CS610 Mid Term Question (Solved)

How many methods are available to span a network over longer distances? Just write their names. (2 Marks) ESCON , FICON , legacy bus and tag, Fibre Channel (FC), Storage Area Networks (SANs), and IP and ATM long-distance networks

Which two identifier in ATM are used to make Virtual Circuit? (2)Virtual Path identifier (VPI) and Virtual Channel Identifier (VCI)

When a person makes call what steps are involved in it, write every step and determine how a connection established. (5 Marks)

The connection-oriented service paradigm for networking is similar to the manner in which telephones are used. This is given as follows: A caller dials a number of the destination. The telephone at the destination signals the arrival of a connection request. If the called person does not answer; the caller gives up after waiting for a timeout. If the called person does answer, then the connection is established.

If a organization uses Repeaters in its network, when a frame comes from external network how it will read frame? Support your answer with a reason; also describe three drawbacks to organization. (5 Marks)

REPEATERS: Repeaters are used when copper wire communication is carries out. According to the fact that electrical signal gets weaker while traveling over copper wires. A repeater is used to increase the signal strength. It amplifies the weakening signal received from one segment and then retransmits onto another segment. One repeater doubles, two repeaters triple the maximum cable length limitation. Computers attached to different segments communicate as if they are connected to the same cable. It is to be noted that we cannot increase the maximum cable length as many times as we wish by just adding repeaters. The reason for this is that every repeater introduces a delay and the access mechanism such as CSMA/CD does not work with long delays. Ethernet standard specifies that any two stations cannot be separated by more than four repeaters. The figure shows repeaters using the vertical segment. We see that only two repeaters separate any two stations in this scheme. DISADVANTAGES OF REPEATERS: Repeaters do not recognize frame formats, they just amplify and retransmit the electrical signal. If a collision or error occurs in one segment, repeaters amplify and retransmit also the error onto the other segments.

Suppose an organization wants to build a lab of 8 computers in a single room with low budget. Which Ethernet cable scheme will be used among thick and thin Ethernet? Give Two Reasons. (3 Marks)

THIN ETHERNET WIRING:  Thin Ethernet uses thin coax cable that is cheaper and easier to install than thick Ethernet coax. In this case transceiver electronics are built into NIC and NIC connects directly to network medium. Coax cable use BNC connector on NIC. Coax runs directly to back of each connected computer by T-connector. The T-connector directly attaches to NIC. Thin Ethernet is useful when many computers are located close to each other. It may be unreliable because any disconnection disrupts entire net.

Suppose you are a Network Engineer in ISP, providing different technologies services like one of these may be , as Network Engineer you must know that which term is used to refer “information” related to the network but not refers to the “information” that only uses the network, give name of this term and reserved values. (3 Marks)

Refers to physical telecommunications systems and networks (cellar, broadcast, cable, satellite, postal) and the services that utilize them (Internet, voice, mail, radio, and television)

Why the connection oriented service uses connection identifiers instead of full address? Address is a complete unique identifier. Connectionless delivery requires address on each packet. Connection-oriented delivery can use a short hand that identifies the connection rather than the destination.

Describe two major components of thick Ethernet? (2) 1.Transceiver, 2.AUI cable, 3.multiplexer

Suppose a Network Admin wants to get automatic updates of routing information in a router if a change occurs in the network which routing algorithm will be used in this case? (3)

DYNAMIC ROUTING:

It allows automatic updates by a programmer. It can work around network failures automatically.

Wiring scheme: a) Thick Ethernet b) Thin Ethernet c) Twisted pair Ethernet

Virtual private network (5)

Virtual Private Network (VPN) combines the features of both private and public networks. It is limited to single organization and uses public network for connectivity. These connections are sometimes called tunnels and connect sites. Each site sees tunnel as point-to-point link. There is no access for other users of public networks.

NIC(5) in order to connect to the network computer systems use special purpose hardware for network connections which consists of typically a separate card in the back plane which is called Network Adapter Card or Network Interface Card (NIC). The connector on NIC at the back of computer then accepts cable to physical network.

ATM designers chose cells over packets 5 reason 5 marks

• Cells are not variable length and memory management for them is simpler. Handling variable length packets leads to memory fragmentation.

• Variable length packets require hardware to accommodate the largest possible packet, and thus to detect the end of the packet. With cells bits can just be counted as they arrive.

• The length of time required to send a variable length packet is variable and requires complicated interrupt scheme to detect completion of transmission. QoS can’t be guaranteed with variable length packets as easily as it can with fixed length cells.

Why packet switch check the header frame before forwarding the packet (3)

If a packet switch has a queue of packets waiting when a new packet arrives. The new packet will be placed on the entire queue and will need to wait while the switch forwards the previous packets.

ATM provide best support for multiple services, Due to which reason ATM is not adopted as a single underline technology give ay three reasons to justify your answer.(5) Telephone companies (Telco’s) introduced ATM to meet several goals. It provides universal service for all subscribers and support for all users for voice, video and data. It has a single unified infrastructure (no separate LANs and WANs). It gives guaranteed service when it is appropriate and support for low cost devices

Star Textile has huge network of systems and switches. A task is given to IT Officer that if some link goes the entire network works smoothly. Which routing method will be use? (5)

DISTANCE-VECTOR ROUTING:• It is very simple to implement.• Packet switch updates its own routing table first.• It is used in RIP.