Vocabulary practice setion 3

1. What do the following abbreviations stand for? Choose the correct answer.

1. LAN

a. local area network b. large area network

2. PAN

a. private area network b. personal area network

3. MAN

a. managed area network b. metropolitan area network

4. WAN

a. wide area network b. wireless area network

5. VPN

a. virtual private network b. virtual public network

6. GAN

a. global area network b. great area network

7. WLAN

a. wireless local area network b. wide large area network

2. Read the information in Key information section 3 and correct the following statements.

1. LANs link computers and other devices that are placed far apart. 2. In a client-server architecture, all the workstations have the same capabilities. 3. The word protocol refers to the shape of the network. 4. Routers are used to link two computers. 5. Access points don't need to be connected to a wired LAN.

6. Wireless adapters are optional when you are using a WLAN.

7. Hotspots can only be round inside a building.

8. The Internet is an example of a LAN.

9. Wireless WANs use fibre and cable as linking devices.

10. Enterprise Private Network is a public network.

11. VPNs make links via wire devices.

12. Extranet is the same as Internetwork.

13. An overlay network is a telephone network.

3. Use the words in the box to complete the sentences.

LAN WLAN nodes peer-to-peer hub server backbones

1. All the PCs on a … are connected to one … , which is a powerful PC with a large hard disk that can be shared by everyone. 2. The style of … networking permits each user to share resources such as printers. 3. The star is a topology for a computer network in which one computer occupies the central pan and the

remaining …. are linked solely to it.

4. At present Wi-Fi systems transmit data at much more than 100 times the rate of a dial- up modem, making it an ideal technology for linking computers to one another and to the Net in a … .

5. All of the fibre-optic … of the United States, Canada and Latin America cross Panama.

6. A … joins multiple computers (or other network devices) together to form a single network segment, where all computers can communicate directly with each other.

4. Fill in the gaps in the network description with the words from the box.

ports monitoring traffic services data center nodes transmit

The RETN network is designed to (1) … huge amounts of IP (2) … and to lease large capacity channels. The network currently comprises 1 GE, STM-16 and 10 GE channels.

Reference network (3) … are located in Moscow, Yaroslavl, Vladimir, Nizhny Novgorod, Saint Petersburg, London, New York, Stockholm, Helsinki, Washington D.C., Amsterdam and Frankfurt. Network (4) … and management is performed from a Network Management Center, which is located in Moscow. Currently, the main (5) … of the RETN network are IP traffic transmission along with connection to main stream nodes using (6) … with a capacity from 10 Mbit/s to 10 Gbit/s, leasing MPLS VPN L2/L3 channels with bandwidth up to 10 Gbit/s and collocation of equipment in its own (7) … in Saint Petersburg, and in the data centers in Moscow, London, Stockholm, Amsterdam, Frankfurt and New York, using connection ports with a capacity of up to 1 Gbit/s.

KEY INFORMATION SECTION 4

Topology of networksrefers to the shape of a network. There are some basic physical topologies.

Star: there is a central device to which all the workstations are directly connected. This central position can be occupied by a server, or a hub, a connection point of the elements of a network that redistributes the data.All traffic that transverses the network passes through the central hub. The hub acts as a signal booster or repeater. The star topology is considered the easiest topology to design and implement. An advantage of the star topology is the simplicity of adding additional nodes. The primary disadvantage of the star topology is that the hub represents a single point of failure.

Extended star: a type of network topology in which a network that is based upon the physical star topology has one or more repeaters between the central node (the 'hub' of the star) and the peripheral or 'spoke' nodes, the repeaters being used to extend the maximum transmission distance of the point-to-point links between the central node and the peripheral nodes beyond that which is supported by the transmitter power of the central node or beyond that which is supported by the standard upon which the physical layer of the physical star network is based.

If the repeaters in a network that is based upon the physical extended star topology are replaced with hubs or switches, then a hybrid network topology is created that is referred to as a physical hierarchical star topology, although some texts make no distinction between the two topologies.

Bus: every workstation is connected to a main cable called a bus.Each computer or server is connected to the single bus cable through some kind of connector. A terminator is required at each end of the bus cable to prevent the signal from bouncing back and forth on the bus cable. A signal from the source travels in both directions to all machines connected on the bus cable until it finds the IP address on the network that is the intended recipient. If the machine address does not match the intended address for the data, the machine ignores the data. Alternatively, if the data does match the machine address, the data is accepted. Since the bus topology consists of only one wire, it is rather inexpensive to implement when compared to other topologies.

Ring: the workstations are connected to one another in a closed loop configuration.Each machine or computer has a unique address that is used for identification purposes. The signal passes through each machine or computer connected to the ring in one direction. Ring topologies typically utilize a token passing scheme, used to control access to the network. By utilizing this scheme, only one machine can transmit on the network at a time. The machines or computers connected to the ring act as signal boosters or repeaters which strengthen the signals that transverse the network. The primary disadvantage of ring topology is the failure of one machine will cause the entire network to fail.

Mesh networking is a type of networking wherein each node in the network may act as an independent router, regardless of whether it is connected to another network or not. It allows for continuous connections and reconfiguration around broken or blocked paths by “hopping” from node to node until the destination is reached. A mesh network whose nodes are all connected to each other is a fully connected network. Mesh networks differ from other networks in that the component parts can all connect to each other via multiple hops, and they generally are not mobile.

Hierarchical network (also known as tree network): the type of network topology in which a central 'root' node (the top level of the hierarchy) is connected to one or more other nodes that are one level lower in the hierarchy (i.e., the second level) with a point-to-point link between each of the second level nodes and the top level central 'root' node, while each of the second level nodes that are connected to the top level central 'root' node will also have one or more other nodes that are one level lower in the hierarchy (i.e., the third level) connected to it, also with a point-to-point link, the top level central 'root' node being the only node that has no other node above it in the hierarchy (The hierarchy of the tree is symmetrical.) Each node in the network has a specific fixed number of nodes connected to it at the next lower level in the hierarchy, being referred to as the 'branching factor' of the hierarchical tree.