[j-nsp] MIC-3D-4XGE-XFP in a MX104?

[Tim St. Pierre]

Well, that clears that up.

Seems odd they would choose the same form factor for incompatible 
designs, but that explains why the 2-port card is more expensive.

Thanks!


On 2017-12-03 05:27 PM, Saku Ytti wrote:
> Hey Tim,
>
> Simple answer, not possible, as you need PHY and 4x10GE does not have
> one, while 2x10GE does have one.
>
>
>
>
>
> Longer answer.
>
> This is quite interesting question. I'll first explain why the answer
> is decidedly 'not possible on MX80'. Trio MQ WAN side can operate as
> SERDES or 4x10GE PHY. which can drive XFP ports directly. On MPC cards
> and  MX80 the front-plate 4x10G use the PHYs on MQ. Rest of the ports
> on MX80vsit on 'fabric' side, which can only run as SERDES. To attach
> any more ports than 4x10GE on-boardvports to MX80, you need chip to
> talk to the fabric side, which is SERDES only, you need some chip to
> interface with SERDES and offer PHY (IX chip.
>
> So 4x10GE MIC is simpler, stupider (And lower BOM) than 2x10GE MIC, as
> it does not have IX chip at all, as PHY is driven by MQ. Where as
> 2x10GE MIC has IX chip and PHY. This allows us to put the 2x10GE
> interfaces on the 'fabric' side of the MQ.
>
> Now for reasons I don't fully understand MQ PHY actually cannot drive
> SFP+, only XFP. So MX104 is using IX chip and external PHY to drive
> the on-board SFP+. Technically it /could/ sit on 'fabric' side, and
> you could wire the box so that on WAN side you can attach 4x10GE XFP
> MIC. However I'm almost certain that the on-chassis SFP+ ports are
> still connected on the WAN side, so reason why it wouldn't never work
> on MX104 is same as MX80, no PHY on the 4x10GE XFP MIC.
>
>
>
> On 24 November 2017 at 19:20, Tim St. Pierre <tim at communicatefreely.net> wrote:
>> Hello,
>>
>> As anyone ever put a 4XGE MIC card in a MX104?  Only the 2XGE card is
>> supported obviously, but I'm curious to know what would happen if someone
>> did?  Is it just oversubscribed?  Would it not work at all?
>>
>> -Tim
>>
>> --
>>
>> --
>> Tim St. Pierre
>> System Operator
>> Communicate Freely
>> 289-225-1220 x5101
>>
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>
>


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Tim St. Pierre
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Communicate Freely
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tim at communicatefreely.net
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