72
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 ...
- 81.5k
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 ...
- 27.2k
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 ...
- 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 ...
- 451
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 ...
- 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 ...
- 14.8k
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
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 ...
- 493
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 ...
- 4,487
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 ...
- 669
20
votes
Accepted
Reason for half-duplex mode in Ethernet?
The reasons for half-duplex ethernet are as you understand them. In fact, there was a movement to not include half-duplex for 1000Base-T, but it still made it into the standard. For 10 Gb ethernet, ...
- 98.3k
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 ...
- 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 ...
- 66.9k
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 ...
- 14.8k
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 ...
- 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 ...
- 98.3k
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 ...
- 81.5k
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) ...
- 98.3k
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 ...
- 81.5k
14
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, ...
- 98.3k
14
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 ...
- 13k
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&...
- 13k
13
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 ...
- 81.5k
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 ...
- 733
13
votes
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 ...
- 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 ...
- 16.1k
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 ...
- 8,674
11
votes
Can a single optical fiber support full-duplex communication?
Can a single optical fiber support full-duplex communication?
Yes. There are "BX" standards, e.g. 100BASE-BX, which use different wavelengths for send and receive. The transmit wavelength on one end ...
- 98.3k
11
votes
Accepted
Do layer 3 protocols use layer 2 protocols?
Layer 3 (mostly IP) generally relies on the underlying layer-2 network (mostly Ethernet or Wi-Fi) for delivery. Just like a layer-2 network uses layer-1 links to actually move the bits.
The ...
- 81.5k
Only top scored, non community-wiki answers of a minimum length are eligible