Cisco SFPs have established a positive reputation in the telecommunications market as a global leader in IT and networking. With their high level of flexibility, reliability, and compatibility, Cisco SFPs have gained popularity among Gigabit Ethernet users. However, the demand for a new transceiver with a longer transmission distance than the 1000BASE-T SFP for copper networks has led to the development of Cisco 1000BASE-SX SFP transceivers. These transceivers support up to 1 km over-optimized 50 μm multimode fiber cable.
Two common types of Cisco 1000BASE-SX SFPs are the Cisco GLC-SX-MM and Cisco GLC-SX-MMD. Although they have similar specifications, they are two distinct SFPs.
Similarities between GLC-SX-MM and GLC-SX-MMD SFP
Both GLC-SX-MM and GLC-SX-MMD SFP transceivers are designed for multimode fiber (OM2), used commonly for data transmission at a short distance. They operate at a wavelength of 850nm that is suitable for transmission over multimode fiber. Other than this, the maximum transmission distance for transceivers is 550 meters. It’s said that 550 meters are ideal for short-distance applications.
Last, the GLC-SX-MM and GLC-SX-MMD SFP transceivers use the Dual LC/PC connector. The Dual LC/PC connector is referred to as a standard connector that is used for fiber optic networking. This connection assures easy and secure connections that provide a reliable and efficient link between network devices.
Differences between GLC-SX-MM and GLC-SX-MMD SFP
Cisco GLC-SX-MM SFP
The Cisco GLC-SX-MM SFP 1000BASE-SX SFP is compliant with IEEE 802.3z and functions using a wavelength of 850 nm. It is a duplex transceiver that has been specifically designed for multimode fiber (OM2) and is intended for short-range connections between equipment. The transceiver can be used with LC connectors, and according to the GLC-SX-MM specifications, it can transmit data at a rate of 1Gbps over a maximum distance of 550m.
Cisco GLC-SX-MMD SFP
The Cisco GLC-SX-MMD is an additional variant of 1000BASE-SX SFPs that enables the transfer of data over short distances. This transceiver has several similarities to the GLC-SX-MM SFP and can be considered an upgraded version of it. The GLC-SX-MMD is compliant with the SFP Multi-Source Agreement (MSA) standards. It is different from the GLC-SX-MM SFP in that it is capable of reaching data rates of 1.25 Gbps. Extended operating temperature range and DOM support are additional primary distinctions between the two transceivers.
What more?
The GLC-SX-MM is an older version of the 1000BASE-SX SFP transceiver that does not include a DOM function. It is compatible with multimode fiber and can transmit data over a longer distance. However, as it lacks the DOM function, it is no longer aligned with the trend of intelligent optical modules and has been discontinued in favor of the GLC-SX-MMD, which includes a DOM function.
At present, the GLC-SX-MMD is the preferred 1G SFP transceiver for affordable fiber networking because it utilizes the cost efficiency of the GLC-SX-MM. This upgraded version now includes a DOM function, which is in line with the trend of intelligent optical modules.
How should you install and configure Cisco GLC-SX-MMD and GLC-SX-MM transceivers?
Turn the equipment off
You should start the transceiver installing after turning off the equipment in which it will be installed. This is done to avoid any electrical shock or damage to the equipment during installation. Many incidents have been reported that people have been severely injured because of electric shock during installation.
Remove the existing transceiver
If you are replacing the old transceiver, remove it carefully before installing the new one. You shouldn’t just pull it out and finish your removal task as it can lead to damage. For removing the transceiver, you should gently press on the transceiver release latch which is located on its sides. Then, you should slide the transceiver out of the slot.
Insert the transceiver
You will find an empty SFP plot in the equipment. You should insert the transceiver (Whichever you are using), in the empty SFP plot carefully. You should push the transceiver until it clicks into place. When inserting the transceiver, make sure it is in the correct orientation and the release latch clicks into place.
Connect the fiber optic cable
Connecting the fiber optic cable is a critical step. The cable should be securely connected, making sure that there is no damage to the cable. When connecting the fiber optic cable, it’s one side should be connected to the transceiver and the other end should be connected to the appropriate port on the network device.
Turn on the equipment
After installing the transceiver and optic cable, you should turn on the equipment. Once you switch on the equipment, it will detect the new transceiver automatically and start configuring. Wait for the process to happen.
Configure the transceiver
Sometimes, the equipment fails to detect and configure the transceiver. In this case, you should configure the transceiver with the equipment manually. For this, you should log in to the network device and navigate to the SFP configuration page. On the configuration, you should select the GLC-SX-MM or GLX-MM-MMD transceiver and configure their appropriate settings. The settings include speed and duplex mode.
Test the connection
Without testing, you shouldn’t start using the equipment. You should test the connection after installing and configuring the transceiver to the equipment. For testing the connection, you should either use a network diagnostic tool or run a simple ping test.
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