10 Gigabit Ethernet SFP + Kabel Definition, Typen & Deployment Guide

Die Netzwerkverkabelung hat im Laufe der Jahre tief greifende Änderungen durchlaufen und macht einen großen Sprung nach vorn zu hoch Geschwindigkeits Faserkabeln. Aber in einigen Fällen, Kupfer Twinax Kabel, zB SFP+ Kabel oder SFP + DAC Twinax Kabel noch als eine optimierte Lösung für 10-GbE-Anwendungen über kurze Strecken. Dieser Beitrag stellt einige grundlegende Informationen über SFP + DAC-Kabel und Überlegungen für die Bereitstellung von 10 Gigabit-Ethernet-SFP +-Kabel.

SFP + Cable Basics: Definition & Typen

Das SFP + DAC Twinax-Kabel ist eine Kupferverbindung mit einer Twinax-Kabelkonfektion, die direkt in das SFP +-Gehäuse integriert wird. Durch die direkte Verbindung von zwei SFP + Slots eliminiert es effektiv den kostengünstigen optischen Transceiver, der in der Ausrüstung benötigt wird, und reduziert den Stromverbrauch, die Latenz und die Installationszeit erheblich. Daher hat sich das SFP + DAC-Kabel zu einer optimalen Wahl für moderne Kurzstrecken-Hochgeschwindigkeits-10-Gigabit-Ethernet-Anwendungen. Obwohl es eine Entfernungsbegrenzung von 10M hat, wird 10G SFP + DAC-Kabel häufig in Intra-Rack-und Inter-Rack-Verbindungen verwendet: einschließlich der Verbindung von Top-of-Rack-Switches mit Servern und Speichergeräten innerhalb eines Racks oder in benachbarten Racks.

10-Gigabit-SFP + Direct-Attach-Kabel können in direkt anbringen Kupfer-Kabel (DAC) und direktes aktives optisches Kabel (AOC) klassifiziert werden. Das DAC-Kabel kann entweder passiv oder aktiv sein. Direktes aktives optisches Kabel AOC Bonds die Faserverbindung innerhalb des Transceivers endet, so dass eine komplette Faserkabel Montage ähnlich wie ein direktes Kupferkabel, aber mit einem 3-200 Meter erreichen Fähigkeit. Die obige Abbildung zeigt die führenden Typen von passiven und aktiven Direct-Attach-Kabeln für das Rechenzentrum Tor-Zusammenschaltung.

Passives DAC-Kabel und aktives DAC-Kabel

Passive DAC-Kabel enthält keine elektrischen Komponenten, so hat es minimalen Stromverbrauch von < 0.15 w, aber die Verknüpfung Abstand ist auf 5M begrenzt. Während aktive Kupferkabel enthält elektrische Komponenten in den Anschlüssen, die Signalpegel erhöhen können, so dass größere Entfernungen (5M oder mehr) über Kupfer-Medien und eine bessere Übertragungsqualität zu gewährleisten. Dies macht die aktiven Kupferkabel etwas teurer und verbraucht mehr Leistung als direkte Anbringen von passiven Kupferkabeln. Die Details sind in der folgenden Tabelle zu sehen.

SFP + Kabel Kauf Überlegungen

Marken-oder kompatibles SFP + DAC-Kabel

Als OEM oder Vendor Branded SFP + Twinax Kabel sind eher Kosten-unerschwinglich, sind die Nutzer eher geneigt zu wählen kompatiblen SFP + DAC-Kabel mit dem gleichen Industrie-Standard, aber nur einen Bruchteil der Kosten. FS.com SFP + zu SFP + Kabel ist getestet und mit Geräten von namhaften Herstellern kompatibel. Wir entwerfen auch speziell SFP + DAC Twinax Kabelkonfektionen mit unterschiedlichen Marken kompatiblen Gehäuse an zwei Seiten, und Sie können nach Ihren Bedürfnissen anpassen. Auf diese Weise ist das Anschließen von Switches von mehreren Anbietern kein Hindernis mehr.

Produkt Details des SFP + DAC Twinax-Kabels lesen

Um die Kauf Besprechung mit ihren spezifischen Anforderungen zu treffen, sollten sich die Käufer der RoHS-Konformität, der Speichertemperatur und der MSA-Konformitäts Funktionen hinsichtlich der SFP + DAC Twinax-Kabel voll bewusst sein. Dies ist wichtig für die ordnungsgemäße Ausführung Ihres Netzwerksystems.

AWG ist auch ein wichtiger Faktor

Ein weiterer wichtiger Faktor im Zusammenhang mit SFP + DAC Kupferkabel ist die AWG. Es gibt verschiedene Optionen von SFP + DAC Twinax Kabellänge und Draht Lehren, wie 24AWG, 28AWG und 30AWG. Beachten Sie bei der Wahl des AWG immer eine Regel: je länger der Abstand, desto niedriger ist die AWG-Bewertung. Gesehen in der unteren Bild, das Messgerät von SFP + Kabel 2M ist 30AWG, während SFP + Kabel 5M ist 24AWG.

SFP + Kabel Bereitstellungstipps

Hier bieten wir Antworten auf einige häufig gestellte Fragen über SFP + DAC Twinax Kabel, in der Hoffnung, es würde helfen, mit allen Verwirrungen in Bezug auf SFP + DAC Kupfer-Kabel befassen.

Soll ich passives oder aktives SFP + DAC-Kabel wählen?

Passive SFP + DAC Twinax Kabel enthält keine elektrischen Komponenten, daher erfordert wenig oder gar keine Macht zu bedienen. SFP + Active Copper-Kabel, im Gegenteil, benötigt DC-Strom, um Signalverarbeitung Schaltung in seine eingebauten Anschlüsse integriert, so dass es teurer. Es wird empfohlen, passive SFP + DAC zu verwenden, wenn der Abstand nicht mehr als 7M beträgt. Wie für die Verbindung Abstand größer als 7 m (wie Tor zu EOR), aktive DACs erforderlich wäre.

Kann ich ein kompatibles SFP + DAC-Kabel für Cisco-Switches verwenden?

Ja, genau wie optische Transceiver werden kompatible SFP + DAC Twinax-Kabel mit dem gleichen Industriestandard wie die Cisco-Kabel hergestellt. Ein qualifiziertes 10-GbE-SFP +-Kabel sollte getestet und von Cisco-Geräten vollständig erkannt werden, um eine einwandfreie Funktion zu gewährleisten. Holen Sie sich einen zuverlässigen Direct-Attach-Kabelhersteller, um SFP + DAC Twinax-Kabel zu kaufen, damit Ihr kompatibles SFP + DAC-Kabel genauso groß wie die Branded One-mit deutlich recuded Kosten-leisten kann.

Kann ich SFP + DAC-Kabel in SFP-Ports verwenden?

Ja, SFP +-Kabel sind abwärtskompatibel zu SFP-Ports und funktionieren einwandfrei. SFP-Kabel sind jedoch nicht kompatibel zu SFP +-Ports. SFP-Kabel können an SFP +-Ports angeschlossen werden, Sie sind jedoch nicht für 10Gb/s-Datenraten ausgelegt.

Quellartikel:

https://www.fs.com/de/10-gigabit-ethernet-sfp-kabel-definition-typen-deployment-guide-aid-692.html

 

ABC of GPON SFP: Understanding GPON OLT / ONU / ONT SFP Module

Since the advances in Ethernet technology, “last mile” connectivity is expected to realize between the network backbone and local area networks (end users). Gigabit Passive Optical Network (GPON) is a cost-effective point-to-multipoint access network, which brings great improvement in data transmission distance (up to 20km) and bandwidth (an downstream capacity of 2.5Gbit/s and an upstream capacity of 1.25Gbit/s ). However, GPON’s higher bandwidth and split ratios are only achievable by using GPON-capable optical transceivers. It is well positioned to help meet the needs for higher bandwidth in FTTx applications, and continues to fuel growth in demand for GPON SFP modules. So this article will introduce the basics of GPON SFP, including GPON OLT, GPON ONU and GPON ONT SFP module.

What Is GPON SFP Module?

GPON SFP is a new higher-speed bi-directional optical transceiver, which can deliver 2.5 Gbits/sec of bandwidth. And it is a kind of single fiber transceiver which comes with SC connector and can transmit data up to 20km. In addition, it features a 28-dB optical loss budget to enable 1:64 split ratios and provides adequate optical loop lengths. Most EPON and some BPON systems deployed today use 25-dB optics, which limit the split ratio and loop length. For this reason, GPON transceiver enjoys the added advantage of industrial demand. The key performance advantage is to reduce the upstream split loss arising from utilizing the mode-coupled-receivers (MCR) in a PON application. Moreover, this innovative module dose not outweigh the costs over a standard module. For these two reasons, the GPON SFP modules are very attractive to the network operators to improve the utilization of GPON network. On top of that, GPON SFP transceiver is an essential part of GPON system which is necessary both for optical network unit (ONU) installed at the subscriber’s premises and for the optical line terminal (OLT) at the central office (CO). The following part will respectively introduce the GPON OLT, GPON ONU and GPON ONT SFP module.

GPON OLT SFP Module

GPON OLT SFP is designed for OLT side in GPON network. OLT is a equipment integrating L2/L3 switch function, which is located in central office (CO). The main function is to control the information float in both directions: upstream and downstream. The GPON OLT module plays an inevitable role in the upstream and downstream transmission. In order to put across the transmission process, the downstream transmission is taken as an example. A single mode optical fiber coming from OLT (at the central office) PON port, runs to the passive optical splitter (POS) located near end users. And then the optical splitter will divide signals into separate paths which can provide service up to 64 end users. In this basic GPON topology, a GPON OLT module is used to connect a single-mode fiber patch cable to a passive optical splitter. Therefore, GPON OLT transceiver works to get the data, voice and video traffic from metro network or from a long-haul network.

GPON ONU/ONT SFP Module

Since the ONU and ONT are deployed at customer’s premises, they are connected to the OLT by means of optical fiber and no active elements are present in the link. In GPON network, the ONU/ONT transceiver is the physical connection between the customer premises and the central office OLT. This type of modules gets the signals from OLT, so they have the opposite characteristic of GPON OLT transceiver, incorporating a high performance 1310nm burst mode DFB transmitter and 1490nm CW mode APD receiver. By being plugged into advanced “triple play” (data, voice & video) ONT or ONU equipment (with SFP ports), such as Ethernet switches, routers, DSLAMs or home gateway, ONU/ONT SFP module fits seamlessly into existing communications equipment and provides end users with a smooth upgrade to GPON. Therefore, GPON ONU/ONT SFP module plays an important role in the applications for point-to-multipoint (P2MP) ONT / ONU equipment in GPON network.

Conclusion

GPON SFP transceiver meets the the requirements of FTTx network to accelerate the speed or capacity. GPON OLT, ONU and ONT SFP module have their respective roles to play in the GPON networks. Many people may worry the high attenuation losses from optical splitter in the GPON networks, as above mentioned, the GPON optical module is just used to solve this problem in that it utilizes the MCR technology that protects large numbers of signals. In a word, this new module is a compelling network alternative to save cost and increase bandwidth and security.

Related Article: ABC of PON: Understanding OLT, ONU, ONT and ODN

24-Port Gigabit Switch Selection

An Ethernet switch acts as a bridge to connect different parts of a network together. Although many routers also possess the network switching capabilities and multiple Ethernet ports, the Ethernet switch is not the replacement for routers. It is worth emphasizing that Ethernet switches are smarter than routers in that they operate at the data link layer (Layer 2) and the network layer (Layer 3) of the OSI Reference Model and therefore support any packet protocol. Ideally, switches will make better use of bandwidth if you prefer wired to wireless connections but have more devices than available Ethernet ports. On the other hand, an Ethernet switch is a costly way to expend the network in home or small business. So it is very important to invest an Ethernet switch with the appropriate number of ports to fit your needs. In the midst of various Gigabit Ethernet switches, a 24-port switch is considered as the most common Gigabit switch that connect devices in a local area network. Then this article will explore how to select a suitable 24-port Gigabit switch.

Popular 24-Port Gigabit Switch in the Market

FS S3800-24F4S 24-Port Gigabit Switch

FS S3800-24F4S 24-port Gigabit switch comes with 20x 100/1000BASE SFP, 4x 1GE combo and 4x 10GE SFP+ slots. The flexible port combination form provide a high bandwidth aggregation connectivity for multiple switch in network to enhance network capacity. Moreover, it is a stackable SFP managed switch, which can provide true stacking of up to 4 switches in a stack acting as a single unit with totally 106 ports (96x 1G Ports and 10x 10G ports). The switching capacity is 128Gbps. This 24-port Gigabit managed switch fits for enterprise network operators who need high performance and low power processor to provide full speed forwarding and line-dormant capacity.

Figure 1: FS S3800-24F4S 24-Port Gigabit Switch

Cisco SGE2000 24-Port Gigabit Switch

Cisco SGE2000P comes with 24 10/100/1000BASE-T RJ45 ports and 4 shared Gigabit SFP slots. This 24-port Gigabit managed switch can provide ACL (access control lists), DoS (denial-of-service), VLAN and IEEE 802.1X port authentication. And the enhanced quality of service (QoS) and traffic-management features help ensure clear and reliable voice and video communications. This Gigabit network switch enable you to take advantage of the comprehensive feature set for a better-optimized, more secure network.

Figure 2: Cisco SGE2000 24-Port Gigabit Switch (Source: Cisco)

NETGEAR ProSAFE GS724T 24-Port Gigabit Switch

The Netgear ProSafe GS724T is armed with 24 copper 10/100/1000 ports and 2 SFP 100/1000 ports. Each port can transfer data at maximum throughput for a total maximum switching speed of up to 48 Gbps. This 24-port switch is intended for SMB organizations using the switch for applications like VoIP, video conferencing, and system security, etc. And it features a fanless system, allowing the switch to work silently without overheating. This is great for use on homelab, as its quiet operation won’t cause a distraction.

Figure 3: NETGEAR ProSAFE GS724T 24-Port Gigabit Switch (Source: NETGEAR)

TP-Link TL-SG1024 24-Port Gigabit Switch

The TP-Link TL-SG1024 features 24 Gigabit Ethernet ports and non-blocking switching, which can provide large file transferring and also be compatible with 10Mbps and 100Mbps Ethernet devices. Moreover, this network switch has 48Gbps switching capacity with 8K MAC address table, 10KB Jumbo Frame and 4MB buffer memory. This TP-Link switch is a fanless rack mount design with LED diagnostic lights, so you can easily tell which ports are in use. It can automatically adjust power consumption according to the link status to limit the carbon footprint of your network. The price is $69.99 on Amazon. So this fanless Ethernet switch is good for your wallet both because it is inexpensive to buy and because of its energy-saving technology.

Figure 4: TP-Link TL-SG1024 24-Port Gigabit Switch(Source: TP-Link)

Comparison of 24-Port Gigabit Switch

Gigabit Switch Mode	Ethernet ports	Gigabit SFP	SFP+ Uplink ports	Switching Capacity	Forwarding Rate	Power Consumption	Price
FS S3800-24F4S	24	4 combo	4	128Gbps	95Mpps	≤60W(Full-loaded)	$449
Cisco SGE2000	24	4	/	48Gbps	35.7Mpps	90W	$390
NETGEAR ProSAFE GS724T	24	2	/	48Gbps	No Information	29W	$219.99
TP-Link TL-SG1024	24	/	/	48Gbps	35.7Mpps	13.1W	$69.99

From the chart we can see, all the Gigabit switches listed above provide 24 port Ethernet RJ45 ports, only FS S3800-24F4S 24-port Gigabit switch has 4 SFP+ uplink ports. They have some characteristics in common that make them suitable for being used in places like home or small business office. In terms of the power consumption, TP-Link TL-SG1024 and NETGEAR ProSafe GS724T are lower than others, but the huge price spread exists between these two switches because NETGEAR ProSafe GS724T has another two SFP ports for more flexible application. Among these four switches, if you have no limited cost budget, FS S3800-24F4S is a good choice. It has more flexible port combination and higher switching capacity, that is why it may cost a little more than the other three switches. If you need stronger data transferring capability, FS S3800-24F4S is a better choice considering its forwarding rate. On the contrary, TP-Link TL-SG1024 is the best budget choice. If you want a fanless switch, NETGEAR ProSafe GS724T is an inexpensive and reliable choice, but the install program only works on Windows and the secure management is very difficult to be enabled.

Conclusion

When choosing a Gigabit Ethernet switch, the first factor to consider is how many devices need to be networked together. Purchasing a network switch with too few ports and not enough capacity will prove ineffective, and one that is too large can be a waste of money. Generally, small offices with a few employees should start with a 16-port switch, but a business that is looking to expand its operations soon needs a 24-port switch. So 24-port Gigabit switch is the most future-proofing and cost-effective choice in small business network. Except the above mentioned S3800-24F4S, FS.COM also provides other three cost-effective 24-port switch for different demands.

FS.COM 24-port Gigabit Switches Mode	Description
S2800-24T4F	Fanless Gigabit managed switch with 24 100/1000BASE-T ports and 4 combo SFP slots
S3700-24T4S	Gigabit managed switch with 24 10/100/1000BASE-T ports and 4 10GE SFP+ uplinks ports
S3800-24T4S	Gigabit stackable managed switch with 24 10/100/1000BASE-T ports and 4 10GE SFP+ uplinks ports

Related Article: 48-Port 10GE Switch Selection: What Is the Right Choice?

 

A Brief Introduction of Cisco BiDi SFP Transceiver

In the early stage of optical fiber communication, one optical fiber can only transmit signals of one wavelength. This is known as conventional two-fiber Bi-Directional communication – at least two fibers are needed to accomplish the full-duplex communication with TX and RX optical signals. With the development of WDM technology, transmitting and receiving of optical signals on separate wavelength can be achieved through only one single fiber. This single fiber BiDi transmission gradually becomes a popular and cost-effective solution for today’s data center and IT infrastructure, because it helps to maximize the capacity and usage of optical fibers. Consequently, BiDi optical transceiver as the basic component plays an irreplaceable role in the WDM BiDi transmission application. This article will generally introduce Cisco BiDi SFP transceivers, including GLC-BX-U, GLC-BX-D, GLC-BX-20U, GLC-BX-20D, GLC-BX40-D-I, GLC-BX40-U-I, GLC-BX80-D-I, GLC-BX80-U-I, GLC-BX120-U, GLC-BX120-D, etc.

What Is a BiDi SFP?

BiDi SFP transceiver can be defined as a compact, hot swappable, input/output optical module that can transmit and receive data to/from interconnected equipment through a single optical fiber. Unlike traditional optical transceivers, BiDi optical 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. To simplify it, conventional optical module has two ports – the TX for the transmit port and the RX for receive port; but BiDi transceiver has only one port to complete the 1310nm optical signal transmitting and 1550nm optical signal receiving, or vice versa. Therefore, BiDi transceivers must be deployed in matched pairs with their diplexers tuned to match the expected wavelength of the transmitter and receiver. These BiDi optical transceivers can offer bi-directional data links over single-mode fiber up to 120 km. BiDi SFP transceiver is applicable to many access networks: passive optical networks (PON) and point-to-point, digital video and closed circuit television (CCTV) applications, inter-system communication between servers, switches, routers, optical add drop multiplexer (OADM), WDM fast Ethernet links, SDH/STM-1, SONET/OC3, metropolitan area networks and other optic link.

Common Types of Cisco BiDi SFP

1G BiDi SFP is also known as 1000BASE-BX SFP, which use two different wavelengths (1310nm-TX/1490nm-RX, 1310nm-TX/1550nm-RX, 1490nm-TX/1550nm-RX and 1510nm-TX/1570nm-RX) for transmission in different distance. The following will list some main Cisco BiDi SFP modules in 10km, 20km, 40km, 80km and 120km.

10km Cisco BiDi SFP

The Cisco GLC-BX-D and GLC-BX-U is a pair of 10km BiDi SFP transceiver with LC duplex connectors, operating on a single strand of standard SMF. The GLC-BX-U transceiver operates at 1310nm-TX/1490nm-RX wavelength with upstream bidirectional single fiber, while the GLC-BX-D transceiver operates at 1490nm-TX/1310nm-RX wavelength with downstream bidirectional single fiber. These two BiDi optical modules, compliant to 1000Base-BX standard, are rated for distances up to 10 km over SMF and a maximum bandwidth of 1Gbps. A 1000BASE-BX-D device is always connected to a 1000BASE-BX-U device with a single strand of standard SMF. In addition, the GLC-BX-D and GLC-BX-U BiDi SFPs also support digital optical monitoring (DOM) functions according to the industry-standard SFF-8472 multisource agreement (MSA). This feature gives the end user the ability to monitor real-time parameters of the SFP, such as optical output power, optical input power, temperature and transceiver supply voltage.

(GLC-2BX-U and GLC-2BX-D are 2-channel 1000BASE-BX SFP modules, also known as compact SFPs that integrate two IEEE 802.3ah 1000BASE-BX10 interfaces in one SFP module. They are designed to connect to any standard-based Customer Premises Equipment (CPE) in FTTx links.)

20km Cisco BiDi SFP

GLC-BX-20U and GLC-BX-20D are Cisco 20km BiDi SFP transceivers that work with single mode fiber. The GLC-BX-20U operates at 1310nm-TX/1550nm-RX wavelength, and GLC-BX-20D operates at 1550nm-TX/1310nm-RX. So these two BiDi SFPs always work in pairs. Their max data rate is 1000Mbps. FS.COM compatible Cisco BiDi transceivers are high performance, cost effective modules supporting data-rate of 1000Mbps and 20km transmission distance with SMF. Among the Cisco 20km BiDi SFPs, Cisco Linksys MFEBX1D provides up to 155Mbps bi-directional data transfer rate at distances up to 20km on a single fiber core. These bidirectional SFP transceivers allow data transfer in either direction through a single optical fiber by employing separate wavelengths travelling in either direction.

40km Cisco BiDi SFP

Cisco GLC-BX40-D-I and GLC-BX40-U-I is a pair of 40km BiDi SFP modules for Gigabit Ethernet 1000BASE-BX and Fiber Channel communications. They support link length of up to 40km point to point on single mode fiber at 1Gbps bidirectional and use an LC connector. The GLC-BX40-D-I is 1550nm-TX/1310nm-RX 40km BiDi WDM SFP simplex transceiver module, GLC-BX40-U-I is 1310nm-TX/1550nm-RX BiDi WDM SFP module. They are specified for duplex optical data communications such as 1000BASE-BX Gigabit Ethernet per IEEE802.3z and 1G Fiber Channel extended reach application.

80km Cisco BiDi SFP

The Cisco GLC-BX80-D-I and GLC-BX80-U-I SFPs are 1G BiDi SFP modules that provide 80km transmission distance over single strand of single-mode fiber. GLC-BX80-D-I operates at 1570nm-TX/1490nm-RX wavelength, whereas GLC-BX80-U-I operates at 1490nm-TX/1570nm-RX. These bidirectional SFP transceivers are intended mainly for connecting high-speed hubs, Ethernet switches, and routers together in different wiring closets or buildings using long cabling runs, and developed to support longer-length on fiber backbones. Compared with commonly used dual fiber SFP transceiver modules, the BiDi SFP transceiver allows end users to reduce the total cost on fiber cabling infrastructure by requiring half of fiber cables, providing increased transmission capacity very convenient without installing new fibers.

120km Cisco BiDi SFP

The Cisco GLC-BX120-U and GLC-BX120-D are 1490nm and 1550nm bidirectional SFP transceivers that are used with single mode optical fiber. They also use two wavelength 1490nm-TX/1550nm-RX(1550nm-TX/1490nm-RX) simultaneously. These BiDi SFP modules can support transmission distance up to 120 km, which are connected through pluggable LC connector type optical interface. They have a DFB (Distributed Feedback) type transmitter, an APD (Avalanche Photo-Diode) type receiver, an LD (Laser Driver), a limiting amplifier and digital diagnostic monitor. Those BiDi SFP transceivers are Class 1 laser safety product which complies with US FDA regulations, SFP MSA, SFF-8472 and RoHS standards. More importantly, 120km SFP modules have the same or even lower transmit power as compared to 80km SFP. It is the reason that 120km modules extend the range thanks to receiver not transmitter. 120km modules have much better receiving sensitivity than 80km modules.

Conclusion

BiDi SFP transceiver serves as an ideal and feasible solution in situations where only limited fibers or limited conduit space is available. And the deployment of BiDi optical transceivers efficiently enhances the bandwidth capacity of the existing optical fiber infrastructure and help to achieve economical and reliable performance of the optical network. Although BiDi transceivers may be more expensive than common transceiver modules, they can save you the cost on fiber cables from the long run.

 

SFP-GE-S-2 VS. GLC-SX-MM: What’s the Difference?

SFP-GE-S-2 and GLC-SX-MM are Cisco 1000BASE-SX SFP multimode fiber transceivers. Since there are similar specifications for these two multimode modules, many end users may be confused when choosing a multimode fiber SFP LC connector SX transceiver for their Cisco switches. So, are they the same one? This post intends to give a simple explanation of SFP-GE-S-2 vs. GLC-SX-MM.

SFP-GE-S-2 Module

Cisco SFP-GE-S-2 is a 1 GbE SFP SX fiber transceiver that supports the maximum data rate of 1Gbps. It’s compatible with the IEEE 802.3z 1000BASE-SX standard, and can operate on standard multimode fiber optic link spans of up to 2 km.

Module/Specs	Cisco SFP-GE-S-2
Interface	LC duplex
Wavelength	1310nm
Tx power	-9.5 ~ -3dBm
Receiver Sensitivity	< -17dBm
DOM Support	Yes
Temperature Range	32℉to 158℉ (0℃ to 70℃)
Data Rat	1G
Fiber Mode	MMF

GLC-SX-MM Module

GLC-SX-MM transceiver is also a Cisco 1000BASE-SX fiber transceiver that designed for Gigabit Ethernet applications. This SX module is compatible with the IEEE 802.3z 1000BASE-SX standard, and can operate on standard multimode fiber optic link spans of up to 550m.

Module/Specs	Cisco GLC-SX-MM
Interface	LC duplex
Wavelength	850nm
Tx power	-9.5 ~ -3dBm
Receiver Sensitivity	< -17dBm
DOM Support	No
Temperature Range	32℉to 158℉ (0℃ to 70℃)
Data Rat	1G
Fiber Mode	MMF

SFP-GE-S-2 VS. GLC-SX-MM

From the above specs comparison, we can learn that these two SX multimode modules support same data rate and operating temperature range. They all can operate on the multimode fiber optic cables. The main differences include:

• Wavelength

SFP-GE-S-2 can support a wavelength of 1310nm, whereas GLC-SX-MM works in 850nm.

• Transmission Distance

SFP-GE-S-2 can support up to 2km over laser-optimized 50 μm multimode fiber cable, while GLC-SX-MM can operate on legacy 50 μm multimode fiber links up to 550m.

• DOM Support

SFP-GE-S-2 can support DOM, but GLC-SX-MM does not have DOM function. DOM (Digital Optical Monitoring) is an important function available on fiber optic transceiver. It allows users to monitor parameters of modules, such as optical output power, optical input power, temperature, laser bias current and transceiver supply voltage. In real time, it offers users more convenience when using optical modules.

• Price

GLC-SX-MM is a legacy model, it doesn’t feature DOM function. It comes with the lowest price compared with other SX modules . Take FS.COM compatible transceivers as example, SFP-GE-S-2 costs $ 11.00, while GLC-SX-MM is only $ 6.00.

Conclusion

From the contents above – SFP-GE-S-2 vs. GLC-SX-MM, we can draw a conclusion that these two SX multimode fiber transceivers nearly can be used as the same one type module sometimes, but their existing differences still differ them from some applications. Most of the Cisco switches and routers support all two models, but please note, some of the switches require different models, you may visit Cisco SFP Compatibility Matrix for more detailed information.

 

SFP 40 km VS. DWDM SFP: Which to Choose?

Small Form-factor Pluggable (SFP) is a compact, hot-pluggable transceiver used for both telecommunication and data communications applications. It is also called mini-GBIC for its smaller size, which is the upgraded version of GBIC transceiver. These 1Gb SFP modules are capable of supporting speeds up to 4.25 Gbps. And they are most often used for Fast Ethernet of Gigabit Ethernet applications. It interfaces a network device motherboard (for a switch, router, media converter or similar device) to a fiber optic or copper networking cable. SFP modules are commonly available in several different categories: 1000BASE-T SFP, 1000BASE-EX SFP, 1000BASE-SX SFP, 1000BASE-LX/LH SFP, 1000BASE-BX SFP, 1000BASE-ZX SFP, CWDM SFP and DWDM SFP. These modules support different distance according to the different Gigabit Ethernet standard. Today’s main subject will discuss SFP 40 km vs. DWDM SFP.

SFP 40 km

SFP 40 km transceiver is designed for highly reliable fiber optic network links up to 40 km. It is a cost effective transceiver designed to enable 1Gb for data center and core network applications. 1000BASE-EX SFP is the most popular SFP 40 km transceiver which runs on 1310nm wavelength lasers and achieves 40km link length. Except that, 1000BASE-BX BiDi SFP, 1000BASE-LH SFP and 1000BASE-LX SFP can also realize the transmission distance up to 40 km. The following will introduce these 1GbE SFP 40 km transceivers respectively.

1000BASE-EX SFP 40 km

1000BASE-EX SFP transceiver module is designed to connect a Gigabit Ethernet port to a network and has dual LC/PC single mode connectors. It operates on standard single-mode fiber-optic link spans of up to 40 km in length. The SFP Ethernet module provides a dependable and cost-effective way to add, replace or upgrade the ports on switches, routers and other networking equipment. Cisco GLC-EX-SM1550-40 and Cisco GLC-EX-SMD are 1G single mode fiber SFP 40 km modules for 1000BASE-EX Gigabit Ethernet transmission. GLC-EX-SM1550-40 supports a 1550nm wavelength signaling, while GLC-EX-SMD supports a 1310nm wavelength signaling.

1000BASE-BX SFP 40 km

1000BASE-BX SFP is a kind of BiDi transceiver, which can be divided into 1000BASE-BX-D SFP and 1000BASE-BX-U SFP. These two SFP transceivers must be used in pairs to permit a bidirectional Gigabit Ethernet connection using a single strand of single mode fiber (SMF) cable. 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.

• 1000BASE-BX-D BiDi SFP 40 km

Cisco GLC-BX40-D-I and GLC-BX40-DA-I are pluggable fiber optical transceivers for Gigabit Ethernet 1000BASE-BX and Fiber Channel communications. They support link length of up to 40 km point to point on single mode fiber at 1Gbps bidirectional and use an LC connector. The GLC-BX40-D-I transceiver transmits a 1490nm channel and receives a 1310nm signal, whereas GLC-BX40-DA-I transmits at a 1550nm wavelength and receives a 1310nm signal.

• 1000BASE-BX-U BiDi SFP 40 km

Similar to 1000BASE-BX-D 40 km SFP , Cisco GLC-BX40-U-I and GLC-BX40-UA-I also support link length of up to 40 km point to point on single mode fiber at 1Gbps bidirectional and use an LC connector. The main difference is the wavelength: GLC-BX40-U-I transmits a 1310nm channel and receives a 1550nm signal, whereas GLC-BX40-UA-I transmits at a 1310nm wavelength and receives a 1490nm signal. A GLC-BX40-D-I or GLC-BX40-DA-I device connects to a GLC-BX40-U-I or GLC-BX40-UA-I device with a single strand of standard SMF with an operating transmission range up to 40 km.

1000BASE-LX SFP 40 km

1000BASE-LX is a standard specified in IEEE 802.3 Clause 38 which uses a long wavelength laser. The “LX” in 1000BASE-LX stands for long wavelength, indicating that this version of Gigabit Ethernet is intended for use with long-wavelength transmissions (1270 – 1355nm) over long cable runs of fiber optic cabling. Allied Telesis AT-SPLX40 and Allied Telesis AT-SPLX40/1550 are 1000BASE-LX SFP single-mode modules supports Gigabit Ethernet over single-mode cables at distances up to 40 km. AT-SPLX40 operates over a wavelength of 1310nm for 40 km, whereas AT-SPLX40/1550 operates over a wavelength of 1550nm.

1000BASE-LH SFP 40 km

Unlike 1000BASE-LX, 1000BASE-LH is just a term widely used by many vendors. Long Haul (LH) denotes longer distances, so 1000BASE-LH SFP modules operate at a distance up to 70 km over single mode fiber. Cisco Linksys MGBLH1 is a easy-to-install modules that provide a simple way to add fiber connectivity or to add an extra Gigabit Ethernet port to switches. The MGE transceiver can support distances up to 40 km over single-mode fiber at a 1310nm wavelength.

DWDM SFP

DWDM SFP transceivers are used as part of a DWDM optical network to provide high-capacity bandwidth across an optical fiber network, which is a high performance, cost effective module for serial optical data communication applications up to 4.25Gb/s. DWDM transceiver uses different wavelengths to multiplex several optical signal onto a single fiber, without requiring any power to operate. There are 32 fixed-wavelength DWDM SFPs that support the International Telecommunications Union (ITU) 100-GHz wavelength grid. The DWDM SFP can be also used in DWDM SONET/SDH (with or without FEC), but for longer transmission distance like 200 km links and Ethernet/Fibre Channel protocol traffic for 80 km links. Cisco C61 DWDM-SFP-2877-40 is a 1000BASE-DWDM SFP 40km transceiver, which is designed to support distance up to 40 km over single-mode fiber and operate at a 1528.77nm DWDM wavelength (Channel 61) as specified by the ITU-T.

SFP 40 km VS. DWDM SFP

• Transmission Medium

Generally, the standard SFP 40 km transceivers transmit through the single mode fiber, while DWDM SFP carries signals onto a single optical fiber to achieve maximum distances by using different wavelengths of laser light. So the DWDM SFP transceivers do not require any power to operate.

• Wavelength

The standard SFP 40 km transceivers support distances up to 40 km over single-mode fiber at a 1310nm/1550nm wavelength. (the BiDi SFP has 1490nm/1550nm TX & 1310nm RX or 1310nm TX & 1490nm/1550nm RX ). However, DWDM SFP operates at a nominal DWDM wavelength from 1528.38 to 1563.86nm onto a single-mode fiber. Among them, 40 km DWDM SFP operates at a 1528.77nm DWDM wavelength (Channel 61).

• Application

DWDM SFP is used in DWDM SONET/SDH, Gigabit Ethernet and Fibre Channel applications. These modules support operation at 100Ghz channel. The actual SFP transceiver offers a transparent optical data transmission of different protocols via single mode fiber. And for back-to-back connectivity, a 5-dB inline optical attenuator should be inserted between the fiber optic cable and the receiving port on the SFP at each end of the link.

• Price

DWDM provides ultimate scalability and reach for fiber networks. Boosted by Erbium Doped-Fiber Amplifiers (EDFAs)  – a sort of performance enhancer for high-speed communications, DWDM systems can work over thousands of kilometers. Most commonly, DWDM SFP is much more expensive than the standard SFP. You can see the price more clearly in the following cable.

Conclusion

1000BASE SFP transceiver is the most commonly used component for Gigabit Ethernet application. With so many types available in the market, careful notice should be given to the range of differences, both in distance and price of multimode and single-mode fiber optics. Through SFP 40 km vs. DWDM SFP, if you are looking for SFP modules over long distance and with better scalability, DWDM SFP module is the ideal choice.

Related Article: SFP Transceiver: To Be or Not To Be?

 

10G DWDM Tunable XFP – Up to 80 km Reach

With the spread of cloud computing and mobile broadband service, the volume of communications traffic has rapidly increased. In order to enable high-capacity optical networks, using a single optical fiber for optical signals of several different wavelengths in DWDM system is widely used. For this reason, tunable transceiver that enables ROADM functionality in next-generation networks is becoming more and more popular. In today’s market, there are mainly two kinds of tunable DWDM transceivers: tunable XFP and tunable SFP+. This article will take you to explore the DWDM C-band tunable XFP transceiver with 40 / 80 km transmission distance options.

Tunable XFP Transceiver

Tunable XFP transceiver is an integrated fiber optic transceiver that provides a high-speed serial link at signaling rates from 9.95 Gbps to 11.35 Gbps. It complies with the ITU-T G.698.1 S-D100S1-2D standard with 50GHz channel spacing for SONET/SDH, IEEE DWDM 10GBASE-ZR for 40 or 80 km reach (Ethernet), and DWDM 10G FC (Fibre Channel) for 40 or 80 km reach applications. Tunable XFP can be tuned from channel C17 (1563.86nm) to C61 (1528.38nm). The maximum distance of this transceiver on a single mode fiber is up to 80 km. As mentioned above, tunable XFP optical transceiver is a full-duplex serial electric, serial optical device with both transmit and receive functions contained in a single module. On the transmit side, the 10 Gbps serial data stream is recovered, retimed, and passed to a modulator driver. The modulator driver biases and modulates a C-band-tunable integrated laser Mach-Zehnder (ILMZ), enabling data transmission over singlemode fiber through an industry-standard LC connector. On the receive side, the 10 Gbps optical data stream is recovered from an APD/transimpedance amplifier, retimed, and passed to an output driver. This module features a hot-pluggable XFI-compliant electrical interface. Here is a simple picture showing its working process.

Tunable XFP Optics Specifications:

– 50 GHz ITU channel spacing with intergrated wavelength locker

– Available in all C-Band Wavelengths on the DWDM ITU grid

– Available distances 40 or 80 km

– Supports 9.95Gb/s to 11.35Gb/s

– Built-in Digital Diagnostic Functions

– Tempereature Range: -5°C to 70°C

Two Transmission Distance Options: 40 km or 80 km

There are two transmission distance options for tunable XFP transceiver: 40 km or 80 km. Tunable XFP DWDM 80 km transceiver is designed for long distance optical communications up to 80 km with signaling rates up to 10Gbps. Obviously, the main difference is transmission distance. On account that 10G tunable DWDM XFP optical transceiver provides digital diagnostic functions via a 2-wire serial interface, which allows real-time access to the following operating parameters: transmitted optical power, received optical power, transceiver temperature, laser bias current and transceiver supply voltage. Therefore, the differences between 40 km tunable XFP and 80 km tunable XFP mainly lie on theses parameters. One thing to note is that 40 km tunable XFP optics is designed with high performance PIN receiver, while the 80 km tunable XFP transceiver is APD receiver. The APD (avalanche photodiode) receiver employed in these extended-reach optical transceivers has an enhanced sensitivity to allow for these extended distance fiber runs. However, it is to be noted that the input power is typically between -7 and -24 dBm. Therefore, the receiver sensitivity between these two distance has a big difference. Generally, the max receive dBm of 40 km tunable XFP transceiver is -15, while the 80 km tunable XFP transceiver is -24. And for power budget, 40 km tunable XFP is 14dB while a distance up to 80 km is up to 22dB power budget. The following table lists the main differences.

Conclusion

In general, the channel switching of tunable switches can enable the service operators to turn up circuits faster and reduce their sparing costs dramatically in today’s DWDM systems. On the other hand, tunable transceiver is usually two or four times more expensive than the regular static DWDM optical module, because a special tunable laser is applied in it. Tunable XFP transceiver provides a full C-band window covering 1528nm to 1566nm for DWDM optical networks, which meets the need of rapid increase in the volume of communications traffic from telecom carrier and operator. The tunable DWDM XFP module can replace the fixed DWDM channel XFP transceivers that are currently used, while reduce the large stock since all wavelengths can now be covered with one transceiver module.

Unveil 10G DWDM Tunable SFP+

Optical transceivers play a key role in handling all storage, data, voice and video traffic whether linking rack to rack, bottom to top of rack, data center to data center or enterprise networks to network. A range of flexible fiber optic transceiver modules cover all of network needs, such as SFP, SFP+, QSFP, QSFP28, CFP, etc. But for 10G DWDM tunable SFP+, many people might find themselves in the mire. When I first heard about this tunable transceiver, I thought that it would definitely bring revolutionary change to future metro Ethernet and optical transport networks with its important practical value for flexibly selecting working wavelength. So this article will unveil all of the things about tunable SFP+ optical transceiver.

About 10G DWDM Tunable SFP+

As the demand for great traffic capacity keeps growing, more optical transceivers of different wavelengths are needed. So tunable transceivers are recent innovations in DWDM transport systems. DWDM tunable transceivers are within the scope of DWDM transceivers, through which different DWDM wavelengths can be configured and output in the same optical module. But compare with conventional fixed-wavelength DWDM SFP+, the tunable SFP+ uses tunable laser as light sources in DWDM systems, which is tunable across the entire C-band with 96 channels on the ITU-T 50-GHz grid.

The tunable laser technology is firstly introduced by Oclaro, a leading supplier and and innovator of tunable laser and transceiver solutions. In 2013, it announced a standards-compliant, multi-rate tunable SFP+, which supports rates between 9.95 and 11.3 Gbps. But the first-generation tunable SFP+ optical transceivers were not widely adopted, because they did not meet the critical requirement of less than 1.5 W of power consumption at high operating temperatures. So in 2014, Oclaro demonstrated a new tunable SFP+ module based on a new Oclaro InP tunable laser platform. With the innovative new chip design and the use of next generation materials, the new module is fully compliant to the SFP MSA form factor and can operate at 1.5W at 70 degrees C with excellent OSNR tolerance. With the breakthrough of technology, the 10G tunable SFP+ transceivers become an important component for next generation data center, metro and regional optical network equipment. They meet the world’s growing bandwidth demands while reducing the size and power consumption for 10G connections.

Key Highlights of Tunable SFP+ Module:

(1) Fully compliant with MSA standard size based on SFF-8432 specification for Improved Pluggable Form Factor, rev. 5.1

(2) Tunable across the full C-band with 96 channels on the ITU-T 50GHz grid

(3) Multi-rate operation: 9.95 Gbit/s to 11.3 Gbit/s

(4) Operates at 1.5W at 70 degrees C with excellent OSNR tolerance

Advantages of Tunable SFP+

The tunable SFP+ transceivers are high-performance optics which can be tuned to the appropriate wavelength. The ability to operate on various wavelengths has set these optics apart from fixed-wavelength DWDM SFP+. Besides, These tunable optics will become popular among DWDM systems due to the several advantages.

• Flexible network management

A tunable SFP+ transceiver will be remotely configured for a specific wavelength to support bandwidth changes as needed in Enterprise or Metro networks.

• Reduced network inventory

One tunable SFP+ transceiver will support more than 80 different wavelengths. It will allow network operators to hold one tunable device code as opposed to 80+ fixed wavelength transceivers.

• Reduced power consumption

It will provide a significant reduction in electrical power dissipation compared to other tunable solutions.

• Compact and high-density form factor

The new tunable SFP+ transceiver will be about the size of a pack of gum, saving valuable real estate in data centers.

• Increased network capacity

The tunable SFP+ will double the number of channels supported in this compact transceiver form factor. Upgrading to 50GHz channel spacing doubles the capacity potential in Enterprise and Metro networks.

Conclusion

The advent of 10G DWDM tunable SFP+ transceivers in the market will accelerate the trend for pace-, power-, and cost-efficient network solutions. Because tunability is critical for minimizing inventory and enabling flexible rapid service provisioning. Although now the market share for DWDM tunable SFP+ transceiver is not big enough, the huge potential will be demonstrated in the near future.

Original Source: www.fiber-optic-components.com/unveil-10g-dwdm-tunable-sfp.html

 

Optics Solutions for Netgear ProSAFE XS712T (XS712T-100NES)

With the growth of virtualization, cloud-based services and applications like VoIP, video streaming and IP surveillance, SMB networks need to extend beyond simple reliability to higher speed and performance. As a leading provider of networking equipment for SMBs, Netgear had launched a variety of cost-effective 10GBASE-T switches including Netgear ProSAFE XS708Ev2, XS716E, XS708T, XS712T, XS716T, XS728T, XS748T and XSM7224. When looking for a lower cost and high capacity 10GBASE-T switch in SMB home/office lab environments, the Netgear ProSAFE XS712T is one of the best options. It comes in at around $1,100 at Amazon which is more budget friendly than the larger data center switches. This article will review the Netgear ProSAFE XS712T (XS712T-100NES) 10GBASE-T switch.

Netgear ProSAFE XS712T (XS712T-100NES): 12-Port 10GBASE-T Switch

Netgear ProSAFE XS712T is a powerful smart managed switch that comes with 10 dedicated 10GBASE-T RJ-45 copper ports supporting 100M/1G/10G speeds and 2 combo copper/SFP+ fiber 10G ports. The 2 combo SFP+ ports can be used as 10GASE-T ports or as SFP+ 10Gb Ethernet ports. This is an awesome feature as it allows an inexpensive SPF+ link via DAC to a 24 or 48 port 1Gb Ethernet switch for non-10Gb networking needs. All ports can automatically negotiate to the highest speed, which makes the switch ideal for environments that have a mix of Ethernet, Fast Ethernet, Gigabit Ethernet, or 10-Gigabit Ethernet devices. Cat 5e/Cat 6/Cat 6a/Cat 7 can be used to make 10G connections. Cat 6a/Cat 7 cables are recommended if the cable distance is greater than 45 meters. Besides, the smart switch can be freestanding or rack mounted in a wiring closet or equipment room. This 10G smart managed switch is purposely designed as a cost-effective way to provide 10G connections to 10G-capable servers and NAS (Network Attached Storage) systems. It also can be used at the center of a small business network or as an aggregation/access switch in a larger organization.

Figure 1:  Netgear ProSAFE XS712T (Source: www.netgear.com )

Highlights of Netgear ProSAFE XS712T

In order to meet the current and future needs on virtualization, converged network and mobility, the XS712T provides comprehensive L2+/Layer 3 Lite features, such as VLAN, QoS, IGMP and MLD snooping, Static Routing, Link Aggregation, ACL binding. Besides, it has an easy-to-use Web-based management GUI which makes setup and management simple. Some of main features include:

10GBASE-T Connection

The RJ-45 copper ports of XS712T comply with IEEE 10GBASE-T standards. They support low-latency, line-rate 10G copper “Base-T” technology with backward compatibility to Fast Ethernet and Gigabit Ethernet. So it allows for a cost effective and simpler upgrade path to 10-Gigabit Ethernet. The existing Cat5/Cat5e is supported for Gigabit speeds up to 100 meters, Cat6 for 10-Gigabit speeds up to 45 meters and Cat6a/Cat7 for 10GBASE-T connection up to 100 meter.

Designed as Core Switch for SMB Network

The powerful L2+/Layer 3 Lite features make XS712T the most cost-effective core switches for SMB and virtualization environment. This switch is also a future-proofing choice with 10G bandwidth, advanced traffic management and comprehensive IPv6 support.

Figure 2: Netgear ProSAFE XS712T in SMB Network (Source: www.netgear.com )

Act as Aggregation Switch for Medium Sized Networks

The XS712T used as a aggregation switch has many useful purposes. It can help to resolve the congestion issue between network edge and core, which is caused by the broader adoption of Gigabit-to-the-desktop. Unlike multiple Gigabit Ethernet links, it provides greater scalability resulting in a simplified and highly efficient network infrastructure. What’s more, it can reduce cabling complexity because it can use existing cabling efficiently.

Optics Solutions for Netgear ProSAFE XS712T (XS712T-100NES)

As mentioned above, The Netgear ProSAFE XS712T smart switch provides 12 twisted-pair ports that support nonstop 100M/1000M/10G networks. The switch also has two built-in SFP+ GBIC combo slots that support 1000M and 10G optical modules. Using these Gigabit slots, 100M/1000M/10G copper and 1000M/10G fiber connectivity can create high-speed connections to a server or network backbone. So 1000BASE-T SFP copper transceiver, 1000BASE SFP and 10G SFP+ transceivers are suitable for this switch. The following table lists the compatible transceivers and optic cables from FS.COM.

MFG PART#	Description
AGM734	NETGEAR AGM734 Compatible 1000BASE-T SFP Copper 100m Transceiver, RJ-45 Interface
AGM731F	NETGEAR Compatible 1000BASE-SX SFP 850nm 550m DOM Transceiver, LC Interface
AGM732F	NETGEAR Compatible 1000BASE-LX SFP 1310nm 10km DOM Transceiver, LC Interface
AXM761	NETGEAR Compatible 10GBASE-SR SFP+ 850nm 300m DOM Transceiver, LC Interface
AXM762	NETGEAR Compatible 10GBASE-LR SFP+ 1310nm 10km DOM Transceiver, LC Interface
AXM763	NETGEAR Compatible 10GBASE-LRM SFP+ 1310nm 220m DOM Transceiver, LC Interface
AXM764	NETGEAR Compatible 10GBASE-LR Lite SFP+ 1310nm 2km DOM Transceiver, LC Interface
AXC761	1m NETGEAR Compatible 10G SFP+ Passive DAC
AXC763	3m NETGEAR Compatible 10G SFP+ Passive DAC

Conclusion

The Netgear XS712T (XS712T-100NES) provides a solid cost-effective solution especially for those with SMB home/ office lab environments. If you are seeking for afforable 10GBASE-T switch for your home lab, the XS712T can be taken into consideration. What’s more, the compatible fiber transceivers and cables can be found in many third party vendors with reasonable prices, such as cablestogo, fluxlight, smartoptics, FS.COM, and etc. You have a lot of choices to save money.

Originally published: http://www.fiber-optic-components.com/optics-solutions-for-netgear-prosafe-xs712t.html

 

Layer 3 Switch VS. Router

In the OSI model, we know that traditional network switches operate at Layer 2 while network routers operate at Layer 3. Besides, switches are understood to be forward traffic based on MAC address, while routers perform the forwarding based on IP address. Layer 3 switches have a lot in common with traditional routers: they can also support the same routing protocols, inspect incoming packets and make dynamic routing decisions based on the source and destination addresses inside. For this reason, many networking beginners are puzzled over the definition and purpose of a Layer 3 switch. So what is on earth Layer 3 switch and how is it different from router?

Layer 3 Switch

Layer 3 switch is also called multilayer switch. It is a specialized hardware device used in network routing, which is conceived as a technology to improve network routing performance on large local area networks (LANs) like corporate intranets. A Layer 3 switch is both a switch and a router. So Layer 3 switch is a switch that can route traffic, and a router with multiple Ethernet ports has a switching functionality. It can switch packets by checking both IP addresses and MAC addresses. On this account, Layer 3 switches separates ports into VLANs and perform the routing between them, in addition to supporting routing protocols such as RIP, OSPF and EIGRP.

Layer 3 Switch VS. Router

From the basics of Layer 3 switch, it may seem to perform the same functionality with the router. In fact, they have some key distinction facts. The key differences between Layer 3 switches and routers lay in the hardware technology used to build the unit. The hardware inside a Layer 3 switch merges that of traditional switches and routers, replacing some of a router’s software logic with hardware to offer better performance in some situations. The table below illustrates the differences between Layer 3 switch and router.

Main Differences:

• Cost – Layer 3 switch is much more cost effective than router for delivering high-speed inter-VLAN routing. High performance router is typically much more expensive than Layer 3 switch.
• Port density – Layer 3 switch has much higher port count while router has a lower port density than Layer 3 switch.
• Flexibility – Layer 3 switch allows you to mix and match Layer 2 and Layer 3 switching. It means that you can configure a Layer 3 switch to operate as a normal Layer 2 switch.
• WAN technologies support – Layer 3 switch is limited to usage over LAN environment where Inter VLAN routing can be performed. However, when it comes to working on WAN and edge technologies, Layer 3 switch lags behind. Router is the front runner in such scenario where WAN technologies such as Frame Relay or ATM need to be fostered.
• Hardware/Software decision making – The key difference between Layer 3 switch and router lies in the hardware technology used to making forwarding decision. Layer 3 switch uses ASICs for forwarding decisions. Conversely, the router makes forwarding decisions based on hierarchical Layer-3 addresses.

Layer 3 Switch with VLANs

As here is mentioned the VLAN, so let’s talk about it firstly. A VLAN (virtual LAN) is a logical subnetwork that can group together a collection of devices from different physical LANs. VLANs can improve the overall performance of busy networks. So they are often set up for improved traffic management by larger business computer networks. With a VLAN, traffic can be handled more efficiently by network switches.

Each virtual LAN must be entered and port-mapped on the switch. Routing parameters for each VLAN interface must also be specified. Some Layer 3 switches implement DHCP support that can be used to automatically assign IP addresses to devices within a VLAN. Alternatively, an outside DHCP server can be used, or static IP addresses configured separately. The diagram below shows an example of a layer 3 switching routing between VLANs through its two VLAN interfaces.

These switches are most commonly used to support routing between virtual LANs (VLANs). Benefits of Layer 3 switches for VLANs include:

• Reduction in the amount of broadcast traffic
• Simplified security management
• Improved fault isolation

Conclusion

From what we have discusses, Layer 3 switch may be more preferable in result of its capability of routing and switching. Besides, it can perform as a top of rack device and a distributed core switching layer at the same time. This reduces the L2 complexity of the client access layer, which makes the network more reliable and easier to manage.