Do PC to PC LAN connections go through the WiFi Router

x509

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I have always wondered about that situation. If true, then I will get a wired hub for the home office.
 

BinarySynapse

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I doubt the difference is meaningful these days, but you’d want a switch rather than a hub.

But if I understand what you’re asking, that two PC’s talking to each other through the router’s hard wired LAN ports is affected by the same router’s WiFi feature, then not as long as there isn’t so much traffic going though the router that it doesn’t have enough resources to keep up. That hasn’t been a problem in any modern router that I know of.

If you’re asking if WiFi will affect hard wired PC’s available bandwidth from your ISP, the yes.A separate switch won’t resolve that either.
 

BlueLineSwinger

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No, packets going between nodes on the same subnet do not go through any kind of routing. They may, however, still traverse the switch portion of the home router, depending on the network topology. Having them go through a separate switch won't do anything for security/privacy/etc.
 

x509

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No, packets going between nodes on the same subnet do not go through any kind of routing. They may, however, still traverse the switch portion of the home router, depending on the network topology. Having them go through a separate switch won't do anything for security/privacy/etc.
As the OP, I was wondering if System A on Wi-Fi can send packets directly to System B on WiFi, without having to go down to the router and then back up. IOW, if System A and System B are in the same room, is performance better than say System A to System C which is at the other end of the house. That's sort of my setup.
 

x509

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I doubt the difference is meaningful these days, but you’d want a switch rather than a hub.

But if I understand what you’re asking, that two PC’s talking to each other through the router’s hard wired LAN ports is affected by the same router’s WiFi feature, then not as long as there isn’t so much traffic going though the router that it doesn’t have enough resources to keep up. That hasn’t been a problem in any modern router that I know of.

If you’re asking if WiFi will affect hard wired PC’s available bandwidth from your ISP, the yes.A separate switch won’t resolve that either.
ryan_975 when is a hub not a switch?
 

Vengance_01

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You need to seperate the wifi signal, the hub/switch and the router portion of the device. Typically if you had 2 devices connected on the same switch it would never route out passed that switch as the switch would have an arp table.

But due to the nature of a consumer router it acts as the following function.

Layer 2 switch
Layer 3 routing
Wifi AP
 

BinarySynapse

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ryan_975 when is a hub not a switch?

Hubs are dumb devices that just forward all packets coming in one port to all other ports. In a busy network this creates a lot of unnecessary traffic that can slow down or even cripple the network, especially when using certain media where collisions can occur causing packet retransmission.

Switches are able to inspect the packets coming in on each port and send them only to the port where the destination device is connected.
 
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EniGmA1987

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As the OP, I was wondering if System A on Wi-Fi can send packets directly to System B on WiFi, without having to go down to the router and then back up. IOW, if System A and System B are in the same room, is performance better than say System A to System C which is at the other end of the house. That's sort of my setup.
No they do not talk directly to each other from A to B, all devices talk to the router. The router is sending out the wifi network and all wifi devices connect to the router. A connection directly from computer A to B is often called an Ad Hoc network and is almost never done.
There are some people who have a home server and they set up a second subnet directly between computer A and their server as a point to point subnet with a higher bandwidth wired connection, often a 10gb link. This is done when they transfer a lot of data to their server and they dont want to bog down the network and instead just go direct with higher bandwidth. This does require a separate NIC in both the server and other PC and a cable between those two NICs, and manually setting static IP information for both devices.

As for "do A and B have better performance than C", if all 3 have the same wifi cards then most likely whichever is closest to the router itself will have the best performance, and as you get farther or go through more walls the performance will be less.



Hubs are dumb devices that just forward all packets coming in one port to all other ports. In a busy network this creates a lot of unnecessary traffic that can slow down or even cripple the network, especially when using certain media where collisions can occur causing packet retransmission.
Switches are able to inspect the packets coming in on each port and send them only to the port where the destination device is connected.
Though switches can act like hubs if a device is sending out multicast traffic and the switch is not set up with IGMP Snooping turned on and configured. High multicast traffic is a problem for a lot of industrial ethernet devices and IGMP Snooping switches are important in those industrial places and large corporate networks.
edit: and apparently if you do a lot of airplay or chromecast mirroring IGMP is also important at home since those protocols seems to send out multicast traffic to the whole home network.
 
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Col_Temp

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EniGmA1987 is kind of right.
A lot though depends on the router in use.
Many of the better routers out there can be set up to do exactly what you want.
For instance I use Datto AP's with a couple of clients. I can set up with individual SSID's whether they are LAN aware or not. The guest network never is and stays fire walled for internet access only.
The in house SSID and another are set with LAN access turned on. With that you can easily connect them. the router handles the packet transfers.

Now what I thought the OP was saying is using two LAN ports on the router to connect two PC's. If that is the case sure. Just make sure you don't have one connected tot he WAN port by mistake! I have used a WiFi router in the past to act like a switch. No problem.
 

x509

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EniGmA1987 is kind of right.
A lot though depends on the router in use.
Many of the better routers out there can be set up to do exactly what you want.
For instance I use Datto AP's with a couple of clients. I can set up with individual SSID's whether they are LAN aware or not. The guest network never is and stays fire walled for internet access only.
The in house SSID and another are set with LAN access turned on. With that you can easily connect them. the router handles the packet transfers.

Now what I thought the OP was saying is using two LAN ports on the router to connect two PC's. If that is the case sure. Just make sure you don't have one connected tot he WAN port by mistake! I have used a WiFi router in the past to act like a switch. No problem.
I'm the OP, but no I didn't mean connecting two systems via Ethernet ports. My bad for not describing my situation better. Both systems are running WiFi and I wanted to know if they can WiFi directly to each other, without going through the router.

And no, I am pretty careful about not plugging a client system into the WAN port. That port is plugged into the cable modem. :)
 

BlueLineSwinger

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I'm the OP, but no I didn't mean connecting two systems via Ethernet ports. My bad for not describing my situation better. Both systems are running WiFi and I wanted to know if they can WiFi directly to each other, without going through the router.

And no, I am pretty careful about not plugging a client system into the WAN port. That port is plugged into the cable modem. :)

As others have mentioned above: In infrastructure mode (i.e., using an AP), all communications pass through the AP. This is true even if the two nodes communicating are on the same SSID/VLAN/subnet/etc.

Wireless nodes can communicate directly when using ad-hoc mode. However, ad-hoc scales horribly (each node has to continuously track every other) and you completely lose the AP/router (and therefore anything beyond it).
 
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x509

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As others have mentioned above: In infrastructure mode (i.e., using an AP), all communications pass through the AP. This is true even if the two nodes communicating are on the same SSID/VLAN/subnet/etc.

Wireless nodes can communicate directly when using ad-hoc mode. However, ad-hoc scales horribly (each node has to continuously track every other) and you completely lose the AP/router (and therefore anything beyond it).
Ok, I need performance out of my wifi just as much as the next guy. I'm good with the responses and I've learned something important. :)
 

MrGuvernment

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EniGmA1987 is kind of right.
A lot though depends on the router in use.
Many of the better routers out there can be set up to do exactly what you want.
For instance I use Datto AP's with a couple of clients. I can set up with individual SSID's whether they are LAN aware or not. The guest network never is and stays fire walled for internet access only.
The in house SSID and another are set with LAN access turned on. With that you can easily connect them. the router handles the packet transfers.

Now what I thought the OP was saying is using two LAN ports on the router to connect two PC's. If that is the case sure. Just make sure you don't have one connected tot he WAN port by mistake! I have used a WiFi router in the past to act like a switch. No problem.
Col_Temp , EniGmA1987 is 100% right. All devices on Wifi will always traverse the AP / Router to send data to each other. At no point in time, will Laptop A connected to SSID MyWifi and Laptop B connected to SSID MyWifi send data "directly" to each other. They will traverse the AP/Router because they have to.

Unless you set up a WiFi Hot Spot on Laptop A and connect Laptop B directly to it, but now you need another Wifi Adapter if you want to also have internet on Laptop A with out using a hard wired link.
 
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