Månadsvis arkiv: November 2016

The Truth About OS1 and OS2 Optical Fiber

Several years ago, OS1 fiber optic cable was the only one standard for single-mode fiber with the maximum link length for campus cabling around 10km, but 10km can no longer satisfy people’s increasing needs nowadays. Therefore, OS2 fiber that can support much longer distance than 10km has been widely utilized in telecommunication industry. But there has been some debate and confusion as to the differences between OS1 and OS2 fiber types and what the terminology actually means. Thus, the following article is provided to assist the users in understanding the differences between OS1 and OS2 fiber types. The following image shows the LC to LC fiber patch cable single mode plugging in a switch.

single-mode-fiber

OS1 and OS2 Single-mode Fibers

Firstly, OS in the term OS1 and OS2 specifications refers to the Optical Single-mode fiber. Single-mode OS1 is indoor tight buffered fiber. An OS1 cable could be a micro-core LSZH indoor cable that consists of 250 micron fibers, with the fibers being tightly enclosed in a cable with aramid strengthening yarn and a LSZH jacket. The attenuation of a OS1 fiber is higher than an OS2 fiber. From the above table, the maximum attenuation allowed per km of installed cable is 1.0 dB for OS1 for 1310nm and 1550nm, while the maximum attenuation allowed per km of installed cable is 0.4 dB for OS2 for 1310nm and 1550nm.

os1-and-os2-maximum-attenuation

Single-mode OS2 is an outdoor loose tube optical fiber cable, which is suitable for outdoor applications where the cabling process applies no stress to the optical fibers. For instance, a 250 micron coated multi-fiber, which is loose inside an enclosure or tube and/or is free to move, is classified as OS2.

OS1 or OS2 performance cables are constructed from B1.3 optical fibers (or ITU specification G.652D). Furthermore, OS1 and OS2 cable types can also include cables manufactured from B6_A fiber, which is commonly known as bend insensitive single-mode optical fiber, or ITU specification G657A2 (compatible with B1.3 optical fiber). OS1 or OS2 single mode fiber performance, does not relate to ITU specification G.655 (Non-dispersion shifted single mode optical fibers.

Why Should We Use OS2 Over OS1 Fiber?

Single-mode fiber was mainly used for long-hual applications but not marked as a cost-effective investment for future application in building. One reason is that the single-mode related products like cables and optical transceivers are offered with high price. The other is that with the price decrease of the VCSEL or laser power source, the performance gap (namely link length) between multimode or single-mode fiber is smaller everyday.

Considering this, why not use the best single-mode fiber (OS2) to create better performance and ready for high speed data networks? Besides the difference in link distance, OS1 and OS2 fibers have different attenuation—OS2 has two times less losses than OS1 fibers.  And in CWDM or DWDM network, OS1 has poor result in the wavelength range called E-band or water peak band, which makes it not suitable for the WDM-based network.

cwdm-allocation-and-fiber-loss

Figure 3: CWDM wavelength allocation and fiber loss. The solid line represents OS2 fibers. The dotted line represents the water peak.

Another good news is that if you use OS2 fiber, it will be more suitable for you to support the IEEE 802.3 multiplexed series (40G BASE-LR4 and 100G BASE-ER4). You even don’t need to change your existing OS1 fibers, as the OS2 can be mixed with OS1 in the same link. What’s more, active or passive component for OS1 like connectors, adapters also works with OS2.

Conclusion

To sum up, OS1 optical fiber is appropriate for indoor and universal tight buffered cable constructions, which are mainly deployed in internal building/campus networks, as well as internal cabling within telecommunication exchanges and data centers. While OS2 optical fiber is appropriate for outdoor and universal loose tube solutions, which would include external plant and most back-haul networks. Therefore, when deciding which single-mode optical fiber type to specify, consider the application as well as how and where the cable will be installed. For further information on optical fiber products, please contact FS.COM. Our fiber optic cable price is the cheapest with great feedback.

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Cisco SFP Transceivers Overview

Cisco Small Form-Factor Pluggable (SFP) transceiver can be defined as a device that comprises of both a transmitter and a receiver of analog or digital signals. It is a compact, hot swappable, input/output device based on the available fiber cable type (copper cable or multimode/single-mode optical fiber). In addition, SFP transceivers can be leveraged both at 100Base and 1000Base rates in the following standards:

sfp-standard

SFP transceivers are mainly used to link equipment in telecommunication and data communications like switches and routers. They support applications like 2G/4G Fiber Channel, SONET/SDH Network, Gigabit Ethernet, High-speed computer links, and with CWDM and DWDM interfaces. Today’s article will generally introduce the Cisco SFP transceivers including the Cisco 100M SFP, Cisco 1000BASE SFP, CWDM/DWDM SFP, SONET/SDH SFP as well as Cisco BiDi SFP to you.

Cisco 100Mbqs SFP

Cisco offers two different types of 100BASE SFP—100BASE SFP for Fast Ethernet (FE) SFP Port and 1000BASE SFP for Gigabit Ethernet (GE) port. Besides the above standards, the Cisco 100BASE SFP portfolio includes 100BASE-FX, 100BASE-LX, and 100BASE-BX SFPs.

Cisco 100BASE-FX SFP operates on MMF for link spans of up to 2km. 100BASE-LX SFP operates on SMF up to 10km. 100BASE-BX SFP operates on SMF for a link length of up to 10km. A pair of a 100BASE-BX-D and a 100BASE-BX-U SFP is needed for the single strand deployment. The following table displays the compatible Cisco 100M and 1G SFPs from FS.COM.

cisco-sfp

Cisco 1000BASE SFP

Cisco 1G SFP transceivers offer a convenient and cost-effective solution for the adoption of Gigabit Ethernet and Fibre Channel in data center, campus, metropolitan area access and ring networks, and storage area networks. They are available in several Gigabit standards—1000BASE-T, 1000BASE-SX, 1000BASE-LH, 1000BASE-EX, etc. Take Cisco GLC-LH-SM as an example, it operates over standard single-mode fiber spanning distances of up to 10 km and up to 550 m over any multimode fiber (OM3/OM4). If 1000BASE-LX/LH SFP transceiver transmits in the 1300nm wavelength over OM1/OM2 fiber, it requires mode conditioning patch cables.

Cisco CWDM/DWDM SFP Modules

Cisco Coarse Wave Division Multiplexing (CWDM) solution allows scalable and easy-to-deploy Gigabit Ethernet and Fibre Channel services. Similar with traditional SFP module, the Cisco CWDM SFP is a hot-swappable input/output device that plugs into a SFP port or slot of a switch or router. CWDM SFP transceiver modules make use of the SFP interface for connecting the equipment and use dual LC/PC fiber connector interface for connecting the optical network with a link distance of up to 80km. It usually comes in 8 wavelengths covering from 1470 nm to 1610 nm. Color markings on the devices identify the wavelength to which the Gigabit Ethernet channel is mapped. The following picture lists the FS.COM compatible Cisco CWDM SFPs with their wavelengths and color codes.

cwdm-sfp

DWDM (Dense Wavelength-Division Multiplexing) SFP transceivers, however, are used as part of a DWDM optical network to provide high-capacity bandwidth across an optical fiber network. Cisco DWDM SFP is a high performance, cost effective module for serial optical data communication applications up to 4.25Gb/s. There are 32 fixed-wavelength DWDM SFPs that support the International Telecommunications Union (ITU) 100-GHz wavelength grid.

Cisco SONET/SDH SFP Modules

This Cisco SONET/SDH SFP is compatible with the SONET/SDH standards, and support the digital diagnostic functions specified in the SFF-8742 Multi-Source Agreement (MSA). Cisco SONET/SDH SFP can be directly plugged into a variety of ports on Cisco router interfaces. These SFP optics support OC-3, OC-12, and OC-48 data rates for multimode, short-reach, intermediate-reach, and long-reach (up to 80 km) applications just as seen in the below chart.

cisco-sonet-sdh-sfp-modules

Cisco BiDi SFPs

Bidirectional (BiDi) SFP transceivers can transmit and receive data to/from interconnected equipment through a single optical fiber. BiDi transceivers are fitted with wavelength division multiplexing (WDM) diplexers, which combine and separate data transmitted over a single fiber based on the wavelengths of the light. BiDi transceivers must be deployed in matched pairs, with their diplexers tuned to match the expected wavelength of the transmitter and receiver that they will be transmitting data from or to. These transceivers offer bi-directional data links over single-mode fiber up to 120 km.

Take 1000BASE-BX SFP BiDi transceiver as an example, 1000BASE-BX SFP modules are compliant with SFP Multi-Source Agreement (MSA) specification and SFF-8472, and conform to the IEEE 802.3ah 1000BASE-BX10 standard. 1000BASE-BX SFP modules include 1000BASE-BX-U SFP module and 1000BASE-BX-D SFP module. The 1000BASE-BX-D SFP operates at wavelengths of 1490nm TX/1310nm RX, and the 1000BASE-BX-U SFP operates at wavelengths of 1310nm TX/1490nm RX. These transceivers use standard simplex LC connectors for fiber cable connection and provide a long transmission distance of up to 10 km.

Conclusion

It is necessary to select the suitable SFP transceivers for your network. This article has concluded several types of Cisco SFP transceivers, which might be a great help for those who are looking for Cisco SFPs. FS.COM, a leading and professional fiber optic SFP transceiver module provider, has a large inventory of 1000BASE SFP, 100BASE SFP, CWDM/DWDM SFP, BiDi SFP, etc. If you have any needs of our transceivers, please send your request to us.

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C3KX-NM-10G Network Module Overview

Questions like whether a 1G SFP can be used on the SFP+ port of the switch and support 10G data rate are frequently asked by overall users. Generally, you will get the answer “no”. Because Most (95+%) SFPs and SFP+s will only run at the rated speed, no more, no less. Even though SFP and SFP+ have the same port size, it doesn’t mean that you can insert a SFP in a SFP+ port to achieve a 10G connectivity. Not to mention that some SFP+ port can only support 10G SFP+ optics. However, this article will introduce a Cisco Network module in Cisco Catalyst 3750-X and 3650-X Series switches that can both support 1 GbE SFP and 10 GbE SFP+ transceivers.

C3KX-NM-10G Network Module

The Cisco Catalyst 3750-X and 3560-X series switches support four optional network modules for uplink ports, namely C3KX-NM-1G (four GbE port network module), C3KX-NM-10G (two 10GbE SFP+ ports network module with four physical ports with two SFP+ and two regular SFP ports), C3KX-NM-10GT (two 10GB-T ports network module), C3KX-SM-10G (service module with two 10GbE SFP+ ports network module for Netflow and MACsec encryption). C3KX-NM-10G module on the Cisco Catalyst 3750-X and 3560-X has two installation screws on each side, which make it easy to switch things out and make new connection without a fuss. What’s more, when business demands changes, the C3KX-NM-10G network module allows customers to only upgrade their modules from 1 GbE to 10 GbE without replacing a comprehensive upgrade of switch.

c3kx-nm-10g-module

As the above image shows, the C3KX-NM-10G network module has four slots—two SFP+ slots and two SFP slots. These four slots usually work in pair, with one pair supporting 1 GbE data rate and the other achieving 10 GbE. Note that you must use the same form factor transceiver in a pair and never mix the SFP module with SFP+ module. SFP+ can’t auto-negotiate down to 1G to support with SFP module.

To put it simply, let’s name the port from left to right as slot 1, slot 2, slot 3, slot 4. Usually a 10-Gigabit SFP+ module takes precedence over a 1-Gigabit SFP module. But it’s another case when an SFP module is first inserted in Slot 1 and has link. For example, if the SFP in Slot 1 retains link, you insert an SFP+ module in Slot 2 and it will not operate. If the SFP module in Slot 1 is shut down or removed, the SFP+ module in Slot 2 turns on. The SFP module in Slot 1 does not work as long as an SFP+ module is in Slot 2. The following chart concludes the accessible combination of SFP and SFP+ modules.

combination-method

Suitable Cisco Transceivers for C3KX-NM-10G Network Module

As note before, C3KX-NM-10G module on the Cisco Catalyst 3750-X or 3560-X series switch can both support 1 Gigabit Ethernet and 10 Gigabit Ethernet data links. We will list the available Cisco modules attached with detailed information in the below charts.

Cisco SFP transceiver for C3KX-NM-10G module:

cisco-sfp-for-c3kx-nm-10g-module

Cisco SFP+ transceiver for C3KX-NM-10G module:

cisco-sfp-for-c3kx-nm-10g-module

There are many other compliant Cisco SFP+ DAC and AOC cables that I haven’t listed above, if you are interested, you can visit fs.com.

Conclusion

This post lists all of the functions of the Cisco C3KX-NM-10G network module, all the basic and advanced features and tells you how to select the compliant Cisco SFP modules and SFP+ modules. If you want to expand your database from 1GbE to 10GbE, with the Cisco C3KX-NM-10G network module, you only need to upgrade your Cisco SFP and plug it with a brand new SFP+ transceiver, then that’s it.

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