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    Example: Configuring PoE on an EX6200 or EX8200 Switch

    Power over Ethernet (PoE) ports supply electric power over the same ports that are used to connect network devices. These ports allow you to plug in devices that need both network connectivity and electric power, such as voice over IP (VoIP) phones, wireless access points, and IP cameras.

    On EX6200 and EX8200 switches, the PoE power budget—that is, the total amount of PoE power that is available to the PoE ports on the switch—can vary according to the number and type of power supplies installed and the power requirements of other components, such as line cards. To make the most efficient use of the PoE power budget for the switch, you can configure the PoE power budget for each PoE line card so that the line card power budget is tailored to the power requirements of the connected powered devices.

    This example shows how to configure PoE on an EX8200 switch. The principles illustrated by this example apply to EX6200 switches as well.

    This example covers:

    Requirements

    This example uses the following software and hardware components:

    • Junos OS Release 11.2 or later for EX Series switches
    • An EX8208 switch with the following components installed:
      • Six 2000 W AC power supplies using low-line power inputs
      • Two EX8200-48T (48-port RJ-45) line cards
      • Two EX8200-2XS-40P (40-port PoE+ with 4-port SFP and 2-port SFP+) line cards
      • Three EX8200-48PL (48-port PoE+ 20 Gbps) line cards

    Before you configure PoE, be sure you have:

    Overview and Topology

    For EX6200 and EX8200 switches, each line card that supports PoE has its own PoE controller and PoE power budget. The PoE power budget for a line card is allocated by the switch power management out of the total power available on the switch. By default, power management allocates to each PoE card the maximum power for that card—that is, the amount of power needed to supply all PoE ports on the cards with their maximum supported power.

    Depending on the number and capacity of power supplies installed and the power requirements of the installed line cards in a switch, there might not be enough power available to provide the maximum power to all PoE line cards. Because power management by default allocates maximum power to each line card in priority order until available power runs out, lower-priority PoE line cards might receive partial or no PoE power, while higher-priority PoE line cards might receive more PoE power than the connected powered devices require.

    To avoid this issue, you can configure smaller power budgets for line cards than the maximum. For example, power management allocates 915 W of PoE power to a EX8200-48PL line card by default. If the connected powered devices consume no more than a total of 250 W, you can set the PoE power budget for the line card to 250 W. Doing so frees up 665 W, which then can be used to fulfill the PoE power needs of lower-priority line cards.

    The topology used in this example consists of a switch that has a mixture of line cards installed, some of which support PoE and some of which do not.

    Table 1 details the topology used in this configuration example.

    Table 1: Components of the PoE Configuration Topology

    ComponentDescription

    Comments

    Power supplies

    Six 2000 W power supplies with low-line power inputs

    1200 W capacity each

    Line card 0

    EX8200-48T line card (no PoE ports)

    Ports 0 through 47—Access ports for non-PoE devices, such as print and file servers or workstations not connected through VoIP phones

    Line card 1

    EX8200-48PL line card

    Ports 0 through 47—Access ports for PoE class 2 VoIP phones

    Line card 2

    EX8200-48PL line card

    Ports 0 through 47—Access ports for PoE class 2 VoIP phones

    Line card 3

    EX8200-2XS-40P line card

    Ports 0 through 11

    Access ports for high-priority PoE+ class 4 devices, such as door access control devices, pan-tilt-zoom security cameras, and high-power wireless access points.

    Ports 12 through 22

    Access ports for high-priority PoE class 3 devices, such as static security cameras, executive video VoIP phones, and wireless access points.

    Ports 22 through 40

    Access ports for PoE class 2 devices, such as VoIP phones.

    SFP+ ports 44 and 45

    Uplink ports to the distribution switch, link aggregated with the uplink ports on line card 4.

    Line card 4

    EX8200-2XS-40P line card

    Ports 0 through 11

    Access ports for high-priority PoE+ class 4 devices

    Ports 12 through 40

    Access ports for PoE class 2 devices

    SFP+ ports 44 and 45

    Uplinks ports to the distribution switch, link aggregated with the uplink ports on line card 3

    Line card 5

    EX8200-48T line card (no PoE ports)

    Ports 0 through 47—Access ports for non-PoE devices

    Line card 6

    EX8200-48PL line card

    Ports 0 through 47—Access ports for PoE class 2 VoIP phones

    The following output from the show chassis power-budget-statistics command shows how power is being allocated to the switch components before PoE is configured:

    user@switch# show chassis power-budget-statistics
        PSU  0     (EX8200-AC2K)                 :    1200 W  Online
        PSU  1     (EX8200-AC2K)                 :    1200 W  Online
        PSU  2     (EX8200-AC2K)                 :    1200 W  Online
        PSU  3     (EX8200-AC2K)                 :    1200 W  Online
        PSU  4     (EX8200-AC2K)                 :    1200 W  Online
        PSU  5     (EX8200-AC2K)                 :    1200 W  Online
        Total Power supplied by all Online PSUs  :    7200 W  
        Power Redundancy Configuration           :     N+1
        Power Reserved for the Chassis           :    1600 W
        FPC Statistics                            Base power    PoE power   Priority
        FPC  0   (EX8200-48T)                    :     350 W          0 W      7
        FPC  1   (EX8200-48PL)                   :     267 W        915 W      7
        FPC  2   (EX8200-48PL)                   :     267 W        915 W      7
        FPC  3   (EX8200-2XS-40P)                :     387 W        792 W      7
        FPC  4   (EX8200-2XS-40P)                :     387 W        792 W      7
        FPC  5   (EX8200-48T)                    :     350 W          0 W      7
        FPC  6   (EX8200-48PL)                   :     267 W         96 W      7
        
        Total (non-PoE) Power allocated          :    3875 W
        Total Power allocated for PoE            :    3510 W
        Power Available (Redundant case)         :    2675 W
        Total Power Available                    :       0 W

    The Total Power Available field shows that all available power is being used. Because there is not enough power, the line card in slot 6 is allocated a PoE power budget of only 96 W, which is insufficient to meet the requirements of the connected VoIP phones.

    In addition, the assigned power priorities of the line cards do not align with their actual power priority. Line cards 3 and 4 should have the highest power priorities because they provide PoE power to critical security devices and because they provide the connections to the distribution switch. Because the default configuration gives all line cards the same assigned priority (the lowest priority), the power priority for line cards is determined by their slot numbers. Under the default configuration, line card 0 has the highest power priority, not line card 3.

    To solve these issues, this example configures the PoE power budgets and power priorities for the line cards as shown in Table 2.

    Table 2: Line Card PoE Power Budget and Power Priority

    FPC

    Power Requirements of Powered Devices

    PoE Power Budget for Line Card

    Power Priority of Line Card

    0

    Not applicable

    Not applicable

    7

    1

    48 class 2 devices (maximum of 7 W each)

    336 W

    7

    2

    48 class 2 devices (maximum of 7 W each)

    336 W

    7

    3

    12 class 4 devices (maximum of 30 W each)

    10 class 3 devices (maximum of 15.4 W each)

    18 class 2 devices (maximum of 7 W each)

    640 W

    0

    4

    12 class 4 devices (maximum of 30 W each)

    28 class 2 devices (maximum of 7 W each)

    556 W

    1

    5

    Not applicable

    Not applicable

    7

    6

    48 class 2 devices (maximum of 7 W each)

    336 W

    7

    Other than ensuring that the PoE interfaces are enabled for PoE, this example performs no configuration of the PoE interfaces because the default settings for the PoE interfaces are acceptable in this example. You can, however, configure the PoE interfaces on an EX6200 or EX8200 switch as described in Configuring PoE on EX Series Switches (CLI Procedure) or as shown in Example: Configuring PoE Interfaces with Different Priorities on an EX Series Switch.

    Configuration

    To configure PoE on an EX8200 switch:

    CLI Quick Configuration

    To quickly configure the PoE power budget for PoE line cards and to set the power priority for high-priority line cards, copy the following commands and paste them into the switch terminal window:

    [edit]

    set poe interface all
    set poe fpc 3 maximum-power 640
    set poe fpc 4 maximum-power 556
    set poe fpc 1 maximum-power 336
    set poe fpc 2 maximum-power 336
    set poe fpc 6 maximum-power 336
    set chassis fpc 3 power-budget-priority 0
    set chassis fpc 4 power-budget-priority 1

    Step-by-Step Procedure

    To configure PoE on an EX8200 switch:

    1. Verify that PoE is enabled on all PoE interfaces by entering the [edit poe] hierarchy and showing the current configuration:
      [edit]
      user@switch# edit poe
      
      [edit poe]
      user@switch# show
      interface all;

      If the interface all statement does not appear, enable PoE on all PoE interfaces:

      [edit poe]
      user@switch# set interface all
      
    2. Set the PoE power budget for line card 3 to 640 W:
      [edit poe]
      user@switch# set fpc 3 maximum-power 640
      
    3. Set the PoE power budget for line card 4 to 556 W:
      [edit poe]
      user@switch# set fpc 4 maximum-power 556
      
    4. Set the PoE power budgets to 336 W for the remaining PoE line cards:
      [edit poe]
      user@switch# set fpc 1 maximum-power 336
      
      [edit poe]
      user@switch# set fpc 2 maximum-power 336
      
      [edit poe]
      user@switch# set fpc 6 maximum-power 336
    5. Enter the [edit chassis] hierarchy and set the line card power priority to 0 and 1 for line cards 3 and 4:
      [edit poe]
      user@switch# top edit chassis
      
      [edit chassis]
      user@switch# set fpc 3 power-budget-priority 0
      
      [edit chassis]
      user@switch# set fpc 4 power-budget-priority 1

    Results

    Check the results of the configuration:

    [edit]
    user@switch# show
    
    chassis {
        fpc 3 {
            power-budget-priority 0;
        }
        fpc 4 {
            power-budget-priority 1;
        }
    }
    poe {
        fpc 3 {
            maximum-power 640;
        }
        fpc 4 {
            maximum-power 556;
        }
        fpc 1 {
            maximum-power 336;
        }
        fpc 2 {
            maximum-power 336;
        }
        fpc 6 {
            maximum-power 336;
        }
        interface all;
    }

    Verification

    To verify that the PoE line cards have been configured correctly and that their PoE power budgets have been fully allocated, perform the following tasks:

    Verifying the Poe Line Card Configuration and Power Budgets

    Purpose

    Verify that the line card PoE power budgets have been allocated correctly.

    Action

    Show the PoE controller settings for the line cards:

    user@switch> show poe controller
    Controller  Maximum   Power         Guard    Management  Status
    index       power     consumption   band 
       1        336.00W   0.00W           0W     Class       AT/AF COMBO
       2        336.00W   0.00W           0W     Class       AT/AF COMBO
       3        640.00W   0.00W           0W     Class       AT/AF COMBO
       4        556.00W   0.00W           0W     Class       AT/AF COMBO
       6        336.00W   0.00W           0W     Class       AT/AF COMBO
     

    Meaning

    As shown by the Maximum power field, the PoE power budgets for the PoE line cards have been correctly configured and power management was able to allocate the configured PoE power budgets to the line cards.

    Verifying the Power Budget for the Switch and Line Card Power Priorities

    Purpose

    Verify the overall power budget for the switch and the line card power priorities.

    Action

    Show the power budget for the switch:

    user@switch# show chassis power-budget-statistics
        PSU  0     (EX8200-AC2K)                 :    1200 W  Online
        PSU  1     (EX8200-AC2K)                 :    1200 W  Online
        PSU  2     (EX8200-AC2K)                 :    1200 W  Online
        PSU  3     (EX8200-AC2K)                 :    1200 W  Online
        PSU  4     (EX8200-AC2K)                 :    1200 W  Online
        PSU  5     (EX8200-AC2K)                 :    1200 W  Online
        Total Power supplied by all Online PSUs  :    7200 W
        Power Redundancy Configuration           :     N+1
        Power Reserved for the Chassis           :    1600 W
        FPC Statistics                            Base power    PoE power   Priority
        FPC  0   (EX8200-48T)                    :     350 W          0 W      7
        FPC  1   (EX8200-48PL)                   :     267 W        336 W      7
        FPC  2   (EX8200-48PL)                   :     267 W        336 W      7
        FPC  3   (EX8200-2XS-40P)                :     387 W        640 W      0
        FPC  4   (EX8200-2XS-40P)                :     387 W        556 W      1
        FPC  5   (EX8200-48T)                    :     350 W          0 W      7
        FPC  6   (EX8200-48PL)                   :     267 W        336 W      7
          
        Total (non-PoE) Power allocated          :    3875 W
        Total Power allocated for PoE            :    2204 W
        Power Available (Redundant case)         :    2675 W
        Total Power Available                    :    1306 W

    Meaning

    After each PoE line card has been allocated its configured PoE power budget, 1306 W remain unallocated on the switch. If one of the 1200 W power supplies fails, the PoE line cards will still receive their configured PoE power budgets.

    Line cards 3 and 4 have the highest priorities, priority 0 and 1 respectively. The remaining line cards have the same assigned priority, 7. Within the group of line cards of the same assigned priority, power priority is determined by slot number, with lower-numbered slots having higher priority. Thus PoE line cards are allocated PoE power in this order: line card 3, 4, 1, 2, 6. If two or more power supplies fail, PoE power is removed from the line cards in reverse priority order, starting with line card 6.

    Modified: 2016-12-06