Axiom: Leading the Way for 800G Connectivity

Up-and-coming applications for HPC (High-Performance Compute) environments, AI/ML workloads, and edge computing have skyrocketed the demand for 800G connectivity. Estimates project that the bandwidth requirements for these applications will reach 30 Tb/s and the 800G market will eclipse the billion-dollar threshold in the next decade. With increasing network demands on the horizon, the road to building the foundation for next generation networks starts with 800G. 

Axiom has developed a full lineup of 800G optics that are ready for deployment in any 800G infrastructure or environment. From 400G to 800G, Axiom optics are engineered for hyperscaling networks, as detailed in this closer look at Axiom 800G optics.

QSFP-DD and OSFP form factor adoption

In gigabit plus transceivers, improving form factor packaging has been a key development. One of the major differences between 800G transceivers and previous generation transceivers is in the high-density form factor packaging for 800G. Although the standard SFP form factor is viable for most transceivers up to 100G, the SFP form factor is capped with its single channel design, limiting the amount of aggregated data that can be transferred simultaneously.

800G transceivers are packaged in two different types of form factors: the QSFP-DD (Quad Small Form Factor Pluggable Double Density) and the OSFP (Octal Small Form Factor Pluggable). As the DD (double density) denotation would suggest, QSFP-DD is a double density form factor. The modified double density transceiver adds a second row of contact pads to the module, which doubles the channels from 4 channels (QSFP) to 8 channels. 

Likewise, the OSFP is designed with 8 traditional built-in lanes, making it a slightly larger transceiver than its QSFP-DD counterpart. Its multi-channel form factor design gives the 800G transceiver higher port density, allowing it to send more data simultaneously.

Heatsink design

The additional surface area on both QSFP-DD and OSFP transceivers also allows for larger heat sinks to be implemented. This improves the thermals and makes them more well-suited to handling the excess heat output that is associated with higher power consumption in ultra broadband servers. 

There are two types of heatsinks for 800G OSFP transceivers: a RHS (Riding Heat Sink) and a IHS (Integrated Heat Sink).

An OSFP transceiver with an RHS heatsink is one with a “flat” top heatsink on the transceiver. This type of transceiver is often paired with NIC cards as the heatsink is placed on the adapter in the connector slot as opposed to the transceiver itself.

An OSFP transceiver with an IHS heatsink comes with a finned heatsink as the heatsink is integrated on top of the module. Although NIC cards utilize a flat heatsink, some switches support flat heatsinks while others use finned heatsinks.

Advanced modulation schemes and packaging technologies

As is the case with 400G optics, 800G transceivers utilize PAM4 (Pulse-Amplitude Modulation 4-Level) modulation, which can deliver 2 bits of data per clock cycle instead of 1 bit. This halves the amount of time it takes to transfer the same amount of data compared to transceivers using less advanced schemes. 800G transceivers utilize an 8 x 100 configuration in which it leverages PAM4 to modulate each lane at 100Gbps over 8 electrical lanes to output. This data transfer efficiency cuts down on the amount of fiber cables and wavelengths required, reducing CapEx and optical complexity for 800G networks. 800G can be configured as 8 x 100 (8x112G) or 4 x 200 (4x224G) for an aggregate of 800 Gb/s. This will depend on the number of the lanes and breakout.

DSP and Silicon Photonics

In high-data rate transceivers and those with a relatively high data rate per electrical lane, there is a greater amount of signal distortion. Select 800G transceivers are designed with a cutting-edge DSP (Digital Signal Processor) ICs that minimize the latency caused by the supporting circuitry residing on the modules. FEC (Forward Error Correction) is also an important feature as it improves data transmission accuracy. For long range options, coherent technology is applied to increase the data rates, bandwidth, and transmission distances. 

The optical complexity on high-data rate transceivers can also be an issue as it increases the costs for optical assembly. 800G fiber optic transceivers utilize silicon photonics to streamline transceiver design by replacing redundant components with silicon counterparts. Optical complexity also correlates with higher power consumption. Thus, by simplifying optical complexity, silicon photonics can minimize power consumption.

800G QSFP-DD vs 800G OSFP

800G QSFP-DD

The 800G QSFP-DD is generally lower in cost and has lower power consumption, which makes it a versatile option for 800G data centers. The 800G QSFP-DD has the benefit of being backwards compatible with QSFP, QSFP112, QSFP28+ transceivers and network equipment. This allows network operators to scale from 400G to 800G without replacing key network equipment. The QSFP-DD transceiver is smaller than its OSFP counterpart, and its flexible nature makes it more ideal for a client level data center.

800G OSFP

The 800G OSFP has higher power consumption and does not have backwards compatibility with QSFP equipment, but it is designed to handle more robust workloads. Although it is slightly larger than an 800G QSFP-DD transceiver, the higher density allows it to pack more effective thermals. It can handle higher power consumption and dissipate excess heat more efficiently, making it a perfect fit for HPC environments and long-range networks with significantly higher power requirements. 800G OSFP transceivers can tackle next-generation applications and workloads while also accommodating for network scaling. 

By-the-numbers comparison:

Axiom 800G

Axiom features a complete lineup of 800G optical transceivers with both QSFP112-DD and OSFP options to choose from, which fully supports both Ethernet and InfiniBand (IB - NDR, XDR) environments. As is the case with all of our optics, Axiom 800G optical transceiver modules are stress tested in simulated environments that mimic outside application workloads. Exclusive testing irons out any performance issues to ensure that the transceivers can perform in any deployment, in any setting. This testing and verification are reflective in the overall performance and low failure rate of our transceivers. Axiom optics boast a sub 0.05% failure rate, which is significantly lower compared to the higher failure rate for third-party transceivers. Uptime is everything in a network, so minimize downtime in HPC environments with Axiom 800G optics.

Standards compliance

Axiom 800G transceivers are MSA, IEEE and CMIS (Common Management Interface Systems) compliant. CMIS is a newer protocol that applies to high-speed transceivers with data rates of 100 Gbps or faster. With greater complexity in optical networks, CMIS compliance on all 800G modules is beneficial in that it provides improved interoperability with different brands of network equipment. CMIS also offers advanced diagnostics and monitoring so that network operators can monitor optical performance to minimize potential downtime. With the development of QSFP-DD and OSFP form factors, standardized support is also needed and CMIS offers this support. CMIS also offers enhanced security features for added security. Axiom 800G transceivers with CMIS have better scalability and future proofing for network architectures.

Multiple heatsink options

Axiom 800G OSFP come with both a RHS option as well as an IHS option for added flexibility with different types of switches. Axiom 800G OSFP is ready for integration with either Nvidia NIC cards or different types of switches. 

Axiom 800G lineup:

Axiom offers both SMF (single-mode fiber) as well as MMF (multi-mode fiber) 800G transceivers. Axiom also offers cabling solutions with our 800G DAC cables, which are designed primarily for intra-rack applications and AOC for intra-rack or inter-rack applications. 

Axiom boasts a strong track record of developing cutting-edge optics for today's and next-generation applications. Axiom 800G optics have been fully tested for compatibility, interoperability and multi-coding deployments for a variety of applications including 5G, AI, HPC, cloud computing, edge servers, data center interconnect and much more. Power your 800G networks with Axiom. 

Contact an Axiom representative today to learn more about our 800G solutions