CABLExpress
Respect Layer One

40/100 Gb Ethernet: Transition Your Cable Environment

The migration to 40/100 Gb Ethernet is in full swing in today’s data centers. There are some critical changes occurring in the Layer One cabling infrastructure. Change of connectors, overall design and a reduction of optical loss budget are the keys to a smooth transition.

Change of Connectors


Due to budget constraints, it is projected that most data centers will continue to purchase short reach, multimode optics for their 40/100 Gb Ethernet hardware upgrades. The importance of this is that short reach multi-mode transceivers require an MPO style (or MTP®) connector. The MTP® connector holds 12 or 24 fibers in one ferrule and has the potential to hold up to 72 fibers in one connector. The reason for this is that the 40/100G Ethernet standard for multi-mode transmission requires the use of parallel optics. Rather than one fiber carrying the send signal and one fiber receiving (called serial transmission), parallel optics aggregates multiple fibers to send and also receive. This is arguably the biggest change in cabling infrastructures in the past decade.

 

Overall Design


Overall cabling infrastructure design will also be impacted. Massive growths in data center port counts over the past decade have taught us that the structured cabling design is critical for future growth and changes. Before 2005 there was no standard for cabling infrastructure design. Now we have the TIA-942 standard to utilize. Research and planning according to this standard will be critical in not repeating the same mistakes that we have seen in data center cabling “sprawl.”

 

 

Reduction of Optical Loss Budget


Another important factor to consider is the optical loss budget of 40/100 Gb Ethernet. These high speeds require less optical loss per channel than any previous standard. That number is 1.5dB utilizing OM3 and 1.5dB for OM4 fiber at distances of 100m and 150m accordingly. This is significant because, combined with the requirement of the MTP® connector, these loss budgets could easily be exceeded without the careful choice of cabling provider. Combined with a proper design according to the TIA-942, lower loss MTP® connections are required. This is where research and thorough evaluation should be done in choosing your cabling infrastructure.

For more information on the transition to 40/100 Gb Ethernet, download our free white paper here.