40 FIBRE STANDARDS
40 FIBRE STANDARDS
200GBASE-LR4 : 200 Gb / s using 200GBASE-R encoding and 4-level pulse amplitude modulation over four WDM lanes on SM fibre , with reach up to at least 10km .
400GBASE-DR4 : 400 Gb / s using 400GBASE-R encoding and 4-level pulse amplitude modulation over four lanes of SM fibre , with reach up to at least 500m .
400GBASE-FR8 : 400 Gb / s using 400GBASE-R encoding and 4-evel pulse amplitude modulation over eight WDM lanes on SM fibre , with reach up to at least 2km .
Additional cost considerations SWDM electro-optics that take advantage of OM5 are currently nearer in price to singlemode devices than multimode due to market demands and volume of shipments . This factor will change when the OCP pushes forward with their ‘ short-reach , low-cost ’ project . This could potentially bring the singlemode cost below that of OM4 devices , never mind OM5 .
Due to low demand , the current cost of OM5 glass is between 5-10 times higher than OS2 despite the reported shortages in the latter . This means a 100m link of OM5 could cost € 450 , and one using OS2 costing € 45 . This more than negates the cost difference in singlemode and multimode SFPs . Over time costs will reduce as demand increases , but the same can be said about singlemode SFPs .
The final nail in OM5 ’ s coffin ? Could the news that the IEEE 802.3 group has voted down a proposal for 200Gb / s over a pair of multimode fibres proves to be the final roadblock for OM5 ? This would leave only 802.3cd for OM4 / OM5 to support 200GBASE-SR4 over 8 fibres up to 100m , being the last standard to be ratified that involves multimode and next-generation Ethernet at higher speeds .
The 802.3bs Standard supports : 200GBASE-DR4 : 200 Gb / s using 200GBASE-R Encoding and 4-level pulse amplitude modulation over four lanes of SM fibre , with reach up to at least 500m .
200GBASE-FR4 : 200 Gb / s using 200GBASE-R encoding and 4-level pulse amplitude modulation over four WDM lanes on SM fibre , with reach up to at least 2km .
400GBASE-LR8 : 400 Gb / s using 400GBASE-R encoding and 4-level pulse amplitude modulation over eight WDWDM lanes on SM fibre , with reach up to at least 10km .
400GBASE-SR16 : 400 Gb / s using 400GBASE-R encoding over sixteen lanes of MM fibre , with reach up to at least 100m .
These are the options available within the new standard ; it should be noted that the only option using multimode fibre requires eight or more fibres using MPO / MTP , with a distance supported up to 100m . These are also notoriously difficult to terminate , and if any damage occurs in the field to a single fibre core then the whole connector and assembly need to be replaced . This makes them expensive , especially compared to 2 x LC duplex connections using singlemode fibre .
Future-proofing All the standards recommend that you should design your infrastructure to be able to support two iterations of technology or hardware upgrades . With the pace of the development of new technology , it makes sense to base any new installations on the flexibility and future-proofing provided by singlemode . Not only because of the longer distances and fewer channels , it will also come down to the economies of scale .
Bodies such as the Open Compute Project , which includes all the major equipment vendors , are pushing to introduce new low-cost , short reach SFP and QSFPs that have previously provided a cost barrier for the wider adoption of singlemode . It ’ s an argument that has been clearly accepted as leading data centre and cloud Services operators are moving to a singlemode model to give themselves the edge in the future . This approach will soon filter down to the rest of the market . n
www . networkseuropemagazine . com