Solution#5.23
The concatenated vitual circuit implementation the distant connection connection is established through number of gateways. The gateway takes care of changing between the packet format as packet goes from the network ot one type to the other. So if the maximum packet length differs for the two networks then the gateway does fragmentation also. So like datagram systems the concatenated vitual circuit internets need fragmentation.
Solution#5.23
Convering the subnet mark into binary we get 11111111 11111111 11110000 00000000. This shows that 12 bits are available for numbering hosts in the given subnet. So total number of hosts in the subnet can be 212 - 2 = 4094.
Solution#5.30
ARP protocol is used by the machine to find out the physical/MAC or 48 bit address of the machine from the IP address of 32 bits. For this the machine broadcast the ARP querry. The machine whose IP address in mentioned in the querry replies providing its 48 bit address.
RARP is used by diskless machines which when boot ask the server their IP address giving the server its physical address.
Solution#5.33
IP routers use store and forward technique. Each of the packet is stored in the buffer till the routing dicision is taken and output line is available. In ATM the routing decision is taken as soon as the header arrives and then all the cells follow the header. The ATM switches use wormhole routing. So there is no delay in the switch unless the channel is not available. So number of hops are not important for ATM networks.
Solution#5.34
Here both IP and ATM are concerned with routing the data. So the address part is important. If the error occurs in the address part then the packet gets delivered incorrectly. Also the header part is comparatively smaller in size. So the checksum for heaser can be computed faster that that for entire packet including both data and header.