Which type of optics module is supported by a 6-port 40 GE Cisco Nexus 7000 M2 Series I/O module?

CPAK is a Cisco-proprietary 100GE module format used in platforms such as the Nexus 7000 F3-series line cards and ASR 9000 routers; it is not supported on the M2-series 40GE module.

QSFP+ (Quad Small Form-factor Pluggable Plus) is the industry-standard module for 40GE, supporting four 10 Gbps serial lanes aggregated to 40 Gbps total throughput. The Cisco Nexus 7000 M2 6-port 40GE line card is specifically designed to accept QSFP+ transceivers, providing flexible short-range and long-range 40G connectivity options.

SFP and SFP+ modules support speeds up to 1GE and 10GE respectively and are electrically and physically incompatible with the 40GE ports on this module.

CFP (C Form-factor Pluggable) is a large optical transceiver designed for 100GE interfaces and is not used for 40GE applications on any Nexus 7000 line card.