2MARKS

1. UNIT-2
1. Define hidden node problem. MAY/JUNE 2016
It is a situation that occurs on a wireless network where two nodes A and C are sending to a
common destination at the same time because A and C not aware of each other’s transmission.
Eg:
A and C both are within the range of B but not each other. Suppose both A and C wants to
communicate with B. But A and C are unaware of each other and so their frames collide with
each other at B. As A and C is unaware of this collision they are said to be hidden nodes with
respect to each other.
A,B,C are nodes in networking
2. What is Bluetooth? NOV/DEC 2012, MAY/JUNE 2016
 Bluetooth is designed for communication over short distances (on the order of 10 m) with
a bandwidth of 1 Mbps.
 It fills the place of very short-range communication between mobile phones, PDAs,
notebook computers, and other personal or peripheral devices.
 For example, Bluetooth can be used to connect mobile phones to a headset, or a notebook
computer to a printer.
Advantages:
 It creates adhoc connection immediately without any wires.
 It has low power consumption.
 It has range better than Infrared communication.
 Bluetooth devices are available at very cheap cost
3. Write the types of connecting devices in internetworking. MAY/JUNE 2016
1. Hub
2. Repeater
3. Modem, NIC (Network Interface Card)
4. Media Converters, Basic Switches and Bridges
4. Expand ICMP and write the function. MAY/JUNE 2016 , MAY /JUNE 2015
 IP is always configured with a companion protocol known as the Internet Control
Message Protocol (ICMP).
 It defines 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.
For example, ICMP defines the following error messages
 Source Quench
 Time Exceeded

2.  Parameter Problem
 Redirection
 Destination Unreachable
5. What is meant by exponential back-off? NOV/DEC 2016
 It is a retransmission strategy that doubles the timeout value each time, when a packet is
retransmitted.
 Once an adaptor has detected a collision and stopped its transmission, it waits a certain
amount of time and tries again. Each time it tries to transmit but if it fails again, then the
adaptor doubles the amount of time. This strategy of doubling the delay interval between
each retransmission attempt is a general technique known as exponential back-off.
6. What is scatternet? NOV/DEC 2016
 A scatternet is a type of ad hoc computer network consisting of two or more piconets.
 It is defined as a number of interconnected piconets that supports communication
between more than 8 devices.
 Upto 8 devices can communicate in a small network and is called as piconets.
 The terms "scatternet" and "piconet" are typically applied to bluetooth wireless
technology.
7. Define subnetting. NOV/DEC 2015
 A subnetwork or subnet is a single IP network address to denote multiple physical
networks.
 Routers within a subnetwork use a subnet mask to discover the physical network to
which a packet should be forwarded.
 Subnetting effectively introduces a third level to the two-level hierarchical IP address.
Advantage:
Address space utilization
Subnetting
8. What is the need of ARP? NOV/DEC 2015
 ARP (Address Resolution Protocol) is a mechanism to determine the MAC address of
the node.
 It is used to translate global IP addresses into local link-layer addresses.
9. Identify the class of the following IP address: NOV/DEC 2015
(a) 110.34.56.45
(b) 212.208.63.2

3. Answers:
Ranges for communication:
CLASS A : 0.0.0.0 to 127.255.255.255
CLASS B : 128.0.0.0 to 191.255.255.255
CLASS C :192.0.0.0 to 223.255.255.255
CLASS D :224.0.0.0 to 239.255.255.255
CLASS E :240.0.0.0 to 255.255.255.255
(a) 110.34.56.45 - ClassA
(b) 212.208.63.23- Class C
10. What is the average size of an Ethernet frame? APR/MAY 2014, NOV/DEC 2017
 The Ethernet IEEE 802.3 standard defined the minimum Ethernet frame size as 64 bytes
 The Ethernet IEEE 802.3 standard defined the maximum Ethernet frame size as 1518 bytes.
 The maximum was later increased to 1522 bytes to allow for VLAN classification.
Ethernet frame format
11. What are the access methods used by wireless LAN? APR/MAY 2014
 Frequency Division Multiple Access (FDMA)
 Time Division Multiple Access (TDMA)
 Code Division Multiple Access (CDMA)
 Space Division Multiple Access (SDMA)
12. State the uses of valid transmission timer. NOV/DEC 2014
 The Valid Transmission Timer (TVX) calculates the period between correct frame
transmissions, therefore it is used to check for faults on the ring. If it expires then a new
claim process begins.
13. What is the purpose of Network Interface Card? MAY/JUNE 2013
 A network interface controller or card is a computer hardware component that connects a
computer to a computer in a network society.
 It manages or controls the wired & wireless connection to exchange the information
between PC’s & internet.
14. What are Virtual LANs? MAY/JUNE 2013
 To increase the scalability of extended LANs .
 VLANs allow a single extended LAN to be partitioned into several separate LANs.
 Each virtual LAN is assigned an identifier and packets can only travel from one segment to
another if both segments have the same identifier.
Advantages:
Like a router, it partitions the network into logical segments, which provides better
administration, security, and management of multicast traffic.

4. Virtual LANs
15. Why IPV6 is preferred than IPV4? NOV/DEC 2013, MAY/JUNE 2013 , APRIL/ MAY 2017
IPng or IPV6 were
 Support for real-time services.
 Security support is more.
 Auto configuration (i.e., the ability of hosts to automatically configure themselves
with such information as their own IP address and domain name)
 Enhanced routing functionality, including support for mobile hosts
Internet Protocol (also known as IPv4).
 Support connectionless service
 Support best-effort delivery service of datagram across the internet
Compared with IPv4 and IPv6, IPv6 supports multiple networking features than IPv4.
16. What is the use of multicast routing? NOV/DEC 2013
 Multicast routing protocols are used to distribute data (for example, audio/video
streaming broadcasts) to multiple recipients simultaneously.
 In multicast, a source can send a single copy of data to a single multicast address, which
is distributed to an entire group of recipients.
17. Why Ethernet is said to be an I-persistent protocol? NOV/DEC 2012
An adaptor with a frame transmits with probability “1” whenever a busy line
goes idle is said to be a I-persistent protocol.
18. Define ICMP. NOV/DEC 2012
Internet Control Message Protocol (ICMP).
 This protocol is an integral part of IP.
 It allows a router or destination host to communicate with the source, typically to
report an error in IP datagram processing.
19. When is ICMP redirect message used? APR/ MAY 2017
 The ICMP redirect message is used to notify a remote host to send the data packets
on an alternative route.
 Redirects the message only through gateways.

5. 20. What is DHCP? NOV/DEC 2012
The Dynamic Host Configuration protocol has been derived to provide dynamic
configuration. DHCP is also needed when a host moves from network to network or is
connected and disconnected from a network.