A new generation of optical transceivers for 100 Gigabit Ethernet client interconnection and line system transmission are now being developed and deployed for data center and transport applications. This article provides an overview and status of the 100 G Form-factor Pluggable Multi-Source Agreement for client applications and the Optical Internetworking Forum 100 G Transponder Module. Implementation Agreement for long distance DWDM transmission applications.
When Ethernet was invented nearly 40 years ago, it was all about simplicity – plug and play. That is how Ethernet won out over competing technologies and became the lingua franca of networking. However, the only way to achieve this tremendous popularity was to extend and adapt Ethernet to address new uses and applications, ranging from campuses to data centres to telecom applications. In fact, its adaptability has been a core reason for Ethernet’s success. At the same time, all the additions and modifications have also made Ethernet increasingly complex. How can the industry balance between the ever-increasing demands of a tremendous variety of applications while still keeping Ethernet simple and easy to understand and use?
Even though 40 GbE and 100 GbE are just beginning to appear in data centres, it is surely now time to start thinking about a new generation. Now that 10GbE has become commonplace, aggregation links will have to provide much higher throughput. A new generation will also be necessary for telecom backbones, cloud computing, wireless backhaul, supercomputing, video networks, and many other applications. We will need new standards, new signalling methods, new test equipment, new cabling and connectors, new power reduction approaches, and many other components and system-level elements. Starting now will mean that initial terabit Ethernet implementations could be available in the 2015-2016 period.
Designers and operators often believe that eliminating delay and packet loss in networks would require a complete rebuild or “clean slate”. Since this is virtually impossible to do, the International Telecommunications Union (ITU) has taken a new approach. ITU has recently approved the Q.3313 protocol, which optimizes response time and throughput and eliminates lost packets. Usually, when TCP, UDP, and IPSec traffic traverses Ethernet networks, switches and routers introduce delay and packet loss even under modest loads. TCP, in particular, operates with slow start, causing major delays for interactive traffic while the flows try to increase their speed. The new ITU protocol provides optimal performance for TCP, eliminating slow start and allowing each flow to jump to the maximum rate feasible, considering other traffic, after one round trip. For web access, this would provide sub second page times, a 10:1 improvement. The protocol also eliminates network delay and delay jitter, leaving only speed of light delays. This means the round trip time would be improved typically 3:1. Peak TCP data transfer rates are currently limited by retransmission buffer size to under 100 Mbps, but Q.3313 would immediately permit transfer rates up to 1 Gbps or more, depending on the minimum trunk speed. If deployed in an office complex, Q.3313 could greatly reduce file transfer times and provide fractional second interactive access, thus greatly increasing productivity. In an ISP point of presence, it would improve customer satisfaction dramatically. The presentation will explain the reasons for current network congestion problems and how the new protocol fixes them.