C Form-factor Pluggable

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The C form-factor pluggable (CFP) is a multi-source agreement to produce a common form-factor for the transmission of high-speed digital signals. The c stands for the Latin letter C used to express the number 100 (centum), since the standard was primarily developed for 100 Gigabit Ethernet systems.

CFP standardization[edit]

The CFP transceiver is specified by a multi-source agreement (MSA) between competing manufacturers. The CFP was designed after the small form-factor pluggable transceiver (SFP) interface, but is significantly larger to support 100 Gbit/s. While the electrical connection of a CFP uses 10 x 10 Gbit/s lanes in each direction (RX, TX)[1] the optical connection can support both 10 x 10 Gbit/s and 4 x 25 Gbit/s variants of 100 Gbit/s interconnects (typically referred to as 100GBASE-SR10 in 100 meter MMF, 100GBASE-LR10 and 100GBASE-LR4 in 10 km SMF reach, and 100GBASE-ER10 and 100GBASE-ER4 in 40 km SMF reach respectively.)[2]

In March 2009, Santur Corporation demonstrated a 100 Gigabit pluggable CFP transceiver prototype.[3]

Supported signals[edit]

CFP transceivers can support a single 100 Gbit/s signal like 100GbE or OTU4 or one or more 40 Gbit/s signals like 40GbE, OTU3, or STM-256/OC-768.

Variants[edit]

The original CFP specification was proposed at a time when 10 Gbit/s signals were far more achievable than 25 Gbit/s signals. As such to achieve 100 Gbit/s line rate, the most affordable solution was based on 10 lanes of 10 Gbit/s. However, as expected, improvements in technology has allowed higher performance and higher density. Hence the development of the CFP2 and CFP4 specifications. While electrical similar, they specify a form-factor of 1/2 and 1/4 respectively in size of the original specification. Note that CFP, CFP2 and CFP4 modules are not interchangeable (but would be inter-operable at the optical interface with appropriate connectors).

CFP[edit]

[1]

  • 82mm nominal width
  • 148 pin electrical connection
  • integrated digital signal processor within package
  • less than 24W power usage
  • 10x10G or 4x25G lanes

CFP2[edit]

[4]

  • 41.5mm nominal width
  • 104 pin electrical connection
  • no digital signal processor in package, relies on host card
  • less than 12w power usage
  • 10x10G or 4x25G or 8x25G lanes

CFP4[edit]

[5]

  • 21.5mm nominal width
  • 56 pin electrical connection
  • no digital signal processor in package, relies on host card
  • less than 6w power usage
  • 10x10G or 4x25G lanes

MSA 5"x7" (Gen 1)[edit]

[6][7]

  • 168 pin electrical connection (designed to be built into a line card)
  • digital signal processor within package
  • less than 80w power usage

MSA 4"x5" (Gen 2)[edit]

  • 168 pin electrical connection (designed to be built into a line card)
  • digital signal processor within package
  • less than 40w power usage

See also[edit]

References[edit]

External links[edit]