AnsAnsAnsName: Jinesh G. SanghviCIS617 Final Term Question BankQ1 Compare the Connection oriented and connectionless oriented internetworking approaches?Ans Connection Oriented: Advantages:1. Buffers can be reserved in advance2. Sequencing can be guaranteed.3. Short headers.Disadvantages:1. No alternate routing around congestion.2. Vulnerability to router failures along the path.3. Requirement of table spaces at the routers.4. Difficult to implement if one of the networks involved is an unreliable datagram network.Connectionless Oriented approach:Advantages :1. Can be used to connect subnets without VC’s inside.2. Robust to router failures.3. More potential for adapting congestionDisadvantages :1. No sequencing.2. Longer headers.Q2. Explain Fragmentation? Explain different types of Fragmentation with their advantages and disadvantages?AnsFragmentation: When a large packet wants to travel through a network whose maximumpacket size is too small to handle, then the packet is break up into small chunks called fragments and each fragment is sent as a separate Internet packet.Transparent Fragmentation: This strategy makes fragmentation caused by a “small packet” network transparent to any subsequent networks through which the packet must pass on its way to ultimate destination.. In this approach when an oversized packet arrives at a gateway, the gateway breaks it up into fragments. Each fragment in addressed to the same exit gateway, where the pieces are recombined. In this way passage through the small-packet network has been made transparent and the subsequent networks are not even aware that fragmentation has occurred. Eg : ATM Disadvantages : 1. The exit gateway must know when it has received all the pieces, so a count field or an “end of packet” bit must be provided.2. All fragments must exit via the same exit gateway.3. Overhead required to repeatedly reassemble and then re-fragment a large packet passing through a series of small-packet networks.Non-Transparent Fragmentation: This strategy refrains from recombining fragments at any intermediate gateways. Once a packet has been fragmented, each fragment is treated as though it were an original IP packet. Advantages :1. Multiple exit gateways can be used because reassembly occurs only at the destination host, and thereby higher performance can be achieved. Disadvantage : The total overhead increases, as each fragment must have a header.Q3. Give the different techniques of dropping packets to disappear congestion.AnsLoad Shedding: A router drowning in packets can just pick packets to drop depending onthe application running. There are two policies:a. Wine (drop new packets and keep old) : For file transfer an old packet is worth more than a new one because dropping packet 6 and keeping packets 7 through10 will cause a gap at the receiver that may force packet 6 through 10 to be re transmitted(if the receiver routinely discards out-of-order packets).b. Milk (drop old packets and keep new) : For multimedia a new packet is more important then the old one because a user may not mind dropping few packets while using real time applications.Random Early detection: When the average queue length exceeds a threshold, packets are picked at random from the queue and discarded.Q4. Explain the 6 one bit flags in the TCP headerAns URG : URG is set to 1 if the urgent pointer is in use. The urgent pointer is used to indicatea byte offset from the current sequence number at which urgent data are to be found.ACK : The ACK bit is set to 1 to indicate that the Acknowledgement number is valid. If ACK is 0, the segment does not contain an acknowledgementso the acknowledgement number field is ignored.PSH : The PSH bit indicates PUSHED data. The receiver is hereby kindly requested to deliver the data to the application upon arrival and not buffer it until a full buffer has beenreceivedRST : The RST bit is used to reset a connection that has become confused due to a host crash or some other reason. It is also used to reject an invalid segment or refuse anattempt to open a connection.SYN : The SYN bit is used to establish connections. The connection reques has SYN =1 and ACK =0 to indicate that the piggy back acknowledgement field is not in use. The connection reply doesnot bear an acknowledgement, so it has SYN = 1 and ACK =1. In essence the SYN bit is used to denote CONNECTION REQUEST and CONNECTION ACCEPTED, with the ACK bit used to distinguish between those two possibilities.FIN : The FIN bit is used to release the connection. It specifies that the sender has no more data to transmit.Q5. Given the Class C network of 204.15.5.0/24, subnet the network in order to create thefollowing network with the host requirements shown. Looking at the above network, you can see that you are required to create five subnets. The largest subnet must support 28 host addresses. Is this possible with a Class C network? and if so, then how?You can start by looking at the subnet requirement. In order to create the five needed subnets you would need to use three bits from the Class C host bits. Two bits would only allow you four subnets (22).Since you need three subnet bits, which leaves you with five bits for the host portion of the address. How many hosts will this support? 25 = 32 (30 usable). This meets the requirement.Therefore you have determined that it is possible to create the above network with a Class C network. An example of how you might assign the sub-networks is as follows:netA: 204.15.5.0/27 host address range 1 to 30netB: 204.15.5.32/27 host address range 33 to 62netC: 204.15.5.64/27 host address range 65 to 94netD: 204.15.5.96/27 host address range 97 to 126netE: 204.15.5.128/27 host address range 129 to