{"id":3538,"date":"2026-10-21T23:28:22","date_gmt":"2026-10-21T15:28:22","guid":{"rendered":"http:\/\/www.sparklesodaspot.com\/blog\/?p=3538"},"modified":"2026-10-21T23:28:22","modified_gmt":"2026-10-21T15:28:22","slug":"what-is-the-transmission-distance-of-25g-sfp28-44f5-6af986","status":"publish","type":"post","link":"http:\/\/www.sparklesodaspot.com\/blog\/2026\/10\/21\/what-is-the-transmission-distance-of-25g-sfp28-44f5-6af986\/","title":{"rendered":"What is the transmission distance of 25G SFP28?"},"content":{"rendered":"

Hey there, if you\u2019ve been digging around 25G networking gear lately, you\u2019ve probably stumbled on 25G SFP28 transceivers and wondered, \u201cHow far can these things actually reach?\u201d As someone who\u2019s been working with 25G SFP28s for years now\u2014running a small, reliable supply for folks building data centers, server closets, or enterprise networks\u2014I get it. You don\u2019t just want a vague \u201cit depends\u201d answer; you need the real, on-the-ground breakdown that actually helps you pick the right transceiver for your run. Let\u2019s cut through the jargon and get into the nitty-gritty. 25G SFP28<\/a><\/p>\n

<\/p>\n

First off, let\u2019s start with the basics to make sure we\u2019re all on the same page. 25G SFP28 is that tiny, hot-pluggable module used to move data at 25 gigabits per second, right? It slots into SFP28 ports on switches, servers, firewalls\u2014whatever network gear you\u2019re working with. The \u201c28\u201d stands for the physical form factor\u2019s specification, meaning it\u2019s designed to handle up to 28Gbps throughput, so it\u2019s perfect for locking in that steady 25G you need for high-bandwidth tasks like video streaming, server-to-server storage traffic, or even running multiple virtual machines at once.<\/p>\n

Now, the big question: transmission distance. This isn\u2019t a one-size-fits-all number, though. It all comes down to two big things: what kind of cable or fiber you\u2019re pairing the SFP28 with, and what type of transceiver it is (like SR, LR, ER, that kind of stuff). I\u2019ve seen so many people grab a cheap SR module and expect it to run 10km, and then they\u2019re confused when it cuts out half a kilometer in. Let\u2019s break down each type, since that\u2019s how we structure our inventory at the supply I run\u2014we don\u2019t just sell random modules, we match them to the use case.<\/p>\n

First, let\u2019s talk about multimode fiber (MMF), which is the go-to for shorter runs\u2014think inside a single data center or between racks in the same server closet. Most 25G SFP28s labeled SR (Short Range) are designed for MMF. What\u2019s the distance here? Let\u2019s get specific: for OM4 MMF (the best, highest-performance multimode out there right now), a 25G SR SFP28 can push data up to 100 meters. Wait, some people say 85 meters? No, that\u2019s for older OM3 MMF. OM4 is rated for 100 meters at 25G\u2014we test every single SR module we sell to make sure they hit that, because I\u2019ve heard horror stories of modules that only make it 70 meters in OM4. Then there\u2019s OM3 MMF, which is still common in older data centers\u2014those SR modules run up to 70 meters on OM3. And if you\u2019re on OM2? Skip SR for anything over 30 meters, it\u2019s not reliable. That\u2019s a big tip: always check your fiber grade first before picking a module. We always ask customers for their fiber type when they reach out, because that changes everything.<\/p>\n

Now, what if you need to go longer than 100 meters, like between two buildings on a campus, or up to a kilometer between server rows in a large data center? That\u2019s where single-mode fiber (SMF) comes in, and the LR (Long Range) 25G SFP28s. These are way more powerful because single-mode fiber only lets one light beam travel through, so less signal loss over distance. LR modules on standard SMF (like G.652, the most common single-mode fiber) typically hit 10 kilometers. That\u2019s our best-selling module for campus deployments\u2014most people don\u2019t need longer than that for on-campus links. There are some LR variants that go 20km, too, usually labeled LR Lite or just extended LR, but those are a step up in price, so most folks stick to the standard 10km LR unless they know they need more. I\u2019d only recommend the 20km LR if you\u2019re absolutely sure your link is over 10km and you can\u2019t get another transceiver in there.<\/p>\n

Wait, what about even longer distances, like 40km or 80km for metro networks or long-haul links? That\u2019s ER (Extended Range) or ZR (Zero Range, no, wait ZR is even longer) 25G SFP28s. ER modules are usually rated for 40km on SMF, and ZR can go up to 80km or even 100km with the right equipment. But be warned\u2014these aren\u2019t cheap, and you only need them if you\u2019re running a link between two different cities\u2019 network hubs, not a standard office or data center. Most of our customers don\u2019t even touch ER or ZR because their runs are under 10km. We only stock ER if someone specifically asks for it, since it\u2019s a niche use case.<\/p>\n

Also, hold up\u2014there\u2019s another thing that affects distance that people sleep on: connectors and splices. If your fiber has loose connectors, or a bunch of splices that aren\u2019t properly sealed, that eats into signal strength. I once had a customer who installed our 10km LR module and it only worked for 6km\u2014turns out they had 3 bad splices along the fiber run. Once they fixed those, it ran the full 10km no problem. So even if your transceiver is rated for X distance, bad cable work will drop that. That\u2019s why we always tell customers to test their fiber link first, or at least make sure their connectors are clean and their splices are solid.<\/p>\n

Another thing to note: some 25G SFP28s are direct attach cables (DACs), not optical transceivers. Wait, I know a lot of people mix those up! DACs are copper cables that plug directly into SFP28 ports\u2014they\u2019re cheaper, shorter, and super reliable for very short runs, like between two servers in the same rack or two ports on the same switch. What\u2019s the distance for a DAC? For active DACs (the good kind, not passive which are shorter), you can get 10 meters, 15 meters, even 30 meters if you need it. We stock DACs too, because a lot of data center operators prefer them for top-of-rack switch links since there\u2019s no optical signal to deal with, and they\u2019re way less likely to fail than optical transceivers for short runs. Passive DACs only go up to 5 meters, so we usually don\u2019t push those unless someone\u2019s on a super tight budget and knows they only need 2 or 3 meters.<\/p>\n

Now, let\u2019s talk about real-world use cases, because that\u2019s where the rubber meets the road. If you\u2019re building a small server closet with 10 servers, each with a 25G SFP28 port connected to a top-of-rack switch\u2014grab a 10-meter or 15-meter active DAC. No need for optics here, it\u2019s overkill and more expensive. If you\u2019re linking two racks in a data center that\u2019s 80 meters apart, grab an SR module with OM4 MMF. If you\u2019re linking two buildings on your campus 5km away, go for an LR module with SMF. If you\u2019re linking two office buildings 30km apart, then get an ER module, but that\u2019s rare.<\/p>\n

Wait, also, there are some newer 25G SFP28 variants, like the CWDM ones, that use wavelength division multiplexing to push longer distances over single-mode fiber. Those can go up to 40km too, but they\u2019re more specific\u2014you have to match the wavelength on both ends, so they\u2019re not as plug-and-play as standard LR modules. I usually only recommend CWDM if you need to run multiple links over the same fiber pair, since they let you split the fiber into 4 or 8 different wavelength channels. That\u2019s good for saving fiber in dense networks, but overkill for most basic deployments.<\/p>\n

Let\u2019s address some common myths I hear all the time. Myth 1: All 25G SFP28s can run 10km. No, only LR and above on SMF can do that. SR is for multimode, max 100 meters on OM4. Myth 2: Longer distance modules are always better. No, they\u2019re more expensive, and if you use an ER module for a 100-meter run, you\u2019re wasting money and dealing with a more complex device that might not play nice with old switches. Myth 3: Cable length doesn\u2019t matter for optics. Like I said earlier, signal loss from bad connectors or splices is just as big an issue as the module\u2019s rating.<\/p>\n

At the supply I run, we make a point to not oversell modules. If you come to us saying you need a link between two racks 50 meters apart, we\u2019ll ask if you\u2019re using OM3 or OM4 fiber, and if you can use a DAC (cheaper, more reliable) instead of an SR optic. We don\u2019t push expensive modules when a cheaper, better fit is available. That\u2019s why our customers come back\u2014we give straight answers, not sales fluff.<\/p>\n

<\/p>\n

Now, let\u2019s wrap this up with what you need to actually go do: 1. Figure out two things: your link\u2019s total distance, and what kind of fiber (or copper) you\u2019re using. 2. Check your gear\u2019s SFP28 port compatibility\u2014most modern switches and servers work with all standard SR\/LR\/ER modules, but older gear might have quirks, so double-check your manual. 3. If you\u2019re unsure, reach out\u2014we\u2019re happy to help you pick the right module or DAC, no pressure.<\/p>\n

Optical Transceiver<\/a> If you\u2019re gearing up for a new data center build, upgrading your server network, or linking multiple sites for your business, you don\u2019t want to waste time or money on the wrong 25G SFP28. We\u2019ve got a full inventory of SR, LR, ER, and DAC options, all tested for reliability, and we can answer any questions you have about distance, compatibility, or installation. Hit us up to chat through your project and get the right gear for your needs.<\/p>\n

References<\/h3>\n
    \n
  1. IEEE 802.3by-2016, 25GBASE Ethernet Standard<\/li>\n
  2. Cisco SFP28 Transceiver Data Sheets<\/li>\n
  3. Finisar 25G Transceiver Specifications<\/li>\n
  4. Fiber Optic Association (FOA) Multimode and Single-Mode Fiber Performance Guidelines<\/li>\n<\/ol>\n
    \n

    Shenzhen Circle Interconnect Electronics Co., Ltd.<\/a>
    As one of the leading 25g sfp28 manufacturers and suppliers in China, we warmly welcome you to buy bulk high-grade 25g sfp28 for sale here from our factory. All customized products are with high quality and competitive price.
    Address: Building 47, the second industrial zone,Tianliao community, Yutang street, Guangming District,Shenzhen City, Guangdong Province, China
    E-mail: sales@szcircleinterconnect.com
    WebSite:     https:\/\/www.szcircleinterconnect.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

    Hey there, if you\u2019ve been digging around 25G networking gear lately, you\u2019ve probably stumbled on 25G … What is the transmission distance of 25G SFP28?<\/span>Read more<\/a><\/p>\n","protected":false},"author":757,"featured_media":3538,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[3501],"class_list":["post-3538","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-25g-sfp28-4f80-6b52d0"],"_links":{"self":[{"href":"http:\/\/www.sparklesodaspot.com\/blog\/wp-json\/wp\/v2\/posts\/3538","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.sparklesodaspot.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.sparklesodaspot.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.sparklesodaspot.com\/blog\/wp-json\/wp\/v2\/users\/757"}],"replies":[{"embeddable":true,"href":"http:\/\/www.sparklesodaspot.com\/blog\/wp-json\/wp\/v2\/comments?post=3538"}],"version-history":[{"count":0,"href":"http:\/\/www.sparklesodaspot.com\/blog\/wp-json\/wp\/v2\/posts\/3538\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.sparklesodaspot.com\/blog\/wp-json\/wp\/v2\/posts\/3538"}],"wp:attachment":[{"href":"http:\/\/www.sparklesodaspot.com\/blog\/wp-json\/wp\/v2\/media?parent=3538"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.sparklesodaspot.com\/blog\/wp-json\/wp\/v2\/categories?post=3538"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.sparklesodaspot.com\/blog\/wp-json\/wp\/v2\/tags?post=3538"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}