Network LAN question.

[bigegg]

I have a question, but I don't know enough about the terminology to ask Google...


Is the "network speed" on a LAN an overall speed? Or per connection?

Eg:

If I have 3 PCs - call them "A" and "B" and "C" connected to a switch, then that switch connected via a single cable to another switch which also has 2 PCs +"D" and "E" connected.

(Assume everything, individually, allows say, a 1gb connection).

A -> B 1gb.
A -> D 1gb

If I transfer files from A-B, and simultaneously transfer C-D, will the 1Gb throughput be split in the first switch between the two connections, or will each have full speed?


If I install a second cable between the switches, can I connect A and C at full speed, and ALSO connect B and D at full speed? (Or, again, is the throughput split between the connections?)

If it makes any difference, the DHCP router is connected to the same switch as A,B, and C.

Ta.

 

[m_c]

Depends on the switch.

However with modern wired LAN speeds, the bottle neck is more likely to be the PC.

 

[MetalMonkey]

Assuming that every PC connects at 1gb to the switch (which it may or may not depending on the PC, the network interface, the switch, the cabling etc - but lets assume it does)
Then each PC will have 1gb of bandwidth to any of the other PCs on the network.

Each switch will have a maximum internal capacity that it can cope with - so it may not be able to supply a full 1gb concurrently to every port if they are all being maxed out at the same time. However it is unlikely you will run into this in normal usage.

In your scenario above, when connecting one switch to the other, the maximum bandwidth will be 1gb, which will be shared between all the transfers between the first and second switch.
You can't just add a second cable as this will create a network loop. You can do, with advanced things with vlaning and trunking connections to increase the switch to switch bandwidth, but these features are usually only available on expensive switches.

As @m_c says, in practice the bottleneck is likely to be the PC so it isn't something you should worry too much about at home.

 

[gaz1]

If I have 3 PCs - call them "A" and "B" and "C" connected to a switch, then that switch connected via a single cable to another switch which also has 2 PCs +"D" and "E" connected.

on that set up you will split the connection up by 4 and then split that again by 2

no need for the 3rd wire as it would send through the network just the same

only direct would give you full speed then the pc's will be the bottle neck

the search term is office network or lan

 

[MetalMonkey]

on that set up you will split the connection up by 4 and then split that again by 2

no need for the 3rd wire as it would send through the network just the same

only direct would give you full speed then the pc's will be the bottle neck

the search term is office network or lan

The connection speed doesn't get split gaz, its not how switches work.

 

[maroon]

assuming your "trunk" between switches is capable of 1gb it will be the same.
there's different types and also different connections.
computer wizardry on modern switches can automatically sort out tx/rx pin outs.
when connecting a switch to a switch years ago you needed to cross over the pins.
there's also different types of switches. managed and unmanaged.
it's better to give your nodes (pc's) an address if using an array of switches.

managed ones are more for commercial businesses, where you can segregate the network.
this can talk to that but that cant talk to that kind of thing, this is for accounts, this is for production, this is for sales... these can go on the internet, these can't.

 

[bigegg]

Got it
Thank you everyone.

My "takeaway" from this is that to get most efficient/economical speed, I'm better updating both switches, and the cable between them - say to a 10Gb/CAT 8(?) - before upgrading the various other "nodes" to a 1Gb connection. (Some are only 100Mb).
It's for a home automation system with various IP cameras, NASs and TVs/monitors showing streamed content.
Now I have an overview of how it works, I can plan various subnets and stuff.
The main thing is, I don't necessarily need to run a grands worth of cat 8 Ethernet cable - I can use the five rolls of cat 5e I bought cheap last year.

 

[maroon]

Got it
Thank you everyone.

My "takeaway" from this is that to get most efficient/economical speed, I'm better updating both switches, and the cable between them - say to a 10Gb/CAT 8(?) - before upgrading the various other "nodes" to a 1Gb connection. (Some are only 100Mb).
It's for a home automation system with various IP cameras, NASs and TVs/monitors showing streamed content.
Now I have an overview of how it works, I can plan various subnets and stuff.
The main thing is, I don't necessarily need to run a grands worth of cat 8 Ethernet cable - I can use the five rolls of cat 5e I bought cheap last year.

i wouldn't bother with cat8 anything. optical fibre would probably be cheaper, i'd guess you can get an offcut somewhere for next to nothing for a short run. however you would need the optical switches.

for a home running a few movies. cat5e is more than more than sufficient.

 

[MetalMonkey]

Got it
Thank you everyone.

My "takeaway" from this is that to get most efficient/economical speed, I'm better updating both switches, and the cable between them - say to a 10Gb/CAT 8(?) - before upgrading the various other "nodes" to a 1Gb connection. (Some are only 100Mb).
It's for a home automation system with various IP cameras, NASs and TVs/monitors showing streamed content.
Now I have an overview of how it works, I can plan various subnets and stuff.
The main thing is, I don't necessarily need to run a grands worth of cat 8 Ethernet cable - I can use the five rolls of cat 5e I bought cheap last year.

Which switches do you have at the moment?
I wouldn't bother with CAT8.

Home automation, CCTV, etc are going to consume next to sweet FA in terms of bandwidth. Unless you do a massive amount of file transfers or serious video editing, 1gb is going to be just fine.

Streaming is going to be largely limited by your internet connection unless you are coming off your NAS - in which case you are limited by its network interface and backplane.
Even then. streaming a raw 8K video is only going to be using something like 120gb and most compressed streams are going to be less than 100mb.

Keep in mind, you can run a sizable commercial network for hundreds of users and not touch the sides of 10gb.
2.5gb and 5gb are available, but really not worth the price tag - 10gb often works out cheaper.

If you absolutely have to spend money, get some decent 1gb switches that will support trunking and connect them together so you can have a 2 or 4gb link and still enough ports for 1gb to all your devices.
I doubt you will need to upgrade it anytime soon IMHO.

 

[bigegg]

Which switches do you have at the moment?
I wouldn't bother with CAT8.

Home automation, CCTV, etc are going to consume next to sweet FA in terms of bandwidth. Unless you do a massive amount of file transfers or serious video editing, 1gb is going to be just fine.

Streaming is going to be largely limited by your internet connection unless you are coming off your NAS - in which case you are limited by its network interface and backplane.
Even then. streaming a raw 8K video is only going to be using something like 120gb and most compressed streams are going to be less than 100mb.

Keep in mind, you can run a sizable commercial network for hundreds of users and not touch the sides of 10gb.
2.5gb and 5gb are available, but really not worth the price tag - 10gb often works out cheaper.

If you absolutely have to spend money, get some decent 1gb switches that will support trunking and connect them together so you can have a 2 or 4gb link and still enough ports for 1gb to all your devices.l
I doubt you will need to upgrade it anytime soon IMHO.

Cool.
I won't spend anything, then.