[j-nsp] MX480 DC Power

[Ernie Rubi]

Thanks, this is very helpful indeed.
On Mar 18, 2009, at 1:48 PM, Matt Yaklin wrote:

>
>
> On Wed, 18 Mar 2009, Ernie Rubi wrote:
>
>> Thanks, a quick read makes it look like we need 4 DC feeds to the  
>> router in order to have it be redundant.
>>
>> We have only an A+B feed, so only 2 out of the 4 needed.
>>
>> If I operate this way, the power supplies won't be redundant?
>>
>> Also, what other info would you need to fully answer the question?   
>> We are going to be running 2 x 10GE as well as 6 GigE interfaces on  
>> a DPC line card plus redundant RE-2000s.
>>
>
> Please keep in mind that I do not have a MX480. I own other Juniper
> gear.
>
> The missing information to me was the amount of power supplies.
> I also understood the pdf as saying if you wanted 4 power supplies
> you would need 4 feeds with each feed having 32 AMPs @ -48 VDC.
>
> The back contains 4 power supply slots. PEM0-3 they are called.
> If you only have two power supplies you need to insert them in PEM0
> and PEM2 for example** (See below). If one fails you are down.
>
> With 4 power supplies you can have one each fail among PEM(0-1) and
> PEM (2-3). But if PEM(0-1) both fail you are down. This all assumes
> you are running a fully loaded chassis***(See below).
>
> Here is a pdf to help you out:
>
> http://www.juniper.net/techpubs/hardware/mx480/fru-mx480-dc-power-supply/fru-mx480-dc-power-supply.pdf
>
> **I am also not sure if the manual has a typo under "DC Power Supply
> Configurations for the MX480 Router" where it states, "If only two DC
> power supplies are installed, they must be installed in slots PEM0 and
> PEM1 or in slots PEM2 and PEM3." That really does not make sense to me
> if you look at Table 1 and how they back each other up.
>
> ***Notice how the DPC slots 0 and 1 are powered by PEM(0-1) and
> DPC slots 2 through 5 and powered by PEM(2-3).
>
> I hope this helps.
>
> matt
>
>> Ernie
>>
>> On Mar 18, 2009, at 1:06 PM, Matt Yaklin wrote:
>>
>>> Here you go:
>>> http://www.juniper.net/techpubs/en_US/release-independent/junos/topics/reference/specifications/mx480-power-components-dc.pdf
>>> It seems it is hard to answer your question straight away as
>>> we do not know enough information.
>>> I hope that link helps.
>>> matt
>>> On Wed, 18 Mar 2009, Ernie Rubi wrote:
>>>> Hi folks,
>>>> I currently have a -48 vDC, 2 phase (A+B) 70 Amp (total) DC  
>>>> circuit.
>>>> I need to order an MX 480 with DC power, will the DC circuit that  
>>>> I currently have work?
>>>> Thanks,
>>>> Ernesto M. Rubi
>>>> Sr. Network Engineer
>>>> AMPATH/CIARA
>>>> Florida International Univ, Miami
>>>> Reply-to: ernesto at cs.fiu.edu
>>>> Cell: 786-282-6783
>>>> _______________________________________________
>>>> juniper-nsp mailing list juniper-nsp at puck.nether.net
>>>> https://puck.nether.net/mailman/listinfo/juniper-nsp
>>
>>
>>

Ernesto M. Rubi
Sr. Network Engineer
AMPATH/CIARA
Florida International Univ, Miami
Reply-to: ernesto at cs.fiu.edu
Cell: 786-282-6783