CSMA/CD

CSMA/CD (Carrier Sense Multiple Access with Collision Detection) helps hosts to decide when to send packets on a shared network segment and how to detect collisions if they occur. For example, in a hub network, two devices can send packets at the same time. This can cause a collision. CSMA/CD enables devices to “sense” the wire to ensure that no other device is currently transmitting packets. But, if two devices “sense” that the wire is clear and send packets at the same time, Read more [...]

Collision & broadcast domain

Collision domainA collision domain is, as the name implies, the part of a network where packet collisions can occur. A collision occurs when two devices send a packet at the same time on the shared network segment. The packets collide and both devices must send the packets again, which reduces network efficiency. Collisions are often in a hub environment, because each port on a hub is in the same collision domain. By contrast, each port on a bridge, a switch or a router is in a separate collision Read more [...]

How switches work

Each network card has a unique identifier called a Media Access Control (MAC) address. This address is used in LANs for communication between devices on the same network segment. Devices that want to communicate need to know each other MAC addresses before sending out packets.Switches also use MAC addresses to make accurate forwarding or filtering decision. When a switch receives a frame, it associates the media access control (MAC) address of the sending device with the port on which it was received. Read more [...]

Layer 2 switching

Layer 2 switching (or Data Link layer switching) is the process of using devices’ MAC addresses to decide where to forward frames. Switches and bridges are used for Layer 2 switching. They break up one large collision domain into multiple smaller ones.In a typical LAN, all hosts are connected to one central device. In the past, the device was usually a hub. But hubs had many disadvantages, such as not being aware of traffic that passes through them, creating one large collision domain, etc. Read more [...]