CRS812 DDQ Question

Hardware MikroTik hardware general
1

Hello Guys,

Going to buy CRS812-DDQ switch. However, i want to know if the 8x50G ports can be splitted into 16x25G ports. This means 2x25G per 50G port via a patch cable. Can anyone confirm on this? Mikrotik staff are super rigid and neither they mention such details on the specs nor they tell when contacting them and always ask to contact a consultant.

Thanks

2

On brochure...

  • QSFP56/QSFP-DD ports also support breakout modes to 1G/2.5G/5G/10G/25G/50G
1 Like
3

Yes, that is mentioned and supported but my question was about 8x 50G (SFP56) ports the switch has.

4

As its not in the brochure you can take a guess :slight_smile:

But for more of a direct answer:
No

SFP56 is a single Lane. So only one “connection”.
Youd need a switch :wink:

If you didnt know this maybe you should ask a consultant before buying :slight_smile:

Also you got that reply already 3 days ago:

5

Thank you for the clarification on this. What about the 200G and 400G ports? Can they be split into 100G and 200G?

2x200G (switch) = 4x100G (breakout)

2x400G (switch) = 4x200G (breakout)

6

According to the Documentation that should work.

QSFP56

  • 1x 200G
  • 2x 100G
  • 4x 50G
  • 1x 100G
  • 2x 50G
  • 1x 40G
  • 4x 25G
  • 4x 10G
  • 4x 1G

QSFP56-DD

  • 1x 400G
  • 2x 200G
  • 4x 100G
  • 8x 50G
  • 8x 25G
  • 2x 40G
  • 8x 10G
  • 8x 1G

STH did show the use of 2x200G breakout DACs in their review.

https://youtu.be/rX46MLBOIok?t=1051

7

According to specs, the Q in QSFP stands for "Quad" ... meaning that interface uses 4 electrical data lanes ... which are converted to 4 optical lanes by QSFP module ... And the DD in QSFP-DD stands for "Double Density" which means that number of interface lanes (and consequentially optical lanes) is doubled to 8. The 56 in name is talking about speed over each individual lane so it doesn't contribute to the "split ratio".

So the above means that breakout cables from QSPF can create up to 4 independent connections and breakout cables from QSFP-DD can create up to 8 independent connections. Which means it can't be split into 16 individual connections (regardless the speed).
Speed of individual connection depends on variety (QSFP vs. QSFP56) and module implementation (I guess not all modules can support different speeds of individual lanes ... even though they are used independently).

And, BTW, that's the standardization (and physics) of QSFP ... not much to do with individual vendor implementation.