71 votes

Is 30 Mbit/s fibre for WAN faster than 30 Mbit/s copper?

30 Mbit/s is the same speed, no matter if it runs over copper or fiber. However, there are important link parameters other than link speed/pure bandwidth, so there may be differences. First, latency ...
Zac67's user avatar
  • 84.4k
61 votes
Accepted

Is Ethernet port blinking really useful?

Yes, blinkenlights are your friends! The lights can be very helpful when diagnosing problems - especially when dealing with non-managed switches or remote diagnosis with unexperienced users. Rule of ...
Zac67's user avatar
  • 84.4k
43 votes

Why are Ethernet Standards written in the form of 10/100/1000? Why not just 1000?

They include this because not all ports are able to run at multiple speeds or certain speeds. Running at only one speed was probably most common when 100BASE-TX first came out and a number of ...
YLearn's user avatar
  • 27.3k
43 votes

Does having a longer Ethernet cable slow your connection?

No, it will not slow down a connection, but you need to be aware of the maximum length of a copper connection which is 100 meters. This needs to include the length of your patching cable from the host ...
SleepyMan's user avatar
  • 2,016
35 votes

Does having a longer Ethernet cable slow your connection?

For all practical purposes, there will be no effect on the speed of your connection. There will be a very insignificant amount of delay due to long cables. This won't affect the maximum speed of ...
Cort Ammon's user avatar
31 votes
Accepted

Why does an Ethernet cable have four pairs?

10BASE-T saw first light as StarLAN that made use of the already existing twisted-pair category 3 telephone cabling (instead of the dedicated coax that 10BASE5/2 required). That multi-purpose cabling ...
Zac67's user avatar
  • 84.4k
29 votes

Is Ethernet port blinking really useful?

My very first step in troubleshooting network issues is this: "Are there winky-blinky lights?" It's the network port equivalent of asking someone if their computer and/or monitor is actually ...
Dustin Kreidler's user avatar
28 votes

Is 30 Mbit/s fibre for WAN faster than 30 Mbit/s copper?

30Mb/s is 30Mb/s, but ISPs usually sell you “up to 30Mb/s” because the speed of DSL technologies is highly dependent on the distance between your equipment and theirs. With fibre, you are more ...
jl6's user avatar
  • 381
26 votes

Why are Ethernet Standards written in the form of 10/100/1000? Why not just 1000?

Good question. To answer it fully would involve a pretty deep look at Ethernet Wiring. But I'll try to explain it in simpler language. All three speeds (10, 100, 1000) run over the same physical ...
Eddie's user avatar
  • 15k
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....
helrich's user avatar
  • 346
22 votes
Accepted

Minimum ethernet frame is 64 bytes, Why the payload must be padded to at least 46 bytes

The entire frame has to be at least 64 bytes. This is not just the payload, this includes the headers and the frame check sequence. The FCS takes up 4 bytes at the end. An Ethernet header consists of ...
alex.forencich's user avatar
21 votes
Accepted

How does a packet get corrupted in a network?

Packets are long streams of binary numbers (zeros and ones). The zeros and ones are usually changes of an electric signal, specifically voltage changes. To simplify, suppose that 0 is 0 volts and 1 ...
jcbermu's user avatar
  • 4,507
21 votes
Accepted

How LAN works in video games if only one station is permitted to transmit?

Only one device is allowed to transmit at any given time. At any other given time, another device is allowed to transmit. How can you have a conversation at a dinner table if only person can speak at ...
Jörg W Mittag's user avatar
19 votes

Does having a longer Ethernet cable slow your connection?

Sort of, to a very tiny extent. The longer your cable, the higher latency you experience - gamers call this "ping" time. However, the effect is about one nanosecond per foot of cable, which is ...
pjc50's user avatar
  • 321
19 votes

Is 30 Mbit/s fibre for WAN faster than 30 Mbit/s copper?

You might consider pointing out to your "network engineering professional" that the propagation delay in copper is LESS that that of fiber (in most cases). The difference between the two is ...
Ron Trunk's user avatar
  • 67.5k
18 votes
Accepted

Why do I need a crossover cable to connect devices of the same type?

When you need crossover cables is often explained, but why is seldom explained. It has to do with the copper (often referred to as Ethernet) wire itself. In copper wiring, there are four pairs of two ...
Eddie's user avatar
  • 15k
18 votes

Is 30 Mbit/s fibre for WAN faster than 30 Mbit/s copper?

It doesn't appear that any one has explicitly addressed the reliability of transmissions over fiber vs copper. It may be true that, for example, your router is throttled to 30 Mbps, but the ...
Jim's user avatar
  • 281
18 votes

How LAN works in video games if only one station is permitted to transmit?

Some LAN protocols, on some media, are half duplex. That means that only one host on a LAN can send a frame at any given time. The classic example of this is the original ethernet, but the modern ...
Ron Maupin's user avatar
  • 99.6k
17 votes
Accepted

What do the positive and negative (+/-) transmit and receive pins mean on Ethernet cables?

Twisted pair uses differential signaling - in a pair, one wire is always the negative/complimentary signal of the other. In the simplest example, Transmit+ > Transmit- (higher voltage level) means 1 ...
Zac67's user avatar
  • 84.4k
15 votes

How exactly does an Ethernet collision happen in the cable, since nodes use different circuits for Tx and Rx?

A hub is really just a powered cable that repeats every signal it receives on one interface to all the other interfaces. If two devices transmit at the same time to the receive of the hub interfaces, ...
Ron Maupin's user avatar
  • 99.6k
15 votes
Accepted

How exactly does an Ethernet collision happen in the cable, since nodes use different circuits for Tx and Rx?

To understand this you need to understand the historical context. Originally Ethernet used a shared coaxial cable. Only one device could successfully transmit on this at a time. If two devices ...
Peter Green's user avatar
  • 13.3k
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) ...
Ron Maupin's user avatar
  • 99.6k
14 votes

What does the naming convention for Ethernet standards mean: 1000BASE-T, BASE-TX, BASE-SX, etc.? What is the meaning of the components of the name?

BASE indicates baseband signaling - there is no modulated carrier, the frequency starts near zero and extends to a certain cut-off frequency. BROAD indicates broadband modulation - there is a wide ...
Zac67's user avatar
  • 84.4k
14 votes

Do network adapters read incoming bits in a single stream?

That depends. While many Ethernet PHYs transmit data in a purely serial fashion (e.g. 100BASE-TX, 1000BASE-SX, 10GBASE-SR), some split the data stream into multiple lanes that are transmitted in ...
Zac67's user avatar
  • 84.4k
13 votes

What is the purpose of an Ethernet magnetic transformer, and how are they used?

I have been told that Ethernet magnetic transformers are used for base-t Ethernet when transmission is sent over a lengthy cable. They are always used, not just when "sent over a lengthy cable&...
Peter Green's user avatar
  • 13.3k
13 votes

Do network adapters read incoming bits in a single stream?

Let's ignore the Gigabit part for now, and focus on your "2 devices are sending at the same time" part for a bit. On shared media, this can actually happen and be a problem. Most wireless ...
jcaron's user avatar
  • 783
13 votes

Using sound waves in layer 1

It's been done. I used to have a 300-baud acoustic layer 1 device.
Mark's user avatar
  • 230
12 votes

Is 30 Mbit/s fibre for WAN faster than 30 Mbit/s copper?

Copper (ADSL or VDSL) specifies a maximum peak speed whereas fiber specifies a maximum average speed. My glass fibre (FTTH) connection is artificially limited to 50 Mbit/s average. At the start of a ...
StessenJ's user avatar
  • 221
12 votes

Do network adapters read incoming bits in a single stream?

This particular case is a complex one. Regarding 1000baseT. First: when we say in general that two devices are transmitting at the same time, they are not normally actually sending bits at the same ...
jonathanjo's user avatar
  • 16.2k
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 ...
Marc 'netztier' Luethi's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible