With the advent of cloud computing,
over-the-top on-demand video (Netflix, YouTube, Hulu etc.), high definition TV
there has been immense rise in the IP traffic with most aggressive rise seen in
financial sector thus demanding huge scalability and availability of the data
centers. The standardization of 100G has been a massive success for optical
industry and with the collaboration of ITU-T and IEEE, has led to the
commercial availability of products featuring 100G in the market. But the strive for
improving the bandwidth need and network capacity has required to look what’s
ahead 100G. As 40G and 100G are already standardized, the next Ethernet rate
with OTN is supposed to be 400G or 1T.
The Task Force that has been appointed
for 400G are going through many architectures based on advanced modulation
formats including 16 channels x 25Gb/s NRZ, 8 channels × 50 Gb/s duo binary and
PAM-4, 4 channels × 100 Gb/s PAM4, hybrid CAP-16/QAM- 16, and QAM-16-OFDM. Among
these, all except 16 channels x 25 Gb/s NRZ shows greater power efficiency
improvement while 16 channels x 25 Gb/s NRZ provides best optical power budget
margin. In order to make 400G commercially feasible, there is a need for denser
photonic integration as the optical parallelization will increase compared to
the standards set by 100G Ethernet. The issues with high lane rates can be addressed
using advance format of modulation with photonic integration.
Looking at 1T Ethernet
and OTN, it requires great extent of parallel transport in LAN and moderate
spectral efficiencies in WAN. There have been experiments with results of 1.2Tb/s
optical super channels, but solutions to such results needs substantial optical
parallelization. Under WAN, a move from 8bit/s/Hz (which is for 400G) to a
higher value is extremely difficult, but nevertheless not impossible. Results
like this makes 400G much more achievable as the next target for LAN and WAN.
The growing needs of
operators and end users requires network change in terms of addition of
stations/ improved reliability and cost-efficiency. Ethernet requires to cope
up with situations, thus adapting and evolving to all the levels of network changes.
Ethernet has its widespread use in transport, data centers, data connectivity
services which asks for new improved standards to address market demands. We
have seen Ethernet evolving from shared CSMA/CD to switched point-to-point Ethernet
and then bringing multi-lane technology over shared media of passive optical
networks. Now Ethernet has undertaken new brand by providing common transport platform
for control and multimedia applications.
The introduction of 40Gb
and 100Gb Ethernet standards for the very first time, saw the Ethernet network
at 40G and 100G. This was called High-Speed Optical Point-to Point Links. Keeping
into account the huge demand of customers and the network providers, the
optical standards for 40G and 100G aims at reducing the cost and complex nature
of broad deployment of 100G Ethernet. Then we had EPON which provided low cost
deployment of optical access lines from carrier’s central office to customer
site. Even though EPON was hugely successful, there were issues in addressing
problems such as deployment of EPON architecture in rural areas in cost
effective manner, how to decrease the cost of connection per subscriber,
serving more people at longer distance. To address all these issues came
Extended EPON Taskforce.
Next there was a shift from MPEG-2
to MPEG-4 video distribution over IP Ethernet. This aimed at mixing EPON and EPoC
while reusing existing coaxial distribution infrastructure along with
fiber-deep access technologies. Metro Ethernet Forum (MEF) service performance
and competitive service level agreements (SLAs), are all being managed by Data
over Cable Service Interface Specification (DOCSIS) Provisioning of EPON technology,
which is jointly developed by operators, vendors, and CableLabs. This was how
EPON Protocol was tied together to work with coaxial.
Ethernet continues to evolve by providing
support to new media types, addressing new application space. It has now
entered in the new market of Automotive Industry as it has variety of solutions
for optical media and electrical backplanes. The modern cars have infotainment,
auto braking, collision avoidance, GPS which creates huge traffic for in car
network, all of which was not managed in the previous automotive networks.
Having new standards for 40G and 100G already in the market, Ethernet now has
broader market for products that are more cost effective, decreases complexity
and power consumption.