Hi all,

The building works on our house have started, and now I've been looking into which type of ehernet cable I'll put inside my walls. The idea is that every room in the house will have at least 4 ethernet drops.

At first I thought to use regular Cat6 ethernet cable. But then I was thinking, I'll only do this ONCE. There is no way I'll ever be able to replace all the cables that will be put inside the walls if something better comes along in time... So So I figured I'd better make this future-proof. That's how I ended up with the idea of using Cat 6A cables, which are rated for speeds up to 10 Gigabit. That's about as future-proof as it gets right now I believe.

But I still have some questions:

1) I'm in doubt whether I should use regular, unshielded UTP cable, or maybe shielded STP cable (not plenum). I believe the extra shielding in the cable may benefit the signal quality, 'cause at some points inside the walls, dozens of these cables will run in it, all right next to each other. (and in some cases also next to or at least very close to electrical cables) Of course STP cable is a bit more expensive, but not all that much. I would like to ask your opinion if this extra investment will be worth it. Keep in mind that most likely at some point in time, my LAN will be upgraded to 10gigabit.

2) Is Cat6A is just like Cat6 ? I mean, I can use regular Cat6 certified RJ-45 connectors to crimp my cables with, right?

3) Cat 7 also exists, but I believe this still isn't a standard? It's also about twice the price of Cat 6a, which I don't really believe is worth it's price, because I will probably also need to use a different (read:more expensive) type of RJ-45 connectors with it, correct? What exactly are the benefits of using Cat7 over Cat6a?

Thanks for any info you can provide.

Cheers!

Here's a really cheap solution for future proofing...run string.

Seriously. Run string and conduit if necessary to get around possible hangups. Then run the cheapest thing that meets your needs for the moment. You could then rewire the whole house in a single day if you decide to change somewhere down the road and you possibly save hundreds of dollars and a lot of stress on whether you made the right choice.

Agreed. They make plastic twine specifically for this purpose.

While I do intend to also put some empty tubes with string in it inside the walls, your solution is not very handy for the entire house. Nowadays all the wiring comes pre-fitted into so-called 'pre-flex' tubing. This is flexible, ribbed tubing which usually comes on a reel. (see here for a photo). This is a very good solution for installing (saves a lot of time), but this is very bad if you ever need to replace the cables inside the tubes. The tubes themselves are just too flexible for that, and it also doesn't help that they're ribbed...

So good suggestion, but simply not do-able. Thanks for your thought though...

The only thing that is even vaguely going to approach future-proof is fiberoptic cabling. But you'd spend a fortune in adapters. (Not to mention the cabling itself.)

Cat6a is the highest-spec UTP cable available. (Cat7 is super-shielded. Each pair is shielded and then the whole cable is shielded.) Cat6a was designed specifically so that you didn't need shielding for 10GigE when run in bundles. The next step up from there is 40GigE and 100GigE, each of which are being designed to run only 10m via copper. So unless you've got fairly short runs in your house, Cat6a is realistically the best you can do with copper. Anything faster than that is going to require fiber.

Thanks Bitt, that's those are the answers I was after.
I might at one time use fiber in the house, that's what I intend to use the currently empty tubes for. By the time I ever need that, I hope either the price of fiber has gone down, or those new 'plastic' fiber cables have become more mainstream.

BTW, I thought that UTP cable was unshielded, FTP cables had a shield around all eight wires, and STP cables shielded each pair and the whole cable? You say this is only true for Cat7 ?

Do you know if the RJ-45 connectors used with Cat6A are the same as the regular ones used with Cat6 ?

Thx!

I'm pretty sure that Cat6a cables are just twisted differently than Cat6, so the connector should be the same. However, there are Cat6a-specific jacks, since the distance between the cable termination and the connector interface is longer.

In regards to cable shielding, I'm just saying that Cat6 and Cat6a don't specify that shielding is required, while Cat7 does.

Noted! Thanks Bitt!

Hi,

The benefit of a shielded cable is EMI control and a more pristine environment for the Twisted Pairs in the cable bundle. The shield provides immunity to power line and reception of other radiated noise from the surrounding environment. This provides a more error free connection for all nodes as the network is not clogged with transmission errors due to a susceptible cable on the network. It also contains emissions that may affect other devices or receivers in the home.

This works only if the connectors AND the equipment you connect to (both ends) include the mating connectors that provide the shield connection.

The shielded RJ-45 cable connectors are made to allow the shield to be terminated to a metal shell that surrounds at least 3 sides of the RJ-45 plastic connector. This mates with wiper fingers in the end user equipment that they are connected to.

If the shield is not terminated on both ends, it forms a mono-pole antenna and with the length of cables in the wall, it will have no trouble radiating noise with activity on the cable to nearby cable receptors and antennas. Same thing with UTP cabling.

There are a few inherent problems with shields though. One is that they introduce additional capacitance from the conductor pair to the shield which can sometimes reduce data rates or cable length for a given data rate (50m instead of the 100m specification). At 10Gbps it may make a difference or not. Another problem with STP is that a foil shield can break if the bend radius is exceeded (going around tight bends in the walls), which results in a compromised shield (cracked), or open shield. A braid shielded cable is much better for this but some of the cable connectors are not designed for braid (many are for foil and drain wire termination - FTP). At frequencies above 1 MHz or edge rates faster than 1 us the shield needs to be terminated on both ends for proper EMI control and Signal Integrity.

If you poorly terminate the connector and do not preserve the twist (resulting in reflections and Near End Crosstalk - NEXT), you might have problems. At 10Gbps you may also have to deal with Alien Near End Crosstalk (ANEXT) with adjacently routed cables. ANEXT is caused by noise coupled from adjacent cables. With many cables in the walls near each other, or near a common server, this could be a real problem. The CAT-6a STP prevents this problem.

They make a foil shielded twisted pair cable (S/FTP or PiMF) where the four individual twisted pairs are individually shielded and there is a braid overshield similar to the Cat-7 cable mentioned above. This would be the best choice for your upgrade if it is cost effective.

Despite the difficulties with shielding, I would recommend it. The recommended path for commercial and industrial upgrade is to STP cables to avoid ANEXT, provide a controlled environment for the transmission/reception media, and reduce EMI emissions and susceptibility.


BTW, my understanding of STP is that the individual pairs within the bundle do not have a separate shield for each pair, just the overall cable that goes to a connector has the shield. In other words, the TX/RX pairs are unshielded and the overall cable has the shield. Some manufacturers indicate STPs (individually shielded pairs) within an overshielded cable as double shielded. To me that also might mean a foil and braid overshield shield, or 2 over braids separated by mylar (to obtain additional magnetic shielding properties). However I commonly refer to STPs or TSPs (same thing) as a single twisted pair with a single shield.

Good luck with your decision.

Ross

Thanks Ross for your very extensive reply!

Summarizing your post, I guess I can best go for shielded solid Cat6A. I'm not really worried about bending the STP cable past its bend radius since this will be installed in a newly build house. Basically I can put the cables wherever I want, I don't have to tuck them away in corners as would probably be the case if they were installed after the house was built. (in my case they will be plastered into the walls)

I must say this correct termination necessity worries me a bit. I've crimped hundreds of Cat5e and Cat6 cables, but never shielded ones. In order words, I don't really know the correct way how to do it. I've been searching and Googling for the last 4 hours on the internet, but that didn't help much. I can't really find a guide, or even better an instructional video that would show me how. Those are available in abundance for Cat5e UTP cables, but I can't find any for shielded cables... bummer, because I want to be absolutely sure I'm doing this correctly! Anybody can point me towards such a guide or video? Much obliged!

I also can't seen to be able to find Cat6A RJ-45 jacks for use with STP cable. It's like they don't exist! It also took me a while before I was able to find the correct cable, but at least I was able to find that. (same with Cat 7!). I've also learnt there is a different between RJ-45's for solid cable and for stranded cable. Even the crimp tools are different then! Phew! I never suspected this was going to be so much work (finding all the correct parts, I mean!)

This is the way I understood it:
UTP (Unshielded Twisted Pair): no foil, obviously
FTP (Foiled Twisted Pair): one foil covering all the pairs
STP (Shielded Twisted Pair): individual pairs are shielded, and they are all foiled as well...
I could be wrong, but that's how I understood it.

Cheers!

The nice thing about STP is, you can initially just ignore the fact that it is shielded, and use regular connectors and stuff.

The important future-proofing part is just ensuring that you have it inside the walls. If you ever need to use it's full bandwidth capabilities, then at that point you can upgrade the connectors and stuff.

Just be sure and leave a slack loop behind every wall box -- a good idea regardless.

Cheers

Not quite. STP means the bundle of four pairs has one outer shield wrapped around it, either foil or foil+braid (best).

Dunno about FTP, but I suspect it is the variety with extra shielding on the individual pairs.

Cheers

Frankly, I'd present the counter viewpoint that bothering with shielded cat6a in your house is never going to pay off. By the time that plain cat6 or even cat5e isn't sufficient, cat6a isn't going to be much of an improvement. Spend money on running conduit then run good cable but don't throw money away.

Fiber To The Desktop was the next big thing, and many buildings built in the 90's have very expensive fiber going to every network jack. It was a cash cow for the wiring contractors, but it's looking like it's going to be dark fiber until their tear the buildings down.

That's because Cat6a doesn't specify STP.


All the RJ45 connectors I've used in the last five to ten years have been able to deal with both stranded and solid. Regardless, go with solid cable. Stranded is only useful for cables that bend a lot, which doesn't describe in-wall cabling, and terminating stranded cable is a pain in the ass. It's hard enough trying to fit the little wires inside the connector without having to deal with the fact that they refuse to be straight.

And, IIRC, the different crimper is not a stranded vs. solid issue, but for one particular brand of RJ45 connectors that I've (apparently) never come across.

Ah? I didn't know that was possible. Indeed, that's a very good option!

Agreed! I always keep some slack behind the boxes... If only to be able to re-crimp the connector if this ever becomes necessary for some reason...

I've been reading up a lot on this in the last couple of days, and I've seen both explanations used on several sites. So you could be right (and probably are ).

Cheers!

Acitually, I found that Cat6A STP cable is not that much more expensive than regular Cat6 cable is. It's the connectors that make it expensive.

I agree with you on fiber though. That I won't even consider...

Thanks for your input!

It doesn't? That would be a good reason, of course. I guess regular Cat6 RJ45's can be used then. What else would be there to use?


Yes, my reading up on this has taught me that solid cable is always used for cables that are put inside walls. But as you say, I'd probably use solid cables regardless. If I ever needed a real flexible cable, I'd buy a pre-made one.

Cheers!

You can still get connectors which are specifically for stranded and ones only for solid. The metal pin is slightly different.


I've never had any issues with crimping the plug on the end of a cable.

Would this be any good? This type of cable promises 10 Gigabit speeds over unshielded Cat6 cable.

Is this credible? Or merely marketing?

It's just Cat6a cable. There are any number of manufacturers.