11-19-2015 01:50 PM - edited 03-08-2019 02:46 AM
Hello,
We have a stack of 3 x Cat3850-48T-S switches (no PoE). Each switch has one 350W power supply. Here's the output of the "show stack-power detail" command:
Power Stack Stack Stack Total Rsvd Alloc Unused Num Num
Name Mode Topolgy Pwr(W) Pwr(W) Pwr(W) Pwr(W) SW PS
-------------------- ------ ------- ------ ------ ------ ------ --- ---
Powerstack-1 SP-PS Ring 1050 210 840 0 3 3
Power stack name: Powerstack-1
Stack mode: Power sharing
Stack topology: Ring
Switch 2:
Power budget: 280
Power allocated: 280
Low port priority value: 21
High port priority value: 12
Switch priority value: 3
Port 1 status: Connected
Port 2 status: Connected
Neighbor on port 1: Switch 1 - 2834.a2b3.8100
Neighbor on port 2: Switch 3 - 84b5.1755.1080
Switch 1:
Power budget: 280
Power allocated: 280
Low port priority value: 20
High port priority value: 11
Switch priority value: 2
Port 1 status: Connected
Port 2 status: Connected
Neighbor on port 1: Switch 2 - 2834.a2fd.5980
Neighbor on port 2: Switch 3 - 84b5.1755.1080
Switch 3:
Power budget: 280
Power allocated: 280
Low port priority value: 22
High port priority value: 13
Switch priority value: 4
Port 1 status: Connected
Port 2 status: Connected
Neighbor on port 1: Switch 2 - 2834.a2fd.5980
Neighbor on port 2: Switch 1 - 2834.a2b3.8100
Can someone explain the meaning of "Rsvd Pwr" and "Alloc Pwr" in the first table? In this scenario, if one switch loses a power supply, total power will go down to 700W. Will we have enough power then to power all three switches?
Thanks for your help,
Patrick.
11-19-2015 04:34 PM
Hello,
Please take a look at the link below. A lot of questions and answers regarding your inquery.
http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3850-series-switches/qa_c67-722110.pdf
Masoud
11-19-2015 05:52 PM
Hello,
So if I understand correctly, each switch reserves 280W for operation, even if the switch does not actually consume that amount of power (the datasheet says that a 3850-48T switch with a 4 x 10G NM actually uses about 120W).
Then if I unplug a power supply in my stack that switch will shut down? (700W available, 840W needed)
Thanks.
11-19-2015 06:38 PM
Hello,
show power inline police
Check this command to see the actual power is used by switches. If actuall power usage is less than allocated, you should implement redundant mode instead of sharing. Because sharing may cause shuting down of one the switches if reserve is not enough. In your case, I guess one of your switces will be shutdown in case of power failure. To completely make sure, in downtime, cut power of one of the switches and check if the amount of allocation will change or not, but I do not think allocation is dynamic.
Please check the link below.
http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/3se/int_hw_components/configuration_guide/b_int_3se_3850_cg/b_int_3se_3850_cg_chapter_01000.html
Masoud
10-14-2016 07:16 AM
Hi Everybody,
would you explain the following questions please,
Q1:
The meaning of "Rsvd Pwr", "Unused Pwr" and "Alloc Pwr" in the tables below?
@ Masoud:Because in the links that you have posted, there is nothing mentioned or explained about these terms?
the show stack-power detail as shown in Case 1 has only one (Powerstack-11) power stack formed but after i did the following command
CoreSwitch#stack-power switch 3 port 1 disable
CoreSwitch#stack-power switch 4 port 2 disable
then
CoreSwitch#stack-power switch 3 port 1 enable
CoreSwitch#stack-power switch 4 port 2 enable
The stack configuration has been changed as shown in Case 2
Q2:
Do you know what is the reason that make the switch to form a new stack ring (Powerstack-1) as shown in CASE2 below?
Q3:
Unused Pwr (W) for Powerstack-1 was 0 but later has been changed to -280 in CASE3. any idea why the nummber has been Changen?
just for information, there is NO PoE device is connected to stacked switch!
CASE1:
CoreSwitch#show stack-power detail
Power Stack Stack Stack Total Rsvd Alloc Unused Num Num
Name Mode Topolgy Pwr(W) Pwr(W) Pwr(W) Pwr(W) SW PS
-------------------- ------ ------- ------ ------ ------ ------ --- ---
Powerstack-11 SP-PS Ring 1400 840 1120 -560 4 4
Power stack name: Powerstack-11
Stack mode: Power sharing
Stack topology: Ring
Switch 3:
Power budget: 280
Power allocated: 280
Low port priority value: 22
High port priority value: 13
Switch priority value: 4
Port 1 status: Not connected
Port 2 status: Connected
Neighbor on port 1: 0000.0000.0000
Neighbor on port 2: Switch 1 - 5067.aefc.9000
Switch 4:
Power budget: 280
Power allocated: 280
Low port priority value: 19
High port priority value: 10
Switch priority value: 1
Port 1 status: Connected
Port 2 status: Not connected
Neighbor on port 1: Switch 2 - 5067.aefc.a100
Neighbor on port 2: 0000.0000.0000
Switch 2:
Power budget: 280
Power allocated: 280
Low port priority value: 22
High port priority value: 13
Switch priority value: 4
Port 1 status: Connected
Port 2 status: Connected
Neighbor on port 1: Switch 1 - 5067.aefc.9000
Neighbor on port 2: Switch 4 - 3462.8813.4d80
Switch 1:
Power budget: 280
Power allocated: 280
Low port priority value: 21
High port priority value: 12
Switch priority value: 3
Port 1 status: Connected
Port 2 status: Connected
Neighbor on port 1: Switch 3 - 3462.8892.7880
Neighbor on port 2: Switch 2 - 5067.aefc.a100
CASE2:
CoreSwitch#show stack-power detail
Power Stack Stack Stack Total Rsvd Alloc Unused Num Num
Name Mode Topolgy Pwr(W) Pwr(W) Pwr(W) Pwr(W) SW PS
-------------------- ------ ------- ------ ------ ------ ------ --- ---
Powerstack-11 SP-PS Ring 700 420 560 -280 2 2
Powerstack-1 SP-PS Ring 700 140 560 0 2 2
Power stack name: Powerstack-11
Stack mode: Power sharing
Stack topology: Ring
Switch 2:
Power budget: 280
Power allocated: 280
Low port priority value: 22
High port priority value: 13
Switch priority value: 4
Port 1 status: Connected
Port 2 status: Connected
Neighbor on port 1: Switch 1 - 5067.aefc.9000
Neighbor on port 2: Switch 4 - 3462.8813.4d80
Switch 1:
Power budget: 280
Power allocated: 280
Low port priority value: 21
High port priority value: 12
Switch priority value: 3
Port 1 status: Connected
Port 2 status: Connected
Neighbor on port 1: Switch 3 - 3462.8892.7880
Neighbor on port 2: Switch 2 - 5067.aefc.a100
Power stack name: Powerstack-1
Stack mode: Power sharing
Stack topology: Ring
Switch 3:
Power budget: 280
Power allocated: 280
Low port priority value: 22
High port priority value: 13
Switch priority value: 4
Port 1 status: Not connected
Port 2 status: Connected
Neighbor on port 1: 0000.0000.0000
Neighbor on port 2: Switch 1 - 5067.aefc.9000
Switch 4:
Power budget: 280
Power allocated: 280
Low port priority value: 21
High port priority value: 12
Switch priority value: 3
Port 1 status: Connected
Port 2 status: Not connected
Neighbor on port 1: Switch 2 - 5067.aefc.a100
Neighbor on port 2: 0000.0000.0000
CASE3:
CoreSwitch#show stack-power detail
Power Stack Stack Stack Total Rsvd Alloc Unused Num Num
Name Mode Topolgy Pwr(W) Pwr(W) Pwr(W) Pwr(W) SW PS
-------------------- ------ ------- ------ ------ ------ ------ --- ---
Powerstack-11 SP-PS Ring 700 420 560 -280 2 2
Powerstack-1 SP-PS Ring 700 140 560 -280 2 2
Power stack name: Powerstack-11
Stack mode: Power sharing
Stack topology: Ring
Switch 2:
Power budget: 280
Power allocated: 280
Low port priority value: 22
High port priority value: 13
Switch priority value: 4
Port 1 status: Connected
Port 2 status: Connected
Neighbor on port 1: Switch 1 - 5067.aefc.9000
Neighbor on port 2: Switch 4 - 3462.8813.4d80
Switch 1:
Power budget: 280
Power allocated: 280
Low port priority value: 21
High port priority value: 12
Switch priority value: 3
Port 1 status: Connected
Port 2 status: Connected
Neighbor on port 1: Switch 3 - 3462.8892.7880
Neighbor on port 2: Switch 2 - 5067.aefc.a100
Power stack name: Powerstack-1
Stack mode: Power sharing
Stack topology: Ring
Switch 3:
Power budget: 280
Power allocated: 280
Low port priority value: 22
High port priority value: 13
Switch priority value: 4
Port 1 status: Not connected
Port 2 status: Connected
Neighbor on port 1: 0000.0000.0000
Neighbor on port 2: Switch 1 - 5067.aefc.9000
Switch 4:
Power budget: 280
Power allocated: 280
Low port priority value: 21
High port priority value: 12
Switch priority value: 3
Port 1 status: Connected
Port 2 status: Not connected
Neighbor on port 1: Switch 2 - 5067.aefc.a100
Neighbor on port 2: 0000.0000.0000
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