It is a well-known fact that the future of internet connectivity will be dictated by the changes that will emerge in the manner in which we work in our data centers. And it is for this very purpose that the 40GbE physical layer is differentiated against the high speed 100 Gigabit Ethernet physical layers. Bringing in the concept of a physical layer, it is the need of the hour to understand the functionalities of a physical layer.

In the connectivity parlance, a physical layer is an entity that is concerned with the operations done in the physical medium including the data rate and fulfillment of distance requirements that are crucial to any system. The physical layer which can be either wired or wireless is also supposed to aid in detecting errors alongside making its presence felt in correcting irregular functionalities. Primarily acting as a reliable link between the two ends of a data center, the physical layer ensures proper connectivity at all times.

While 40GbE and 100GbE are two categories of networking technologies majorly meant to transmit Ethernet frames at speed rates measuring 40 and 100 Gigabits per second respectively, let us now look into the technical specifications that come in as differentiating pointers between these two connections. The differences majorly come in the form of optical and electrical interfaces along with the specific numbers of optical fiber strands that are required for every port of 40 or 100GbE connection.

The Essentials of 40GbE Physical Layer

True to its name, the 40GbE Ethernet type operates with a speed of 40 gigabits per second. This Ethernet essentially supports five types of ports with a capability to offer link distances stretched from 1 meter up to 10 kilometers. Incorporating the 40 GBASE-R encoding, all the 40GbE connections require 4 lanes operating with 64B/66B scrambled encoding type. These connections are prominent with two types of electrical links, namely: 40GBASE-KR4 and 40GBASE-CR4.

Alternatively, a system which operates with 40GbE connectivity works through three optical links which are recognized as 40GBASE-FR, 40GBASE-LR4 and 40GBASE-SR4. With regard to number of cables, a 40GbE connection requires 8 fiber cores with a standardized QSFP connector.

On the costing front, the 40GbE components come as cheaper options alongside offering timely solutions to a number of bandwidth issues to different business verticals.

The Determinants of 100 Gigabit Ethernet Physical Layer

Again, the 100GbE connectivity is an Ethernet type that operates with a laser sharp speed of 100 gigabits per second. Facilitated by electrical lanes of 10Gbps, the 100GbE is meant to create 100 GB per second links through scrambled encoding. Manifesting in the form of a jumper cable assembly, the 100 GBASE-CR10 ensures links stretching up to 7 meters through 10 pairs of copper wires running to and fro.

On the other hand, the 100 GBASE-SR10 is an optical link that operates through 10 parallel fibers running back and forth, making use of short wavelength lasers. This cabling supports Short Reach links that can span across distances up to 100 meters on OM3 fiber. As in the case with engineered links, this connectivity option can support 150 meters over OM4 fibers. This connection requires 20 fiber cores with a standardized CXP connection.

As regards cost constraints, it comes as an inevitable move to opt for different switches as most of the existing Ethernet switches are not lined up to offer 100GbE speeds.