R&M Data Center Handbook

www.datacenter.rdm.com
3.6.4. Connection Technologies / Interfaces (RJ45, SC, LC, MPO, GBICs/SFPs)
Active network components have different interfaces available, and different methods exist for linking up different
devices:
• Permanently installed interfaces (the network technology in use must be known for the purchase decision)
• Flexible interfaces, so-called GBICs (gigabit Interface Converters) / SFPs (Small Form-factor Pluggable)
Data centers support different transmission media
(listed in section 3.9), depending on the network technology
they use (transmission protocols listed in
section 3.8), which can be classified into two groups:
• Copper cables with RJ45 plug type
• Fiber optic cables (multi-mode / single-mode)
with SC / SC-RJ, LC / duplex plug types
GBICs / SFPs are available for both media types.
Cisco Nexus 7000 series 48-port gigabit Ethernet SFP module
Gigabit Ethernet can be implemented using copper cables without a problem for normal distances in LAN. This
becomes more difficult in 10 gigabit Ethernet, even if network interface cards with a copper interface for 10 GbE
are available. The IEEE 802.3an standard defines transfers with a maximum of 10 Gbit/s via twisted-pair cabling
over a maximum length of 100 m.
In the backbone area, fiber optic cables are usually used for 10 gigabit Ethernet, with LC plugs used for greater
distances in single-mode implementation.
So-called next-generation networks – 40/100 gigabit Ethernet networks with a maximum data transmission rate
of 40 Gbit/s and 100 Gbit/s respectively – must, by standard, be implemented using high-quality OM3 and OM4
fiber optic cables and MPO-based (multipath push-on) parallel optic transceivers in combination with equally
high-quality MPO/MTP ® connection technology.
12-fiber MPO/MTP ® plugs are used for the transfer of 40 gigabit Ethernet. The outer four fibers are used to send
and receive signals, while the remaining middle channels remain unused. By contrast, the transfer of 100 Gbit/s
requires 10 fibers for transmission and reception. This is realized either by means of the 10 middle channels in
two 12-fiber MPOs/MTPs ® , or a 24-fiber MPO/MTP ® plug can be used instead. Additional information on this
follows in sections 3.10.1 and 3.10.2.
GBIC / SFP
The prevailing design in expansion slots is Small Form-Factor Pluggable (SFP),
also known as Mini-GBIC, SFF GBIC, GLC or "New GBIC" or "Next Generation
GBIC". The regular design is usually just called Mini-GBIC for short. Mini-GBICs
are pushing their physical limits in gigabit Ethernet, since they are only specified
up to 5 Gbit/s. Higher speeds like 10 gigabit Ethernet require, in addition to SFP+,
the somewhat bigger XFP- or XENPAC modules. XENPAC already has two
successors, XPAK and X2.
Netgear module / 1000Base-T
SFP / RJ-45 / GBIC
The QSFP module (Quad Small Form-Factor Pluggable) is a transceiver
module for 40 gigabit Ethernet and is meant to replace four SFP modules. The
compact QSFP module has dimensions of 8.5 mm x 18.3 mm x 52.4 mm, and
can be used for 40 gigabit Ethernet, Fibre Channel and InfiniBand.
The idea for new designs arises from the need to house more connections in
the same area.
Mellanox ConnectX®-2 VPI adapter
card, 1 x QSFP, QDR
• 1 gigabit Ethernet: Mini-GBIC, SFP
• 10 gigabit Ethernet: SFP+, XFP, XENPAC, XPAK, X2
• 40 gigabit Ethernet: QSFP, MPO
• 100 gigabit Ethernet: MPO
The official GBIC standard is governed by the SFF Committee (http://www.sffcommittee.org).
R&M Data Center Handbook V2.0 © 08/2011 Reichle & De-Massari AG Page 87 of 156