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 ...
- 27.1k
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 ...
- 14.5k
20
votes
Worst-case efficiency of PPP escaping mechanism
You might care to read RFC 1547 "Requirements for an Internet Standard Point-to-Point Protocol" which explains how the PPP was chosen. The thing I'd suggest you are missing is that ...
- 16.1k
17
votes
Accepted
Trying to find out exact TCP overhead cost
Ethernet packets 1.5k
1500 - 20 B (IPv4) - 20 B (TCP+checksum) = 1460 B DATA (and 40 B Overhead)
Add 40 B + 14 B (Ethernet) + 4 B (FCS) + 12 B (Interframe gap) + 8 B (preamble) = 78 B Overhead
78 / ...
- 1,417
15
votes
Accepted
What does bandwidth (digital) really mean?
Does it mean it's electric circuitry is capable of serializing/deserializing (SERDES) 400G bits per second of data onto a wire while maintaining a relativley clean signal (low SNR)?
Yes, that's what ...
- 79.8k
14
votes
Accepted
Can throughput exceed the bandwidth of a network
The bandwidth is the number of bits that can be sent on a link in one second. The throughput is the amount of data that is sent, and that will need to subtract the protocol overhead from the bandwidth,...
- 97.7k
13
votes
Accepted
If TCP packets are pre acknowledged, what happens if packets are dropped?
Pre-ACKing is only possible because the near accelerator keeps the segment data in queue. Therefore, it can ACK in stead of the far destination, prompting the sender to advance the send window and ...
- 79.8k
11
votes
Why is 10Gb SFP+ port showing 4.3Gbps Speed?
Just to address the SNMP portion of your question, I'm guessing that you are seeing the 4.3Gbps result from querying the SNMP object 'ifSpeed'. If so, you are simply getting back the maximum value ...
- 111
11
votes
Accepted
Bandwidth vs Throughput vs Data(bit) rate
Some of these terms are used differently by different people, but below is what is generally accepted.
Bandwidth is the number of bits per second that a link can send or receive, including all flows. ...
- 97.7k
11
votes
Bandwidth vs Throughput vs Data(bit) rate
Daily I see peoples even specialists in communication do mistakes about the three mentioned terms:
Bandwidth: The unit of it is Hz, so it is mathematically is: High_Used_Frequency - Low_Used_Frequency....
- 111
9
votes
Accepted
iperf: send specific volume?
The -l option is for the buffer and doesn't influence the amount of data transferred.
You have to specify the desired amount of data with the client-only option -n in KByte or MByte.
So for 10GB, ...
- 19.3k
8
votes
Accepted
How does link aggregation work in reality?
What really happens is that any one flow only uses one of the links. Different flows are assigned to different links based on a hashing algorithm, so, in aggregate, you get the full bandwidth of the ...
- 97.7k
8
votes
Speed benefits when switching LAN from 1Gb copper to Fiber Optic
You are conflating many things here, so let's try to detangle the issues in your question.
Data rate is data rate, regardless of the physical medium. A 1Gb
connection has the same data rate whether ...
- 66.1k
8
votes
Accepted
Stupid question about bandwidth
IP subnetting / address ranges and bandwidth have absolutely no correlation whatsoever.
IP networks are based on packets. Packet networks don't allocate bandwidth for devices that are just connected. ...
- 79.8k
8
votes
How do two computers with different speeds communicate
I would imagine that with TCP A will resend the packages until it's
gotten an acknowledgement for them all which would degrade A's
performance because of having to resend packages all day long (...
- 1,491
8
votes
Accepted
Cisco Router (ISR4221) Throughput - Why so slow?
That's by product design. ISR 4k come with a platform shaper (upgradeable to ~2x the value by license upgrade with the "PERF" license).
Cisco say that the limits of the platform shapers can be fully ...
- 8,410
8
votes
Accepted
Why are there 11 channels in WiFi communication instead of 3?
IEEE 802.11 (Wi-Fi) uses the 2.4 GHz ISM band that existed decades before IEEE 802.11 was defined, and the band was divided into 5 MHz channels.
Wi-Fi uses 22 MHZ bandwidth, more bandwidth than a ...
- 97.7k
7
votes
Accepted
Throttling among Data Centers
I am unable to throttle the network by submitting my UDP packets among such links because I worry about packet drops and message losses.
At first blush, this sounds more like a design problem with ...
- 29.8k
7
votes
Why are Ethernet Standards written in the form of 10/100/1000? Why not just 1000?
It really boils down to needing to support legacy devices and cabling. Cisco has a pretty good document, Ethernet Technologies, which explains a lot in depth.
Ethernet has been around for a very long ...
- 97.7k
7
votes
How do two computers with different speeds communicate
With directly connected computers, both need to use the same speed when sending to each other.
Transmitting and receiving with different speeds requires splitting up the data into packets and some ...
- 79.8k
7
votes
What is the difference between Ethernet types, considering bandwidth?
Different types of Ethernet (standard Ethernet, Fast Ethernet, Gigabit Ethernet) have different speed of data transfer (10 Mbit, 100 Mbit, 1 Gbit). Why is that?
Progress - technology advances.
...
- 79.8k
6
votes
Accepted
In 802.11 Wi-Fi, Is it better to be on the same channel as other networks instead of being in an overlapping channel?
It is better to be in the same channel as your interfering signals (if you can't find a free channel) rather than in overlapping channels that are not the same channel - if you are in a nearby channel,...
- 2,746
6
votes
Accepted
Differences between Enterprise internet connections with the same nominal bandwidth
A few things you should look at:
is the bandwidth symmetrical? I.E. do you get 150Mbps download AND 150Mbps upload?
is the bandwidth guaranteed?
what are the S.L.A. (Service Level Agreement)? In case ...
- 19.3k
6
votes
How do two computers with different speeds communicate
In addition to the completely correct answers about speed matching directly connected systems ...
One of the fundamentals of the internet (including all the private routing portions) is that the ...
- 16.1k
6
votes
Accepted
Why is internet speed called Bandwidth?
You might find this answer helpful as regards the engineering terms What is the meaning of the word 'band' in the following terms: broadband, baseband and bandwidth?
But I believe the ...
- 16.1k
6
votes
Accepted
Fiber to copper conversion, what are the odds?
Fiber media converter is a small device with two media-dependent interfaces and a power supply, simply receive data signals from one media, convert and transmit them to another media. It can be ...
- 1,732
5
votes
Accepted
Why is 10Gb SFP+ port showing 4.3Gbps Speed?
Little late to the website so you may have moved on but, We use Solarwinds. Under the edit node properties there is a check box for 64-bit counters. It is probably not checked. Seen the problem you've ...
- 261
5
votes
Trying to find out exact TCP overhead cost
Overhead is usually calculated based on the total data size. That way, the figure matches the efficiency value.
For TCP over IPv4 over Ethernet you have (without header options):
L1 overhead - ...
- 79.8k
5
votes
Accepted
can average througput be greater than bandwidth?
Is it possible for the throughput to be greater than the bandwidth of the cable ?
Like many things, the devil is often in the details. Depending on how the measurement is taken, then yes it is ...
- 27.1k
Only top scored, non community-wiki answers of a minimum length are eligible