The optical connectivity layer in COSMOS allows an experimenter to reconfigure connectivity between devices at the L1 (physical) layer. This provides the ability to restructure the physical topology of the entire testbed, changing not just latency between nodes but how individual signals are routed, with no overhead, throughout the testbed.

Space Switch

The Calient MEMS space switch is a 320x320 any-to-any optical circuit switch which allows an experimenter to redirect the entire optical link coming in from one fiber strand to another. The switch itself introduces ~2dB of loss to the signal and has a switching time of ~25ms. Configuration of the switch is possible via Openflow and netconf as well as several other methods.


There are several Lumentum Whitebox20 degree-one ROADMs (reconfigurable optical add/drop multiplexer) in COSMOS, the majority of which are at the core datacenter. Each of the ROADMs features 20 ports and allows individual wavelengths to be redirected from one fiber strand to another. This permits physically separate network links to share fibers yet still be routable (with no overhead delay) to physically different end-points. The ROADMs are compatible with C-band DWDM. Configuration of the ROADMs is done via netconf.

Pilot Phase Implementation Progress

On the 2nd February 2020 COSMOS Optical network consists of next elements:

Cosmos Fiber Diagram

Transmission Setup

COSMOS Transmission setup consists of Cassini ACOs, Lumemtum ROADMs, Lumemtum OAs, Calient space switch, Comb source, and Telemetry units (IQ):


10/14/2019: Moved SFP from port 1/33 on sw-tor-lg1 to port 52 on 8LE1 Pica8 1 : Artur Minakhmetov

10/16/2019: Moved back SFP from port 52 on 8LE1 Pica8 1 to port 1/33 on sw-tor-lg1 : Artur Minakhmetov

12/12/2019: Add COSMOS Transmission Setup with Cassini ACOs, Lumemtum ROADMs/OAs, Comb source and Telemetry units: Jiakai Yu

2/1/2020: Update COSMOS Optical Topology: Manav Kohli and Jiakai Yu

3/30/2020: Upload SDN controller guide: Jiakai Yu

Last modified 10 days ago Last modified on 03/31/20 07:18:49

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