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Question 1

switching

Answer 1

helps in deciding the best route for data transmission if there are multiple paths in a larger network. One to one connection

Question 2

switches

Answer 2

Devices capable of creating temporary connections between two or more devices linked to the switches . Some of these switches are connected to the end systems ( computers or telephones) . Others used only for routing

Question 3

taxonomy of switched networks

Answer 3

circuit switched networks, packet switch networks: datagram networks and virtual circuit networks, message switched networks

Question 4

phases in circuit switching

Answer 4

The Setup Phase: means creating dedicated channels between the switches.
Data Transfer Phase: After the establishment of the dedicated circuit (channels), the two parties can transfer data.
Teardown Phase: When one of the parties needs to disconnect, a signal is sent to each switch to release the resources.
until the connection is not closed we cannot used that path

Question 5

circuit switching

Answer 5

A circuit-switched network is made of a set of switches connected by physical links, in which each link is divided into n channels.
Circuit-switched networks are not so efficient as the resources are allocated during the entire duration of the connection.
These resources are unavailable to other connections n If no data, capacity will be waste.

Question 6

circuit switching delay

Answer 6

long initial delay
- low data delay

Question 7

Drawback of Circuit Switched Network

Answer 7

Designed for voice channel
Resource dedicated to particular call
Date Rate is fixed

Question 8

PACKET SWITCHED Network

Answer 8

Messages need to be divided into individual chunks called as
packets.
Each packet is sent individually
Each packet will have source and destination IP address with sequence number.
Sequence number help the receiver to reorder the packet
detect missing packet
send acknowledgments
In a packet-switched network, there is no resource reservation;
resources are allocated on demand

Question 9

Datagram Network

Answer 9

• Each packet (called as datagrams in this approach) is treated independently of all others - All packets (or datagrams) belong to the same message may travel different paths to reach their destination
• This approach can cause the datagrams of a transmission to arrive at their destination out of order with different delays between the packets.
• Packets may also be lost or dropped because of a lack of resources.
• In most protocols, it is the responsibility of an upper- layer protocol to reorder the datagrams or ask for lost datagrams before passing them on to the application.
• The datagram networks are referred to connectionless networks. There are no setup or teardown phases.

Question 10

Virtual-Circuit Networks

Answer 10

-It’s a cross between circuit switched network and datagram network and has some characteristics of both.
Packets from a single message travel
along the same path.
Three phases to transfer data (set up, data transfer and tear down)
Resources can be allocated during setup phase
Data are packetized and each packet carries an address in the header
Implemented in data link layer