Network switch question.

[link955]

Hey guys,

Recently I was discussing with my friend about reorganizing my home network. I was gonna buy some sort of switch for my living room and one for my bedroom. My friend said it was better to plug what I needed into the router instead off a switch because if  i am using multiply devices on the same switch and was  streaming video, My friend said the switch would get slower speeds over all devices, He used the analogy, Picture a pipe with flowing water, then you split it off in 4 directions, if all 4 are being used you will get lower water presure in one of the pipes. I was wondering if this applied to network switchs if i had 1 cable running from the port to my router, will the other ports be slower if im getting data from all of them? Hope this makes sense. Thanks

[suchamoneypit]

Provided the switch isnt slower than the router, everything on the switch shares the speed from the router. I don't believe in that analogy.

 

If you have gigabit from the router, and a 10 port gigabit switch, all ten ports will be able to use up to a gigabit, but if you have two devices trying to use gigabit speeds connected to 2 ports, you are bottle-necked by the gigabit from the router and the devices will have to share the speed. That analogy seems to think that by plugging in 4 devices you are only getting 1/4 the gigabit speed per device right from the start.

 

If anyone feels thats wrong, correct me. I am taking a college computer networking class, but I've never had the chance to use a switch where I would need to max out the bandwidth on multiple ports at once, but im pretty confident in that answer.

[Samfisher]

8 minutes ago, link955 said:

Hey guys,

Recently I was discussing with my friend about reorganizing my home network. I was gonna buy some sort of switch for my living room and one for my bedroom. My friend said it was better to plug what I needed into the router instead off a switch because if  i am using multiply devices on the same switch and was  streaming video, My friend said the switch would get slower speeds over all devices, He used the analogy, Picture a pipe with flowing water, then you split it off in 4 directions, if all 4 are being used you will get lower water presure in one of the pipes. I was wondering if this applied to network switchs if i had 1 cable running from the port to my router, will the other ports be slower if im getting data from all of them? Hope this makes sense. Thanks

In a way it's true but in another it's not.  Depending on the switch you get, it may not be able to deliver full Gigabit speeds if all ports are connected.  Better switches can support Gigabit throughout all devices.

[link955]

7 minutes ago, suchamoneypit said:

Provided the switch isnt slower than the router, everything on the switch shares the speed from the router. I don't believe in that analogy.

 

If you have gigabit from the router, and a 10 port gigabit switch, all ten ports will be able to use up to a gigabit, but if you have two devices trying to use gigabit speeds connected to 2 ports, you are bottle-necked by the gigabit from the router and the devices will have to share the speed. That analogy seems to think that by plugging in 4 devices you are only getting 1/4 the gigabit speed per device right from the start.

 

If anyone feels thats wrong, correct me.

Hey thanks, Will make sure to show my friend this

[Oshino Shinobu]

This depends on the switch's backbone bandwidth. If you have a 4 port gigabit switch that has a 4Gbps backbone, then you'll be able to get the full 1Gbps from each port. However, if you have a 4 port gigabit switch with a 2Gbps backbone, then you'd theoretically only be able to get 500Mbps from each port if they're all being used at once. 

In general, the lower end switches will have a smaller backbone than higher end ones, and ones with more ports will likely have a larger backbone than switches with less ports. 

To be honest, unless you're connecting a lot of devices that use a lot of bandwidth, you're not going to be running into serious bandwidth issues on a home network. Bear in mind the router's switch (the LAN ports on a router are a switch) will have the same potentially limiting backbone. Moving all the devices over to the router wouldn't alleviate the bottlenecks if you encountered them. If anything, it would actually make them worse by limiting the available paths for data to be transferred. 

Imagine if you have 2 severs and 2 PCs. In one case, you have two switches, each with a server and a PC connected. If the PC on switch 1 wants to access data on server on switch 1, it just has to go across the switch. If a PC wants to communicate with a device on the other switch, then data needs to pass through the router's switch. 

In another case, you just have everything connected to the router's switch. Here, all data will have to pass through the router's switch backbone, regardless of destination. The chances of being limited in terms of bandwidth are more likely in this case (if we're assuming the router's switch isn't capable of providing the full bandwidth to each port at the same time).

[link955]

2 minutes ago, Oshino Shinobu said:

This depends on the switch's backbone bandwidth. If you have a 4 port gigabit switch that has a 4Gbps backbone, then you'll be able to get the full 1Gbps from each port. However, if you have a 4 port gigabit switch with a 2Gbps backbone, then you'd theoretically only be able to get 500Mbps from each port if they're all being used at once. 

In general, the lower end switches will have a smaller backbone than higher end ones, and ones with more ports will likely have a larger backbone than switches with less ports. 

To be honest, unless you're connecting a lot of devices that use a lot of bandwidth, you're not going to be running into serious bandwidth issues on a home network. Bear in mind the router's switch (the LAN ports on a router are a switch) will have the same potentially limiting backbone. Moving all the devices over to the router wouldn't alleviate the bottlenecks if you encountered them. If anything, it would actually make them worse by limiting the available paths for data to be transferred. 

Imagine if you have 2 severs and 2 PCs. In one case, you have two switches, each with a server and a PC connected. If the PC on switch 1 wants to access data on server on switch 1, it just has to go across the switch. If a PC wants to communicate with a device on the other switch, then data needs to pass through the router's switch. 

In another case, you just have everything connected to the router's switch. Here, all data will have to pass through the router's switch backbone, regardless of destination. The chances of being limited in terms of bandwidth are more likely in this case (if we're assuming the router's switch isn't capable of providing the full bandwidth to each port at the same time).

Thanks!

[TechFnatic]

Switches are layer 2 devices which means they essentially deal with MAC addresses. In other words this means that packets intended for a specific device connected to the switch will only be sent to that specific device, they will not be broadcasted across all devices plugged into the switch unlike a hub. What I'm trying to get at here is there are going to be no collisions or bottlenecks because a switch is smarter than a hub. As long as the switch can support the same or faster speeds as your router you're good to go.