Cassini Optical Switch

Open and Dissagregated Coherent Switch (with integrated Open Transponder) for deploying high capacity open networks

Cassini allows leveraging existing optical line systems, maximizing the capacity per optical 50 Ghz channel, collapsing layer 1, 2 and 3 functions in the same box.

The next generation networks will need to manage Terabits, and need to rely on different technologies.

As data center traffic volumes increase each year, the demands on data center interconnects also grow. Using coherent optical technologies to meet the bandwidth and distance requirements has become standard for these links. Coherent optics transport more data over a single fiber for greater distances using higher order modulation techniques, which results in better spectral efficiency and lower power consumption.

Significant technology advances in photonic integrated circuits and DSP design have enabled transceiver modules to fit into smaller form-factors as speeds have increased from 100G to 400G and above. To reduce costs and complexity, as well as to create true interoperability, new coherent optical standards are in development and promise not only to meet data center interconnect needs, but also to drive coherent optics into backhaul, distributed campus, and other metro Ethernet applications.

Cassini, designed by the Telecom Infra Project

Cassini started as a project involving a number of large service providers (that weren’t able to find the solutions they needed from the traditional vendors), technology vendors (highly specialized in specific network functions), and TIP‘s OOPT (Open Optical Packet Transport) group.

The result of this collaboration: a new open packet/optical transponder, which matches the highest industry densities. Cassini integrates 100GbE Layer-3 routing and switching with Layer-1 optical transport functions as line-card modules, and covers data center interconnect, metro and access backhaul use cases.

Cassini fills the existing gap for efficient solutions for Datacenter interconnects and/or 5G Mobile backhaul, providing a highly-performant and open solution with no vendor lock-in.

Benefits

Using Cassini, operators can deploy or expand their existing network, moving away from the legacy design approaches, which encouraged maintaining existing MPLS solutions that can become extremely expensive as the bandwidth demand increases.

Cassini is already deployed in extensive geographical areas, providing an efficient solutions for transporting massive IP traffic.

Cassini implements advanced networking (the same found in large carrier routers) with long-haul optics, in the same layer, reducing the complexity of managing different networks planes.

What is Coherent Optics

In standard optical fiber communications, the optical transmission and detection is based on the intensity of the signal. The on-off modulation of the light signal carries the information from the transmitter and the receiver directly detects the signal modulation. This method has worked well for transmission rates up to 10G, but as demands for more speed and capacity over long-haul fiber links has grown, other technologies are required that can send data at rates of 100G or more on a single channel over a single fiber pair.

To achieve higher data rates, more information needs to be encoded in each transmitted symbol. Higher order modulation techniques encode information into the phase, amplitude, and polarization of the light signal rather than just the intensity. Binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), and quadrature amplitude modulation (QAM, 8QAM, or 16QAM) are all known methods for encoding more bits per symbol. These modulation methods are used to encode bits on two polarizations of a single carrier light wave, a technique that is known as “polarization multiplexing.”

Bandwidth is maximized, by using dual polarization on the same optical carrier

The result, is a very high spectral efficiency, that permits moving massive traffic over existing DWDM systems:

Coherent optical module refers to a typically hot-pluggable coherent optical transceiver that uses coherent modulation and is typically used in high-bandwidth data communications applications. Optical modules typically have an electrical interface on the side that connects to the inside of the system and an optical interface on the side that connects to the outside world through a fiber optic cable. The technical details of coherent optical modules were proprietary for many years, but have recently attracted efforts by multi-source agreement (MSA) groups and a standards development organizations such as the Optical Internetworking Forum. Coherent optical modules can either plug into a front panel socket or an on-board socket. Coherent optical modules form a smaller piece of a much larger optical module industry.

Advanced Software Stack

Cassini’s architecture is designed for Open Networking, by leveraging traditional x86 processors and powerful networking ASICs that support a broad range of software options.

Features (summary)

• Layer 1
  • Software controlled modulation (DP-QPSK, DP-8QAM, DP-16QAM)
  • Software controlled Laser frequency (Ghz intervals)
  • Software controlled TX power
  • Hardware implemented Forward Error Correction (FEC)
  • Monitoring of all relevant optical parameters (Power, OSNR, BER, Chroamtic Dispertion, Q-Margin)
• Layer 2
  • Jumbo Frames
  • VLAN / VLAN Trunks
  • LAG (LACP)
  • LLDP
  • Spanning Tree: STP, MSTP
  • BDPU Filters
• Layer 3
  • IP Routing
    • BGP4
    • OSPFv2 / OSPFv3
    • IS-IS
    • BFD
  • Multicast (IGMP / PIM)
  • QoS
    • DiffServ
    • WRED
    • IEEE 802.1P
  • VRF

Open Standards

In terms of management, we are implementing the most popular industry standards, in order to build multi-vendor networks that can be managed from a common orchestration architecture.

Cassini fills the existing gap for efficient solutions for Datacenter interconnects and/or 5G Mobile backhaul, providing a highly-performant and open solution with no vendor lock-in.