CRS Power Consumption

[Pedro Morais]

Hello all,

I'm trying to find info regarding the power consumption of a CRS. However I cannot find any information about the following CRS modules (no datasheet):

CRS-8-FC/S

CRS-8-FC-140/S

CRS-8-LCC-FAN-TR

Any idea of where can I find this info?

Thanks!

Cheers,

Pedro

[Nicolas Fevrier · Accepted solution]

Hi Pedro,

AFAIK, no public doc available on this.

CRS-8-FC/S: 185W

CRS-8-FC-140/S: 90W

CRS-8-LCC-FAN-TR: 150W nominal

Kind regards,

N.

[Pedro Morais]

Hi Nicolas,

Thanks for your reply!!!! I notice a very big difference between FC and FC140... Nice to see that contrary to the PLIMs/MSCs/FPs, the power consumption is lower in the new FCs.

Thanks!!!!

Cheers,

Pedro

[Nicolas Fevrier]

Hi Pedro,

the lower consumption is simple to explain. In the FC/S we used to have 3 ASICs for each fabric stage (S1, S2 and S3) per card.

In the FC-140/S, we collapsed these 3 ASIC into a single one (S123) reducing the power usage significantly.

Cheers,

N.

[Pedro Morais]

Thanks for your explanation Nicolas!!!

Cheers,

Pedro

[Pedro Morais]

Hi Nicolas,

One last question.. Why does the value reported by the router are so diferent (lower) then the ones I got in the datasheets and in power calculator tool?

For example, from my calculations, for the configuration I have:

Nominal Power: 4636W

Max Power: 5260W

However when collecting the output from the router, i got:

RP/0/RP0/CPU0:CC-LAB01# admin show env power-supply

Wed Jun  5 18:58:04.483 WEST

                     Power Supply       Voltage               Current

                     DC-PEM DC-PEM                  (V)          (A)

Zone 1:               [A], [B] 52.712, 53.005   10.237, 10.655

Zone 2:               [A], [B] 52.810, 52.614   7.939,  7.834

Zone 3:               [A], [B] 52.516, 52.418   8.565,  7.312

Total Current:   52.542 A

Total Power  : 2768.897 W

That is a huge diference...

Thanks!!!

Cheers,

Pedro

[Nicolas Fevrier]

Hi Pedro,

all values produced by the power calculator are "absolute worst case" and that's for this particular worst case that the system should be dimensioned. (power consumtion varies a bit depending of the activity but most of the time, the peak consumption is at the boot up of the chassis).

Cheers,

N.

[Pedro Morais]

Hi Nicolas,

I totally understand that, however the difference between the "real" power and the nominal/max power is huge! Even if we dimension the power system for the nominal power it is almost the double of “real” power. And this is really hard to explain to the costumer… Can you help me with that???

Thanks.

Cheers,

Pedro

[Nicolas Fevrier]

Hi Pedro,

I'm afraid it's going to be difficult to "prove" this point.

As an example, I'll take the fan trays: at nominal speed (4000rpm), they use 151W each ---> 302W

When the system boots up the card are pushed to full speed (7500rpm) and use 860W each ---> 1720W.

Then the line cards PLIM+MSC140 are defined for 450W but typical load is 320W, that a 130W difference (x8 slots).

Etc, etc...

I strongly advise that your customer doesn't try to "push to the limit" here and trust the values provided.

Kind regards,

N.

[Pedro Morais]

Thx for your help Nicolas!

Cheers,

Pedro