100G DSFP Network Card and 100G DSFP AOC Solution for Data Center - NADDOD Blog

100G DSFP Network Card and 100G DSFP AOC Solution for Data Center

NADDOD Jason Data Center Architect Dec 12, 2022

Based on the trend of high throughput and large bandwidth in data centers, server NICs and access switches are evolving to next-generation 100G interfaces. The biggest difference between the next-generation 100G interface and the QSFP28 interface at this stage is in the size. There are three interface standards for the 100G interface: DSFP, SFP-DD and SFP112. These standards have in common the small mechanical size. Having the same size as SFP series transceiver, they can support 48*100G under the 1U switch panel to connect servers. Compared with SFP28 interface, the port density is increased by 4 times, greatly reducing the cost of equipment, operation and maintenance.

Hardware Specification

DSFP, SFP-DD and SFP112 are not very different in appearance, but they differ greatly in specifications and parameters. SFP112 uses 100G Lambda, which is limited by product power consumption and 100G SerDes is not yet widely used in switches and NIC ports, so there is no market demand for SFP112 optical transceivers and cables for the time being. DSFP is similar to SFP-DD in that it has two electrical channels, each running up to 56 Gbps using NRZ and up to 112 Gbps using PAM4. Their main difference is in the number of pins: SFP-DD doubles the original SFP pins and has two rows of connecting fingers (20 pins to 40 pins); DSFP mainly follows the SFP pins but adds two pins on the basis of SFP.

In comparison, DSFP has a simple structure, resulting in a simpler connectors design, and for the device, DSFP female port will be much easier to be produced. NADDOD thinks DSFP will be more widely used in 100G networks because of its advantages.

Introduction of DSFP Specification

1. Definition

The Dual Small Form-Factor Pluggable Multi-Source Agreement (DSFP MSA) released its Rev. 1.0 hardware standard for optical transceiver dimensions. DSFP is intended to double the density of SFP transceivers in the same space and interoperate with existing SFP transceivers and cables.

2. Features

DSFP optical transceivers support two electrical lanes, twice as many as standard SFP transceivers. Each channel of the SFP supports transmission rates up to 28 Gbps (modulated by NRZ) and 56 Gbps (modulated by PAM4), so the DSFP transceiver can support transmission rates up to 56 Gbps (modulated by NRZ) and 112 Gbps (modulated by Pam4).

DSFP CONNECTORS PIN NAMES

The new DSFP MSA standards (available for download from the DSFP MSA website dsfpmsa.org) include electrical, mechanical, and heat dissipation standards for transceivers and host adapters, as well as connectors, cages, power supplies, and hardware I/O, and applications for operating parameters, data rates, protocols and support. The DSFP Management Interface Specification (MIS) is currently under development and is a simplified version of the CMIS (Common MIS) developed by the QSFP-DD, OSFP, and Cobo advisory groups.

DSFP MSA aims to develop an SFP+/SFP28 compatible form factor for 5G mobile applications. DSFP has two TX/RX high speed pin pairs, one more TX/RX pin pair than SFP+/SFP28; it is mechanically the same as SFP+/SFP28 transceiver, and its host port is compatible with SFP+/SFP28 transceiver. The DSFP module does not have some of the hardware control and alarm pins that SFP+/SFP28 transceiver has, but the same function is realized through I2C.

100G DSFP Network Card and 100G DSFP AOC Solution

Based on cost, power consumption and ecological considerations, DCN (Data Center Network) will not consider 200G and go directly to 400G. From the perspective of optical transceiver architecture, both 200G and 400G optical transceivers are based on 4-lane architecture and PAM4 modulation, which leads to the advantage of 400G optical devices over 200G optical transceivers in cost per bit. From the perspective of optical transceiver ecology, 400G transceivers are more diversified, giving customers more choices. At present, there are only 4 types of 200G transceivers: 200G-SR4, 200G-FR4, 200G-2SR4, 200G-LR4, but there are many types of 400G transceivers, including 400G-SR8, 400G-DR4, 400G-XDR4, 400G-FR4, 400G-LR4, 400G-ER8, 400G-ZR and more.

From the data center architecture evolution, the ratio of server NIC and network rate is 1:4, i.e. 25G NICs link to 100G network, 100G NICs link to 400G network. Thus 100G NICs will be massively used in a 400G network environment.

Market Network Adapters Speeds

For 100G NICs, QSFP28 (4X25G) interface or QSFP56 (2X50G) interface is more commonly used at this stage. Compared with QSFP28, QSFP56 supports PAM4 transmission, but their port mechanical specifications are the same. Therefore, if TOR switches are directly connected to servers using 100G to 100G, there is a problem of low connection density, which greatly increases the equipment cost, and if TOR switches are connected to servers using 200G to 2X100G, it is more troublesome in operation and maintenance.

To address this, NADDOD offers a high speed, high density, and high reliability solution with 100G DSFP NIC and 100G DSFP AOC cable. 100G NIC uses NVIDIA ConnectX-6 DX chip and supports up to 2 DSFP ports, which is the industry’s most secure and advanced cloud network interface card to accelerate mission-critical data center applications, such as security, virtualization, SDN/NFV, big data, machine learning, and storage.

The NADOOD 100G DSFP AOC is compliant with the DSFP MSA standard, and the DSFP 100G AOC integrates 2 independent transmitters and 2 independent receivers. The transceiver features dual 850nm VCSEL arrays, PIN arrays, amplifiers and drivers, offering the advantages of small size, low power consumption, low cost and so on.