NETWORK+ I Assignment Module 1

NETWORK + I
09/30/15
Harrison Valetski
Module 1 Assignment

Provide a brief overview of the function of the below devices and describe which layers of the OSI Model they operate.

• Hubs
  A hub is a device that has multiple ports into which connections can be made. There are two major types of hubs: active and passive. An active hub is plugged into a power source so that it can amplify signals as well as connect them. A passive hub does not provide power but provides only connectivity. All devices connected to a hub are also connected to each other. A hub does not filter any communication or provide any intelligence in regard to the data stream; it simply lets all the information flow through it and connects anything and everything that is connected to it. It works at layer 1 (Physical) of the OSI model. 
• MAUs
  These are a lot like hubs in that they are unmanaged typically (although they do come in managed control access units on occasion) non-switched and generally passive.They form a logical token ring for a star shaped network. They operate at layer 1 physical and often have lots of bnc connectors.
• Switches
   switch is a network device that optimizes traffic flow on your network. A switch works at layer 2 (Data Link).
• NIC cards
  Network interface cards (NICs) are used to connect a computer to the network. A network interface card is like a small computer in itself. Its job is to translate a stream of serial data (one bit at a time) into several streams of parallel data that will be used by the computer. The network interface card also examines every packet on the network cable to determine whether the packet has a destination MAC address that matches its MAC address. If it does not, then the NIC does nothing more with the packet. However, if the address does match, then the NIC will forward the packet to the appropriate port of the computer based on the information contained in the packet. They work at the layer 4 (Transport) of the OSI model.
• Gateways
  In a communications network, a network node equipped for interfacing with another network that uses different protocols. Gateways work at layer 3 (Network).
• Routers
  Routers are the devices that connect the Internet and make the World Wide Web possible.Routers use logical addresses and work at layer 3 (Network) of the OSI model and forward traffic from one network (or subnet) to another.
• Wireless access points
  In computer networking, a wireless access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, or related standards. They work at layer 2 (Data Link).
• CSU/DSUs
  A CSU/DSU is a digital-interface device used to connect a data terminal equipment (DTE), such as a router, to a digital circuit, such as a Digital Signal 1 (T1) line. The CSU/DSU implements two different functions. The channel service unit (CSU) is responsible for the connection to the telecommunication network, while the data service unit (DSU) is responsible for managing the interface with the DTE. They work at layer 3/4.
• Cables related to any of these components
  An electrical cable comprises two or more wires running side by side and bonded, twisted, or braided together to form a single assembly, the ends of which can be connected to two devices, enabling the transfer of electrical signals from one device to the other. Cables are used for a wide range of purposes, and each must be tailored for that purpose. Cables are used extensively in electronic devices for power and signal circuits. They work at layer 1 (Physical).
• Bridges
  A bridge is a legacy device that is similar to a switch in that it can provide some intelligence to segment a network. There are two main types of Ethernet bridges. A transparent bridge can connect two dissimilar networks, but it is “invisible” to both networks, and it does not provide translation of any kind. A translational bridge, as you might expect, actually performs a translation between two dissimilar networks. Bridges, like switches, can learn the MAC addresses of all the hosts connected to them and use the addresses to control traffic to each of their ports and are slower than switches. They work at layer 2 (Data Link) of the OSI Model.