27
votes
Accepted
What's the point of auto-sensing 10/100 Mbit/s Ethernet?
Some devices could only run at 10 megabit/s, so the device at the other end would autosense the speed to match. If a device that has a maximum speed of 10 Mbit/s is connected to a 10 Mbit/s /...
- 2,102
23
votes
Accepted
What is this thread-like material on this Cat6 U/UTP cable?
It is used to split the outer shielding away without needing to use a sharp object which could potentially damage the wires themselves. It is commonly called a ripcord.
Image taken from http://netx....
- 346
14
votes
What's the point of auto-sensing 10/100 Mbit/s Ethernet?
Remember 10Mbps came first, then 100Mbps, then 1000Mbps.
The advantage of supporting multiple speeds and automatically switching between them is you can upgrade your network gradually without having ...
- 13k
14
votes
Accepted
The maximum length of CAT6 for intranet network?
Per the ANSI/TIA/EIA 568, Commercial Building Telecommunication Standard, UTP cabling is limited to 100 meters. That length assumes up to 90 meters of solid-core (better performance, but fragile) ...
- 98.4k
12
votes
Accepted
Does bridging add delay?
Hi and welcome to Network Engineering.
As for "delay" vs "latency":
The terms are not always used consistently. Some hints may be found here.
I think generally, the term latency is used when ...
- 8,729
10
votes
Where to cross RX/TX line in fibre optical cabling
This is directly addressed by the ANSI/TIA/EIA 568-B Commercial Building Telecommunications Cabling Standard:
Connecting Hardware and Polarity
Optical fiber shall be installed with odd ...
- 98.4k
10
votes
Accepted
Multiple POE over a single cable
I know this is an older question, hopefully you've solved it by now, but I wanted to toss in my two cents, for the benefit of future generations if nothing else.
First of all, yes, ethernet and PoE ...
- 116
9
votes
What is this thread-like material on this Cat6 U/UTP cable?
Its called a ripcord and is used to cut thru the outer casing of the wire so you don't have to use a knife. To those who say it is not strong enough your not using it right. Grab it with a pair of ...
- 91
8
votes
Why are patch panels used (instead of connecting directly to a switch)?
The horizontal cable needs to be solid-core cable. this type of cable gives better performance, but it is much more fragile, and it needs to to terminate in a fixed location, and not be moved after ...
- 98.4k
8
votes
Does bridging add delay?
Yes, a bridge / switch adds some delay to a frame - in the order of 1 to 20 µs.
For switches you usually speak of latency - the delay between receiving a frame and forwarding it out another port. A ...
- 81.5k
7
votes
Accepted
Determine Core Size of Fiber Run
If you have a fiber scope (you really should, to check if connections are clean) the core size (but not OM level) is obvious by inspection, especially if you look at a known connector and then the ...
- 2,746
7
votes
Accepted
Will OM4 Fiber Work with my 1GbE Fiber Transceiver?
As per IEEE 802.3 Clause 38, 1000BASE-SX requires OM2 (500 MHz·km for 850 nm) for max. 550 m reach. As a superset, OM4 is fine as well (there's little point buying OM2). With 10GBASE-SR the reach over ...
- 81.5k
7
votes
How can twinaxial cables be faster than CAT cables
Simply put, twinaxial cables allow only very short distances, under 10 meters.
And they are used in networking, for example both 40Gb and 100Gb standards support twinaxial cables... ...up to 7 ...
- 19.4k
7
votes
Accepted
Are LC-UPC connectors compatible with LC-PC?
Yes.
PC, SPC and UPC are just different polish grades of perpendicular, physical contact connectors. Their end-faces match, so they work nicely together.
In contrast, APC uses an angled surface (...
- 81.5k
6
votes
Speed of Light in Copper VS Fiber - Why is Fiber Better?
The propagation speed is often expressed as the velocity factor of a medium - the fraction of the speed of light in vacuum that you get.
On the physical side, light going through a medium is slowed by ...
- 81.5k
6
votes
What is the minimum diameter for Power over Ethernet?
As I know the main problem of transporting power over ethernet cables is temperature rise and resistance.
802.3af defines the max power as 12.95 W and max current as 350 mA over 2 pairs.
802.3at ...
- 4,487
6
votes
Accepted
How to verify CAT type?
The cable category should be printed on the cable sheath.
Just having cable rated at a particular category doesn't mean the cable plant is actually rated at that category. All the components of the ...
- 98.4k
6
votes
Why are patch panels used (instead of connecting directly to a switch)?
There's several reasons:
Cable Length and rack organization
as explained by @John K in his answer this allow to adjust cable length at need. This also allow to organize the rack properly.
Cable ...
- 19.4k
6
votes
The maximum length of CAT6 for intranet network?
For twisted-pair Ethernet, maximum cable length is 100 m (Cat-6A for 10GBASE-T, Cat-5e for 1000BASE-T or 100BASE-TX, Cat-3 for 10BASE-T). The only exceptions are 2.5G and 5GBASE-T where the maximum ...
- 81.5k
6
votes
Accepted
Practical limits of shielded Ethernet cable
As everybody has said, including the original question, this is a terrible idea and don't do it. I recommend some kind of fibre solution, which can be cheaper than you might think. I recently did an ...
- 16.1k
6
votes
Accepted
LC dual pair converter to 10GBASE-T
If using dual pair LC fiber to run 10GbE over a long distance, what's
the best way to connect it to a server on one end which has a
10GBASE-T port?
The best way is to get a server NIC with SFP+ slots ...
- 98.4k
5
votes
ELI5 – basic questions regarding MMF
No, that is not the same as CWDM.
Most fiber is connected with separate Tx and Rx fibers. There is
nothing unusual about the MMF connections.
MMF used to be cheaper, the fiber transceivers still are, ...
- 98.4k
5
votes
Is ethernet a term describing just the protocol or the interfaces also?
The IEEE 802.3 standards define certain L1 characteristics/operation, but do not define the connectors to use to connect the devices.
For instance, while 802.3 does define that 100BASE-TX will use ...
- 27.2k
5
votes
Running Cat 7 STP cables in the same cable trays as 3-phase power cables
Theres two seperate issues to consider, safety and interference. The authorities tend to mostly be concerned with the former.
Capacitive and inductive coupling are highy unlikely to be strong enough ...
- 13k
5
votes
Multiple POE over a single cable
If 100 Mbit/s is enough for camera to work, You can try split single 4-pairs cat5 cable in two 2-pairs links. It can be done by 2 Ethernet splitter or by proper cable crimping.
"This adapter brings 4-...
- 754
5
votes
Is there an IEEE recognized method for splicing Category 5e or 6 cabling?
Copper cable splices are not allowed. Cabling standards are set by ANSI/TIA/EIA 568 Commercial Building Telecommunications Cabling Standard. For instance, this is for copper cabling:
Only one ...
- 98.4k
5
votes
Can normal CAT6 be buried?
Indoor UTP cabling is not at all suitable for outdoor use. It cannot tolerate any moisture. Category-6 cabling is difficult for even professionals to install and terminate properly in order to pass ...
- 98.4k
5
votes
Accepted
When is "grounding" a concern when running Cat6a cables?
Category-6a cabling is UTP (Unshielded Twisted Pair) cabling. If your cable has a shield, it is something else. Any shielded cable must be properly grounded. That requires connectors and equipment ...
- 98.4k
Only top scored, non community-wiki answers of a minimum length are eligible