intermediary devices functions

Any network infrastructure contains three types of the network component which is Devices, Media, and Services. Data takes a path from source to destination can be simple as a single connecting one device to another.

Devices and media are the physical network components also known as Hardware network component. We can touch or its take some physical place such as the PC, switch, router, wireless access point, or the cabling used to connect the devices.

Services include many of the common network applications people use every day, like email hosting services and web hosting services. Processes give the functionality that directs and moves the messages through the network. Processes are less obvious to us but are critical to the operation of networks.

End Devices

End devices are the first network component. End devices are either the source or destination of a message or data transmitted over the network. To differentiates one end device from another, each end device on a network recognized by an address. When an end device initiates communication, it uses the address of the destination end device to specify where the message should be sent. Laptop, Desktop, Printer, IP Phone, tablet, and telepresence are examples of end devices.

Intermediary devices

Intermediary devices connect the individual end devices to the other network components. It can connect multiple networks to form an internetwork. These intermediary devices provide connectivity. These devices also make sure data flows across the network. Intermediary devices use the destination end device address, with information about the network interconnections, to decide the path that messages should take through the network. Router, Switch, Wireless router, and firewall are examples of intermediary devices. The most important intermediary devices are:

Hub

Hub is a network technology but not really used in modern networks. In networking, it is just studied because it is helpful to understand switch if somebody understands it then he can easily understand a switch. It is a device that simply copies a data which received on any port to all its ports.  So, if a packet of data arrives on interface 1 of a 5 port hub, It will blindly copy that data out the interfaces 2 through 5. It’s a common connection point for devices in a network. Different segment of LAN commonly connected to the hub. It was a cheap and quick way to link up multiple computers in the early days.

The main issue with hubs though is that only one computer can talk at a time.  So, If 2nd computers going to talk at the same time, their traffic would get joined as it was echoed out the other interfaces.  This is called a collision, and it would corrupt the data being transmitted by both computers. So, each computer would have to try again, after a random time period.  This becomes a real problem when the network gets busy or when more than a hand full of computers are on a network.  A switch solves the collision issue. Hub is a single broadcast and single collision domain.

Switch

An Ethernet Switch is a device which is used to connect multiple computers and devices within  LAN. It is work at Layer Two (Data Link Layer) of the OSI model. Some switches also work at layer 3 ( Network Layer). These switches referred to as Layer 3 switches or multilayered switches.

Basic Function of a Network Ethernet Switch and a Network Ethernet Hub are same. That is to forward Layer 2 packets (Ethernet frames) from source device to the destination device. But, a Network switch is more intelligence than a hub. Because an Ethernet switch uses MAC addresses to make forwarding decisions. It does not know about the protocol carried in the data portion such as an IPv4 packet. The switch makes its forwarding decisions based only on the Layer 2 Ethernet MAC addresses.

Unlike an Ethernet hub that repeats bits out all ports except the incoming port; an Ethernet switch consults a MAC address table to make a forwarding decision for each frame. The MAC address table is sometimes referred to as a content addressable memory (CAM) table. Network Switches of different input and output bandwidths are available. Today’s Ethernet Network Switches can have bandwidths of 10, 100, 1000 or 10,000 Megabits per second.

Switch Features and Advantages

• Connect network devices together in a Local Area Network (LAN).
• Its learn Layer 2 (MAC) addresses and forward Layer 2 packets (Ethernet frames); to exact destination with the help of device mac address
• It’s control of who has access to various parts of the network.
• Provision to monitor network usage.
• High-end switches have pluggable modules.
• Allow to connect multiple device and port can be managed  VLAN can create security also can apply
• First broadcast; then unicast & multicast as needed.
• Switches use content accessible memory CAM table which is typically accessed by ASIC (Application Specific integrated chips).
• Half/Full duplex
• Connecting two or more nodes in the same network or different network
• The switch has one broadcast domain [unless VLAN implemented]

Router

The router is a network device. It selects the best path for a data packet. The router is located at any gateway (where one network meets another). Its forward data packets from one network to another based on the address of the destination network in the incoming packet and an internal routing table. It also determines which port (line) to send out the packet (ports typically connect to Ethernet cables).

Routers also require packets formatted in a routable protocol. The global standard being TCP/IP, or simply “IP.” Routers operate at Layer 3 (network layer) of the OSI model and it uses the destination IP address in a data packet to determine where to forward the packet. Router store IP address in Routing table and maintain address on its own.

Media

Communication Medium is an important component of the network. If the medium works well and properly, then the speed of transferring data is good but if the medium is not working properly, then your data would be delayed or would not be sent or even can be lost during transmission wires, Optical fiber cable and, wireless is the main component of Media