CCN Assignment
Chapter 7
Chapter 8
Describe the need for switching and define a switch.
What are the two approaches to packet-switching?
Compare space-division and time-division switches.
Define blocking in a switched network.
A path in a digital circuit-switched network has a data rate of I Mbps. The exchange
of 1000 bits is required for the setup and teardown phases. The distance between
two parties is 5000 km. Answer the following questions if the propagataion speed is
2 X 108 m:
a. What is the total delay if 1000 bits of data are exchanged during the data transfer
phase?
b. What is the total delay if 100,000 bits of data are exchanged during the data
transfer phase?
c. What is the total delay if 1,000,000 bits of data are exchanged during the data
transfer phase?
d. Find the delay per 1000 bits of data for each of the above cases and compare
them. What can you infer?
An entry in the switching table of a virtual-circuit network is normally created
during the setup phase and deleted during the teardown phase. In other words, the
entries in this type of network reflect the current connections, the activity in the
network. In contrast, the entries in a routing table of a datagram network do not
depend on the current connections; they show the configuration of the network and
how any packet should be routed to a final destination. The entries may remain
the same even if there is no activity in the network. The routing tables, however, are
updated if there are changes in the network. Can you explain the reason for these
two different characteristics? Can we say that a virtual-circuit is a connectionoriented
network and a datagram network is a connectionLess network because of the
above characteristics?
Answer the following questions:
a. Can a routing table in a datagram network have two entries with the same destination
address? Explain.
b. Can a switching table in a virtual-circuit network have two entries with the same
input port number? With the same output port number? With the same incoming
VCls? With the same outgoing VCls? With the same incoming values (port, VCI)?
With the same outgoing values (port, VCI)?
Consider an n X k crossbar switch with n inputs and k outputs.
a. Can we say that switch acts as a multiplexer if n > k?
b. Can we say that switch acts as a demultiplexer if n < k?
DEADLINE : TUESDAY 20th Dec, 2016
Chapter 7
What is the position of the transmission media in the OSI or the Internet model?
What is the significance of the twisting in twisted-pair cable?
What is the purpose of cladding in an optical fiber?
How does sky propagation differ from line-of-sight propagation?
A beam oflight moves from one medium to another medium with less density. The
critical angle is 60°. Do we have refraction or reflection for each of the following
incident angles? Show the bending of the light ray in each case.
a. 40°
b. 60°
c. 800
What is the significance of the twisting in twisted-pair cable?
What is the purpose of cladding in an optical fiber?
How does sky propagation differ from line-of-sight propagation?
A beam oflight moves from one medium to another medium with less density. The
critical angle is 60°. Do we have refraction or reflection for each of the following
incident angles? Show the bending of the light ray in each case.
a. 40°
b. 60°
c. 800
Chapter 8
Describe the need for switching and define a switch.
What are the two approaches to packet-switching?
Compare space-division and time-division switches.
Define blocking in a switched network.
A path in a digital circuit-switched network has a data rate of I Mbps. The exchange
of 1000 bits is required for the setup and teardown phases. The distance between
two parties is 5000 km. Answer the following questions if the propagataion speed is
2 X 108 m:
a. What is the total delay if 1000 bits of data are exchanged during the data transfer
phase?
b. What is the total delay if 100,000 bits of data are exchanged during the data
transfer phase?
c. What is the total delay if 1,000,000 bits of data are exchanged during the data
transfer phase?
d. Find the delay per 1000 bits of data for each of the above cases and compare
them. What can you infer?
An entry in the switching table of a virtual-circuit network is normally created
during the setup phase and deleted during the teardown phase. In other words, the
entries in this type of network reflect the current connections, the activity in the
network. In contrast, the entries in a routing table of a datagram network do not
depend on the current connections; they show the configuration of the network and
how any packet should be routed to a final destination. The entries may remain
the same even if there is no activity in the network. The routing tables, however, are
updated if there are changes in the network. Can you explain the reason for these
two different characteristics? Can we say that a virtual-circuit is a connectionoriented
network and a datagram network is a connectionLess network because of the
above characteristics?
Answer the following questions:
a. Can a routing table in a datagram network have two entries with the same destination
address? Explain.
b. Can a switching table in a virtual-circuit network have two entries with the same
input port number? With the same output port number? With the same incoming
VCls? With the same outgoing VCls? With the same incoming values (port, VCI)?
With the same outgoing values (port, VCI)?
Consider an n X k crossbar switch with n inputs and k outputs.
a. Can we say that switch acts as a multiplexer if n > k?
b. Can we say that switch acts as a demultiplexer if n < k?
DEADLINE : TUESDAY 20th Dec, 2016
