MT - 101: NETWORKING & TELECOM MANAGEMENT

PART - A

1.(a). Give an Advantage/Disadvantage for each type of Network Topology?

   b. What are some of the factors that determine whether a communication system is a LAN, WAN, MAN?

   c. Describe the functions of a Bridge, switch, Router,Gateway.

2.(a). How does Token Ring LAN Operates?

   b. Group the OSI layers by function.

   c. List two advantages and two Disadvantages of having international standards for internet protocol?

3.(a). Explain the following: TCP, UDP, ITU, ETSI.

   b. List two ways in which the OSI reference model and the TCP/IP reference model are the same?

Now list two ways in which they differ

   c. Explain the type of cables briefly? Among them which cables can transmit data at high speeds?

4.(a). What is the Principal difference between connectionless communication and connection oriented communication?

   b. Write shorts notes on following: ATM, MODULATION, VSAT.

5.(a). What is the Difference between Data Switching and Packet Switching

   b. Explain the following-

     •Analog- to- Digital Conversion

     •Digital- to -Analog Conversion

     •Analog- to -Analog Conversion

PART - B

1. A large population of ALOHA users manage to generate 50 requests/sec., including both originals and retransmissions. Time is slotted in units of 40 msec.

i. What is the chance of success on first attempt?

ii. What is the probability of exactly K collisions and then a success?

iii. What is the expected number of transmission attempts needed?

2. (a) What are the two categories of encryption and decryption methods? What is the main difference between the categories?

     (b) Describe the structure of an optical fiber and explain the mechanism of light propagation alongthe fiber?

     (c) What are the merits and demerits of a single mode fiber in comparison to a multi-mode fiber?

Describe the structure and composition differences between two.

3. (a) What is ISDN? Explain and differentiate between BRI and PRI.

     (b) Explain in brief the concept of ATM?

     (c) What is idea behind sub netting a LAN?

4. (a)What is logical topology? What is difference between logical and physical topology?

     (b) What is transceiver and what does it do?

     (c) Do hubs have a MAC address and IP address? Why or why not?

     (d) What is collision domain? What devices can cut down the size of collision domain?

5. (a) What are the different sections of a frame? Briefly describe each?

     (b) What is a NIC? What layer of OSI model does it fall? Why?

     (c) State some differences between IP address and MAC address?

     (d) What is ARP? What is the structure of ARP request?

PART - C

1. (a) What is the definition of Presentation layer? State at least three of its functions?

     (b) What are the differences between Bridging, switching and routing?

     (c) What is network mask and why it is important?

2. (a)What are the advantages of dynamically maintained networks and statically maintained networks?

     (b) Compare and contrast circuit switched services and packet switched services with help of suitable examples

3. Consider the following address:

171.19.123.112

a. Eight bits have been borrowed from this network to create subnets.

b. Into what class this network falls?

c. What is the network address for this node?

d. How many useable subnets have been created?

e. How many useable hosts per subnet will be there?

f. What is the subnet mask?

4. (a) Compare between ATM and FDDI. What do you think is the future of ATM and FDDI in the backbone

     (b) Explain and differentiate Time division multiplexing, Phase division multiplexing and frequency division multiplexing?

     (c) Explain and differentiate horizontal cabling and vertical cabling?

5. (a) Differentiate between token bus and token ring?

     (b) What is virtual terminal protocol? Why it is required?

     (c) What is cellular radio? Explain the cell pattern for cellular radio.

CASE STUDY-1

While IP Telephony, and the resultant savings in communication costs, has been gaining considerable attention, its adoption has been slow because of the high initial investment required to set up a Voice-over-IP (VoIP) network. And with the recent cut in national long distance (NLD) charges, a question mark has formed around the cost-effectiveness of this technology. Enterprises are reluctant to invest lakhs of rupees on VoIP, with concerns that they may not get decent RoI (Return on Investment).

But since the needs, options, and viability patterns are wildly different for enterprises and customers, lets look at the enterprise angle first. Ravi Chauhan, vice president, Enterprise Solutions-India and SAARC, Nortel Networks, says, "Given the fact that 70 percent of a company's communication costs are in the form of intraoffice STD bills, VoIP continues to make sense. We have seen cases where communication costs have reduced by 60 percent after implementing an IP telephony solution. The period for return on investment on equipment has dropped from ten years to three."

It's not just about saving money. VoIP lets corporates take advantage of a host of value-added services like integrating voicemail, video, e-mail and fax. Raj Pawate, director-DSP Application, TI India, says, "IP networks are easier to maintain and manage than switched circuits." And if an organisation already has an enterprise WAN set-up with an existing data network, with a 64 Kbps leased-line facility, there is all the more reason to add voice capabilities to the data network, thus making even better use of precious bandwidth.

Cisco's solution

To set up a data network, which consists of LAN and WAN (switches and routers) the investment in equipment will be Rs 27.3 lakh. The cost of cabling will be Rs 2.5 lakh and, for IP telephony solution (Call Manager, IP phones and DSP resource), another Rs 25.4 lakh.

With Cisco's solution the equipment will cost Rs 55 lakh, inclusive of all the IP telephony features. An additional Rs 6 lakh per year would go toward leased line charges for one 128 Kbps line and four 64 Kbps lines. The total investment would amount to Rs 61 lakh. The depreciation on the equipment over three years would amount to Rs 18 lakh per annum plus Rs 6 lakh for annual bandwidth charges. The enterprise would have a fixed annual inter-office communication cost of Rs 24 lakh using VoIP. This investment is justified if the enterprise has an annual inter-office communication in excess of Rs 60 lakh.

Nortel's solution

The cost of the IP-PBX (hardware, software and 50 digital phones) is Rs 10.1 lakh, routers Rs 11 lakh and 37 IP phones would be Rs 6.4 lakh. The equipment cost would be Rs 28 lakh (voice and data) plus Rs 6 lakh for the leased line charges. This works out to Rs 34 lakh for the equipment.

Depreciation on equipment over three years comes to Rs 9.3 lakh per annum plus Rs 6 lakh for annual bandwidth charges. Using VoIP, the enterprise would have a fixed annual inter-office communication cost of Rs 15.3 lakh. In this case, the investment is justified if the enterprise has annual inter-office communication cost of Rs 40 lakh and above.

From the example cited above, it is clear that if an enterprise's inter-office communication cost is more than Rs 50 lakh then the investment in the VoIP is justified, otherwise it does not make economic sense. Secondly, the higher the communication, shorter will be the payback period.

According to Cisco's Chaitania, "The investment in VoIP for enterprise WAN makes sense if an enterprise has offices in multiple locations or even if they have offices in two locations and their average annual spending on inter-office communication goes above Rs 50 lakh, then the investment will be justified." Cisco's philosophy for the VoIP solution is to give the enterprise headroom for growth, keeping the future requirements of the enterprise in perspective, whereas Nortel's approach is to give the enterprise a low-cost alternative solution at the outset that can be scaled up in future.

Any mid-size or large enterprise whose annual communication cost is more than Rs 50 lakh and has offices in multiple locations should go in for a VoIP solution. Besides the cost it's the value-added services voice, data and video that it brings in, which make it even more worthwhile. While this clearly means that it may not make sense for SMEs to go in for their own VoIP networks, what the government's decision to allow Net telephony will do in the SME space is to encourage companies to replace their legacy PABX systems with IP systems. And since SMEs usually use third-party service providers to meet their network infrastructure needs, ISPs could take over the role and allow SMEs the benefits of VoIP too

Questions

1. What is the CISCO philosophy for VoIP solution?

2. What is the enterprise view about VoIP?

3. When the investment in VoIP will be justified? 

CASE STUDY - 2

Located in, South Carolina, Converse College is a liberal arts college that has been preparing students to be strong leaders in their professions and in their communities for over 100 years. In addition, Converse also offers a graduate program. In total, Converse serves more than 1500 students.

When a college accustomed to using the Internet as a learning and communication tool faces frequent network problems with its legacy equipment and foresees the need to support convergent applications of the future, administrators must determine how to upgrade their network quickly, reliably and cost-effectively. Network outages and connectivity problems were ongoing. With a disparate collection of multi-vendor hubs and switches and no network interface, ITS staff spent hours addressing network issues. Converse required a reliable network for all campus operations with centralized management for diagnosing and resolving network issues. The old network did not support these goals. "Can you imagine having a computer lab full of students and the majority of them can't access valuable academic resources?" says Judy Folk, director of ITS for Converse College. "The college realized that we needed to move forward and one of the first things we identified was that we didn't have a strong foundation. We needed a high performance network that would sustain both current and future demands."

Converse College addresses these challenges with the implementation of an enhanced network infrastructure based on HP ProCurve Networking Adaptive EDGE solutions. Converse now has the capability to implement online admissions, registration, grading and fundraising. Students and faculty can access the network from anywhere on campus. HP ProCurve also enables Information Technology Service (ITS) staff to monitor and resolve network connectivity issues via the Internet, thus saving valuable time and increasing productivity in the department.

Using a combination of HP ProCurve switches including HP ProCurve Switch 2524, HP ProCurve Switch 4108gl and HP ProCurve Routing Switch 9304m, the new local area network (LAN) connects approximately 26 campus buildings. ProCurve Switch 2524 is a high-speed 24-port switch ideal for low-cost migration to 10/100 managed switching with uplinks. The ProCurve Switch 4108gl is a Layer 2 modular switch.

With the deployment of the ProCurve solution, Converse has seen a major improvement in network performance and reliability. In addition, frequent network outages and connectivity problems required the ITS team to replace hardware on a weekly basis. With the ProCurve Networking solution, Converse also now has the ability to monitor the network from a central location, and if a problem occurs, can automatically check via the Internet if a particular switch has connectivity. This saves valuable staff time as they are often able to resolve issues before going out to the location.

Converse students now enjoy faster, more reliable Internet connectivity from the ProCurve solution and can save files to their own space on the server, which they can then access anywhere on campus. This is especially beneficial to commuting students who can easily access their e-mail over the Web. In addition, the new e-mail system and client server have enabled the upgrade of administrative programs, including online admissions and class registration. Faculty members can even enter grades online.

As Converse moves toward the future, including the construction of a new building and the incorporation of distance education, it is ensured that campus services are operating more quickly, reliably and efficiently with the new system.

Questions

1. In your opinion what were the core problems of the system?

2. Do you think that Converse has invested a lot to over come the problems? What are the hidden costs involved with the new system?

3. If you were to improve the performance of this establishment, what would you do? How? Explain