network bottlenecking

bbqsauce · December 11, 2015

quick question,

does having a old device say a wireless N only 5ghz laptop connected to my N/AC mixed 5ghz band slow down the throughput of the router for other concurrent devices in the same network?

1. Laptop wireless N 5ghz
2. Laptop wireless AC 5ghz
3. Smarphones wireless AC 5ghz

All on a gigabit connection with a gigabit AC router.

for example those 3 devices connect to the same network. Will 2 and 3 get reduced speeds because of the older laptop that can't support high speeds.

is this a thing? or will it not affect the network?

Oshino Shinobu · December 11, 2015

It shouldn't do, as wireless devices will be served separately. The speed of a client won't have an effect on other clients unless it is acting as a pass-through.

bbqsauce · December 11, 2015

It shouldn't do, as wireless devices will be served separately. The speed of a client won't have an effect on other clients unless it is acting as a pass-through.

I see so only stuff like switches and range extenders and what not should affect the network performance?

like a non gigabit switch used together with a gigabit ac router etc.

leadeater · December 11, 2015

Well it depends on what the worst device that is connecting supports and what the capabilities of the wireless AP is. If an old device connects using 2.4GHz and the AP is single radio then that is the only frequency the AP will be able to transmit in while that device is connected.

Better AP's are dual radio and can transmit on both 2.4GHz and 5GHz at the same time. Multiple antennas doesn't mean dual radio btw, don't get caught out by devices that have 2/3 antennas and assume it is also multi radio.

Oshino Shinobu · December 11, 2015

I see so only stuff like switches and range extenders and what not should affect the network performance?

like a non gigabit switch used together with a gigabit ac router etc.

Essentially, yes. If data has to pass through it to get somewhere, it can be the cause of a bottleneck.

Say, for example, you have this setup: PC > 10/100 Switch > 10/100/1000 Switch > 10/100/1000 Router LAN Connection.

The PC is going to be limited to 100Mbps, as the switch it is connected to can run at a maximum of 100BASE-T. Even though the rest of the network supports 1000BASE-T, the data will still have to pass through a 100Mbps connection. The bottleneck applies both ways, for inbound and outbound traffic that passes the switch. If you connected the PC to the second switch instead (assuming that the PC'S NIC, as well as the cables used support Gigabit speeds), then it can run at 1000BASE-T (1Gbps) and there would be no (hardware) bottleneck on the local network, as all devices support Gigabit speeds.

If you had the same setup, but also with another PC connected to the second, 10/100/1000 Switch, then the first PC would still be bottlenecked by the 10/100 switch, as data has to pass through it to get to and from the PC. The second PC (again, assuming the NIC and cables support Gigabit) would be able to operate at 1000BASE-T, as it is connected to a switch that supports Gigabit speeds. However, in order to send and receive data to and from the first PC, it will still have to pass through the first switch, so it will bottleneck the network to 100Mbps for connections passing through it.

If you had a setup like this: 4xPC > 10/100/1000 Switch > 10/100/1000 Switch + 5xPC > 10/100 Switch + Server connected > 10/100/1000 Router LAN connection.

All of the PCs on the network would be able to send and receive data between eachother at Gigabit speeds, but any data going to or from the server to the PCs would be limited to 100Mbps, as it has to pass through the 10/100 Switch, which would be the bottleneck. Any data going through the router to/from the PCs or Server would also be limited to 100Mbps, as it has to pass through the 10/100 switch.

If you had a single 10/100/1000 switch with 4 PCs that support 1000BASE-T and 2 PCs that only support 100BASE-T, then the 4 1000BASE-T PCs would be running at 1Gbps, while the 2 100BASE-T PCs would operate at 100Mbps. As long as the data is not going to or coming from either of the two 100BASE-T PCs, they will have no affect on the speed of the 4 1000BASE-T PCs.