CAT 5e or CAT 6 cables for server gigabit speeds
Lately, we have been testing our server environment and setting up our Linux powered lab where all servers are connected to 1Gbps managed switches.
One of the first tests we had was testing Ethernet cables – CAT 5e and CAT 6 category cables. CAT 6 is the standard for Gigabit Ethernet and backward compatible with CAT 5 and CAT 5e. CAT 6 provides performance of up to 250 Mhz.
In our tests we will review data transfers between two servers each connected to 1Gbps switch. Our maximum data throughput for these boxes are at around 350Mbps due to network card drivers, depending how we tune network stack and MTU size. You should not pay attention to the maximum bandwidth throughput, but the bandwidth difference between CAT 5e and CAT 6 cables.
CAT 6 cable:
————————————————————
Server listening on TCP port 5001
TCP window size: 260 KByte (WARNING: requested 130 KByte)
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[ 4] local 192.168.3.10 port 5001 connected with 192.168.3.20 port 38899
[ 4] 0.0- 1.0 sec 37.6 MBytes 315 Mbits/sec
[ 4] 1.0- 2.0 sec 37.6 MBytes 315 Mbits/sec
[ 4] 2.0- 3.0 sec 37.6 MBytes 315 Mbits/sec
[ 4] 3.0- 4.0 sec 37.6 MBytes 315 Mbits/sec
[ 4] 4.0- 5.0 sec 37.6 MBytes 315 Mbits/sec
[ 4] 5.0- 6.0 sec 37.6 MBytes 315 Mbits/sec
[ 4] 6.0- 7.0 sec 37.6 MBytes 315 Mbits/sec
[ 4] 7.0- 8.0 sec 37.6 MBytes 315 Mbits/sec
[ 4] 8.0- 9.0 sec 37.6 MBytes 315 Mbits/sec
[ 4] 9.0-10.0 sec 37.6 MBytes 315 Mbits/sec
[ 4] 0.0-10.0 sec 376 MBytes 315 Mbits/sec
CAT 5e cable:
————————————————————
Server listening on TCP port 5001
TCP window size: 260 KByte (WARNING: requested 130 KByte)
————————————————————
[ 4] local 192.168.3.10 port 5001 connected with 192.168.3.20 port 4192
[ 4] 0.0- 1.0 sec 37.5 MBytes 315 Mbits/sec
[ 4] 1.0- 2.0 sec 37.5 MBytes 315 Mbits/sec
[ 4] 2.0- 3.0 sec 37.5 MBytes 315 Mbits/sec
[ 4] 3.0- 4.0 sec 37.5 MBytes 315 Mbits/sec
[ 4] 4.0- 5.0 sec 37.5 MBytes 315 Mbits/sec
[ 4] 5.0- 6.0 sec 37.5 MBytes 315 Mbits/sec
[ 4] 6.0- 7.0 sec 37.5 MBytes 315 Mbits/sec
[ 4] 7.0- 8.0 sec 37.5 MBytes 315 Mbits/sec
[ 4] 8.0- 9.0 sec 37.5 MBytes 315 Mbits/sec
[ 4] 9.0-10.0 sec 37.5 MBytes 315 Mbits/sec
[ 4] 0.0-10.0 sec 376 MBytes 315 Mbits/sec
There is no real difference – the speed is the same 315 MBits/sec using CAT 5e or CAT 6 cables.
We tested bandwidth throughput using iperf and CAT 6 cable length was 1.6m (5.24 feet) and CAT 5e cable was 0.6m (1.96 feet). In the future, we will try a few tests more, but we need to get better NIC cards with better drivers for much higher throughput.
Kai said,
February 4, 2008 at 12:20 pm
The test architecture was as follows:
Server1 -> Switch -> Server2
Etherealmind said,
August 30, 2008 at 3:21 pm
Your cables will not impact your testing at this level. The extra spectral bandwidth provided by Cat6 is not relevant to Ethernet throughput since it is defined at Layer 2 of the OSI model, and cabling will only be relevant at Layer 1.
Unless you have a poor electrical environment, in which case, Cat6 is more likely to sustain throughput.
Gunnar said,
February 26, 2009 at 6:03 pm
People tend to forget research – the gigabit standard is based on the cat5e cabeling std, all network cards supporting Gbit are therefore also based on this.
I agree that cat6 may give you better margines in the signaling scheme (osi level 1) but that makes a difference only when you have a sloppy installation
since an installation of cat5e should include a test protocol – just like cat6, one might ask, why accept a sloppy installation?
I find it more interesting comparing the physical comparison:
cat6 cabeling often includes a plastic core and has a minimum bend radius of 5 – 10 cm ( 2 – 4 inches) -depending on brand
cat5e cabeling has a more reasonable bend radius 1-2 inches
pls visualize which std is easiest to install correctly
aj said,
June 12, 2009 at 12:44 am
Previous comments are true, but even still, would you not want to use cables that are much, much longer. No way you can get recordable results to compare with a 5ft cable.
Seriously though, good luck with you trials and learning. It’s fun.