Network Devices PDF

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Devices that are use in networking...

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NETWORK INFRASTRUCTURE DEVICES Network Infrastructure devices are the physical components used to build the computer network. Depending on the size of the enterprise network, different models of different capacity and quantity of network infrastructure devices are used in the network.

HUB Hubs were used for connecting different network devices in a Local Area Network (LAN) long back, but network switches had replaced hubs. These days it is very difficult to spot a Network Hub functioning in a live Local Area Network (LAN). Hubs function as the central connection point for Local Area Network (LAN). In Ethernet networks, hubs were designed to work using twisted pair cables and use RJ45 jack to connect different network devices. Network devices (Servers, Workstations, Printers, Scanners etc) are attached to the hub by individual network cables. Hubs were available in different shapes and different numbers of ports. When a hub receives a packet of data (an Ethernet frame) at one of its ports from a network device, it transmits (repeats) the packet to all of its ports to all of the other network devices. If two network devices on the same network try to send packets at the same time, a collision is said to occur. Hubs are considered to operate at Physical Layer (Layer 1) of OSI model. An 8 port hub is shown below.

Bridge or Switch A bridge or switch performs its job by examining the Data Link Layer (Layer 2) data packet (Ethernet Frame) and forwarding the packet to other network devices based on Layer 2 addresses (MAC Addresses). Both switches and bridges function using Datalink Layer (Layer 2) addressing system (also known as MAC addresses), to forward Ethernet frames from one device to another device in an Ethernet standard based LAN (Local Area Network). Each port of a network switch is in a separate collision domain and therefore switches are used to divide a big collision domain into multiple smaller collision domains. Bridge has only few ports and connect only a few collision domains, or Hosts. A bridge has comparatively less ports than a switch. Network switches with 24 ports or 48 ports are usually available in the market. Brides and switches are considered to operate at the Data Link Layer (Layer 2) of the OSI model. The term "Bridge" is not much used in networking industry these days. So, use the term "Switch" instead of "Bridge".

Ethernet network switches are designed to operate using Twisted pair cabling and use RJ45 jack to connect different network devices. Fiber optic ports in Ethernet switches are normally used to connect two different Ethernet switches together. Following picture shows a Cisco 24 Port 10GBase-T (10 Gigabits per second) Ethernet Switch. For more details and technical specifications, please visit official Cisco product page for Cisco SG350XG-24T 24-Port 10GBase-T Stackable Managed Switch.

ROUTER A router is a network infrastructure device that directs packets from one network to another network based on information from Network Layer (Layer 3) of OSI model. A router uses a combination of hardware and software to "route" data from the source network to destination network. The following picture shows a Cisco 4000 Series Integrated Services Router.....