Uttar Pradesh Technical University (UPTU) 2007-8th Sem B.Tech Electronics and Communications Engineering data communication networks - Question Paper

B.Tech.
8th Semester Examination,2007-2008
Data Communication Networks(TEC-802)


Note:Attempt ALL ques..All ques. carry equal marks.

Q.1.Attempt any 4 parts of the following:

(a)Discuss the major design problems for the layered architecture of data communication.How 2 layers exchange information?

(b)How service primitives are classified?Give the service primitives for a connection-oriented service and show relationship pf service to protocols.

(c)Compare the similarities and differences ranging from the OSI and TCP reference models and comment on their usefulness.

(d)Give the mechanical,electrical and functional specifications of RS-232C interface.

(e)Draw a fibre optic ring with active repeaters and provide details of the interface.Also compare optical fibre cable versus coaxial cable.

(f)Show the different interchange circuits associated with X21 and outline their function.Describe the operation of X21 interface protocol with time sequence diagrams.

Q.2.Attempt any 4 parts of the following:

(a)What is flow control?Explain the stop and wait flow control and show that the link utilization efficiency is provided by 1/[1+2(t prop/t frame)]

(b)Give the frame structure for HDLC.Explain the control field of HDLC prtocol.Why this protocol is sometimes called super set of all link level protocols?

(c)Explain the meaning of subsequent terms relating to data link protocols:

(1)Character oriented
(2)Bit oriented
(3)Framing and data transparency
(4)Poll choose
(5)Primary and Secondary

(d)Differentiate ranging from pure and slotted ALOHA.Show frame transmission and vulnerable time for slotted ALOHA and prove that the maximum utilization of slotted ALOHA occurs at G=1 with value 36.8%

(e)Compare the IEEE 802 protocol layers with OSI reference model.How the IEEE 802.3 standard differs from Ethernet?Draw the format of IEEE 802.3 CSMA/CD frame and provide its address fields.

(f)Explain the operation of token ring network and provide IEEE 802.5 frame format.How priority mechanism is included in IEEE 802.5 standards?Make comparison of IEEE 802.3,802.4 and 802.5 standards.

Q.3..Attempt any 2 parts of the following:

(a)What are the basic features of a routing algorithm?Give the Bellman-Ford routing algorithm and illustrate by an example.What is count to infinity problem?How the split horizon algorithm overcomes this problem?When does this approach fail?

(b)What is difference ranging from open loop and closed loop congestion contol?How traffic policing differs from traffic shaping?Draw and discuss the flow chart of the leaky bucket algorithm used for policing the traffic.How the leaky bucket is used as traffic shaper?

(c)(1)Produce a sketch of an internet to illustrate the role of a subnet router,interior gateway and exterior gateway.
(2)In relation to internet produced for part (1),identify the scope of the Address Resolution Protocol(ARP),Interior Gateway Protocol(IGP) and Exterior Gateway Protocol(EGP).
(3)List the message kinds associated with Internet Control Message Protocol(ICMP).

Q.4.Attempt any 2 parts of the following:

(a)Show the fields that make up the header of a TCP segment and discuss the function of every.Why and how TCP pseudoheader is used?In addition to having acknowledgement field in the TCP header,ACK bit is also given.What would happen if the ACK bit were not provided?

(b)Is a deadlock possible using only two-way handshake rather than a 3 way handshake to setup connections?Give an example or prove otherwise.Explain the connection establishment and connection termination using 3 way handshaking.How half open connections are killed off?

(c)What are the basic functions of ATM Adaptation Layer(AAL)?Show that AAL sublayers and their purpos.What are the drawbacks of AAL3/4?How AAL5 overcomes them?Explain the operation of AAL5 clearly showing the Convergence and SAR sublayer and the CPCS-PDU.

Q.5.Attempt any 4 parts of the following:

(a)Under what situations mapping of physical address to logical address is needed?Name the different protocols for this purpose and show how DHCP(Dynamic Host Configuration Protocol)can give static and dynamic address allocation that can be manual or automatic.

(b)What are the functions to be performed by a network management system?Show the components of the SNMP manangement model and explain the object groups of the Management info Base version MIB2.

(c)what is the need of Trivila File Transfer Protocol(TFTP)?Give the various kinds of TFTP messages alongwith their formats.
In TFTP,indicate the next message sent by the client/server when
(1)The learn Request from the client is lost in transit.
(2)Data message containing less than 512 octets from the client is lost in transit and the server times out.
(3)The acknowledgement from the server is lost and client timesout.

(d)What were the deficiencies of IPv4?Give advantages of IPv4 over IPv6.Make comparison ranging from IPv4 and IPv6 packet headers and show how an IPv4 packet header can be converted to IPv6 packet header

(e)Why do we need a DNS system when we can directly use an IP address?What is DNS server?Explain generic domains,country domains and inverse domains in internet and provide structure of the DNS messages.

(f)What is World Wide Web(WWW)?List major components that constitute the Web.How is HTTP related to WWW?Discuss salient features of HTTP and show similarities ranging from HTTP,FTP and SMTP.

Earning:   Approval pending.