Data Communication and Computer Networks - Functions of OSI and TCP/IP Layers
6. The address resolution protocol (ARP) is used for
- Option : D
- Explanation : The Address Resolution Protocol (ARP), allows a host to find the MAC (Physical) address of a target host on the same physical network, given only the targets IP address.
7. Which of the following assertions is FALSE about the Internet Protocol (IP)?
- A
It is possible for a computer to have multiple IP addresses
- B
IP packets from the same source to the same destination can take different routes in the network
- C
IP ensures that a packet is forwarded if it is unable to reach its destination within a given number of hopes
- D
The packet source cannot set the route of an outgoing packets; the route is determined only by the routing tables in the routers on the way
- Option : D
- Explanation : The packet source cannot set the route of an outgoing packets; the route is determined only by the routing tables in the routers on the way.
8. Packets of the same session may be routed through different paths in
- Option : A
- Explanation : TCP and UDP are Transport layer protocols. Packets of same session may be routed through different routes.
- Option : D
- Explanation : The following data is given
File Size = 1000 bytes
Header Size = 100 bytes
Transmission Speed of all links = 10^6 bytes/sec
Case (1) :
Transmission time for one link
= packetsize/bandwidth
= (1000 + 100)/10^6
= 1100 microsecond.
So, Total time(T1) is 3*1100
= 3300 microsecond
Case (2) :
Transmission time for one link and one part
= (100 + 100)/10^6
= 200 microseccond
Note : While a packet is being transmitted from R1 to R2, at the same time other packet is being transmitted from A to R1.
So, Total time(T2) = 3 * 200 + 9 * 200
= 2400 microsecond
Case (3) :
Transmission time for one link and one part
= (50 + 100)/10^6
= 150 microsecond
Total time (T3) = 3 * 150 + 19 * 150
= 3300 microsecond
hence T1 = T3, T3 > T2
| Field | Length in bits |
| P. UDP Header’s Port Number | I . 48 |
| Q. Ethernet MAC Address | II . 8 |
| R. IPv6 Next Header | III . 32 |
| S. TCP Header’s Sequence Number | IV. 16 |
CODES :
| Â | P | Q | R | S |
| (A) | III | IV | II | I |
| (B) | II | I | IV | III |
| (C) | IV | I | II | III |
| (D) | IV | I | III | II |
- Option : C
- Explanation : UDP Header’s Port Number ⇒ 16 bit Ethernet MAC Address ⇒ 48 bit IPv6 Next Header ⇒ 8 bit TCP Header’s Sequence Number ⇒ 32 bit
