PoE planning and
implementation guide
hp procurve
www.hp.com/go/hpprocurve
PoE
Power over Ethernet Devices
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HP ProCurve
PoE Planning and
Implementation Guide
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© Copyright 2003 Hewlett-Packard Development Company,
L.P. The information contained herein is subject to change
without notice.
Disclaimer
HEWLETT-PACKARD COMPANYMAKESNO WARRANTY
OF ANY KIND WITH REGARD TO THIS MATERIAL,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE. Hewlett-Packard shall not be
liable for errorscontained herein orforincidental orconsequential
damages in connection with the furnishing, performance, or use
of this material.
This document contains proprietary information, which is
protected by copyright. No part of this document may be
photocopied, reproduced, or translation into another language
without the prior written consent of Hewlett-Packard.
Publication Number
5990-6045
November 2003
Edition 1
The only warranties for HP products and services are set forth in
the express warranty statements accompanying such products and
services. Nothing herein should be construed as constituting an
additionalwarranty. HP shall notbeliable for technicalor editorial
errors or omissions contained herein.
Applicable Products
Hewlett-Packard assumes no responsibility for the use or
reliability of its software on equipment that is not furnished by
Hewlett-Packard.
HP ProCurve Switch 2626-PWR
HP ProCurve Switch 2650-PWR
HP ProCurve Switch xl PoE Module
(J8164A)
(J8165A)
(J8161A)
Warranty
See the Customer Support/Warranty booklet included with the
product.
HP ProCurve 600 Redundant and
External Power Supply
(J8168A)
A copy of the specific warranty terms applicable to your Hewlett-
Packardproductsandreplacementpartscanbeobtainedfromyour
HP Sales and Service Office or authorized dealer.
Trademark Credits
Windows NT®, Windows®, and MS Windows® are US
registered trademarks of Microsoft Corporation.
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1 Introduction
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Power Through the Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
HP 600 RPS/EPS Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Redundant Switch Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
External Switch Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
EPS Power Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
PoE Power With and Without EPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Switch Port Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Switch Priority Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Line Loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
PD Power Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
3 Planning
PD Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Supported Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Number of PDs per Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Planning Your PoE Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
HP ProCurve 2626-PWR Configurations . . . . . . . . . . . . . . . . . . . . . . . . 3-3
With an HP 600 RPS/EPS Powering One Switch . . . . . . . . . . . . . . 3-3
With an HP 600 RPS/EPS Powering Two Switches . . . . . . . . . . . . 3-4
HP ProCurve 2650-PWR Configurations . . . . . . . . . . . . . . . . . . . . . . . . 3-5
With an HP 600 RPS/EPS Powering One Switch . . . . . . . . . . . . . . 3-6
With an HP 600 RPS/EPS Powering Two Switches . . . . . . . . . . . . 3-7
i
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With an HP 600 RPS/EPS Powering One Module . . . . . . . . . . . . . . 3-8
With an HP 600 RPS/EPS Powering Two Modules . . . . . . . . . . . . 3-9
Infrastructure Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
Glossary
Index
ii
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1
Introduction
This chapter provides an overview of Power over Ethernet (PoE) and a list of
reasons why a user might want to implement PoE in their environment. It
discusses how PoE transmits power over twisted pair cable and the capabili-
ties of the devices used to provide PoE.
Overview
Power over Ethernet technology allows IP telephones, wireless LAN Access
Points and other appliances to receive power as well as data over existing LAN
cabling, without needing to modify the existing Ethernet infrastructure.
IEEE 802.3af is an extension to the existing Ethernet standards. Power Over
Ethernet is likely to become a standard feature of ethernet switches in a few
years, as the cost of adding power supplies to the Ethernet switches is going
to be small. It offers the first truly international standard for power distribu-
tion (consider how many different AC power plugs exist worldwide).
Almost all appliances require both data connectivity and a power supply. Just
as telephones are powered from the telephone exchange through the same
twistedpair thatcarriesthe voice, wecan nowdo the samething with Ethernet
devices.
The technology is bound to make a big impact in the world of embedded
computing. In the realm of embedded computers, where the systems are
increasingly connected to LANs and the internet, the advantages of providing
power and data through a single cable should be obvious. Consider a typical
application: a system for a car park that includes security cameras, informa-
tion signs, call-for-help telephones and vehicle sensors. Such a system is
distributed over a significant area, where mains power is not easily available.
A single link to a PoE Ethernet Switch makes implementing this system less
expensive and faster than using a non-PoE switch.
1-1
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Introduction
Overview
Power Over Ethernet connections to embedded computers will allow much
cheaper installation (no AC cabling, lower labor costs), facilitate updating the
installation and repositioning of sensors without electricians, while main-
taining full control over every node through the Internet, with VoIP and
webcam telephony. Functionality can be changed by downloading new soft-
ware through the network.
Figure 1 shows a typical system implemented to power telephones. The PoE
Ethernet switches are installed to supply power over the twisted pair LAN
cables to run phones or other appliances as required.
Mitel 3300 IP PBX
5300xl
HP PoE switch
HP PoE switch
Figure 1-1. Example of a Typical Implementation
Here are some reasons why you might want to do this:
■
■
■
Only one set of wires to bring to your appliance - simplifies installation
and saves space.
There is no need to pay for additional electrical power runs or to delay
your installation schedule to make them- saves time and money.
The appliance can be easily moved, to wherever you can lay a LAN cable
- minimal disruption to the workplace.
■
■
Safer - no AC voltages need to be added for additional network devices.
As well as the data transfer to and from the appliance, you can use SNMP
network management infrastructure to monitor and control the
appliances.
■
■
Appliances can be shut down or reset remotely - no need for a reset button
or power switch.
WhenimplementingwirelessLANsystemsitsimplifiestheRFsurveytask,
as the access point can easily be moved and wired in.
1-2
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Introduction
Overview
Power Through the Cable
A standard CAT5 Ethernet cable has four twisted pairs, but only two of these
pairs are used for 10Base-T and 100Base-TX data. The specification allows
two options for using these cables for power:
■
The spare pairs are used. The pair on pins 4 and 5 are connected
together and form the positive supply, and the pair on pins 7 and 8 are
connected and form the negative supply.
■
The data pairs are used. Since Ethernet pairs are transformer coupled
at each end, it is possible to apply DC power to the center tap of the
isolation transformer without upsetting the data transfer. In this mode of
operation the pair on pins 3 and 6 and the pair on pins 1 and 2 can be of
either polarity.
The standard does not allow both pairs (spare and data) to be used - a choice
must be made. The Power Sourcing Equipment (PSE) applies power to either
set of wires. Hewlett-Packard has chosen to supply PoE power over the data
pair. The Powered Device (PD) must be able to accept power from both
options.
An obvious requirement of the specification is to prevent damage to existing
Ethernet equipment. A discovery process, run from the PSE, examines the
Ethernetcables, looking for devices thatcomply withthe specification. It does
this by applying a small current-limited voltage to the cable and checks for the
presence of a 25k ohm resistor in the remote device. Only if the resistor is
present, will the full wattage be applied, but this is still current-limited to
prevent damage to cables and equipment in fault conditions.
The Powered Device must continue to draw a minimum current. If it does not
(for example, when the device is unplugged) then the PSE removes the power
and the discovery process begins again.
PoE Capabilities of the Products
The HP ProCurve PoE switch devices are multiport switches that can be used
to build high-performance switched workgroup networks with PoE. These
switches are store-and-forward devices that offers low latency for high-speed
networking. The HP ProCurve PoE switch devices are designed to support
Redundant Power Supply and Power over Ethernet (PoE) technologies.
The 2650-PWR and 2626-PWR switches have 48 and 24 auto-sensing 10/
100Base-TX RJ-45 ports, respectively, and two dual-personality ports—either
auto-sensing 10/100/1000Base-T RJ-45, or mini-GBIC. The dual-personality
ports do not support PoE.
1-3
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Introduction
Overview
The HP ProCurve Switch xl PoE Module (J8161A) is a module for the HP
ProCurve 5300 xl Switch and has 24 auto-sensing 10/100-TX RJ-45 ports. All
24 ports are capable of supplying PoE power. However, for the module itself
to be able to supply PoE power it first must be connected to an EPS port on
an HP ProCurve 600 Redundant and External Power Supply (J8168A), here-
after referred to as the HP 600 RPS/EPS.
The Switch 2600-PWR Series devices can be connected to an HP 600 RPS/EPS
and receive full redundant power from the RPS part of the unit for switch
operation, if the internal power supply in the switch fails. If multiple switches
are connected to the RPS ports and several switches lose power at the same
time, the switch attached to the lowest RPS port number receives power. The
HP 600 RPS/EPS unit can provide all the power necessary to keep the switch
running.
EPS power from the HP 600 RPS/EPS deviceis the PoE capability of the device
and supplies backup and additional power for the ports of the 2626-PWR,
2650-PWR switch devices. It also provides PoE power to the HP ProCurve
Switch xl PoE Module.
These switch devices are designed to be used primarily as high-density wiring
closet or desktop switches. With these switches you can directly connect
computers, printers, and servers to provide dedicated bandwidth to those
devices, and you can build a switched network infrastructure by connecting
the switch to hubs, other switches, or routers. In addition, they support the
PoE standard, IEEE 802.3af, and can supply power over a twisted-pair cable
to power devices such as telephones and wireless access points.
1-4
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2
Operating Rules
This chapter discusses the operating rules and characteristics of PoE and
describes the capabilities of a device used to provide redundant and external
PoE power, the HP ProCurve 600 Redundant and External Power Supply
(J8168A), hereafter referred to as the HP 600 RPS/EPS. The HP 600 RPS/EPS
is an accessory product for the Switch 2600-PWR Series devices, the HP
ProCurve Switch xl PoE Module, and specific other HP ProCurve switches.
The redundant power supply (RPS) and external power supply (EPS) features
are explained below.
HP 600 RPS/EPS Operation
The HP 600 RPS/EPS monitors the power signal from a switch by detecting
that it is connected to the switch with an RPS or EPS cable. When the power
from the switch is no longer detected, the HP 600 RPS/EPS provides power to
the switch within 1 millisecond.
The HP 600 RPS/EPS supports hot plugging of an RPS or EPS cable. For more
information refer to the documentation that came with the HP 600 RPS/EPS.
For connectivity refer to the HP ProCurve Switch 2600 and 2600-PWR Series
Installation and Getting Started Guide that came with your switch.
Redundant Switch Power
The HP 600 RPS/EPS provides redundant power to any one of up to six switch
products, to back up the power supply in a switch in case of loss of AC power,
or a fault condition. The HP 600 RPS/EPS is an unmanaged power supply that
only provides information by way of LEDs or through the port interfaces to
attached devices.
2-1
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Operating Rules
External Switch Power
Operating Characteristics.
The HP 600 RPS/EPS has six RPS ports, each of which can provide redundant
+12V power to a connected switch, but only one port can provide this
power at a given time. If a switch with no AC power is connected to an
operating HP 600 RPS/EPS, it will receive power if power is available (no
higher priority port is already using the RPS power).
If the power to a switch fails, power is provided from the HP 600 RPS/EPS, if
it is available, that is, if the HP 600 RPS/EPS is not already providing power to
a higher priority switch. If two or more devices fail, priority goes to the device
plugged into the lower numbered port on the HP 600 RPS/EPS unit. Conse-
quently the most important switch should be plugged into port one on the HP
600RPS/EPS. Inthisstate, the“Connected”LED shouldbe ON, andthe“Power
Status” LED should be BLINKING on the lower priority RPS port notsupplying
power. (For further information refer to the Installation and Getting Started
Guide that came with your HP 600 RPS/EPS unit.)
External Switch Power
The HP 600 RPS/EPS provides external PoE power to up to two switchdevices
through two EPS ports. The amount of PoE power provided depends on how
many switches (one or two) are connected to these ports on the HP 600 RPS/
EPS. For example, you could connect one EPS port to a Switch 2650-PWR and
connect the other EPS port to an HP ProCurve Switch xl PoE Module.
EPS Power Allocation
The HP 600 RPS/EPS has a maximum PoE power supply of 368 watts that can
supply power to connected switch devices either as the primary source of PoE
power, such as with the Switch xl PoE Module, or as a level of additional PoE
power for devices that have internal PoE power supplies. For the Switch 2626-
PWR the external PoE power is redundant power, used if the internal PoE
power supply fails. However, because the HP 600 RPS/EPS has two EPS ports
and can be connected to two switches, the supplied PoE power to each switch
iscutinhalf. Inotherwords, eachswitchonlyreceives184wattsofPoEpower.
The same holds true, for example, if you have connected one EPS port to a
Switch 2626-PWR and the other EPS port to an HP ProCurve Switch xl PoE
Module. The 368 watts from the HP 600 RPS/EPS will be split between the two
switch devices.
2-2
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Operating Rules
External Switch Power
Maximum PoE Power
The Switch 2626-PWR provisions (allocates power to) ports 1-24 with 406
watts of power for PoE applications compatible with the IEEE 802.3af stan-
dard. The Switch 2650-PWR provisions ports 1-48 with 406 watts. This reduces
the per port wattage by half as compared to the Switch 2626-PWR. However,
by connecting an HP 600 RPS/EPS, you can optionally provision ports 25-48
with 368 watts of external PoE power, thereby bringing the per port wattage
up to 15.4 watts per port, unless you have the other EPS port connected to an
HP ProCurve PoE device. In this case you cannot provision the full 368 watts
to the Switch 2650-PWR, only half, 184 watts.
Table 2-1. Maximum Power Allocations
PoE Power
Sources
PoE for Switch 2626-PWR
PoE for Switch 2650-PWR
HP ProCurve Switch xl
PoE Module
Internal
Only
406 watts available to ports
1-24.
406 watts available to ports 1-48.
406 watts available to ports 1-24
No internal PoE power.
Internal
and EPS
redundant 368/184* watts
availableto ports 1-24. Only if (provided by the internal source).
368/184* watts available to ports
1-24 from the EPS only.
the internal power supply
fails.
368/184* watts available to ports
EPS Only
368/184* watts available to
The internal power supply has
368/184* watts available to ports
1-24.
ports1-24. (The EPS provides failed, and the EPS provides 368/
PoE power to ports 1-24 only
if the internal power supply
fails.)
184* watts to ports 1-48. Note that
38 watts of this power are always
allocated exclusively to ports 1 and
2, or 25 and 26.) See page 3-5.
*
If both EPS ports on the HP 600 RPS/EPS are connected to switches, each switch
can receive 184 watts of power. If a single switch is connected to the EPS ports,
that switch can receive 368 watts.
PoE Power With and Without EPS
It is important to understand the PoE power requirements of these switch
devices because if the PoE power is not planned and implemented correctly,
end devices connected to the PoE switch ports may not receive power if an
internal switch PoE power source failure occurs.
2-3
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Operating Rules
External Switch Power
The Switch 2626-PWR has 24 ports and its internal PoE power supply provides
406 watts across all 24 ports. If an HP 600 RPS/EPS device is connected to the
Switch 2626-PWR for the purpose of supplying external power to the PoE
portion of the switch, there will be either 368 watts or 184 watts of power
available should the switch’s internal PoE power supply fail. If a single switch
is connected to the EPS ports on the HP 600 RPS/EPS, 368 watts are available,
providing fully redundant PoE power to the switch. If two switch devices are
connected to the EPS ports on the HP 600 RPS/EPS only 184 watts are
provided to the switch if the internal PoE power supply fails.
The Switch 2650-PWR PoE power requirements are different. This switch has
48 ports and the internal PoE power supply supplies 406 watts across all 48
ports. The switch reserves 38 watts for either ports 1-24 or ports 25-48, so that
neither set of ports receives the entire 406 watts.
By connecting an HP 600 RPS/EPS to the Switch 2650-PWR, more PoE power
is provided to the switch. With the HP 600 RPS/EPS connected to the Switch
2650-PWR, the internal PoE power supply provides the first 24 ports (1-24)
with 406 watts and the HP 600 RPS/EPS supplies the second 24 ports (25-48)
ports on the HP 600 RPS/EPS; 184 watts if two switches are connected to the
EPS ports).
If the internal PoE power supply in the 2650-PWR switch fails, 368 watts or
184 watts are provided to ports 1-48. 38 watts of power are always allocated
exclusively to ports 1 and 2 or 25 and 26. See page 3-5.
Switch Port Priority
The lower the port number the higher the priority given. For example, port
number one has a higher priority than port number two. Therefore when both
ports need power, port number one is given power priority over port number
two and so on throughout the rest of the ports.
A port can be assigned a power priority that alters the assignment of power
to it by the switch. See the software manual that came with your switch for
details.
2-4
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Operating Rules
External Switch Power
Switch Priority Class
Port priority classification can be used by the switch to allocate power to
ports. It is a prioritization scheme by which the user can assign a low(default),
high, or critical priority to any given port. This assignment is done through
the command line interface (see the software manual that came with your
switch) of the switch and alters the hardware port-number priority for power
allocation.
■
Low - Default. This priority class receives power only if all other priority
classes are receiving power. If there is enough power to provision PDs on
only some of the ports with a low priority, then power is allocated to the
ports in ascending order, beginning with the lowest-numbered port in the
class until all available power is in use.
■
High - This priority class receives power only if all PDs on ports assigned
with a critical priority are receiving full power. If there is not enough
power to provision PDs on ports assigned with a “High” priority, then no
power goes to the low priority ports. If there is enough power to provision
PDs on only some of the “High” priority ports, then power is allocated to
the “High” priority ports in ascending order, beginning with lowest-
numbered high priority port, until all available power is in use.
■
Critical - This priority class always receives power. If there is not enough
power to provision PDs on all of the ports configured for this class, then
no power goes to “High or Low” priority ports. If there is enough power
to provision PDs on only some of the “Critical” ports, then power is
allocated to the “Critical” ports in ascending order, beginning with the
lowest-numbered port in the class.
Line Loss
A certainamountofpower is consumedfromtheswitchtothe powereddevice
(typically a 16% loss), which can be influenced by cable length, quality, and
other factors. The IEEE 802.3af specification has addressed loss of power by
providing more power than a powered device requires. As well, depending
upon the classification (Class 0-3) of the device, the switch will provide more
or less power to address the specific power needs of that end device.
PD Power Classification
A PD is classified based on the maximum power it draws across all input
voltages and operational modes. The most common class is 0, in which the
switch will allow a maximum draw of 15.4 watts per port. As an example, 15.4
watts - Power Loss (16%) = 12.95 watts. See table 2-2.
2-5
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Operating Rules
External Switch Power
Table 2-2. Power Usage
Class
Usage
Minimum Power Levels
at Output of PSE
Range of Maximum
Power required by
the PD
0
1
2
3
Default
15.4 Watts
4.0 Watts
7.0 Watts
15.4 Watts
0.44 to 12.95 Watts
0.44 to 3.84 Watts
3.84 to 6.49 Watts
6.49 to 12.95 Watts
Optional
Optional
Optional
As you can see in the table, any 802.3af compliant PD will never require more
than 12.95 watts. The switch provides a minimum of 15.4 watts at the port in
ordertoguaranteeenoughpowertorunadevice, afteraccountingforline loss.
2-6
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3
Planning
This chapter discusses the planning process a user should follow to success-
fully implement a PoE switch. After understanding what PoE is and its
operating rules, the next step to implementation is planning. The following is
an example list of considerations during the planning phase:
■
■
■
What devices will need PoE power?
How much power will each device require?
What if power is lost to the switch?
•
•
Power for the switch to operate (AC power)
Power for PoE devices
■
■
Which devices to plug into which ports and with what priorities?
Are the appliances to be powered by PoE power supported?
When a PD is initially connected to a PoE port, a minimum of 15.4 watts of
available power is required to begin the power-up sequence. This 15.4 watts
is needed to determine the type of PD requesting power (see “PD Power
Classification” on page 2-5). Once the power classification is determined and
that class of PD is available for use.
In the default switch configuration all PoE ports have a Low priority. If the
switch has less than 15.4 W of PoE power available, the switch transfers power
from lower-priority ports to higher-priority ports. See “Priority Classification”
on page 2-5 for information on the use PoE port priority classifications. Within
each priority class, a lower numbered port is supplied power before a higher
numbered port.
Disconnecting a PD from a port causes the switch to stop providing power to
that port and makes that power available to other ports configured for PoE
operation.
3-1
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Planning
Supported Products
Supported Products
The HP ProCurve Switch 2600-PWR Series devices and the HP ProCurve
Switch xl PoE Module support any products that meet the IEEE 802.3af PoE
standard.
Number of PDs per Switch
The number of PDs supported per switch depends on the power allocation
and how much power each PD uses and how much power is left. The following
examples show the power consumption in some typical configurations.
Planning Your PoE Configuration
This section assists you in building a reliable and, if required, redundant PoE
configuration. Using the following examples you can plan, build, and connect
your PoE devices quickly and easily.
There are three configurations: one for the HP ProCurve Switch 2626-PWR,
one for the HP ProCurve 2650-PWR, and one for the HP ProCurve Switch xl
PoE Module. Each shows a complete configuration including an optional HP
600 RPS/EPS unit. A table shows the PoE power available to connected PoE
devices when using just the switch or when using the switch and the HP 600
RPS/EPS unit. The tables show the available power when the HP 600 RPS/EPS
unit is providing PoE power to one or two devices.
Once you have selected your specific configuration and the PoE power
provided, you then add up the maximum amount of power each of your IEEE
802.3af-compliant devices require (use maximum power in watts, usually
found on a product’s data sheet). Adjust this total maximum power figure by
adding 15% to account for possible line loss. This value must be less than the
maximum power available shown in the table for your configuration.
If you are planning to include redundant power in your configuration you need
todeterminewhichPoEdevicesmustreceiveredundantPoEpower, thentotal
their power requirements as explained in the paragraph above. The maximum
power figure must be less than the maximum power available when the switch
is powered by the HP 600 RPS/EPS unit, taking into consideration the number
of switches the HP 600 RPS/EPS unit is powering (one or two).
3-2
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Planning
Planning Your PoE Configuration
HP ProCurve 2626-PWR Configurations
The tables in the two example configurations contain entries that show the
PoE power available when the 2626-PWR is used alone. When used with the
HP 600 RPS/EPS unit, PoE power is available to the PoE ports should the
internal PoE power supply fail. Table entries show the PoE power available
when the HP 600 RPS/EPS alone provides PoE power.
With an HP 600 RPS/EPS Powering One Switch
Source of
Power
Watts
Available
# of Ports Powered and
Average Watts/Port
Redundant # of Ports
Powered and Average Watts/
Port
Internal PoE 406
Power
Supply
24 @ average 15.4 W each
External PoE 368
Power
24 @ average 15.4 W each
Supply
(Failed
Internal PoE
Power
Supply)
■
A single 2626-PWR switch with a dedicated HP 600 RPS/EPS unit has fully
redundant PoE power for all 24 ports at 15.4 W per port.
3-3
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Planning
Planning Your PoE Configuration
With an HP 600 RPS/EPS Powering Two Switches
Second PoE Switch/Module
Source of
Power
Watts
Available
# of Ports Powered and
Average Watts/Port
Redundant # of Ports
Powered and Average Watts/
Port
Internal PoE 406
Power
Supply
24 @ average 15.4 W each
External PoE 184
Power
24 @ 7.6 W each
12 @ 15.4 W each
Supply
(Failed
Internal PoE
Power
Supply)
■
When two switches are connected to the RPS 600 RPS/EPS ports, the PoE
power available to each switch is a maximum of 184 W. If all of your PDs
consume on average less than 7.6 W each (allowing for any line loss) then
all 24 ports will receive redundant power should a switch’s internal PoE
power supply fail.
■
Redundant power as long as the total power required remains below
184 W.
3-4
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Planning
Planning Your PoE Configuration
HP ProCurve 2650-PWR Configurations
The tables in the two example configurations contain entries that show the
PoE power available when the 2650-PWR is used alone. When used with the
HP 600 RPS/EPS unit, additional PoE power is available to the PoE ports and
PoE power is available should the switch’s internal PoE power supply fail.
Table entries show the PoE power available when the HP 600 RPS/EPS alone
provides PoE power.
In the following examples using the HP ProCurve 2650-PWR switch, reference
is made to two blocks of ports: ports 1-24 and ports 25-48. This applies when
external PoE power is available from an HP 600 RPS/EPS unit. In that case,
the internal switch PoE power supply provides 406 watts of power to ports
1-24 and the HP 600 RPS/EPS provides 368 watts of power to ports 25-48.
If you are using the HP ProCurve Switch 2650-PWR with external PoE power,
the number of ports with available PoE power when the switch is powered by
just the HP 600 RPS/EPS unit may be less than the number of ports powered
when both the switch and the HP 600 RPS/EPS unit are supplying power. In
the default configuration the number and location of ports with redundant
PoE power is determined by three factors:
■
The number of switches drawing external PoE power from the HP 600
RPS/EPS unit. If only a single switch is using external PoE power the HP
600 RPS/EPS provides 368 watts of PoE power. If two switches are using
externalPoE powerfrom theHP600RPS/EPS, a switchreceives168 watts
of PoE power. Should the switch’s internal PoE power supply fail, the HP
600 RPS/EPS provides power up to the wattage stated above.
■
When the internal PoE power supply fails, no bank of ports, either 1-24 or
25-48, receives all of the external PoE power. The HP 600 RPS/EPS
reserves a minimum of 38 watts for the less-loaded bank of ports. In the
default configuration, at a minimum, the first two ports in the bank (1 and
2 or 25 and 26) will have PoE power.
■
In the default configuration PoE power priority is determined by port
number, with the lowest numbered port having the highest priority.
If redundant PoE power is required, use the example tables to determine how
much power is available to which ports.
3-5
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Planning
Planning Your PoE Configuration
With an HP 600 RPS/EPS Powering One Switch
Source of
Power
Watts
Available
# of Ports Powered and
Average Watts/Port
Redundant # of Ports
Powered and Average Watts/
Port
Internal PoE 406
Power
24 @ average 15.4 W each
Supply
48 @ average 8.45 W each
48 @ average 15.4 W each
Internal plus 406
368
25 - 48
+
External PoE
Power
Supply
1 - 24
External PoE 368
24 @ average 15.4 W each
48 @ average 7.6 W each
Power
Supply
(Failed
(38 W is
reserved for
either 1-24 or
Internal PoE 25-48)
Power
Supply)
■
The lowest loaded bank of ports (1-24 or 25-48) has 38 watts reserved.
That power is available for use by the two highest priority ports in the
bank, (in a default configuration ports 1 and 2, or 25 and 26).
3-6
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Planning
Planning Your PoE Configuration
With an HP 600 RPS/EPS Powering Two Switches
Second PoE Switch/Module
Source of
Power
Watts
Available
# of Ports Powered and
Average Watts/Port
Redundant # of Ports
Powered and Average Watts/
Port
Internal PoE 406
Power
Supply
24 @ average 15.4 W each
48 @ average 8.45 W each
Internal plus 406
+
184
25 - 48
24 @ average 15.4 W each
and 24 @ 7.6 W each
External PoE
Power
1 - 24
Supply
or
36 @ average 15.4 W each
External PoE 184
9 (bank 1) and 2 (bank 2) @
average 15.4 W each
Power
Supply
(Failed
(38 W is
reserved for
either 1-24 or
19 (bank 1) and 5 (bank 2) @
average 7.6 W each
Internal PoE 25-48)
Power
Supply)
48 @ average 3.8 W each
■
The lowest loaded bank of ports (1-24 or 25-48) has 38 W reserved and is
‘bank 2’ in the table above.
3-7
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Planning
Planning Your PoE Configuration
HP ProCurve Switch xl PoE Module Configurations
For the HP ProCurve Switch xl PoE Module to function it must be installed in
an HP ProCurve Switch 5300xl. The module will receive it’s operational power
from the switch and it’s PoE power from the HP 600 RPS/EPS.
With an HP 600 RPS/EPS Powering One Module
In this example there is only one module connected to the HP 600 RPS/EPS,
therefore it will be supplied with 368 watts of PoE power to be distributed to
all it’s 24 ports at 15.4 watts per port.
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When planning the installation of the HP ProCurve Switch xl PoE Module you
must pay attention to the cabling. In a rack type installation, the HP 600 RPS/
EPS is installed with the EPS ports in the rear, opposite this graphic. This
means the EPS cable must come from the back of the HP 600 RPS/EPS unit
and connect to the front of the module.
Source of
Power
Watts
Available
# of Ports Powered and
Average Watts/Port
Redundant # of Ports
Powered and Average Watts/
Port
External PoE 368
Power
Supply
24 @ average 15.4 W each
None
3-8
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Planning
Planning Your PoE Configuration
With an HP 600 RPS/EPS Powering Two Modules
In this example there are two modules connected to the HP 600 RPS/EPS,
therefore each module will be supplied with 184 watts of PoE power to be
distributed to each modules 24 ports at 7.6 watts per port.
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Source of
Power
Watts
Available
# of Ports Powered and
Average Watts/Port
Redundant # of Ports
Powered and Average Watts/
Port
External PoE 184/each
Power
Supply
24 @ average 7.6 W each
None
module
3-9
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Planning
Infrastructure Requirements
Infrastructure Requirements
Air conditioning. Power supplies create a great amount of heat. Ensure you
have enough cool air to maintain an ambient temperature between 0°C to 55°C
(32°F to 131°F) around the switch devices inside the rack.
Power requirements.Ensure you have enough power supplied to the area
where the switches will be mounted. Some units have dual power supplies in
themthatyou maywant toconsiderconnecting each powersupply todifferent
circuits.
Space. These devices may be deeper than other equipment in your network.
Have enough space for the switch and around the switch to allow access and
cool air circulation. If placing in an enclosed rack make certain there is
adequate airflow and cooling through the rack.
Racks. These devices may be heavier than other devices in your network.
Rack heavy devices at the bottom of the rack, followed by lighter devices as
you move up the rack. Secure racks as specified by your rack’s manufacturer.
Ensure your racks are compliant with any earthquake rules.
3-10
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Glossary
Glossary
active PoE port - PoE-enabled port connected to a PD request power.
priority class - Refers to the type of power prioritization where the switch
uses Low (the default), High, and Critical priority assignments to determine
which groups of ports will receive power. Note that power priority rules apply
only if PoE provisioning on the switch becomes oversubscribed.
EPS - External Power Supply
PD- Powered Device. This is an IEEE 802.3AF-compliant device that receives
its power through a direct connection to a 10/100Base-TX PoE RJ-45 port on
the switch. Examples of PDs include Voice-over-IP (VoIP) telephones, wire-
less access points, and remote video cameras.
port-number priority - Refers to the type of power prioritization where,
within a priority class, the switch assigns the highest priority to the lowest-
numbered port, the second-highest priority to the second lowest-numbered
port, and so-on. Note that power priority rules apply only if PoE provisioning
on the switch becomes oversubscribed.
PoE - Power-Over-Ethernet
PSE- Power-Sourcing Equipment. A PSE, such as a Switch 2626-PWR or 2650-
PWR, provides power to IEEE 802.3AF-compliant PDs directly connected to
10/100Base-TX PoE RJ-45 ports on the switch. The Switch 2626-PWR and 2650-
PWR are endpoint PSEs.
Gloss-1
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PoE … 1-1-
product capabilities … 1-3-
PoE power-
with and without EPS … 2-3-
C
cable
class method priority … 2-4-
PoE power, maximum … 2-3-
port priority … 2-4-
power loss … 2-5-
power over Ethernet … 1-1-
power requirements … 3-1-
power sourcing equipment … 1-3-
priority, class method … 2-4-
priority, port … 2-4-
E
H
HP 600 RPS/EPS
external power supply … 2-2-
operation … 2-1-
redundant power characteristics … 2-2-
redundant power supply … 2-1-
HP ProCurve Switch xl PoE Module … 1-4–2-2-
R
RPS, operating characteristics … 2-2-
I
S
Introduction … 1-1-
switches-
2626-PWR, 2650-PWR, Switch 2600-PWR -
Series … 1-3-
L
line loss-
power loss … 2-5-
T
The … 2-2
M
maximum PoE power … 2-3-
minimum watts … 3-1-
X
xl module configurations … 3-8-
xl module, EPS … 2-2-
O
xl module, PoE power … 2-2-
overview … 1-1-
P
PDs
power classification … 2-5-
planning … 3-1-
Index – 1-
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Technical information in this document
is subject to change without notice.
©Copyright 2003
Hewlett-Packard Development Company, L.P.
Reproduction, adaptation, or translation
without prior written permission is prohibited
except as allowed under the copyright laws.
Printed in Taiwan
November 2003
Manual Part Number
5990-6045
*5990-6045*
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