CS2302 – COMPUTER NETWORKS
TWO MARKS
UNIT-IV- UDP – TCP – Adaptive Flow Control – Adaptive Retransmission -
Congestion control –Congestion avoidance – QoS
1. Explain the main idea of UDP?
The basic idea is for a source
process to send a message to a port and for the destination process to receive
the message from a port.
2. What are the different fields in pseudo header?
·
Protocol number
·
Source IP address
·
Destination IP addresses.
3. Define TCP?
TCP guarantees the reliable, in
order delivery of a stream of bytes. It is a full-duplex protocol, meaning that
each TCP connection supports a pair of byte streams, one flowing in each
direction.
4. Define Congestion Control?
It involves preventing too much
data from being injected into the network, thereby causing switches or links to
become overloaded. Thus flow control is an end to an end issue, while
congestion control is concerned with how hosts and networks interact.
5. State the two kinds of events trigger a state transition?
·
A segment arrives from the peer.
·
The local application process invokes an
operation on TCP.
6. What is meant by segment?
At the sending and receiving end
of the transmission, TCP divides long transmissions into smaller data units and
packages each into a frame called a segment.
7.
What is meant by segmentation?
When the size of the data unit
received from the upper layer is too long for the network layer datagram or
data link layer frame to handle, the transport protocol divides it into smaller
usable blocks. The dividing process is called segmentation.
8. What is meant by Concatenation?
The size of the data unit
belonging to single sessions are so small that several can fit together into a
single datagram or frame, the transport protocol combines them into a single
data unit. The combining process is called concatenation.
9. What is rate based design?
Rate-
based design, in which the receiver tells the sender the rate-expressed in
either bytes or packets per second – at which it is willing to accept incoming
data.
10. Define Gateway.
A device used to connect two
separate networks that use different communication protocols.
11. What is meant by quality of service?
The quality of service defines a
set of attributes related to the performance of the connection. For each
connection, the user can request a particular attribute each service class is
associated with a set of attributes.
12. What are the two categories of QoS attributes?
The two main categories are,
·
User Oriented
·
Network Oriented
13. List out the user related attributes?
User related attributes are SCR –
Sustainable Cell Rate PCR – Peak Cell Rate MCR- Minimum Cell Rate CVDT – Cell
Variation Delay Tolerance.
14. What are the networks related attributes?
The network
related attributes are, Cell loss ratio (CLR) Cell transfer delay (CTD) Cell
delay variation (CDV) Cell error ratio (CER).
15. What is RED?
Random
Early Detection in each router is programmed to monitor its own queue length and
when it detects that congestion is imminent, to notify the source to adjust its
congestion window.
16. What are the three events involved in
the connection?
For security, the transport layer may
create a connection between the two end ports. A connection is a single logical
path between the source and destination that is associated with all packets in
a message. Creating a connection involves three steps:
·
Connection establishment
·
Data transfer
·
Connection release
17. What is the difference between service
point address, logical address and physical address? Service point addressing
Logical addressing Physical addressing
Service point addressing
|
Logical addressing
|
Physical addressing
|
The transport layer header
includes a type of address
called a service point
address or port address,
which makes a data delivery
from a specific process on
one computer to a specific
process on another
computer.
|
If a packet passes the
network boundary we need
another addressing to
differentiate the source and destination
systems. The network layer adds a
header, which indicate the
logical address of the sender
and receiver.
|
If the frames are to be
distributed to different
systems on the network, the
data link layer adds the
header, which defines the source machine’ s
address
and the destination
Machine’ s address.
|
·
17.What
is Silly Window Syndrome(NOV/DEC 2007)
If the sender or the receiver application program
processes slowly and can send only 1 byte of data at a time, then the overhead
is high.This is because to send one byte of data, 20 bytes of TCP header and 20
bytes of IP header are sent. This is called as silly window syndrome.
ALSO READ ..!
UNIT I NOTES
UNIT II NOTES
UNIT III NOTES
UNIT IV NOTES
UNIT V NOTES
CS 2302 CN - 16 MARKS
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