Support for 100G breakout to 25G with MHO-175

[dcw]

Does anyone know why the MHO-175 does not support a fiber OM3/OM4 MPO to 4xLC breakout/fan out option for QSFP28 100G ports. The NVIDIA 3700C appears to support this and it would be of great benefit for uplinks that connect to data centers switches that are primarily 10/25G capable today (Cisco ToRs with 48x10/25G and 6x100G, but 100G port is not available). It appears that an option to breakout a 40G to 4x10G using 

https://sc1.checkpoint.com/documents/Appliances/GSG_Maestro/EN/Topics/Splitting-Ports-with-Breakout-...

From the document

"it is possible to split the supported 100 / 40 GbE port into four 10 GbE ports.

Insert the splitter cables to convert each applicable QSFP28 100 GbE port into four SFP28 10 GbE ports.

Important - The breakout cable that splits 100 GbE port into four 25 GbE ports is not supported "

Why not QSFP28 port with 100GbE transceiver split to four SFP28 25GbE ports? Seems like most switch vendors support this. NVIDIA supports it with DAC for sure

https://network.nvidia.com/pdf/prod_cables/PB_MCP7F00-A0xxRyyz_100GbE_QSFP28_to_4x25GbE_4xSFP28_DAC_...

[Chris_Atkinson]

It's my understanding support for this was to be introduced for optical splitters in R81.20

Will aim to locate a documentation reference to confirm this.

[Chris_Atkinson]

Source: https://sc1.checkpoint.com/documents/R81.20/WebAdminGuides/EN/CP_R81.20_Maestro_AdminGuide/Content/T...

[dcw]

Thanks Chris, but unless I'm misreading something, those docs show that it is currently *not* possible, even in 81.20 to split the ports on a MHO-175 into 4x25G ports. It suggests support is planned but states that a MHO-175 can only use modes 4x10G, 40G and 100G.

[Chris_Atkinson · Accepted solution]

The documentation was amended, please refer:

https://sc1.checkpoint.com/documents/R81.20/WebAdminGuides/EN/CP_R81.20_Maestro_AdminGuide/Content/T...

[Nyklon]

Is there a timeline to adding 4x25 breakout on the 100g ports?  Will this include the MHO140?  

[Chris_Atkinson]

Checking the status and will update here pending updates to the documentation.

Edit:

[Edward_Waithaka]

Hi @Chris_Atkinson 

Which transceivers and/or splitter cables are compatible with 4x25G splitting on MHO175?

Is it possible to use CPAC-TR-100SR-D with CPAC-MPO-4xLC-MMF-OM3-3M on MHO175 and 2 x CPAC-TR-25SR on GW Appliance with [4x10/25Gbe SFP+] Expansion Module?

[Chris_Atkinson]

From sk92755 - Note 2:

• For 100GbE connections, we recommend using a 100GBASE-SR4 QSFP28 transceiver connected to four 25GBASE-SR transceivers.