# Gigabit Connection Only Getting 100Mbps



## cslayer211

Right now I have a Zoom 5350 Cable Modem routing to a Time Capsule. My server plugs into the gigabit ports on it with dual Cat6 cables. I have another Ethernet cable which routs into my office room from the cable modem and plugs into a Netgear gigabit switch, which then plugs into my desktop computers. For some reason I am only able to achieve around 100Mbps (10 MBps), and the speed won't go over that. Shouldn't I be able to achieve at least a gigabit, or am I misunderstanding something here? What could be the problem as to why my local network is being bottlenecked?


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## driftingforlife

Go to the network setting and check that you LAN port is set to auto or 1.0Gb.

Go to the LAN connection, properties, configure, link speed.


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## cslayer211

This is the option you're talking about? It was defaulted to Auto Negotiation, so I should set it to 1.0 Gbps Full Duplex?


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## driftingforlife

Ah, my bad. I see from the other ss it is already running at 1Gb.

What exactly are you doing. Internet, PC to PC file transerfer?


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## cslayer211

PC to PC over my local network. Right now it's doing a backup of one my drives. I may just try plugging directly into cable modem and see the results... a Cat5 cable could be connected to my office (I can't be sure because the cable is routing through my walls), so I don't know if that would make a difference in speed compared to a Cat6. It seems like the cap is 100Mbps which is weird considering the connection is 1Gbps.


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## cslayer211

I found the problem, my desktop computer I'm backing is only running at 100Mbps. The NIC it has also has a light on indicting it's running at 100Mbps and not 1000Mbps even though it has that capability.

Should I follow what I was doing before to enable 1Gbps and change the speed and duplex settings)?


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## driftingforlife

Yeap.


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## cslayer211

I tried it but the connection reverts back to 100Mbps. My other desktop is running at the same sped. I'm definitely going to have to upgrade my cables to Cat6. Thanks for the help anyways


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## subassy

Looks like this might be closed but sometimes there is a setting on the switch, or perhaps in the web UI of what sounded like a cablemodem/switch/router combo device...I've seen stranger things.


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## cslayer211

I was able to resolve the issue by replacing my Ethernet cables with Cat6. One of my computers continued to get 100Mbps, and I found that I had plugged the cable into the second RJ-45 Ethernet port, and plugging it into the first one made it 1.0Gbps. Although I don't get full or near full network utilization. At the moment, my speeds are roughly 30% utilization or 300Mbps. What kind of speeds do you guys normally get off of a gigabit connection?


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## coachmark2

Quote:


> Originally Posted by *cslayer211*
> 
> I was able to resolve the issue by replacing my Ethernet cables with Cat6. One of my computers continued to get 100Mbps, and I found that I had plugged the cable into the second RJ-45 Ethernet port, and plugging it into the first one made it 1.0Gbps. Although I don't get full or near full network utilization, which is roughly 30% or 300Mbps. What kind of speeds do you guys normally get off a gigabit connection?


Aye, CAT5 won't carry gigabit reliably. You need at least CAT5e or CAT6 preferably.


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## cslayer211

I've replaced every cable that my server and desktop computers are using to communicate with Cat6 except for the one that leads from my router to my office (in my wall). I'm guessing that means it's this (presumably Cat5 cable) bottlenecking my speeds. Is there any way to tell which version it is by looking at it? If it needs replacing, should I get something like a Cat6a or Cat7 because the cable will be long (50ft-100ft)?


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## coachmark2

Quote:


> Originally Posted by *cslayer211*
> 
> I've replaced every cable that my server and desktop computers are using to communicate with Cat6 except for the one that leads from my router to my office (in my wall). I'm guessing that means it's this (presumably Cat5 cable) bottlenecking my speeds. Is there any way to tell which version it is by looking at it? If it needs replacing, should I get something like a Cat6a or Cat7 because the cable will be long (50ft-100ft)?


If you can bring the device closer and verify that you're connecting ONLY through CAT6 cable and it goes to gigabit, you know it's a CAT5 cable that's holding you back. You can look at the twisted pairs to determine which type of cable it is.


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## the_beast

Quote:


> Originally Posted by *coachmark2*
> 
> Quote:
> 
> 
> 
> Originally Posted by *cslayer211*
> 
> I've replaced every cable that my server and desktop computers are using to communicate with Cat6 except for the one that leads from my router to my office (in my wall). I'm guessing that means it's this (presumably Cat5 cable) bottlenecking my speeds. Is there any way to tell which version it is by looking at it? If it needs replacing, should I get something like a Cat6a or Cat7 because the cable will be long (50ft-100ft)?
> 
> 
> 
> If you can bring the device closer and verify that you're connecting ONLY through CAT6 cable and it goes to gigabit, you know it's a CAT5 cable that's holding you back. You can look at the twisted pairs to determine which type of cable it is.
Click to expand...

No you can't. The only way to tell is to read it off the cable if it's printed on there. Because the standards don't specify anything about cable geometry, they just specify a series of tests that the cable has to pass. The manufacturer can get the cable to pass however he likes.

As for cat5e not supporting gigabit - if it doesn't, then you don't have cat5e. Your terminations or cables or some other component are faulty, because if it's cat5e (and meets the cat5e specs) then it will support gigabit.

One thing to watch out for OP - gigabit requires 4 pairs, 10/100 only 2 pairs. If there is a fault with the wiring that means a conductor is damaged it may allow 100mbps but gigabit won't work. 1000mbps is also much more tolerant of tight bends & poor terminations than gigabit, which could also be the problem. You might need to replace the cables, but you likely won't need cat6 unless your house is so large your runs are over 100m. If you are pulling new cables then cat6a makes most sense - as it's the latest official and thus the most futureproof. The cable cost is small in comparison to the labour and inconvenience involved with new cables, so it's worth putting in the best you can.


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## parityboy

*@the_beast*

Late to this but I'll add something. I've had Ethernet cable which was clearly labelled Cat 5e, and yet it did NOT support GigE. Along the cable housing it said "2-wire", which obviously means two pairs. This was a free Ethernet cable which came with the router from my ISP.


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## driftingforlife

Quote:


> Originally Posted by *parityboy*
> 
> *@the_beast*
> 
> Late to this but I'll add something. I've had Ethernet cable which was clearly labelled Cat 5e, and yet it did NOT support GigE. Along the cable housing it said "2-wire", which obviously means two pairs. This was a free Ethernet cable which came with the router from my ISP.


Funny that. I just noticed this while testing my file server this week so I got 3 10M 1Gb cables of ebay that work a treat.


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## the_beast

Maybe I should have been a little more precise about things...

The category of the cable specifies (among other things) the frequency of data transmission it will support, rather than whether it'll support 10, 100 or 1000mbps ethernet. But it doesn't specify the number of conductors.

So, it's possible for you to have 2 pair cable that is cat5e, but that itself won't support gigabit, because gigabit requires 4 pairs.

If your cable is (properly) cat5e rated, is properly installed (minimum bending radius not exceeded, conductors not untwisted too much at either end, terminations done correctly, etc) and has 4 pairs, then it will support gigabit. If any of these conditions aren't met, then you won't get gigabit speeds. The same is true for cat6 & cat6a - if you balls up the install so it doesn't meet spec, they won't work either. You just get a little more leeway with the higher spec standards.


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## Oedipus

Quote:


> Originally Posted by *parityboy*
> 
> *@the_beast*
> 
> Late to this but I'll add something. I've had Ethernet cable which was clearly labelled Cat 5e, and yet it did NOT support GigE. Along the cable housing it said "*2-wire*", which obviously means two pairs. This was a free Ethernet cable which *came with the router from my ISP*.


Or it came bundled with a 2wire gateway...


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## parityboy

*@Oedipus*

Granted. The router was 100Mbit.


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