CS2302 – COMPUTER NETWORKS
TWO MARKS
UNIT-III-Circuit switching vs. packet switching / Packet switched
networks – IP – ARP – RARP DHCP – ICMP – Queueing discipline – Routing algorithms
– RIP – OSPF – Subnetting– CIDR – Interdomain routing – BGP – Ipv6 –
Multicasting – Congestion avoidance innetwork layer
1. Define packet switching?
A
packet switch is a device with several inputs and outputs leading to and
from the hosts that the switch
interconnects.
2. What is a virtual circuit?
A
logical circuit made between the sending and receiving computers. The
connection is made after both computers do handshaking. After the connection,
all packets follow the same route and arrive in sequence.
3. What are data grams?
In datagram
approach, each packet is treated independently from all others. Even when one
packet represents just a place of a multi packet transmission, the network
treats it although it existed alone. Packets in this technology are referred to
as datagram.
4. What is meant by switched virtual circuit?
Switched virtual
circuit format is comparable conceptually to dial-up line in circuit switching.
In this method, a virtual circuit is created whenever it is needed and exits
only for the duration of specific exchange.
5. What is meant by Permanent virtual circuit?
Permanent
virtual circuits are comparable to leased lines in circuit switching. In this method, the same virtual circuit is
provided between two uses on a continuous basis. The circuit is dedicated to
the specific uses.
6. What are the properties in star topology?
·
Even though a switch has a fixed number of
inputs and outputs, which limits the number of hosts that can be connected to a
single switch , large networks can be
built by interconnecting a number of switches.
·
We can connect switches to each other and to
hosts using point-to point links, which typically means that we can build
networks of large geographic scope.
7. What is VCI?
A
Virtual Circuit Identifier that uniquely identifies the connection at this
switch, and which will be carried inside the header of the packets that belongs
to this connection.
8. What is hop-by-hop flow control?
Each
node is ensured of having the buffers it needs to queue the packets that arrive
on that circuit. This basic strategy is usually called hop-by-hop flow control.
9. Explain the term best-effort?
If
something goes wrong and the packet gets lost, corrupted, misdelivered, or in
any way fails to reach its intended destination, the network does nothing.
10. What is maximum transmission unit?
MTU-
which is the largest IP datagram that it can carry in a frame .
11. Define Routing?
It
is the process of building up the tables that allow thwe collect output for a
packet to be determined.
12. Define ICMP?
Internet
Control Message Protocol is a collection of error messages that are sent back
to the source host whenever a router or host is unable to process an IP
datagram successfully
13. Write the keys for understanding the distance vector routing?
The three keys
for understanding the algorithm are,
·
Knowledge about the whole networks
·
Routing only to neighbors
·
Information sharing at regular intervals
14. Write the keys for understanding the link state routing?
The three keys
for understanding the algorithm are,
·
Knowledge about the neighborhood.
·
Routing to all neighbors.
·
Information sharing when there is a range.
15. How the packet cost referred in distance vector and link state
routing?
In distance
vector routing, cost refer to hop count while in case of link state routing,
cost is a weighted value based on a variety of factors such as security levels,
traffic or the state of the link.
16. Define Reliable flooding?
It
is the process of making sure that all the nodes participating in the routing
protocol get a copy of the link state information from all the other nodes.
17. What are the features in OSPF?
·
Authentication of routing messages.
·
Additional hierarchy.
·
Load balancing.
18. Define Subnetting?
Subnetting
provides an elegantly simple way to reduce the total number of network numbers
that are assigned. The idea is to take a single IP network number and allocate
the IP address with that network to several physical networks, which are now
referred to as subnets.
19. What are the different types of AS?
·
Stub
AS
·
Multi homed AS
·
Transit
AS
20. What is an Area?
An
Area is a set of routers that are administratively configured to exchange
link-state information with each other. There is one special area- the backbone
area, also known as area 0.
21. What is Source Specific Multicast?
SSM
, a receiving host specifies both a multicast group and a specific host .the
receiving host would then receive multicast addressed to the specified group,
but only if they are from the special sender.
22. What is meant by congestion?
Congestion in a network occurs if
user sends data into the network at a rate greater than that allowed by network
resources.
23. Why the congestion occurs in network?
Congestion occurs because
the switches in a network have a limited buffer size to store arrived packets.
24. What are the rules of non boundary-level masking?
·
The bytes in the IP address that corresponds to
255 in the mask will be repeated in the
sub network address
·
The bytes in the IP address that corresponds to
0 in the mask will change to 0 in the
sub network address
·
For other bytes, use the bit-wise AND operator.
25 .With a neat diagram explain the relationship of IEEE Project to the
OSI model?
The IEEE has subdivided the data link layer into two sub layers:
* Logical link control (LLC)
* Medium access control (MAC)
LLC is non-architecture specific. The MAC sub layer contains a
number of distinct modules, each carries proprietary information specific to
the LAN product being used.
26. What
is meant by brouter?
A brouter is a single protocol or
multiprotocol router that sometimes act as a router and sometimes act as a
bridge.
27. Write the keys for understanding the
distance vector routing.
The three keys for understanding the
algorithm are
· Knowledge about the whole networks
· Routing only to neighbors
· Information sharing at regular intervals
28.What is CIDR?(MAY/JUNE2007)
Classless
Inter-Domain Routing (CIDR) is a methodology of allocating IP addresses
and routing Internet Protocol packets. It was introduced in
1993 to replace the prior addressing architecture of classful
network design in the Internet with the goal to slow the growth of routing tables
on routers across the Internet, and to help slow the rapid exhaustion of IPv4 addresses.
CIDR
notation uses a syntax of specifying IP addresses for IPv4 and IPv6, using
the base address of the network followed by a slash and the size of the routing
prefix, e.g., 192.168.0.0/16 (IPv4), and 2001:db8::/32 (IPv6).
29.What is
ARP and RARP?(MAY/JUNE 2009)
ARP stands for Address
Resolution Protocol.It is used to convert IP address to Physical address
RARP
stands for Reverse Address Resolution Protocol.It is used to convert Physical
address into IP address
ALSO READ ..!
UNIT I NOTES
UNIT II NOTES
UNIT III NOTES
UNIT IV NOTES
UNIT V NOTES
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