Cisco Cisco TwinGig Converter Module Libro blanco
Berk-Tek Leviton Technologies’ Connectivity
Performance with Cisco
Performance with Cisco
®
QSFP BiDi Transceivers
Berk-Tek Leviton Technologies recently evaluated its premium OM3/OM4 and OM4+ components for 40 Gb/s Ethernet
transmission using Cisco QSFP BiDi transceivers. Several channel configurations were tested, with Berk-Tek’s Micro Data
Center Plenum (MDP) trunk cables and Leviton’s HDX MTP-LC multi-fiber cassettes.
transmission using Cisco QSFP BiDi transceivers. Several channel configurations were tested, with Berk-Tek’s Micro Data
Center Plenum (MDP) trunk cables and Leviton’s HDX MTP-LC multi-fiber cassettes.
The objective was to simulate typical data center channel configurations and see if it was possible to achieve longer
reach and more connections using premium grade OM4+ cabling.
reach and more connections using premium grade OM4+ cabling.
The results indicate that the Berk-Tek Leviton Technologies data center products offer superior performance with Cisco
QSFP BiDi transceivers. The reach and attenuation of the OM4+ channels exceed Cisco’s maximum recommendations
for 40 Gb/s BiDi transceivers.
QSFP BiDi transceivers. The reach and attenuation of the OM4+ channels exceed Cisco’s maximum recommendations
for 40 Gb/s BiDi transceivers.
Introduction
With capacity requirements increasing rapidly, more data centers are upgrading servers to 10 GbE from 1 GbE, and 40 GbE
has become the most popular connection from the access switch to the aggregation layer. This migration is driving a need
for higher port density on the switches, and several switch manufacturers are offering aggregation layer switches with only
QSFP ports. One way to implement 40 Gb/s is through IEEE-standardized 40GBASE-SR4 technology, which uses four 10 Gb/s
lanes each on an individual fiber and a multi-fiber cabling infrastructure. The complexity of transitioning the infrastructure
from two-fiber duplex to multi-fiber cable might create some challenges for data center managers. However, Cisco is offering
a 40 Gb/s transceiver that uses only two fibers and an LC duplex connection, instead of multi-fiber cable and connectivity
with 40GBASE-SR4.
has become the most popular connection from the access switch to the aggregation layer. This migration is driving a need
for higher port density on the switches, and several switch manufacturers are offering aggregation layer switches with only
QSFP ports. One way to implement 40 Gb/s is through IEEE-standardized 40GBASE-SR4 technology, which uses four 10 Gb/s
lanes each on an individual fiber and a multi-fiber cabling infrastructure. The complexity of transitioning the infrastructure
from two-fiber duplex to multi-fiber cable might create some challenges for data center managers. However, Cisco is offering
a 40 Gb/s transceiver that uses only two fibers and an LC duplex connection, instead of multi-fiber cable and connectivity
with 40GBASE-SR4.
The Cisco BiDi transceiver is named after the bi-directional transmission in the optical channel. As shown in Figure 1,
20 Gb/s data on two different wavelengths (between 832 nm and 918 nm) is transmitted in each fiber bi-directionally.
The aggregated capacity of both the fibers is 40 Gb/s per direction.
20 Gb/s data on two different wavelengths (between 832 nm and 918 nm) is transmitted in each fiber bi-directionally.
The aggregated capacity of both the fibers is 40 Gb/s per direction.
Figure 1: Schematic of bi-directional optical communication using Cisco’s BiDi transceiver.
QSFP-40G-SR-BD
QSFP-40G-SR-BD
20 Gb/s per wavelength transmission over LC multimode optical cable.
I
1
= 832 nm, I
2
= 918 nm
I
1
I
1
I
2
I
2
The BiDi transceiver operates at a wavelength where the bandwidth is not specified in the ISO/IEC 60793 OM3/OM4 standard,
and a direct correlation between fiber bandwidth (typically specified at 850 nm) and performance cannot be assumed.
Cisco specifies a maximum transmission distance of 100 meters and 150 meters over OM3 and OM4
multimode fibers, respectively.
and a direct correlation between fiber bandwidth (typically specified at 850 nm) and performance cannot be assumed.
Cisco specifies a maximum transmission distance of 100 meters and 150 meters over OM3 and OM4
multimode fibers, respectively.
In the TEK Center at Berk-Tek’s Pennsylvania headquarters, several tests were performed under various channel configurations
on OM3, OM4 and OM4+ multimode fiber components to understand the maximum reach and connection limitations.
The OM4+ fiber uses Berk-Tek GIGAlite-10XB glass.
on OM3, OM4 and OM4+ multimode fiber components to understand the maximum reach and connection limitations.
The OM4+ fiber uses Berk-Tek GIGAlite-10XB glass.
1
For a total channel insertion loss of 1 dB.
2
Cisco 40 Gigabit Modules QSFP Data Sheet.
APPLICATION NOTE
BerkTekLevitonTechnologies.com
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