When I connect ten computers over a 100 meters (328ft) UTP Cat5, is the signal loss so large that it will affect my network performance? These computers perform simple office tasks, and the 100m utp is a temporary solution.
UTP cable maximum length
cablenetworkingperformance
Related Solutions
Connect your replacement switches back-to-back with a fiber patch cable and verify for sure that their fiber ports work. If they do, then double check the patch cords you're using at each end in the same manner. If you really want to slog through it yourself and have the right patch cables you can use the switches as cheap testers to test at each of the splices (assuming you have connectors on the splices).
If the switches do work, get a better fiber contractor in there. It sounds like your contractor was dodgy. I agree w/ the other posters re: their meter. My experience with contractors testing fibers for me is that their meter knows far, far more than I do about a given fiber.
Speed of Light:
You are not going beat the speed of light as an interesting academic point. This link works out Stanford to Boston at ~40ms best possible time. When this person did the calculation he decided the internet operates at about "within a factor of two of the speed of light", so there is about ~85ms transfer time.
TCP Window Size:
If you are having transfer speed issues you may need to increase the receiving window tcp size. You might also need to enable window scaling if this is a high bandwidth connection with high latency (Called a "Long Fat Pipe"). So if you are transferring a large file, you need to have a big enough receiving window to fill the pipe without having to wait for window updates. I went into some detail on how to calculate that in my answer Tuning an Elephant.
Geography and Latency:
A failing point of some CDNs (Content Distribtuion Networks) is that they equate latency and geography. Google did a lot of research with their network and found flaws in this, they published the results in the white paper Moving Beyond End-to-End Path Information to Optimize CDN Performance:
First, even though most clients are served by a geographically nearby CDN node, a sizeable fraction of clients experience latencies several tens of milliseconds higher than other clients in the same region. Second, we find that queueing delays often override the benefits of a client interacting with a nearby server.
BGP Peerings:
Also if you start to study BGP (core internet routing protocol) and how ISPs choose peerings, you will find it is often more about finances and politics, so you might not always get the 'best' route to certain geographic locations depending on your ISP. You can look at how your IP is connected to other ISPs (Autonomous Systems) using a looking glass router. You can also use a special whois service:
whois -h v4-peer.whois.cymru.com "69.59.196.212"
PEER_AS | IP | AS Name
25899 | 69.59.196.212 | LSNET - LS Networks
32869 | 69.59.196.212 | SILVERSTAR-NET - Silver Star Telecom, LLC
It also fun to explore these as peerings with a gui tool like linkrank, it gives you a picture of the internet around you.
Best Answer
UTP cable does not have a maximum length.
However, the protocol that runs over UTP has a maximum length for performance and technical reasons (such as collision detection in Ethernet).
You're probably talking about Ethernet, and the maximum end-to-end cable length in Ethernet (at least for 100Base-TX, 1000Base-T and 10GBase-T) is 100M.
Assuming you're running full-duplex, you're withing spec (and hence should be fine) as long as no switch-switch or switch-host connection exceeds 100M.