MPO-24 - 3xMPO-8
Break-out
40G-BiDi 2
40G-SWDM4 2
100G-SWDM4 2
100G-BiDi (?) 2
400G-SR4.2/4.4 (?) 8
LC Duplex
Patch Cord
2 x MPO-12 Trunk
3 x MPO-8 Trunk
FIGURE 2: This illustration shows the leaf-spine architecture used in newer data centers, comparing the
use of MPO-24 to MPO-12 to MPO-8.
January/February 2019 I41
There are even more options when using short wave
division multiplexing (SWDM). With four wavelengths
operating at 50 Gigs each, that goes to 200 Gb right away.
Then, if more lanes or fibers are added, a move to 400
and 800 Gb can be achieved. From 50 Gb, the next step
would be a 100 Gigabit lane rate. By using wave division
multiplexing as well as parallel construction, it is
possible to reach the terabit range on a multimode
fiber infrastructure.
As data rates increase, there will be a combination of
duplex and parallel schemes used in topologies. To ensure
the flexibility of being able to move between duplex
and parallel solutions, the best strategy is to install
MPO-based technology now.
WHICH MPO TO USE FOR
HIGH SPEED NETWORKS?
When considering the selection of the MPO connector
for the leaf-spine trunks, it is important to take into
consideration the expected applications to be supported
and the number of fibers required. Figure 2 shows some
of the potential options for leaf-spine connectivity.
Wherever possible, the industry is driving toward the
use of fewer fibers for higher speeds (i.e., using multiple
wavelengths to support 40 and 100G over a duplex
infrastructure with BiDi and SWDM implementations).
In terms of practical application, the three most common
MPO connector options (Figure 3) are MPO-8, MPO-12
and MPO-24:
• MPO-8 is a legacy standard for the QSFPs,
coming out of the transceivers running 40 Gb
or 100 Gb. It is used for both multimode and
singlemode transceivers and breakouts. It offers
the lowest density option, because there are
more components for the MPO-8 when moving
forward into higher speeds.
• MPO-12 is the legacy embedded base. With the
use of different modules and array fanouts, it can
accommodate multiple configurations.
• MPO-24 is the newest option and is used on the
trunk cables and modules. MPO-24 is one way
to future proof the network, because it provides
the highest panel density, allows the use of
fewer components, and may offer the lowest first
installed cost. For example, a 24-fiber MPO link
would require only one MPO-24 on each end,
taking up only one port in each fiber shelf. A
24-fiber link using 12-fiber MPOs would require
four MPO connectors, taking up two ports in
each fiber shelf. A 24-fiber link using 8-fiber
MPO-24 VS MPO-12 VS MPO-8 FOR MULTIMODE TRUNKS
LC Duplex
Patch Cord
MPO-8
Patch Cord
Leaf-Spine Applications SPINE
Application
10GBASE-SR 2
40G-SR4 8
100G-SR4 8
100G-SR2 4
200G-SR4 8
200G-SR1.2 (?) 2
400G-SR2.4 (?) 4
400G-SR1.4 (?) 2
LEAF
SPINE LEAF
MPO-24 - 3xMPO-8
Break-out
1 x MPO-24 Trunk
1 x MPO-24 Trunk
2 x MPO-12 Trunk
3 x MPO-8 Trunk
MPO-8
Patch Cord
PARALLEL DUPLEX