Computer Architecture and Organization MCQs | Page - 6

 in packet switching, the bits are received in out of order and need to be assembled at the receiver end, whereas in the case of circuit switching, all the bits are received in order. all transmissions may not occur through the same path in case of packet switching.

 application layer is the topmost layer in the osi model. network virtual terminal, mail service, file transfer, access and management are all services of the application layer. it uses protocols like http, ftp, and dns etc. to provide these services.

 the protocol field enables the demultiplexing feature so that the ip protocol can be used to carry payloads of more than one protocol type. its most used values are 17 and 6 for udp and tcp respectively. icmp and igmp are network layer protocols.

 data field usually has transport layer segments, but it can also carry icmp messages. smtp is an application layer protocol. first it must go through the transport layer to be converted into tcp segments and then it can be inserted into ip packets.

 fragmentation makes the implementation of the ip protocol complex and can also be exploited by attackers to create a dos attack such as a teardrop attack. fragmentation won’t be required if the transport layer protocols perform wise segmentation.

 an ip address which is 32 bits long, that means it is of 4 bytes and is composed of a network and host portion and it depends on address class. the size of the host address and network address depends upon the class of the address in classful ip addressing.

 the routing algorithm is what decides where a packet should go next. there are several routing techniques like shortest path algorithm, static and dynamic routing, decentralized routing, distance vector routing, link state routing, hierarchical routing etc.

 in multi-destination routing, there is more than one receiver and the route for each destination which is contained in a list of destinations is to be found by the routing algorithm. multi-destination routing is also used in broadcasting.

 there are several protocols used in network layer. some of them are ip, icmp, clnp, arp, ipx, hrsp etc.

 the ethernet 802.3 framing is used for netware versions 2 to 3.11, and the ethernet 802.2 framing is used for netware versions 3.12 and later plus osi routing, ethernet ii is used with tcp/ip and dec net, and ethernet snap is used with tcp/ip and appletalk. the type field in ethernet 802.2 frame is replaced by a length field in ethernet 802.3.