What is the difference between a network switch and a network router?

When it comes to complexity of network connectors, you have got multiple levels, with a switch (hub) at the bottom and a router at the top.What is the difference between a network switch and a network router?

A hub is an astonishingly dumb gadget. It accepts a packet from one connected device and blurts it out to all the other devices. That is it. Everything connected to a hub sees a constant stream of all the traffic floating over that hub. It is up to each device to filter out anything that is not intended for it.

This means that: a) Only one device can be talking at a time or else there are network collisions, b) There is a ton of needless traffic flowing over every port; and c) Network security?

A switch is a hub that knows the low-level network information (typically, the MAC address) of each device plugged into it. If device 1 sends a packet to device 2, the switch only repeats that packet to the port device 2 is connected to. Devices 3, 4, 5, and 6 do not see it. So, device 3 can talk to device 6 while device 1 is talking to device 2, no problem.

A switch knows nothing about the wider network. A switch only knows about devices that are directly connected to it.

A router is a full-fledged network traffic computer. It knows about IP addresses. It may have tables of the best paths to send traffic to distant networks. It understands high-level network parameters like IP addresses.

A switch can only send information from a device plugged into it to another device plugged into it. A router can direct traffic to distant networks. It can relay information between multiple networks, or between networks of different kinds. It can chat with other routers to determine the fastest way to get information to a device that is not connected to it, but is connected to a different router instead. It can monitor and shape network traffic.

Is router mode the same as bridge mode?

Now I will get a little more technical. Router mode and bridge mode are different. The difference is mainly from a layer perspective.

Bridge mode lets you connect two routers without the risk of performance issues. Bridge mode is the configuration that disables the NAT feature on the modem and allows a router to function as a DHCP server without an IP Address conflict.

Basically, NAT allows a single device, such as a router, to act as an agent between the Internet (or public network) and a local network (or private network), which means that only a single unique IP address is required to represent an entire group of computers to anything outside their network.

Additionally, NAT can provide security and privacy. Because NAT transfers packets of data from public to private addresses, it also prevents anything else from accessing the private device. The router sorts the data to ensure everything goes to the right place, making it more difficult for unwanted data to get by.

The good: NAT is relatively effective as a first line of defense against hackers who might invade your system. While it is not perfect, it is pretty darn effective.

The bad: Doing any Web-based functions that require passing the IP address in the body of the message can have problems working through NAT.

DHCP stands for dynamic host configuration protocol and is a network protocol used on IP networks where a DHCP server automatically assigns an IP address and other information to each host on the network so they can communicate efficiently with other endpoints.

The Dynamic Host Configuration Protocol (DHCP) Reservation feature allows the router to reserve the lease of an IP Address for use of a specific device on your network, effectively ensuring that the router does not assign the IP Address to other devices in the network.

Connecting multiple routers can extend the Wi-Fi coverage in your office/home. But when you have two routers each with their own private Wi-Fi network your personal devices can have a hard time communicating with each other. This scenario is called Double NAT.

In routed mode it can take routing decisions so you can modify the data path from the device. That is what routed devices usually do. But if you want you can extend it to modify other layers’ headers’/functionalities as well.

Let me simplify

A home router typically has a WAN port and one or more LAN ports. The WAN port contexts to the ISP modem, and the LAN ports connect to your home gear.

Home routers have some security features such as NAT applied to the WAN port and if you have more than one router, they can interfere with each other. So, you place one into bridge mode.

Putting a router into bridge mode essentially demotes the WAN port into acting like a LAN port. The router then acts like a switch.

Stay protected!

George Cox is the owner of Computer Diagnostics and Repair. He can be reached at 346-4217.

Leave a Reply

Your email address will not be published. Required fields are marked *