In The Name of Allah the Merciful
Name:
Abdallah F. Alghamdi
University Number:
437006796
Subject:
Data Communications – 1st Homework
Date:
Sunday, February 10, 2019
Q1-1 / Identify the five components of a data communications system?
A1-1 /
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Data communication Textbook, Lecture notes of Data Communication Systems and Computer Networks
Data communication and networking
Typology: Lecture notes
2018/2019
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In The Name of Allah the Merciful
Name:
Abdallah F. Alghamdi
University Number:
Subject:
Data Communications – 1st^ Homework
Date: Sunday, February 10, 2019
Q1-1 / Identify the five components of a data communications system?
A1-1 /
- Message
- Sender
- Receiver
- Transmission Medium
- Protocol
Q1-2 / what are the three criteria necessary for an effective and efficient network?
A1-2 /
- Performance
- (^) Reliability
- Security
Q1-3 / what are the advantages of a multipoint connection over a point-to-point one?
A1-3 / the multipoint connection can be shared with multiple devices, unlike point-to- point connection which can establish only connection between to devices via cables or infrared signals.
Q1-4 / what are the two types of line configuration?
A1-4 /
- Point-to-point
- Multipoint
Q1-5 / Categorize the four basic topologies in terms of line configuration?
- Physical Topology : The term physical topology refers to the way in which a network is laid out physically. Two or more devices connect to a link; two or more links form a topology.
Q1-8 / for n devices in a network, what is the number of cable links required for a mesh, ring, bus, and star topology?
A1-8 /
- Mesh : n(n-1)/2 cable link are required.
- Ring : n cable link for ring.
- Bus : n-1 cable link for bus.
- Star : n cable link for star
Q1-9 / what are some of the factors that determine whether a communication system is a LAN or WAN?
A1-9 /
LAN : Local area network is a network that is connected to a computer, which can be in a small office.
WAN: a wide area network is a collection of networks or many LANs.
Q1-10 / what is an internet? What is the Internet?
A1-10 /
internet : is two or more networks that can communicate with each other.
Internet : The most notable internet is called the Internet (uppercase I), and is composed of thousands of interconnected networks
Q1-11 / why are protocols needed?
A1-11 /
When communication is simple, we may need only one simple protocol; when the communication is complex, we may need to divide the task between different layers, in which case we need a protocol at each layer, or protocol layering.
Q1-12 / In a LAN with a link-layer switch (Figure 1.8b), Host 1 wants to send a message to Host 3. Since communication is through the link-layer switch, does the switch need to have an address? Explain
A1-12 /
Each host in a LAN has an identifier, an address that uniquely defines the host in the LAN. A packet sent by a host to another host carries both the source host’s and the destination host’s addresses.
Q1-13 / how many point-to-point WANs are needed to connect n LANs if each LAN should be able to directly communicate with any other LAN?
A1-13 /
Q1-14 / when we use local telephones to talk to a friend, are we using a circuit switched network or a packet-switched network?
A1-14 /
A circuit-switched network
Q1-15 / when a resident uses a dial-up or DLS service to connect to the Internet, what is the role of the telephone company?
A1-15 /
Dial-Up : The first solution is to add to the telephone line a modem that converts data to voice. The software installed on the computer dials the ISP and imitates making a telephone connection.
DSL : The DSL service also allows the line to be used simultaneously for voice and data communication. We discuss DSL in Chapter 14
Q1-16 / what is the first principle we discussed in this chapter for protocol layering that needs to be followed to make the communication bidirectional?
A1-16 /
The first principle dictates that if we want bidirectional communication, we need to make each layer so that it is able to perform two opposite tasks, one in each direction.