of IEEE 802.3af
●
Class 2 & Class 3 devices devices which on average draw less than 11W per device
Scenario 3: Assumes the PoE devices connected to the switch are all IEEE 802.3af Class 3
●
devices which draw less than 15.4W per device
Cisco ESW 500 Series Total Power and Recommended Device Usage
Table 4.
SKU Total Power
180 Watts
ESW-520-24P-K9
380 Watts
ESW-520-48P-K9
280 Watts
ESW-540-24P-K9
A PoE device in this case could be a wireless access point, IP phone, video surveillance
camera or other network attached device. To find out the power requirement for Cisco Small
Business Pro Series products that use PoE, refer to ESW resources center at
http://www.cisco.com/go/eswhelp
For all other devices, please refer to the manual for that specific device.
The ESW 500 Series Switch Configuration Utility device manager also includes a PoE budget
calculator that shows how much PoE power is being consumed based on the types of devices
connected to the switch.
Note:
When using the Redundant Power Supply Unit (RPS1000) with ESW 500s, the total
available PoE power budget is a maximum of 280W.
Q.
Can the Cisco ESW 500 Series switches with PoE support a device that requires more
than 15.4W from a single PoE port?
A.
No.
Q.
Do the Cisco ESW 500 Series PoE switches support standards-based Power over
Ethernet?
A.
Yes, they support IEEE 802.3af.
Q.
Do the Cisco ESW 500 Series PoE switches support Cisco pre-standard Power over
Ethernet?
A.
No. For Cisco pre-standard PoE, we recommend the Cisco Catalyst 2960 Series Switches,
which support both 802.3af and Cisco pre-standard PoE.
Scenario 1 PoE Scenario 2 PoE
Devices drawing Devices drawing
< 7W < 11W
24 devices 16 devices
48 devices 32 devices
24 devices 24 devices
(live on June 4, 2009).
Q&A
Scenario 3 PoE
Devices drawing
< 15.4W
12 devices
24 devices
18 devices
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