Subject: Data Communications and Computer Networks Christophides Theodoros Code: ACOE 312

curvyrawrNetworking and Communications

Oct 23, 2013 (3 years and 7 months ago)

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Subject:
Data Communications and Computer Networks

Christophides
Theodoros

Code: ACOE 312





Tutorial 2


1.

Explain the term protocol and give the reasons for using layered protocols.

2.

Mention the two disadvantages of layered protocols.

3.

What does OSI stand for?

4.

Using a suitable diagram list all the layers of the
OSI

Reference model and
define and

br
iefly explain the functionality of each layer.

5.

Which layer of the OSI reference model is responsible for the following:

a.

Negotiating data transfer syntax




b.

Addressing devices and routing through an internetwork
Network

c.

Framing


d.

Flow control, acknowledgem
ent, windowin
g

e.

Coordinating communications between systems


f.

Synchronizing sending and receiving applications

g.

Dividing the transmitted bit streams into frames

h.

Determine which route through the subnet to use

6.

At which layer of the OSI reference model are the
following components
positioned?

a.

Router

b.

Repeater

c.

Switch

d.

Hub



7.

A system has an n
-
layer protocol hierarchy. Applications generate messages of
length M
-
bytes. At each of the layers, an h
-
byte header is added. What fraction
of the network bandwidth is filled
with headers?

8.

Contrast and criticize OSI and TCP reference models outlining their
similarities and differences.

9.

Compare OSI and TCP/IP reference models with respect to

a.

Their layers

b.

Their similarities

c.

Their differences

d.

Their critiques

10.

Contrast the OSI ref
erence model vs real world.

11.

What do TCP and stand for?

12.

What is the main difference between TCP and UDP protocols? Give an
example of a service these protocols can support?