CUSTOMER_CODE
SMUDE
DIVISION_CODE
SMUDE
EVENT_CODE
OCTOBER15
ASSESSMENT_CODE MCA3050_OCTOBER15
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
18334
QUESTION_TEXT
Discuss various components of a basic DWDM system.
SCHEME OF
EVALUATION
1.DWDM MUX: Contains one WL converting transponder for each
WL signal is will carry.
2.An intermediate line amplifier it compensates the loss in optical
power while the signal travels along the fiber.
3.An intermediate optical terminal or optical Add-up MUX
4.A DWDM terminal DEmux:
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
73695
QUESTION_TEXT
Explain the various fields present in LAP – D frame format.
SCHEME OF
EVALUATION
1. Flag: The flag field is a one-octet field that delimits.
2. Address: The address field is a two-octet field.
3. Control: The address field is a one or two octet field that
identifies the frame type.
4. Information: The information field is a variable size field with a
max of 260 octet comprising upper layer of information.
5. Frame Check Sequence: The FCS field is a two octet field.
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
73696
QUESTION_TEXT
Name the fields present in OSPF header
1.
2.
3.
SCHEME OF EVALUATION
4.
5.
6.
Version Number.
Packet Length
Router id
Checksum
Authentication Type
Authentication Data
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
73697
QUESTION_TEXT
Briefly explain the different Queue Management Algorithms
SCHEME OF
EVALUATION
1. Different Queue Management Algorithms:
FIFO Algorithm: The heart of this algorithm lies in that if overload
occurs, packets are placed onto a single common queue and retrieved
from it according to other order in which they arrived- that is first in
first out. In all packet switching devices, the FIFO algorithm is used by
default. (2 marks)
2. Priority Queuing: These types of algorithms are popular in many
areas of computing – for example multitasking operating systems,
where certain applications must priority over others. These algorithms
are also used for priority queuing, when some classes of traffic must
have priority over others. The priority-queuing is based on dividing all
network traffic into a small number of classes and assigning some
numeric characteristics, known as priority to each class. (2 marks)
3. Weighted Queuing: This algorithm is developed to provide certain
minimum bandwidth to all classes of traffic, or at least to guarantee
observations of some requirements to delays. Class weight is the
percentage of the total bandwidth of the resource that is guaranteed to
this class of traffic. Like priority queuing, weighted queuing requires the
division of the traffic into several classes. For each class, a separate
queue is created. However in weighted queuing each queue is assigned
the percentage of the resource bandwidth guaranteed to this class
under conditions of resource overload rather than a specific priority.
For input flow, role of resource is played by the processor, and for the
output flow, this role is played by the output interface. (3 marks)
4. Hybrid Algorithm of Queuing: Both of the two algorithms (priority
and weighted) has some advantages and drawbacks. A hybrid algorithm
is trying to find a compromise between those two algorithms. The most
popular type of such an algorithm uses one priority queue and serves all
other queues according to the weighted algorithm. Usually priority
queues are used for real-time traffic and other queues are used for
elastic traffic of several classes. Each class of elastic traffic get some
guaranteed minimum of the bandwidth during congestion periods. This
minimum is calculated as percentage of the bandwidth remaining after
serving the priority traffic. However, it is necessary to limit the priority
traffic somehow to prevent it from consuming the entire bandwidth of
the resource. (3 marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
125308
QUESTION_TEXT
Explain any 5 TCP services.
SCHEME OF
EVALUATION
TCP is stream oriented protocol. It allows the sending process to
deliver data as a stream of bytes and allows the receiving process
to obtain data as a stream of bytes.
TCP offers full duplex service, in which data can flow in both
directions at the same time. Each TCP then has a sending and
receiving buffer and segments move in both directions.
TCP is a reliable and connection oriented transport protocol. It uses an
acknowledgement mechanism to check the safe and sound arrival
of data.
TCP provides flow control and implements an error control
mechanism.
TCP takes into account congestion in the network. The amount of data
sent by a sender is not only controlled by the receiver, but is also
determined by the level of congestion in the network.
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
125317
QUESTION_TEXT
Define Proxy Server. Explain different types of Proxy.
1.
2.
SCHEME OF
EVALUATION
3.
4.
In computer networks, a proxy server is a server (a computer
system or an application) that acts as an intermediary for requests
from clients seeking resources from other servers. A client connects
to the proxy server, requesting some service, such as file,
connection, web page, or other resource available from a different
server. The proxy server evaluates the request as a way to simplify
and control their complexity. (2 marks)
Different types of proxy: Forward Proxy: Forward Proxies are
Proxies where the client server names the largest server to connect
to. Forward “roxies are able to retrieve from a wide range of
resources. (2 marks)
Open Proxy: An Open Proxy is a forwarding proxy server that is
accessible by any Internet user. (1 mark)
Reverse Proxy: A Reverse Proxy (or surrogate) is a proxy server
that appear to clients to be an ordinary server. Requests are
forwarded to one or more origin servers which handle the request.
The response is returned as if it came directly from the proxy server.
Reverse Proxies are installed in the neighborhood of one or more
web servers. All traffic coming from the Internet and with a
destination of one of the neighborhood’s web server goes through
the proxy server. The use of “reverse” originates its counterpart
“forward proxy” since the reverse proxy sits closer to the web server
and servers only a restricted set of websites. Figure below shows
different types of proxies: (5 marks)
(Diagram not required)