The Connectionless Unreliable Service

Published Date: 02 Nov 2017

The Internet provides two services to its applications: a connection oriented reliable service TCP/IP and a connectionless unreliable service UDP/IP.

TCP/IP: the connection oriented reliable service guarantees that data transmitted from a sender to a receiver will eventually be delivered to the receiver in order and in its entirety.

UDP: The connectionless unreliable service does not make any guarantees about eventual delivery.

Answer for Q 2

The TDM has an advantage to being capable to use all of bandwith "multiplexing".

Answer for Q 3

The Ethernet usually runs over twisted-pair, copper wire. It is also can run over Coaxial Cable, Fiber Optics link, Terrestrial Radio Channels and Satellite Radio Channels.

Answer for Q 4

range of transmission rates

bandwidth

Dial-up

Up to 56 kbps

dedicated

ISDN

Up to 128 kbps

dedicated

DSL

5 to 8Mbps downstream

Up to 1Mbps upstream

dedicated

HFC

10 to 30 Mbps downstream.

2Mbps upstream, usually lower than a few Mbps

shared

Answer for Q5

The components of delay are four:

Processing delay: fixed

Queuing: variable

Transmission: fixed

Propagation: fixed

Answer for Q 6

In the Virtual circuit network, the exchange of information happens in custom path between the source and the destination, and each path is given a number of active virtual circuits.

The routers here needs to maintains information on this path which is interface data coming from specific interface to be redirected to the correct interface. This is called the connection state information.

Briefly, the connection status information is the information needed, which is the maintained by router to redirect data to the correct interface, during an active connection.

Answer for Q 8

Commonly a router process layers from 1 to 3 (Network layer, data link layer and physical layers), as also some of modern routers works as firewalls or as a caching, thus process layers will be four.

Answer for Q 10

A)

For a process on one host to identify a process on another host, the sending process must identify the receiving process. To do that, must specify two pieces of information

The IP address of the destination host

And the port number of the destination socket

B)

Handshaking protocol uses when a two communicating entities first exchange controls packets before sending data to each other.

In another way, when a computerA connects to computerB, the first thing must do is contact computerB and asking for identify and then for connect. Than the ComputerB must decide to accept, deny or ignore. and then the connection tells ComputerB about the connection state, (accepted, denied or ignored).

E.g : SMTP uses handshaking at the application layer.

C)

Because, all of this applications associated with these protocols require that all application data must be received in correct order and without loss data or any gaps. TCP provides this service, while UDP not.

D)

Because the control information is not sending over the same connection which the file is sent over.

Typically FTP uses 2 parallel of TCP connections, first one is for sending control information and the second is for transferring data.

Answer for Q 12

A)

Yes it’s to be reliable; application developers may put reliable data transfer into application layer protocol. This operation may require a great deal of work and corrections.

First segment contains = 110 – 90 = 20 bytes.

C)

Because of relatively property of the TCP protocol. Both should have the same connections rate.

Transmission rate = R/2

Answer for Q 13

A)

As known that the role of the network layer is to move packets from a sending host to a receiving host.

The two main functions of the datagram-based network layer are:

1. Routing / Path determination: The network layer determining the route or path taken by packets as it flow from the sender to the receiver.

2. Forwarding: When a packet arrives to the router's input, the router must move a packet to the appropriate output link. (From router’s input to appropriate router output).

The additional function of a VC-based network is call setup.

B)

The OSPF advertisement uses Link state algorithm, this means the router regularly broadcasts information to all of other routers not just to its neighboring routers. This information which sent by a router have one entry for each of the router’s, that can get the distance information from the sender router to the receiver.

The RIP advertisement uses Distance Vector Algorithm, it sends by a router contains information about all routers in the same networks and this information is only sent to this known routers in the network.

C)

Switching via memory

Here the Packet copied by systems, the problem is the speed limited by memory bandwidth.

Switching via bus:

Here the packets moves from input port of memory to output port memory through a shared bus, the Bus contention makes a problem with this type which means limited speed by bus bandwidth

Switching via an interconnection network

It comes to the bus bandwidth limitations

Advanced design: fragmenting the datagram to fixed length cells, switch cells via the fabric

The interconnection networks initially developed to connect processors in multiprocessor.

D)

The Main changes are:

Larger addresses. The addresses size changes from 32 bits to 128 bits

Extended Address Hierarchy. IPv6 uses the larger address space to create additional levels of addressing hierarchy.

Improved Options.

Support for auto-configuration and renumbering

Provision for protocol extension

Flexible Header Format.

Support for Resource allocation.

The following table listing the differences between IPv4 and IPv6.

IPv4 

IPv6

IPv4 address is 32 bit length

IPv6 address is 128 bit length

IPsec support is optional only

Inbuilt IPSec support

The Fragmentation are done by sender and forwarding routers

Fragmentation is done by sender only

There is no packet flow identification

Packet flow identification is available in the IPv6 header using a flow label field

Checksum field is an available in header

No checksum field in the header

Option fields are available in the header

No option fields. But Extension header is available

ARP is available to assign IPv4 addresses into MAC addresses

ARP is replaced with Neighbor Discovery Protocol

IGMP is uses to manage multicast group membership

IGMP is replaced with Multicast Listener Discovery (MLD) message

Broadcast message is available

Broadcast messages are not available

Manual configuration of IP addresses "Static" or Dynamically Configuration "DHCP" to configure IP addresses

Auto configure of IP addresses are available

Answer of Q 14

1*1 = 0 1*0 = 1 0*0 = 0

1*0*1*0*1*0*1*0*1*0*1*0*1*0*1*1 = 1

The Value of checksum = 1

Answer for Q 15

Yes it will be there a collision, means that while a node is transmitting, it will begin to receive a packet from the other node.

sequence.

Answer for Q 17

While a node transmits a frame, the node must wait for a frame to propagate over the whole ring before a node release the token. So if transmission rate is small as compared to time propagation, then the protocol will be inefficient.

Answer for Q 18

Lan = 48 bit

IPv4 = 32 bit

IPv6 = 128 bit

Answer for Q 20

A)

The services that link-layer protocol can offer to network layer are

Framing: there is framing in IP and TCP too.

Reliable delivery: there is reliable delivery in TCP.

Link access.

Flow control: there is flowing control in TCP too.

Error correction.

Error detection: there are error detections in IP and TCP.

Full duplex: in TCP also there is Full duplex.

B)

All of three have the similar frame structures; the difference is just in transmission speeds, which are 10, 100 and 1000 Mbps per seconds.

End-to-end delay is the time that packet takes to travel via the network starts from the source to destination.

Delay jitter is the fluctuation of end-to-end delay from packet to the next packet.

Jitter is the variation in the time between packets arriving (packet transit delay), causes by queuing, network congestion, route changes and sequence effects on the path through the network.

Answer for Q 23

Streaming stored audio/video means the: pause/resume, fast-forward and re-positioning.

Real-time interactive audio and video is people communicating and responding in real time.