Cables needed for Cisco CPAK 100GBASE-SR10

[Colin Higgins]

I have Cisco CPAK 100GBASE-SR10 SFPs in a new Nexus 7k switch, and I am trying to determine what cables are required.

I want to directly connect two Nexus switches with these modules. What type of fiber optic cable would I need here (the data sheet doesn't specify)?

[Andrea Testino · Accepted solution]

Colin,

What you are looking for would be fibre cables that are terminated with MPO/MTP connectors. This is documented in the CPAK 100GBASE Datasheets:

"Cisco CPAK 100GBASE-SR10 Module

The Cisco CPAK 100GBASE-SR10 module (Figure 4) delivers 100-Gbps links over 24-fiber ribbon cables terminated with MPO/MTP connectors. It can also be used in 10 x 10-Gb mode along with ribbon-to-duplex-fiber breakout cables for connectivity to ten 10GBASE-SR optical interfaces. It supports link lengths of 100m and 150m on laser-optimized OM3 and OM4 multifiber cables, respectively."

Hope that helps!

- Andrea

[Colin Higgins]

so this would be a female-to-female MPO/MTP cable? (the MTP is throwing me off--sounds like a different connector)

[Andrea Testino]

Colin,

Yep! I agree that the terms are confusing.

 The term MTP is a registered trademark and identifies a specific brand of the MPO-style connector. Therefore, the MTP connector is an MPO connector. Long story short, if you specify the MTP connector, you are specifying a specific brand. If you specify the MPO connector, you are specifying an interface type.

Hope that makes a bit more sense!

- Andrea

[DavidSenior82442 · Accepted solution]

Make sure you buy the right polarity cables. Fibre cables with MPO 24 fibre connectors have four types of wiring. People often buy Polarity B as this is the polarity used for SR4 100G but this relates to a 12 fibre cable and 12 fibre connectors. Your polarity is actually undefined in the standards so its not A, B or C, but a specific to 100G SR10. You can find the correct cable here

https://www.completeconnect.co.uk/products/100g-base-sr10-mtp-mpo-fibre-patch-cable/

The polarity needs to pair the top row end one with with the opposite fibre in the bottom row end 2. Positions 1 and 13 in end one to 13 and 1 in end 2.

Also, Cisco Transceivers use the MT ferrule. This is the same ferrule as in the MTP connector so you are likely to get better performance with an MTP - MTP cable as opposed to buying a generic MPO - MPO connector cable.

note- all cable connectors for direct connect need to be female