LNMIIT/B.Tech/EC-CC/PE/2021-22/Even/TSSN/CT
The LNM Institute of Information Technology
Electronics and Communication Engineering Department
Telecommunication Switching Systems and Networks
Assignment-1
1. Consider the topology and Routing Tables Figure4, 5,6,7 mentioned in
http://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/multiprotocol-label-switching-trafficengineering/whitepaper_c11-551235.html
a) Explain the Routing table in Figure 7.
b) Mention the steps of implementing traffic Engineering in MPLS
2) Step by Step LSP Set Up (RSVP-TE Signaling) and illustrate LSP path set up
3)How networking requirements are decided in a Campus network?
4) Present a Next generation legacy compatible architectural solution of a Campus network.
5) Show with example VLAN implementation through

IEEE 802.10

Inter-Switch Link (ISL)

LAN Emulation
6) Present a brief overview of Cisco LAN switches and design considerations of LAN Switching.
7) Present a 3 Layer Hierarchy of Campus Network. Show access layer, Distribution Layer and Core layer.
Mention for each layer which product need to be selected. mention brief configuration details.
8) Assume a Digital switching system is equipped with 20,000 lines and 4000 trunks and exhibits 3 failure
modes or types of failures. In the first mode all 30,000 lines and 4000 trunks are lost; in the second mode 3000
lines and 200 trunks are lost; in the third 200 lines and 20 trunks are lost. assume that the calls is about 8 min
and FIT rates of 5000, 700 and 90 respectively for each node. Calculate the call cutoff probability for each
node of failure. Calculate IMA for Modes also.
9) Assume a Digital switching system is equipped with 20,000 lines and 4000 trunks and exhibits 3 failure
modes or types of failures. In the first mode all 30,000 lines and 4000 trunks are lost; in the second mode 3000
lines and 200 trunks are lost; in the third 200 lines and 20 trunks are lost. assume that the calls is about 8 min
and FIT rates of 5000, 700 and 90 respectively for each node. Calculate the call cutoff probability for each
node of failure. Calculate IMA for Modes also. Write a MATLAB code for the same.
LNMIIT/B.Tech/EC-CC/PE/2021-22/Even/TSSN/CT
12. An ATM-switch is to be designed to support 20 STM-4 interfaces. Routing Information Table (RIT)
will be implemented at the input interfaces. Cells are encapsulated into frames for delivery through the
switch fabric. A frame includes a 53-octet payload field and 3 octets of overhead for routing and control
inside the switch fabric ATM cells are encapsulated into VC-4 containers, which includes 9 octets of
overhead and 9x260 octets of payload. One VC-4 container is carried in one STM-1 frame and each
STM-1frame contains 9x261 octets of payload and 9x9 octets of overhead.
i). How fast should RIT lookup process be ?
ii). What is the required throughput of the switch fabric ?
13. In an STS switch, blocking probability is 0.002 and loading is 0.2 erlang per channel. How many time-slot
interchange (TSI) are needed? What is the cost of switch? Given M1= four 128 primary TDM signals and 30
voice channels per input.
14. How many crosspoints are needed in a 1024-line, three-stage space switch if the input loading is six
common-channel signals per line and the maximum acceptable blocking probability (using a Lee graph
analysis) is 0.005? (a) if n=64, N/n=16
LNMIIT/B.Tech/EC-CC/PE/2021-22/Even/TSSN/CT
15. A PBX has 4 operators and receives 300 calls during a busy hour. The average holding time is 36 seconds.
Assume that call arrivals are poisonian and service time is negative exponential distribution. Calculate (i) the
percentage of calls on queue (ii) average delay (iii) percentage of calls delayed for more than 45 seconds, 30
seconds and 20 sec.
16. Design a three-stage, 200 × 200 switch (N = 200) with k = 4 and n = 20. If we apply CLOS criteria k=2n1 and N= 4N(Sqrt2N-1). What will be the Switch complexity?
17. With 8 bits/byte, 8000 frames/sec, and 3 OC-1 carriers multiplexed together, find the total user capacity.
Find also Gross Data rate, SPE data rate and user data rate for OC-3072 line.
18. Given a population of N=10,000 users, each offering Eu=0.02 Erlangs of traffic, define a 3-stage blocking
switch with k sub-arrays in the middle-stage, each containing 200x200 cross-points such that the blocking
probability Pb  10 4 .
(a) Use the Lee graph approach to find this least value of k.
(b) Determine the number of cross-points for the above switch.
(c) For the same value of k as found in (a), it is decided to resize the sub-arrays in the three stages so as to
minimize the number of cross-points. Can you provide at least one other choice for n (or m) that will have a
lower complexity, but again ensuring that Pb  10 4 ? What is this new complexity and the new Pb?
19. Compare Narrowband-ISDN and Broadband-ISDN for the following features:
a) Transmission capacity (give values in terms of kbps and Mbps),
b) Switching type (circuit-switching, packet-switching),
c) Transmission type (synchronous, asynchronous)
20. Which of the following properties belongs to an ATM (Asynchronous Transfer Mode) service? Specify for
each item.
(a) Service type: Connection-oriented service / Connectionless service / Both.
(b) Switching type: Circuit switching / Packet switching / Both.
(c) Transmission rate is suitable for: Only wide-band data transmission / Only narrow-band data transmission
/ Both.
(d) Cell length: Constant / Variable depending on transmission rate / Variable depending on the length
of data field.
(e) Error correction on the data field is performed by: The ATM layer / The TC (Transmission
Convergence) sublayer / The upper layers.
(f) Header error control is performed by: The ATM layer / The TC sublayer / The AAL (ATM Adaptation
Layer).
(g) Congestion control is performed by: The AAL / The ATM layer / The upper layers.
(h) Flow control is performed by: The AAL / The ATM layer / The TC sublayer.
(i) Virtual path and virtual channel management is performed by: The ATM layer / The AAL / The TC
sublayer.
(j) Cell rate adaptation is performed by: The CS (Convergence Sublayer) / The ATM layer / The TC
sublayer.
LNMIIT/B.Tech/EC-CC/PE/2021-22/Even/TSSN/CT
22.Write MATLAB/C/Java/Python program which can take input as
1. Type of Switch ( S, SSS,STS, TST, STTTS, TSSST,TSSSST)
2. Type of Blocking ( Non blocking, Blocking with Lee's method, Blocking with Jacobian's method)
3, Number of Inlet (N)
4. The value of k( either provided then calculate blocking probability, Calculate from N, for Non blocking using
n=sqrt(N/2) and k=2n-1, calculate value of k from Lee's probability equation).
5. Numerical solution method (if k not given).- (Newton-Raphson or any other)
6. occupancy probability,
7.beta ( either calculate beta=k/n or given)
8. alpha(either calculate( alpha=l/c or given)
You may need to use suitable other input parameters not mentioned above.
Output
1.Error message
2.Complexity
3.Complexity variation vs k, beta graph
4.Complexity variation vs beta for Lee and Jacobian