SWITCH
A switch can be used in the local area network (LAN) as a multi-port bridge device. Under discussion mechanism works at the Layer2 (data-link) of the OSI reference model. What’s more, Ethernet frame’s switching between the connecting Ethernet devices is done with its help. But during the transmission process of data, these devices do not think about the frame’s IP addresses and they are flown on their way via switch without examining their IP addresses.
However, Cisco world is using the CAM (Content Addressable Memory) table as a bridge forwarding table. In such cases, a switch when takes the Ethernet frames delivery for a destination source which is by now not contained in its CAM table, then all such frames will be flooded out to every one linked ports. Anyway, a switch is having the ability to learn from the frames overflow responses that will be recorded within the forwarding table as confirmation for the future. Switches are also formed collision domains.
One can say that the switches play data passage cop with the coming in frames by means of packet buffering before its exchange. This is simply a way to avoid any possible collision. Each connected device with the switch is seemed to have their own Ethernet subdivision and they can talk freely without any possibility of collisions with a full speed. Every switch port is in a separate collision domain. It this situation when we are using switch there is no need of CSMA/CD mechanism until someone plugs in a hub on to one of switch’s ports.
Data link layer switching is totally hardware based, that’s why, MAC addresses are used in case of switch for the data frames forwarding purposes. Similarly, switches are made use of the ASICs (application specific integrated circuit) for establishing and maintaining the MAC addresses tables. ASIC (14 up, 5 down) chip inside the switch can be described as an application explicit integrated circuit. That circuit is designed to carry out each individual function in a speedy way. In case of switches, a network hardware chip as ASIC will determine that which port will frontward data or packets.
ASIC (4 up, 13 down) is also a function specific integrated circuit which in a switch as a chip determines that which port will forward the information. These ASICs employed in switches for getting faster functionality. But ASIC (3 up, 14 down) integrated circuit is used for decisions making in the networking components on certain subjects like what port of a network will send data. Anyway, layer 2 switching can provide: Hardware-based bridging, Wire and High speed and Low latency etc. Anyway, this switching technique is best for the workgroup connectivity and infringement of the network collision domains. Switches can peform their jobs by using anyone of following three ways for navigating traffic:
- Cut-through method
- Store and forward method
- Fragment-free method
HUB
LAN switches can make a big difference in the speed and quality of your network. While a hub works at physical layer (layer 1) of OSI reference model. Cisco has introduced a complete line up of hub products which are affordable and provide a simple way for creating a LAN within either a workgroup or an office. Example of Cisco hub is 1538 series Micro Hubs 10/100 that can provide you a flexible 10/100 automatically sensing high-speed Ethernet desktop’s connectivity for the purpose of creating high-performance and managing LAN at a very reasonable price.
DIFFERENCE
Some differences can be observed between the hub and switch functionalities as following:
- Each and every one node, connected to a hub will share its bandwidth. But in case of a switch, any device connected to the switch port will use its full bandwidth. That means in a network system, hub is a common connection for its attached devices.
- Hub is consisted on multiple ports and it is a dumb device in the network. And it knows nothing about those devices that are plugged into that hub. On the other hand, a switch can intelligently manage the data in the network going through it.