The 40G QSFP+ ports on the Advanced Aggregators can be broken out into four 10Gb connections using MTP to 8LC breakout cables. These cables separate out the eight lanes of traffic into individual connections:
On the breakout cable, the connectors should be labeled 1 through 4 and 9 through 12. Connectors 1 through 4 are connected to the lanes on the QSFP that are Transmitting data. These connectors should be connected into the receive port on a SFP+ transceiver. Connectors 9 through 12 are connected to the lanes on the QSFP that are Receiving data. These connectors should be connected into the transmit port on a SFP+ transceiver.
The lanes on the QSFP correspond to each other: 1 & 12, 2 & 11, 3 & 10, and 4 & 9. These connectors need to be kept together when connecting to SFP+ transceivers for the QSFP to keep the correct traffic together.
When connecting the breakout cable to a Passive Fiber Breakout TAP, the monitor ports work differently than connecting to a SFP+ transceiver:
The LC monitor ports on a breakout TAP are both transmitting data, so the Transmit connectors on the breakout cable will not be used. Only connectors 9, 10, 11, and 12 will be used. When connecting a breakout cable to a Passive Fiber Breakout TAP, each QSFP port will be able to support two 10Gb breakout TAPs.