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peper
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RB4011, 260GS and SFP link

Fri Jan 15, 2021 11:13 pm

Hello!

Had some issues with connecting my RB4011iGS+ and 260GS/260GSP switches via SFP direct attach cable so want to share experience for others who can have the same. :)
1) I was not very attentive when reading this https://wiki.mikrotik.com/wiki/MikroTik ... lity_table from smartphone and missed that S+DA0001 (https://mikrotik.com/product/SplusDA0001, already discontinued, but still sold a lot) is not compatible with 4011. So I bough it and have to return after it failed to work.
2) Newer version XS+DA0001 (https://mikrotik.com/product/xs_da0001) is compatible with both 4011 and 260. And is still rather cheap variant to connect those two.
3) You have to manually set 4011 SFP+ port to 1G speed as described here https://wiki.mikrotik.com/wiki/MikroTik ... ansceivers
It won't work with autonegotiation.
4) On 260GS/260GSP side it works automatically without any hassle.

Regards,
Petr
 
mada3k
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Re: RB4011, 260GS and SFP link

Sat Jan 16, 2021 11:24 am

Generally SFP+ is not compatible in SFP devices. I'm amazed that it works. But yes, probably only in manual speed settings.
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peper
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Re: RB4011, 260GS and SFP link

Sat Jan 16, 2021 2:00 pm

Generally SFP+ is not compatible in SFP devices. I'm amazed that it works. But yes, probably only in manual speed settings.
Descriptions for https://mikrotik.com/product/xs_da0001 says that
This is highly cost-effective way to connect two SFP/SFP+/SFP28 devices (for example two units of our new CCR2004-1G-12S+2XS) for very short distances, within racks and across adjacent racks.
The only "contra" here is that I was connecting SFP (260GS) and SFP+ (4011) devices.
Maybe I misunderstood description and it should not work, but it works (at 1Gb speed). :)
 
mkx
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Re: RB4011, 260GS and SFP link  [SOLVED]

Sat Jan 16, 2021 4:46 pm

XS-DA00001 supports 1Gbps (I'd be surprised if it wasn't as it's a passive DAC). What only matters is if devices on both ends support same rate at their SFP (plain/+/28) cages. (And whether they support passive DAC at all). SFP cage rate is usually not auto-negotiated ... it can adjust if active equipment (SFP modules) support DDC (most do, but not all) and device and module understand each other (DDC is completely unrelated to "main" SFP rate). Since passive DAC doesn't have active elements to speak DDC, it's down to manual rate selection (I guess default is SFP's maximum rate, hence need to down-rate SFP+ in 4011 to default rate of SFP in 260GS).
BR,
Metod
 
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Re: RB4011, 260GS and SFP link

Sat Jan 16, 2021 6:59 pm

XS-DA00001 supports 1Gbps (I'd be surprised if it wasn't as it's a passive DAC). What only matters is if devices on both ends support same rate at their SFP (plain/+/28) cages. (And whether they support passive DAC at all). SFP cage rate is usually not auto-negotiated ... it can adjust if active equipment (SFP modules) support DDC (most do, but not all) and device and module understand each other (DDC is completely unrelated to "main" SFP rate). Since passive DAC doesn't have active elements to speak DDC, it's down to manual rate selection (I guess default is SFP's maximum rate, hence need to down-rate SFP+ in 4011 to default rate of SFP in 260GS).
Thank you! That's exactly what my experience was, but while I was not aware of this in advance, have to find it myself (after initial frustration). Hope this will help others with same or similar set of hardware. Overall XS-DA0001 seems to be very nice (and cost effective) for home application.

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