Question 1)a)  With neat diagrams compare switched communication techniques with respect to
(i) Performance & 
(ii) Charcterstics.
b) Describe with an example a distance vector routing algorithm. 
c) With an example describe the bit-stuffing method in datalink layer. 
Question 2)a) Describe the TCP header format. 
b) The receiver of a data communication system which employs CRC scheme with generating polynomial x3 + 1, receives the following message 110101101. Describe the method in steps whether there has been any transmission errors. 
c) An 8 inch by 10 inch picture is scanned by a scanner having a resolution of 600x600 pixels per sq. inch. How many bits are produced if the scanner uses 8 bits/ pixel? How many bits are required if each pixel uses 256 colors? How long does it take to transmit by using ISDN B-channel? 
Question 3)a) Describe the operation of Selective Repeat ARQ with neat sketches. 
b) Describe services offered by ISDN supporting existing voice & non-voice services. 
c) Consider a subnet with 1024 routers. If the subnet is partitioned into 32 regions of 32 routers each. If a 3-level hierarchy is chosen with 8 clusters each containing 4 regions. Determine the number of entries at each & every router? Find the optimal number of levels, entries.