Indicate True/False for the following statements. a) The IP address 128.20.30.54
ID: 3690349 • Letter: I
Question
Indicate True/False for the following statements. a) The IP address 128.20.30.54 is a class-B IP address b) UDP implements congestion control function c) CSMA/CD is used in both wired and wireless networks d) FTP is a network layer protocol e) ARP protocol translates a MAC address into an IP address. 2) For each of the following functions, provide the name of the layer in the TCP/IP model, a) Error detection and correction, b) Media access control, c) Congestion control, d)Routing, e) end-to-end reliable delivery Section B 1) Describe the difference between the client/server model and the peer-to-peer model of applications. 2) Sketch the packet format of an HTTP packet transmitted on Ethernet. Show all packet headers and trailers (i.e. all lower layer protocols used by HTTP). You do not need to show the contents of the headers or trailers. 3) Why do HTTP, FTP and SMTP run on top of TCP rather than on UDP? 4) State three differences between TCP and UDP. 5) What is subnetting? Why it is needed? 6) Is CSMA/CD used in wireless networks? If not, why?Explanation / Answer
Section - A
1) TRUE/FALSE
a) True - as class B networks start from 128.1.0.0 to 191.255.0.0
b) False - UDP cannot implement congestion control function. TCP can provide this funtion
c) False - CSMA/CD can't be used in wireless networks
d) False - FTP is a transport layer protocol
e) False - ARP can convet IP address to MAC but not the reverse
2) Name of layer in TCP/IP model
a) Error detection and correction - datalink layer
b) Media Access Control - datalink layer
c) congestion control - transport layer
d) routing - network layer
e) end to end reliable delivery - transport layer
Section - B
1) Difference between client/ server model and peer to perr model
2) Format of HTTP Packet
3) why do HTTP, FTP and SMTP run on top of TCP rather than on UDP?
the above protocols all assume the presence of a sequenced, loss-free data stream transport. The TCP service is perfectly to those higher level protocols. UDP only sends datagrams and does not manage connection, retransmission, or data sequencing. For protocols that CAN stand losing data or prefer a data pacing strategy other than what TCP provides, UDP is a better choice. Streaming audio and video services where the data streams are designed to endure data losses can sometimes do better with the more lightweight UDP protocol.
4) TCP and UDP differences
5) Subnetting and why it is needed?
Subnetting is a process of dividing large network into the smaller networks based on layer 3 IP address.
6) CSMA/CD is not used in wireless networks. The physical characteristics of WiFi make it impossible and impractical for the CSMA/CD mechanism to be used. This is due to CSMA/CD’s nature of ‘listening’ if the medium is free before transmitting packets. Using CSMA/CD, if a collision is detected on the medium, end-devices would have to wait a random amount of time before they can start the retransmission process. For this reason, CSMA/CD works well for wired networks, however, in wireless networks, there is no way for the sender to detect collisions the same way CSMA/CD does since the sender is only able to transmit and receive packets on the medium but is not able to sense data traversing that medium.
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