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Deploying networks using CFP transceivers presents a set of challenges that did not exist with previous generations of Ethernet. Any CFP based 100G Ethernet deployment will commonly use a WDM interface – the only exception to this is in the case of using SR10 CFPs – and this in itself is enough to require a…(Read More)

Understanding the condition of the PCS lanes is crucial to troubleshooting 100G links during network deployments. At the most basic level understanding that there are errors at the PCS indicates that the root cause of the fault lies with the physical signalling and not at the MAC layer or any of the high network layers…(Read More)

Loss Of Lane Alignment (LOL) is declared on 100G interfaces when it has not been possible to successfully recover the Logical Lane Marker (LLM) from the logical lanes and then re-assemble the OTU4 frame. During the lane recovery process the LLM will be present in a lane every 16320 bytes, when the same LLM…(Read More)

Now more than ever latency is a key network quality metric, with financial institutions and other Enterprise customers demanding absolutely minimal latency from their service provider. With Skew being an inherent part of a 100G Ethernet link, field engineers starting to roll out these services commonly ask how will Skew levels affect the latency measurements…(Read More)

OTN uses a similar multi-lane mechanism to 100G Ethernet to achieve 100G rates. The parallel interfaces are defined in an appendix of the G.709 recommendation.  The recommendation includes definitions of parallel interfaces for both 40G and 100G rates and within this a new signal was defined for parallel interfaces – the Optical Channel Transport…(Read More)

Polarisation multiplexing is commonly used in 100Gb/s line side transmission as a method to increase the bit rate over the line without increasing the transmitted symbol rate. Using polarisation controllers it is possible to generate two perpendicular polarised optical signals on the same wavelength for transmission through a single fibre. As two separate signals…(Read More)

There are a number of challenges to achieving 100Gb/s optical transmission rates using the technologies that have been deployed at 10Gb/s and even 40Gb/s. Using traditional transmission technologies such as NRZ modulation on the line will result in very poor spectral efficiency and a 100G signal using NRZ would not fit into…(Read More)

100G testing plans must include specific attention to the physical interface. The CFP interface is no longer a single transmitter and receiver pair that can simply be checked with simple tests such as a basic optical power measurement or receiver sensitivity measurement. Utilising multiple optical lanes simultaneously makes testing the interface more complex and also…(Read More)

A New Sublayer

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The multi-lane architecture within 100G Ethernet that comprises the PCS Lanes, CAUI and Gearbox (depending on CFP) represent a whole new sublayer of the network that must be specifically tested. This new sublayer exists only between two directly adjacent network elements that are connected via the CFP interfaces. To support this there are a…(Read More)

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