Hubs, Switches and routers, what the hell are they? Have you ever wondered what the differences are among these boxes? Some technicians have a tendency to use the terms hubs, switches and routers interchangeably. Actually, though they have a skilled experience to operate them, they still can not tell the real differences between them and are looking at only one box. Don’t worry, today, let’s learn the differences between hubs, switches and routers together.
Hub is commonly used to connect segments of a LAN (Local Area Network). A hub contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets. Hub acts as a common connection point for devices in a network.
Switch operates at the data link layer (layer 2) and sometimes the network layer (layer 3) of the OSI (Open Systems Interconnection) Reference Model and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs. In networks, switch is the device that filters and forwards packets between LAN segments.
A router is connected to at least two networks, commonly two LANs or WANs (Wide Area Networks) or a LAN and its ISP.s (Internet Service Provider.s) network. Router is generally located at gateways, the places where two or more networks connect. Using headers and forwarding tables, router determines the best path for forwarding the packets. In addition, router uses protocols such as ICMP (Internet Control Message Protocol) to communicate with each other and configures the best route between any two hosts. In a word, router forwards data packets along networks.
In fact, the functions of hub, switch and router are all quite different from one another, even if at times they are all integrated into a single device. Now, let’s begin with the hub and the switch since these two devices have similar roles on the network.
Similar Roles? Hub & Switch Comparison
Each serves as a central connection for all of your network equipment and handles a data type known as frames. Frames carry your data. When a frame is received, it is amplified and then transmitted on to the port of the destination PC (Personal Computer). The big difference between hub and switch is in the method in which frames are being delivered.
In a hub, a frame is passed along or “broadcast” to every one of its ports. It doesn’t matter that the frame is only destined for one port. The hub has no way of distinguishing which port a frame should be sent to. Passing it along to every port ensures that it will reach its intended destination. This places a lot of traffic on the network and can lead to poor network response times.
Additionally, a 10/100Mbps hub must share its bandwidth with each and every one of its ports. So when only one PC is broadcasting, it will have access to the maximum available bandwidth. However, if there are multiple PCs broadcasting, then that bandwidth will need to be divided among all of those systems, which will degrade performance.
In comparison, a switch, keeps a record of the MAC (Media Access Control) addresses of all the devices connected to it. With this information, a switch can identify which system is sitting on which port. So when a frame is received, it knows exactly which port to send it to, without significantly increasing network response times. In addition, unlike a hub, a 10/100Mbps switch will allocate a full 10/100Mbps to each of its ports. So regardless of the number of PCs transmitting, users will always have access to the maximum amount of bandwidth. It’s for these reasons a switch is considered to be a much better choice than a hub.
Reading here, you may find that it’s so easy to distinguish hub and switch although they seem to have the same role in network. So, how about the routers? Actually, router is a completely different device compared with hub and switch. However, today most routers have become something like Swiss Army knife, combining the features and functionality of a router and switch/hub into a single unit. So most of the times, conversations regarding these devices can be a bit misleading — especially to someone new to computer networking.
Be Rememberd! Router Is Completely Different Device
Why say that so? Unlike a hub or switch that is concerned with transmitting frames, a router, as its name implies, is to route packets to other networks until that packet ultimately reaches its destination. One of the key features of a packet is that it not only contains data, but the destination address of where it’s going.
Routers might have a single WAN port and a single LAN port and are designed to connect an existing LAN hub or switch to a WAN. Ethernet switches and hubs can be connected to a router with multiple PC ports to expand a LAN. Depending on the capabilities (kinds of available ports) of the router and the switches or hubs, the connection between the router and switches/hubs may require either straight-thru or crossover (null-modem) cables. Some routers even have USB ports, and more commonly, wireless access points built into them.
What’s more, router is the only one of these three devices that will allow you to share a single IP (Internet Protocol) address among multiple network clients.
More Functions of the Modern Routers
As said above, Today’s router is not just a simple router but an integrated router. A wide variety of services are integrated into most broadband routers. For example, a router will typically include a 4-8 port Ethernet switch (or hub) and a Network Address Translator (NAT). In addition, they usually include a Dynamic Host Configuration Protocol (DHCP) server, Domain Name Service (DNS) proxy server and a hardware firewall to protect the LAN from malicious intrusion from the Internet.
One thing to know is that all routers have a WAN Port that connects to a DSL (Digital Subscriber Line) or cable modem for broadband Internet service. And the role of the integrated switch is to allow users to easily create a LAN. This allows all the PCs on the LAN to have access to the Internet and Windows file and printer sharing services.
Some of the more high-end or business class routers will also incorporate a serial port that can be connected to an external dial-up modem, which is useful as a backup in the event that the primary broadband connection goes down, as well as a built in LAN printer server and printer port.
Besides the inherent protection features provided by the NAT, many routers will also have a built-in, configurable, hardware-based firewall. Firewall capabilities can range from the very basic to quite sophisticated devices. Among the capabilities found on leading routers are those that permit configuring TCP/UDP (Transmission Control Protocol/User Datagram Protocol) ports for games, chat services, and the like, on the LAN behind the firewall.
As you read this, you may be clear about the differences between these three devices. But I still want to say one word further to help you solidify the knowledge you receiver from this post. To remember that a hub glues together an Ethernet network segment; a switch connects multiple Ethernet segments more efficiently and a router can do those functions plus route TCP/IP (Transmission Control Protocol/Internet Protocol) packets between multiple LANs and/or WANs as well as much more of course. This is the main differences between these boxes.
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