Difference between Cisco SFP Module GLC-SX-MM and GLC-SX-MMD

With the widespread used with the Cisco switches and routers, Cisco's GBIC transceivers and Small Form-factor Pluggables (SFP) transceivers for Gigabit Ethernet and Fibre Channel applications have also been popular in the market. These small, modular optical interface 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. The 1000BASE-SX SFP (ie, the GLC-SX-MM and GLC-SX-MMD) is one of the common types of Cisco SFPs. Compatible with the IEEE 802.3z 1000BASE-SX standard, it operates on legacy 50 μm multimode fiber links up to 550 m and on 62.5 μm Fiber Distributed Data Interface (FDDI)-grade multimode fibers up to 220 m. It can support up to 1km over laser-optimized 50 μm multimode fiber cable.

Due to the similar model, users are usually confused with the Cisco GLC-SX-MM and GLC-SX-MMD when they are choosing the SFP modules. So, what's the difference between them? We are going to talk something about the difference between GLC-SX-MM and GLC-SX-MMD in this paper.

As their models suggest, there is only little difference between GLC-SX-MM and GLC-SX-MMD, Obviously the "D". Here, letter D in the model means the DOM functionality. DOM stands for Digital Optical Monitoring. Digital Optical Monitoring (DOM) is an industry wide standard, intended to define a digital interface to access real-time operating parameters such as:

• Optical Tx power
• Optical Rx power
• Laser bias current
• Temperature
• Transceiver supply voltage

Which means you can configure your device to monitor optical transceivers in the system, either globally or by specified ports. When this feature is enabled, the system will monitor the temperature and signal power levels for the optical transceivers in the specified ports. Console messages and syslog messages are sent when optical operating conditions fall below or rise above the XFP or SFP manufacturer’s recommended thresholds. It is an useful function and now is very popular with users.

It is worth noting that the GLC-SX-MM SFP has been no longer for sale since March 8, 2013 in Cisco. It is entirely replaced by GLC-SX-MMD. Cisco official encourages the customers to migrate to new model SFP transceiver modules. However, for usage and cost considerations, many users still use the old model SFPs. GLC-SX-MMD is much more expensive than GLC-SX-MM, but except the additional DOM function, they work as the same when use in the switch. This is why GLC-SX-MM is still used by many users. To a great extent, this situation is caused by the cost. Fiberstore offers a low cost option for you in both GLC-SX-MM and GLC-SX-MMD. No matter you still like to use the GLC-SX-MM, or wanna replace the new version GLC-SX-MMD, you can find the corresponding products in Fiberstore with a very low price and do not worry about the quality because all of Fiberstore's Cisco compatible SFP modules are tested in-house prior to shipment to guarantee that they will arrive in perfect physical and working condition before delivered worldwide. In addition, there is a big stock of these two products, you can enjoy the same-day shipping when you order them in Fiberstore.

Product Recommendation NEW Cisco GLC-SX-MMD Compatible 1000BASE-SX SFP 850nm 550m EXT DDM Transceiver Module

Key Features

• Data-rate of 1.25Gbps/1.063Gbps operation
• 850nm VCSEL laser and PIN photodetector for 550m transmission
• Hot-pluggable SFP footprint duplex LC connector Interface
• Class 1 FDA and IEC60825-1 Laser Safety Compliant
• Compatible with SFP MSA
• Compatible with SFF-8472
• +3.3V single power supply and TTL Logic Interface
• Average Output Power:-9.5~ -3dBm
• Receiver Sensitivity:-17dBm
• Extended temperature range (EXT):-5 to 85°C
• Built-in Digital Diagnostic Function

Applications

• Fiber Channel Links
• Gigabit Ethernet Links
• Fast Ethernet Links
• Other Optical Links

Where to Buy
Cisco SFP transceivers offered by Fiberstore are the most cost-effective standards-based SFP modules fully compatible with Cisco Switches & Routers. Fiberstore provides a series of Cisco comaptible SFP modules which can be equivalent to Cisco GLC SX 1000BASE SX SFP (GLC-SX-MM), Cisco SFP 1000BASE LX LH SM fiber transceiver (GLC-LH-SM), Cisco GLC-SX-MMD, Cisco GLC-LH-SMD, Cisco GLC-T 1000BASE-T SFP (GLC-T), Cisco GLC-ZX-SMD, and Cisco CWDM SFP, Cisco DWDM SFP, etc.
Read More Related Article About SFP Modules:

• Netgear AGM731F Compatible SFP for Gigabit EthernetApplications
• Cisco SFP Module GLC-SX-MM and GLC-SX-MMD

Optical Transceivers for FIs

Understanding FIs

A FI is the core component of a UCS solution. FIs are typically configured as highly available clustered pairs in production environments. It’s possible to run a single FI-based design as a proof of concept test deployment before actually implementing it in production. FIs provide the following two capabilities:

1. Network connectivity to both LAN and SAN
2. UCS infrastructure management through the embedded management software, UCSM, for both hardware and software management

FIs are available in two generations, namely Cisco UCS 6100 series and Cisco UCS 6200 series. The core functionality is the same in both generations; however, UCS 6200 series has a newer generation Application Specific Integrated Circuit (ASIC), higher throughput, and increased number of physical ports. Both generations can be upgraded to the latest UCSM software.

FIs provide converged ports. Depending on the physical Small Form Factor Pluggable (SFP) transceivers and FI software configuration, each port can be configured in different ways. Cisco 200 series FI ports can be configured as Ethernet ports, Fiber Channel over Ethernet (FCoE) ports, or Fiber Channel (FC) ports. On the other hand, 6100 series converged ports only support Ethernet and FCoE (they also support FC, but only in the expansion slot).

In production, FIs are deployed in clustered pairs to provide high availability. Cisco-supported implementation requires that clustered FIs be identical. The only possibility for having different FIs in a cluster is during a cluster upgrade.

Exploring Connectivity Transceivers for FIs

A variety of SFP transceivers are available for The Cisco UCS 6200 series. These transceivers provide south-bound IOM connectivity and north-bound network and storage connectivity. They are based on industry-standard SFP+ specifications.

Transceivers can be selected depending on the technology, for example, Ethernet or FC, and also according to the distance requirements. For shorter distances between FIs, IOMs, and north-bound network switches, twinax cables with integrated SFP is an economical alternative as compared to fiber optic SFP.

The most commonly used transceivers include following:

• Cisco SFP-10G-SR: This is a multimode optical fiber 10Gbps Ethernet SFP that can be used for distances up to 400 meters.
• Cisco SFP-10G-LR: This is a single-mode optical fiber 10Gbps Ethernet SFP that can be used for distances up to 10 Km.
• Cisco SFP-10G-TET: This is a low power consuming multimode fiber optic 10Gbps Ethernet SFP that can be used for distances up to 100 meters.
• Cisco SFP-H10GB-CuxM: These are the twinax cables providing low cost 10Gbps Ethernet connectivity and are available in 1, 3, 5, 7 and 10 meter configurations.
• Cisco SFP-H10GB-ACU10M: This is a 10-meter-long twinax cable providing 10Gbps Ethernet. At a length of 10 meters, this cable requires active transceivers at both ends.
• Cisco GLC-T: 1000BASE-T SFP or SFP-compatible ports only,these are based on the SFP Multi Source Agreement (MSA) and compact RJ-45 connector assembly. For SFP-compatible ports only.
• Cisco GLC-SX-MMD: These modules supporting dual data-rate of 1.25Gbps/1.0625Gbps and 550m transmission distance with MMF, for SFP-compatible ports only.
• Cisco GLC-LH-SMD: These modules supporting dual data-rate of 1.25Gbps/1.0625Gbps and 10km transmission distance with SMF, for SFP-compatible ports only.
• DS-SFP-FCxG-xW: These are multi-mode and single-mode fiber optic FC transceivers that are available at 2, 4, and 8Gbps transfer speeds.

Where to buy These Optical Transceivers

Fiberstore provide a full range of optical transceivers, such as SFP+ (SFP Plus) transceiver, X2 transceiver, XENPAK transceiver, XFP transceiver, SFP (Mini GBIC) transceiver, GBIC transceiver, CWDM/DWDM transceiver, 40G QSFP+ & CFP, 3G-SDI video SFP, WDM Bi-Directional transceiver and PON transceiver. All our fiber transceivers are 100% compatible with major brands like Cisco, HP, Juniper, Nortel, Force10, D-link, 3Com. They are backed by a lifetime warranty, and you can buy with confidence. We also can customize optical transceivers to fit your specific requirements.

Article Source: Fiber Optic Transceiver