Article originally published Sept. 2, 2016, and updated for accuracy and relevance.
Data centers face ever-increasing demands in today’s digital environment. Using the right fiber optic links is the first step to ensuring an efficient, future-proof data center. Learn the benefits of Base-8 and Base-12 connectivity so you can design a network that reaches long-term transmission requirements.
An Introduction to Fiber Optic Links
When describing fiber optic links, people usually point out the connector type and the number of fibers within the link. Base-2 is the easiest to understand and visualize. With Base-2 connectivity, links are based on increments of two fibers. This is commonly seen with LC duplex or SC duplex connections.
Base-12 connectivity uses links based on increments of 12, including 12-fiber connectors like the MTP©. Base-8 connectivity solutions are also starting to appear. Base-8 systems still use the MTP style connector, but the links are built in increments of eight fibers. The systems use eight-, 16-, 24- and 32-fiber trunk cables.
A Shift In the Industry
Base-12 connectivity has served the data center industry for almost 20 years. As deployments of the 12-fiber MTP connector have grown over time, the MTP has become the de facto standard in the backbone for many data centers. But now there’s a greater need for Base-8 connectivity due to changes in:
- the types of transceivers that server, switch and storage makers use in their equipment; and
- the transceiver roadmap guiding the industry from 10G Ethernet to 40G, 100G and 400G.
Fully Using Your Backbone Fiber
One of the most common transceiver types is the QSFP, which uses eight fibers. Base-12 connectivity can be used to connect to QSFP ports. Many data centers operating 40G circuits now have Base-12 connectivity in their backbone. But plugging a 12-fiber connector into a transceiver that requires only eight fibers means four fibers are unused.
In this scenario, there are solutions that enable full, 100 percent use of the backbone fiber via Base-12 to Base-8 conversion modules or harnesses. However, this will add more MTP connectors and insertion loss into the link, which isn’t optimal for cost or link performance.
Moving Toward Base-8
Major transceiver, switch, server and storage makers are making it clear that we’re moving toward transceiver types based on Base-2 or Base-8 connectivity. All roads lead to two-fiber and eight-fiber connectivity solutions for Ethernet transmission ranging from 40G to 400G.
There will be some short-lived solutions with 400G. This includes first and second generations of OM3/OM4 parallel transmission that are proposed as Base-32 and Base-16 solutions. These solutions aren’t expected to be widely deployed due to manufacturing cost and connector complexity concerns. (You probably wouldn’t want to introduce a 32-fiber connector into your network.) The third-generation Base-8 solution should gain widespread market acceptance for 400G using parallel transmission over OM3/OM4 fiber.
One major appeal of the Base-8 solution is its divisibility. The number eight is wholly divisible by the number two. That means Base-8 backbone connectivity can be easily used for two-fiber transceiver systems, just like Base-12 connectivity. However, Base-8 connectivity is more flexible for what are expected to be the most common 40G, 100G and 400G transceiver types. It’s the better solution for 400G requirements because Base-12 is not optimal for eight-fiber transceiver systems.
Base-8 vs. Base-12
Comparing Base-8 and Base-12 connectivity is largely a numbers game. Since 12 is greater than eight, Base-12 connectivity provides higher connector fiber density compared to Base-8. A greater number of fibers can be installed more quickly when using Base-12 connectivity. However, a greater number of 40G and 100G circuits are deployed using eight-fiber transceivers. The benefits of matching the fiber count in the MTP backbone connectivity with the fiber count of the transceiver tends to outweigh the density benefit of Base-12 connectivity.
When using MTP to LC duplex breakout harnesses to connect to switch line cards, the Base-8 harnesses easily route to all common port-count line cards. All common line cards contain a number of ports wholly divisible by four, since a Base-8 harness provides four LC duplex connections. If Base-12 harnesses provide six LC duplex connections, the harnesses won’t easily route to line cards with 16 or 32 ports. (16 and 32 are not wholly divisible by six.)
The Bottom Line
Both Base-8 and Base-12 connectivity offer benefits and have a place in the data center. Which one gains market acceptance will depend on 40G and 100G transmission use.
Don’t be concerned about using Base-12 connectivity if it’s working for you. Base-8 is another option in the network designer’s toolkit that ensures data centers have the most cost-effective, future-proof network available, with a migration path that easily scales out to 400G transmission.
The opinions expressed in this piece are solely Corning's. They do not necessarily represent WESCO’s views.