OK, so the story is this: I'm a school governor for my daughter's primary school here in the UK (roughly equivalent to being 'on the school board' in the USA, I think).
I'm the IT governor (pretty much by default) because I work in IT but my work has never included network engineering. So I don't know much about this specific area.
The school is being extended and refurbished soon, and we want to upgrade the network from 100 Mbit/s to GbE. The new part of the building will be fitted out with appropriate cabling for GbE. We'll be buying new switches for the the whole school.
The existing part of the building is being refurbished and we have the opportunity to replace the existing network cabling. Or we can save money and keep the existing cabling.
So the question that I'd like to find a way to answer is: is the existing cabling capable of working properly at GbE speeds?
If it's the case that an upgrade from 100 Mbit/s to GbE always requires new cabling, then I guess my question is answered quite simply: we just need to replace the cabling. But I'm not clear whether that's the case.
Ideally I'd like to answer this question without paying for an expensive survey from an external company, since the school has fixed budgets and any money that we save here is freed up to be spent on teacher salaries, educational resources, etc…
I don't want to start making holes in the walls and physically looking at the existing cabling – every part of the school is in constant use by teachers and children at the present time.
Neither the school nor the local authority has yet located any plans or diagrams or other details of how the network is cabled and what standard of cabling was used.
The network may well have been added to gradually over the years, rather than installed all-in-one-go. I know that none of it has been installed within the past 7 years. The walls have RJ45 sockets.
I can see a variety of devices billed as 'network cable testers' are available – I could buy one of those but I'm not clear if this is really the purpose they're intended for, or if they're just for checking that a new installation is wired up correctly. Some of them just have LEDs showing a quality result from 1 to 10 – I'm not clear how to interpret that in the context of "is this good enough for GbE?".
We have plenty of laptops supporting GbE that we could plug into the network if there's a way of testing this using them.
Any advice much appreciated. Thanks.
Best Answer
Either hire a professional cable installer to check out your cable installation, or get something similar to a Fluke CableIQ. These meters perform detailed tests on the cable that reveal what you're dealing with. GigE has Signal to Noise requirements that simple continuity testers will not check. Cheaper continuity testers are typically what you'll find at lower prices in consumer electronics stores.
After you have satisfied one of the conditions above, test every cable. That's expensive and time-consuming, but it's the only way to be sure you won't deal with flaky connections down the road.
Some might argue that you could merely look at the jacket of the cable and see whether it's at least Cat5e; however, that's still inadequate to truly know whether you can use this for GigabitEthernet because:
If you're willing to gamble, you can test every cable with a couple of cheap 1GE switches from Wal-Mart, ensure each cable links to 1GE, and hope that those results are repeatable. However, I don't recommend this approach for anyone who cares about whether every cable is done right.