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.
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