FINAL YEAR ECE

CLASS: IV YEAR / VII SEMESTER ECE

SUBJECT CODE AND NAME: CS2062 & HIGH SPEED NETWORKS

UNIT I

HIGH SPEED NETWORKS

PART - A

1) What is common channel signaling?         Nov/Dec 2008

The data’s and control signals of a user are transmitted on separate channel. The control signals of all the user are passed through a single common channel.

2) What is inband signaling?

If the data’s and control signals of a user are transmitted on same channel with same frequency then it is called inband signaling.

3) Define cell sequence integrity?

It is the characteristic of virtual channel to preserve sequence of transmitted cells.

4) What is the purpose of cell loss priority bit in ATM cell format?                                                          Nov/Dec 2009

It provides guidance to the network in the event of congestion. A value of indicates a cell of higher priority which should not be discarded unless no other alternatives is available. A value of 1 indicates that this cell is subject to discard with in the network.

5) what are the AAL services?                     Apr/May 2009

Handling of transmission errors

Segmentation and Reassembly to enable large blocks of data to be carried in the information field

Handling of lost and misinserted cell condition.

Flow control and timing control.

6) What are the two types of sublayer used in ATM adaptation layer?

1. Convergence sub layer

2. Segmentation and Reassembly sub layer.

7) Define sustainable cell rate?

The SCR is the average cell rate over a long time interval. The actual cell rate may be lower or higher than this value, but the average should be equal to or less than SCR.

8) Define peak cell rate?

The PCR defines the sender’s maximum cell rate. The user’s cell rate can sometimes reach this peak as long as the SCR is maintained.

9) Define fabric in fiber channel communication.

The fiber channel communication network consists of one or more switching elements which are collectively called as fabrics.

10) Define collision domain?

The maximum distance that data can travel between two station is called collision domain in Ethernet.

11) Define DTE?                                           Nov/Dec 2008

DTEs generally are considered to be terminating equipment for a specific network and typically are located on the premises of a customer. In fact, they may be owned by the customer. Examples of DTE devices are terminals, personal computers, routers, and bridges.

12) Define DCE?

DCEs are carrier-owned internetworking devices. The purpose of DCE equipment is to provide clocking and switching services in a network, which are the devices that actually transmit data through the WAN. In most cases, these are packet switches.

13) What is Virtual channel?                        Apr/May 2009

A Virtual Channel (VC) denotes the transport of ATM cells which have the same unique identifier, called the Virtual Channel Identifier (VCI). This identifier is encoded in the

cell header. A virtual channel represents the basic means of communication between two endpoints, and is analogous to an X.25 virtual circuit.

14) What are the benefits of ATM?             Apr/May 2011

The benefits of ATM are the following:

high performance via hardware switching

dynamic bandwidth for bursty traffic

class-of-service support for multimedia

scalability in speed and network size

common LAN/WAN architecture

opportunities for simplification via VC architecture

international standards compliance

15) What are the Requirements of Wireless LAN?

Throughput                                         Nov/Dec 2010

Number of nodes

Connection to backbone

Service area

Battery power consumption

Transmission robustness and security

16)What are IEEE 802.11 Services?

Association

Reassociation

Disassociation

Authentication

Privacy

17) What are the functions of AAL5?          Apr/May 2010

The type 5 adaptation layer is a simplified version of AAL3/4. It also consists of message and streaming modes, with the CS divided into the service specific and common part. AAL5 provides point-to-point and point-to-multipoint (ATM layer) connections. AAL5 is used to carry computer data such as TCP/IP. It is the most popular AAL and is

sometimes referred to as SEAL (simple and easy adaptation layer).

18) Define Basic Service Set?

IEEE 802.11 defines the BSS as the building block of a wireless LAN. It consists of stationary or mobile stations and a possible central base station known as Access Point.

19) What is PCF?

Point Co-ordinate Function is a centralized MAC algorithm used to provide contention free service. This is done by polling stations in turn. Higher priority traffic makes use of PCF.

20) What are the topologies used in Fiber channel?

1. Switched topology

2. Point-to-point topology

3. Arbitrated loop topology

21. Define frame relay.

A form of packet switching based on the use of variable-length link-layer frames. There is no network layer, and many of the basic functions have been streamlined or eliminated to provide for greater throughput.

22. Define ATM.                                            Apr/May 2011

ATM is a connection-oriented packet switching technique that generalizes the notion of a virtual connection to one that Provides quality-of-service guarantees. (Or) A form of packet transmission using fixed size packets, called cells. ATM is the data transfer interfaces for B-ISDN. Unlike X.25, ATM does not provide error control and flow control mechanisms.

23. Write down the advantages of packet switching network over circuit switching.

a). Line efficiency is greater, because a single node-to-node link can be dynamically shared by many packets over time.

b). A packet-switching network can carry out data-rate conversion.

c). Priorities can be used.

24. What are the main features of ATM?   Apr/May 2010

1. The service is connection-oriented, with data transfer over a virtual circuit.

2. The data is transferred in 53 byte packets called cells.

3. Cells from different VCs that occupy the same channel or link are statistically multiplexed.

4. ATM switches may treat the cell streams in different VC connections unequally over the same channel in order to provide different qualities of services (QOS).

25. What are the traffic parameters of connection-oriented services?                                                     Nov/Dec 2010

1. Peak Cell Rate (PCR)

2. Sustained Cell Rate (SCR)

3. Initial Cell Rate (ICR)

4. Cell Delay Variation Tolerance (CDVT)

5. Burst Tolerance (BT)

6. Minimum Cell Rate (MCR)

26. What are the quality service (QoS) parameters of connection-oriented services?

1. Cell Loss Ratio (CLR)

2. Cell Delay Variation (CDV)

3. Peak-to-Peak Cell Delay Variation (Peak-to-Peak CDV)

4. Maximum Cell Transfer Delay (Max CTD)

5. Mean Cell Transfer Delay (Mean CTD)

27. Types of ATM network interface.

Two most important interfaces are:

1. User-network interface (UNI)

2. Network-network interface or network-node interface (NNI).

28. What are the two sub layers of AAL?

1. Convergence Sub layer (CS)

2. Segmentation and Reassembly Sub layer (SAR).

29. What is the function of CS?

The Convergence Sublayer (CS) converts the information stream into four types of packets streams, called AAL Type1, Type2, Type3/4, and Type5.The packet

formats match the requirements of the information stream.

30. What are the subdivisions of CS?

1. Upper, service-specific or SSCS sub layer

2. Lower, common part or CPCS sub layer.

31. What do you mean by Type1 traffic?

Type1 traffic is a traffic generated at constant bit rate, and it is required to be delivered at the same rate (with a fixed delay).

32. What are the functions of management and control?

1. Fault management

2. Traffic and congestion control

3. Network status monitoring and configuration

4. User/network signaling.

33. What are the subdivisions of CS?

1. Upper, service-specific or SSCS sub layer

2. Lower, common part or CPCS sub layer.  

34. What are the two basic tasks required for

       internetworking over ATM?

The first is encapsulation of the protocol data units, and the second is Routing or Bridging of these PDUs.

35 Define fast Ethernet                                Nov/Dec 2012

Fast Ethernet refers to a set of specifications developed by the IEEE 802.3 committee to provide a low-cost, Ethernet-compatible LAN operating at 100 Mbps.

36. Define gigabit Ethernet?                        Apr/May 2012

Gigabit Ethernet, which has a data rate of 1000 Mbps (Or) 1 Gbps. In which collision domain is reduced. Gigabit Ethernet is mainly designed to use optical fiber, although the protocol does not eliminate the use of twisted pair cables.

There are four implementations have been designed for gigabit Ethernet:

a)     1000Base-LX

b)     1000Base-SX

c)     1000Base-CX

d)     1000Base-T

37. Define Ethernet.

As packet switching has dominated wide area data networking, Ethernet dominates local area networking. The original experimental Ethernet operated at 3mbps over coaxial cable. This remarkable over twisted pair & optical fiber as well as coaxial cable. It was released commercially at 10 mbps & then was scaled up first to 100bps & none 1 & 10 gbps.

38. Give the data rates for frame relay & X.25?

The lower bit rate for X.25 is 64 kbps. The fixed data for frame relay is 1.544mbps. The higher data rate for frame relay is 44.376mbps

39.List requirements for WLAN?                Nov/Dec 2012

a). Throughput

b). Number of nodes

c). Connection to backbone LAN

d). Service area

e). Battery power consumption

f). Transmission robustness and security

g). Collocated network operation

h). License-free operation

i). Handoff/roaming

j). Dynamic configuration

40. List out the important services of IEEE 802.11?

                                                                        Apr/May 2012

a) Association

b) Reassociation

c) Disassociation

d) Authentication

e) Privacy

41. Mention the requirements for fibre channels?

a) Full duplex links with two fibers per link.

b) Performance from 100 Mbps TO 800 Mbps on a

    single line.

c) Small connectors

d) Support for distances up to 10 km.

e) High capacity utilization with distance insensitivity.

f) Broad availability.

g) Small systems

h) Interface and network protocols.

42. List out the fibre channel elements?

a) Node: The key elements of a fibre channel network

    are the end systems.

b) Fabric: The collection of switching elements

43.What is the datalink control functions provided by LAPF?

LAPF core provides a minimal set of datalink control functions consisting of the following

(i)Frame delimiting, alignment & transparency.

(ii)Frame multiplexing/demultiplexing using the

     address field.

(iii)Inspection of the frame to ensure that it consist of

      an integer no. of octets prior to zero bit insertion or    

     following zero bit extraction.

(iv)Inspection of the frame to ensure that it is neither

     too long nor too short.

(v)Detection of transmission errors.

(vi)Congestion control functions.

44. list the levels of fiber channel & the function of each level?

FC-0 PHSICAL MODE

Includes optical fiber for long distance application, co-axial for high speeds over short distances & shielded twisted pair for lower speeds over short distance.

FC-1 TRANSMISSION POROTOCOL

Defines the signal encoding scheme.

FC-2 FRAMING PROTOCOL

Deals with defining topologies, frame format, flow & error control & grouping of frames into logical entities called sequences & exchanges.

FC-3 COMMON SERVICES

Include multicasting.

FC-4 MAPPING

Defines the mapping of various channel & network protocol to fiber channel, including IEEE 802, ATM, IP & the Small Computer System Interface (SCSI).

45. What is meant by SAR & CS?

The AAL layer is organized in two logical sub layers:

 SAR & CSSAR: Segmentation And Reassembly sub layer is responsible for packing information at the other end.

CS: The Convergence Sublayer provides the function needed to support specific application using AAL .

46. Compare X.25 and Frame Relay Apr/May 2011

X.25

Hop by hop flow control

Multiplexing and switching done in layer 3

Inband signaling

Frame Relay

 End to end flow

Multiplexing and switching done in layer 2

Common channel signaling

PART- B

1.Describe the architecture of IEEE 802.11?                  Apr/May 2012

2.what are the service provided by ATM adaptation layer?Explain the operation of various AAL protocols?                   Apr/May 2010

 3.Compare X.25 and frame relay protocol?

 4.Explain the fibre channel protocol architecture?

 5.Describe the Gigabit Ethernet?

 6.Describe the various requirements and application specific to wireless LAN?

 7.Explain the physical layer access mechanism, MAC layer

     protocol and MAC layer phrame format for 802.11? Nov/Dec 2012

 8.Describe the fast Ethernet?

 9.Describe ATM cell format in detail?         Nov/Dec 2010

10. Explain in detail about various switching techniques.

11. Explain in detail about frame relay bearer and frame switching bearer services.

12. Explain the concept of frame mode call control.            Apr/May 2013

13. Explain in detail ATM protocol architecture      Apr/May 2011

14. Explain in detail ATM logical connection with neat diagram

15. Explain in detail AAL3/4 protocol

16. Explain the concept of ATM service categories Nov/Dec 2009 17. Explain in detail about transmission of ATM cell.

UNIT II

CONGESTION AND TRAFFIC MANAGEMENT

PART - A

1) When queue will be formed in a network?

Queue will be formed if the current demand for a particular service exceeds the capacity of service provider.

2)what are the characteristics of queuing process?

1. Arrival pattern                                Apr/May 2011

2.Service pattern

3.Number of server

4.System capacity

5.Queue discipline

3) What is meant by implicit congestion signaling?

When network congestion occurs packets get discard and acknowledgement will be delayed. As a result source understand that there is congestion implicitly.

4) What are the Congestion-Control Mechanisms?

 Backpressure                                     Apr/May 2010

 Request from destination to source to reduce rate

 Useful only on a logical connection basis

Requires hop-by-hop flow control mechanism

 Policing

Measuring and restricting packets as they enter the network

 Choke packet

 Specific message back to source

E.g., ICMP Source Quench

Implicit congestion signaling

Source detects congestion from transmission delays and lost packets and reduces flow

5) What is meant by FECN?

The FECN bit is part of the Address field in the Frame Relay frame header. The FECN

mechanism is initiated when a DTE device sends Frame Relay frames into the network. If the network is congested, DCE devices (switches) set the value of the frames' FECN bit to 1.  When the frames reach the destination DTE device, the Address field (with the FECN bit set) indicates that the frame experienced congestion in the path from source to destination.

6) What is meant by BECN?             Apr/May 2011

The BECN bit is part of the Address field in the Frame Relay frame header. DCE devices set the value of the BECN bit to 1 in frames traveling in the opposite direction of frames with their FECN bit set. This informs the receiving DTE device that a particular path through the network is congested.

7) What is the use of Discard Eligibility (DE) bit?

The Discard Eligibility (DE) bit is used to indicate that a frame has lower importance than other frames. The DE bit is part of the Address field in the Frame Relay frame header.

8) What is the error checking mechanism used in Frame Relay?

Frame Relay uses a common error-checking mechanism known as the cyclic redundancy check (CRC). The CRC compares two calculated values to determine whether errors occurred during the transmission from source to destination. Frame Relay reduces network overhead by implementing error checking rather than error correction.

9) What are the Considerations for Traffic Management in Congested Network?                                             Apr/May 2008

Fairness

Quality of Service

Reservations

10) Advantages of Frame Relay Congestion Control

 Minimize frame discard

Maintain QoS (per-connection bandwidth)

 Minimize monopolization of network

 Simple to implement, little overhead

Minimal additional network traffic

11) What are the Frame Relay Traffic Rate Management Parameters?

Committed Information Rate (CIR)

Average data rate in bits/second that the network agrees to support for a connection

Data Rate of User Access Channel (Access Rate)

Fixed rate link between user and network (for network access)      

Committed Burst Size (Bc)

Maximum data over an interval agreed to by network

Excess Burst Size (Be)

Maximum data, above Bc, over an interval that network will attempt to transfer

12) Define committed Burst size(Bc)?

This is maximum number of bits in a predefined period of time that the network is committed to transfer without discarding any frames.

13) Define access rate?                                 Apr/May 2009

For every connection in frame relay network, an access rate is defined. The access rate actually depends on bandwidth of channel connecting user to network.

14) What are the steady state performance measures to be determined in Queueing models?

Queueing models allow a number of useful steady state performance measures to be determined, including:

the average number in the queue, or the system,

the average time spent in the queue, or the system, 

the statistical distribution of those numbers or times,

the probability the queue is full, or empty, and

the probability of finding the system in a particular state.

15)Write Kendall’s notation.

(a/b/c): (d/e) is Kendall’s notation

a—distribution of inter arrival time

b—distribution of service time

c—number of server

d—maximum number of allowed items in a system

e—queuing discipline used

16) Compare single server and multi server queue

Single server model                                       Apr/May 2009

Congestion statistics for this model are : M/M/1, M/D/1, M/G/1, Arrival rate=  

Multi server model

Congestion statistics for this model is : M/M/N

Arrival rate for each server= /N

17. When queue will be formed in a network

Queue will be formed, if the current demand for a particular service exceeds the Capacity of service provider.

18. What are the characteristics of queuing process/

Characteristics of queuing process depend on:

a) Arrival pattern

b) Service pattern

c) Number of server

d) Queue discipline

e) System capacity

f) Number of channels

19. compare Single server and Multi server model congestion statistics

Single server model congestion statistics for this model are M/M/1, M/D/1, M/G/1

Arrival rate = λ

Multi server model congestion statistics for this model are M/M/N

Arrival rate = λ/N

20. What is meant by traffic intensity in queuing analysis? And write littles formula for single server queue?

Traffic intensity (or) utilization factor ρ = λ/μ = arrival rate / rate service

Little’s formula ρ = λ TS

r = λ Tr

w = λ Tw

21. What is meant by implicit congestion signaling?

When network congestion occurs, packets get discard and acknowledgement will be delayed. As a result, sources understand that there is congestion implicitly. Here, users are notified about congestion indirectly.

22. What is meant by explicit congestion signaling?

In this method, congestion is indicated directly by a notification. The notification may be in backward or forward direction.

23. Define committed burst size (BC)

It is defined as the maximum number of bits in a predefined period of time that the network is committed to transfer with out discarding any frames.

24. Define committed information rate (CIR) Nov/Dec 2010

CIR is a rate in bps that a network agrees to support for a particular frame mode connection. Any data transmitted in excess of CIR is vulnerable to discard in event of congestion.

CIR < Access rate

25. Define access rate.

For every connection in frame relay network, an access rate (bps) is defined. The access rate actually depends on bandwidth of channel connecting user to network.

26. Write Little’s formula.

Little’s formula is defined as the product of item arrive at a rate of λ, and Served time of items Tr (or) product of item arrive at a rate of λ and waiting time of an items Tw.

It is given as, r = λ Tr (or) w = λ Tw

27. List out the model characteristics of queuing models.

a) Item population.

b) Queue size

c) Dispatching discipline

28. List out the fundamental task of a queuing analysis.

Queuing analysis as the following as a input information.

a) Arrival rate b) Service rate

c) Number of servers

Provide as output information concerning:

a) Items waiting

b) Waiting time

c) Items queued

d) Residence time

29. State Kendall’s notation.                                     Apr/May 2013

Kendall’s notation is X/Y/N, where X refers to the distribution of the interarrival times, Y refers to the distribution of service times, and N refers to the number of servers.

The most common distributions are denoted as follows:

G = General distribution of interarrival times or service times

GI = General distribution of interarrival times with the

         restriction that Interarrival times are independent.

M = Negative exponential distribution

D = Deterministic arrivals or fixed-length service.

Thus, M/M/1 refers to a single-server queuing model with poisson arrivals (Exponential interarrival times) and exponential service times.

30. List out the assumptions for single server queues.

a) Poisson arrival rate.

b) Dispatching discipline does not give preference to items based on service times

c) Formulas for standard deviation assume first-in, first-out dispatching.

d) No items are discarded from the queue.

31. List out the assumptions for Multiserver queues.

a) Poisson arrival rate.

b) Exponential service times

c) All servers equally loaded.

d) All servers have same mean service time.

e) First-in, first-out dispatching.

f) No items are discarded from the queue.

32. State Jackson’s theorem.                       Nov/Dec 2009

Jackson’s theorem can be used to analyse a network of queues. The theorem is based on three assumptions:

1. The queuing network consists of m nodes, each of which provides an independent exponential service.

2. Items arriving from outside the system to any one of the nodes arrive with a poisson rate.

3. Once served at a node, an item goes (immediately) to one of the other nodes with a fixed probability, or out of the system.

33. Define Arrival rate and service rate.

Arrival Rate: The rate at which data enters into a queuing system i.e., inter arrival rate. It is indicated as λ.

Service Rate: The rate at which data leaves the queuing system i.e., service rate.

It is indicated as μ.

34. What is meant by congestion avoidance and congestion recovery technique?

Congestion Avoidance: It is the procedure used at beginning stage of congestion to minimize its effort. This procedure initiated prior to or at point A. This procedure

prevent congestion from progressing to point B.

Congestion Recovery: This procedure operates around at point B and within region of severe congestion to prevent network collapse. Here dropped frames are reported to higher layer and further packet delivery is stopped to recover from congestion.

35. what is the role of de in frame relay?

This bit it indicates frame priority. The DE can taken value of 0 or 1.

DE=0 means frame network element; it can be discard the frame during periods of congestion. DE=1, for generally considered as high priority frames.

36. How does frame relay report congestion?

When the particular portion of the network is heavily congestion. It is Desirable to route packets around rather than through the area of congestion.

37. What are the functions of user plane?  Nov/Dec 2010

It compromise the functions required for the transmission of user informationfor instance, for an internet protocol over ATM, these layers could be HTTP/TCP/IP/AAL5.

38. Draw single server queue model.             Nov/Dec 2013

39. Draw multiple server queue model.

40. Draw multiple single server queue model

PART – B

1.     Explain in detail about queue analysis and queue models                                        Nov/Dec 2013

2.     Explain kendall’s notation. Write equation for single server that follows M/M/1 model Apr/May 2013

3.     Write equation for single server that follows M/G/1 and M/D/1 model

4.     Explain in detail about congestion control in frame relay network and packet switching network

5.     Explain effect of congestion and congestion control mechanism                            Nov/Dec 2011

6.     Explain congestion avoidance and congestion recovery techniques                        Apr/May 2010

7.     Explain in detail about traffic control management

UNIT III

TCP AND ATM CONGESTION CONTROL

1)What are retransmit policies used in TCP traffic control?

1. First only

2. Batch

3. Individual

2) State the condition that must be met for a cell to conform.                                                       Apr/May 2010

In case of ATM, the information flow on each logical connection is organized into

fixed size packets called cells. Cells should arrive within theoretical arrival time but with in CDVT.

3)What are the mechanisms used in ATM traffic control to avoid congestion condition?                        Apr/May 2009

1.Resource management

2.Connection admission control

3.Usage parameter control

4.Traffic shaping

4) What are the TCP congestion control mechanisms?

1.Retransmission Timer Management

2.Window Management

5) What are the Three Techniques to calculate retransmission timer (RTO):

RTT Variance Estimation

Exponential RTO Backoff

Karn’s Algorithm

6) What is reactive congestion control?      Apr/May 2010

Whenever a packet discard takes place due to severe congestion some control mechanism is needed to recover from network collapse , these mechanism is reactive congestion control.

7) What are the requirements for ATM Traffic and Congestion Control?

Most packet switched and frame relay networks carry

non-real-time bursty data

No need to replicate timing at exit node

Simple statistical multiplexing

User Network Interface capacity slightly greater than average of channels

Congestion control tools from these technologies do not work in ATM

8) Why congestion control is difficult to implement in TCP?

The end system is expected to exercise flow control upon the source end system at a higher layer.Thus it is difficult to implement congestion control in TCP.

9)What is meant by silly window syndrome?

If data’s are send as small segments frequently, the response will be speed in the sender side, but it cause degradation in performance. This degradation is called silly window syndrome.

10) What is meant by cell insertion time and allowed cell rate?                                                                Apr/May 2009

Cell insertion time: It is the time taken to insert a single cell on to the network.

Allowed cell rate: The current rate at which the source is permitted to send or transmit cell in ABR mechanism is called allowed cell rate.

11) Define Behavior Class Selector (BCS). Nov/Dec 2013

BCS enables an ATM network to provide different service levels among UBR connections by associating each connection with one of a set of behavior class.

12)What are the Objectives of ATM layer traffic and congestion control

             Support QoS for all foreseeable services

Not rely on network specific AAL protocols nor higher layer application specific protocols

Minimize network and end system complexity

Maximize network utilization

13)What is meant by Open Loop Control and Closed Loop Control?                                                       Apr/May 2012

Open loop control: If there is no feedback to the source concerning congestion then this approach is called as open loop control.

Closed Loop Control: If there is feedback to the source concerning congestion then this approach is called as closed loop control.

14)What are the accept policies used in TCP traffic control?

1.In-order policy

2.In-window policy

15) What are the techniques of Window management?

1.Slow start

2.Dynamic window sizing on congest

3.Fast retransmit

4.Fast recovery

5.Limited transmit

16) What does ‘awnd’ and ‘cwnd’ refers to?

‘awnd’ refers to allowed window. This is window size allowed by TCP to send without waiting for acknowledgement.

‘cwnd’ refers to congestion window. This is window used by TCP during startup and to reduce flow during congestion.

17) Two techniques to reduce the transmission of useless cells?

1. Partial packet discard

2. Early packet discard

18) What are the QoS parameters?

1. Peak to peak cell delay variation

2. Maximum cell transfer delay

3. Cell loss ratio

19) What is Buffer Management?                Apr/May 2013

This mechanism provides the way in which cells are treated that have been buffered at network switch. When congestion occurs, the buffer occupancy becomes maximum. Now tagged cells are discarded to give preference to untagged cells.

20) What is self clocking?

TCP automatically senses the network bottleneck and regulates the flow at source.This is called self clocking.

21.How is times useful to control congestion in TCP?

The value of RTO( Retransmission time out) have a critical effect on TCP’s reaction to congestion. Hence by calculating RTO congestion can be controlled

22. compare flow control and congestion control

In flow control transmitter should not overwhelm the receiver. In congestion control it aim to limit the total amount of data entering the network, to amount of data that network can carry.

23. what is preventive congestion control? Nov/Dec 2008

These are mechanism to avoid congestion before it occurs.

24. what are the accept policies used in TCP traffic control?

1. in order policy

2. in window policy

25. What are the mechanisms used in TVP to control congestion condition?

1. RTO timer management

2. window management.

26. what is meant by ACR (Allowed Cell Rate)

                                                                        Nov/Dec 2012

The current rate at which source is permitted to send or transmit cell in ABR mechanism is called Allowed Cell Rate.

27. What are the two events leads to retransmit?

            1. segment fail to reach destination

            2. segment may be discarded due to error.

28. classify TCP implementation policy

            1. send policy

            2. deliver policy

            3. accept policy

            4.retransmit policy

            5. acknowledge policy

29. How TCP congestion control mechanism?

            1. Retransmission timer management

            2. Window management

30. state the rules of Karn’s algorithm.

            1. Donot use measured RTT

            2. Calculate the back off RTO

            3. Use the back off value for succeeding segments.

31. Mention the techniques for window management

            1. Slow start

            2. Dynamic window sizing

            3. Fast retransmit

            4. fast recovery

32. Mention the modes of operation ABR flow control

            1. Binary mode

            2. Explicit rate mode

33. What is the need for ATM congestion control

            1. not possible to control flow of ATM traffic

            2. Cell transmission time is small

            3. ATM network generates very different traffic pattern

34. what are the four categories of ATM attributes

            1. Traffic descriptor

            2. QoS parameter

            3. Congestion control attributes

            4. other attributes

35. what are the conditions to avoid congestion? Nov/Dec 2012

            1. Resources management using virtual paths

            2. Connection admission control

            3. Usage parameter control

            4. Traffic shaping

36. State the three case of VPC

            1. User to User application

            2. user to network application

            3. Network to network application

37. What are the two version of generic cell rate algorithm?

            1. Virtual scheduling algorithm

            2. Leaky bucket algorithm

38. What is sustainable cell rate algorithm Nov/Dec 2013

            If generic cell rate algorithm is used to control SCR and BT, then it is called sustainable cell rate algorithm.

39. What is peak cell rate

            The maximum value assigned to ACR

40. What is initial cell rate?

            The initial value assigned to ACR

PART – B

1.     Explain credit allocation scheme for TCP flow control in detail                                                     Nov/Dec 2013

2.     Describe TCP implementation policy in detail

3.     Expliain in TCP congestion control in detail Nov/Dec 2008

4.     Explain the concept of RTT variance estimation (Jacobson’s algorithm) and Exponential RTO back off

5.     Explain the concept of Karn’s algorithm Nov/Dec 2009

6.     Explain the concept of window management

7.     Explain in detail about the TCP over ATM Apr/May 2010

8.     Explain ATM traffic control in detail

9.     Explain the algorithms in that specifies ATM traffic management to perform UPC function    Apr/May 2013

10. Explain in detail about ABR traffic management

11. Explain in detail about ABR rate control

12. Explain in detail RM cell format             Nov/Dec 2011

13. Explain the concept ABR capacity allocation

14. Explain in detail about GFR mechanism and GFR traffic management

UNIT IV

1. What is meant by elastic traffic? Give example.

                                                                        Apr/May 2010

Elastic traffic can adjust over wide ranges to changes in delay and throughput across an internet and still meet the needs of its applications.

Example         File transfer

E-mail

Web access

2. What is meant by inelastic traffic? Give example.

Inelastic traffic cannot adjust to changes in delay and throughput across an internet.

Example:        Voice chat

Tele conferencing

3. Define Delay Jitter.                                   Apr/May 2010

The delay jitter is the maximum variation in delay experienced by packets in a single session.

4. What is meant by best effort service?

Flows that are not reserving resources are provided with best effort service. The network will put best effort to deliver the packet but if congestion occurs severely discard the packet.

5. What is meant by guaranteed service?

Flows that are reserving resources are provided with guaranteed service. The service provides assured capacity levels.

6. Define global synchronization.                 Apr/May 2008

Due to packet discard during congestion, many TCP connections entered slow start at the same time. As a result, the network is unnecessarily under utilized for some time. The

TCP connections which entered into slow start, will come out of slow start at about time causing congestion again. This phenomenon is called global synchronization.

7. What are the design goals of RED algorithm?

1. Congestion avoidance

2. Global synchronization avoidance

3. Round on average queue length

8. Define behavior aggregate in per hop behavior.

A set of packets with the same Ds code point crossing a link in particular direction is called behaviour aggregate.

9. Define DS code point.

A specified value of 6 bit DS code point portion of the 8 bit DS field in the IP header which indicate to which class packet belongs and its drop precedence.

10. What is meant by traffic conditioning agreement?

An agreement that specify rules that are to apply for packets selected by the classifier. Control functions performed in TCA are metering, marking, shaping and dropping.

11. Define DS boundary node.                      Apr/May 2009

A DS node that connects one Ds domain to the node in another domain.

12. Define DS interior node.

A node in DS domain, which is not the boundary node is called Ds interior node.

13. Define Ds node.

A router that supports DS policies is called as DS node. A host system that use DS for application is called as DS node.

14. What is meant by differentiated service?

It does not attempt to view the total traffic demand in integrated sense.

It does not reserve network capacity in advance.     

It provides differential level of QOS to different traffic flows.

15. What is meant by integrated services?  Nov/Dec 2012

The Is provider –

Views the total of current traffic demand.

Limits the demand with respect to the current capacity handled by the network.

Reserve resources with in the domain to provide a particular QOS guaranteed.

16. What are the key elements of controlled load services?

1. services approximates tightly the behavior visible to applications receiving best-effort service under unloaded conditions

2. very high percentage of transmitted packets will be successfully delivered

17. Mention two different traffic management framework

            1. Integrated services

            2. Differentiated services

18. Mention two broad categories of traffic

            1. Elastic

            2. Inelastic

19. Define throughput

            Inelastic traffic need minimum throughput

20. Mention the application of Inelastic trafficNov/Dec 2010

            1. Teleconferencing

            2. Telephony

            3. Voice chat

            4. Live video

21. What is discard policy?                           Apr/May 2008

            A discard policy is an important element in managing congestion and meeting QoS guarantees.

22. What are the two main functional area of ISA

            1. Classifier and route selection

            2. Packet scheduler

23. What are the background function in ISANov/Dec 2013

            1. Reservation protocol

            2. Admission control

            3. management agent

            4. Routing Protocol

24. What are the three categories of ISA services

            1. Guaranteed

            2. Controlled load

            3. Best effort

25. What are the limitation of FIFO queue

            1. No special treatment for packets

            2. small packet is queued behind long packet

26. state advantage of RED algorithm         Apr/May 2012

            1. To avoid congestion and global synchronization

27. Mention features of DS architecture

            Provide a simple, easy to implement and low overhead tool

28. What are the elements of traffic conditioning function

            1. Classifier

            2. Meter

            3. Marker

            4. Shaper

            5. Dropper

29. Define Classifier

            Separate traffic only on the basis of DS code point

30. Define Meter

            Determines whether given packet is within or exceeds the SLA guaranteed for that class

31. Define Marker                                         Apr/May 2013

            Packets that exceeds the traffic profile (TCA) , then such packets are remarked to provide best effort handling.

32. Define Shaper

            It helps the packets to transmit at specified traffic rate

33. Define Dropper

            Drops the packets if its exceeds SLA

34. What are the two types of PHB mechanism?

            1. Expedited forwarding PHB

            2. Assured Forwarding PHB

35. Define behavior aggregate.                    Nov/Dec 2010

            A set of packets with the same DS code point crossing a link in a particular direction is called behavior aggregate.

36. what are the key elements of explicit allocation schemes

            1. Each class  has different traffic profile

            2. The packets are marked in and marked out

37. Define TCA

            An agreement that specifies rules that are to apply for packets selected by classifier

38. Define DS boundary node

            A DS node that connects one DS domain to the node in another domain

39. Define DS interior node

            A node in DS domain, which is not the boundary node

40. Define DS node

            A router that supports DS policies is called DS node.

PART-B

1.     Explain in detail about integrated service architecture with neat dig                                              Nov/Dec 2010

2.     Explain Bit round fair queuing method in detail Apr/May 2012

3.     Explain weighted fair queuing method in detail

4.     Explain the random early deduction in detail Apr/May 2008

5.     Explain in detail about differentiated service architecture with neat diagram                                            Nov/Dec 2013

UNIT V

1. What is meant by soft state in RSVP?     Nov/Dec 2010

RSVP use connectionless approach, each intermediate router maintain state information about nature of flow, that will be refreshed by end system at predetermined amount of

time. This is called soft state.

2. Why receiver is responsible to initiate reservation in RSVP?

Each member (destination) in multicast may require different resources to be reserved depending on QOS it needs. So it is therefore better for receiver to make resource

reservation.

3. Define session in RSVP?

Once a reservation is made to the router by a particular destination, the router considers this as a session and allocates resources for the life of that session.

Session is defined by

Session: Destination IP address

IP protocol identifier

Destination port

4. Define flow specification in RSVP.          Nov/Dec 2011

The flow specification of RSVP specifies a desired QOS and is used to set parameters in a node’s packet scheduler.

Flow spec is defined by

Flow spec:      Service class

R spec

T spec

R spec is Reserve Specification

T spec is Traffic Specification

5. Define filter specification in RSVP.         Nov/Dec 2009

Filter spec in RSVP defines the set of packets or flow, for which a reservation is requested.

Filter spec is defined by

Filter spec: Source address

UDP/TCP source port

6. What are the types of reservation style used in RSVP? Wild card filter reservation style.

Fixed filter reservation style.

Shared explicit reservation style.

7. What is meant by label merging and frame merging?

Label merging: The replacement of multiple incoming labels for a particular equivalent class with a single outgoing label is called label merging.

Frame merging: Label merging, when it is applied to operation over frame based media, then it is called as frame merging.

8. Define label swapping in MPLS.

The basic operation of looking up an incoming label to determine the outgoing label and forwarding is called label swapping.

9. Define Label switched hop in MPLS.

The hop between two MPLS nodes on which forwarding is done using labels is called label switched loop.

10. What is meant by ingress edge and egress edge in MPLS domain?                                                    Nov/Dec 2009

Ingress edge: Label switched router through which packets from internet router enters

into MPLS domain is called ingress edge.

Egress Edge LSR: LSR through which packets leaves the MPLS domain is called egress

edge.

11. Define Label switched router in MLPS

An MPLS network consists of a set of nodes called label switched router (LSR) capable of switching and routing packets on the basis of which a label has been added to each

packets.

12. What is purpose of time to live field in label format?

The value of this field is decremented at each router and the packet is dropped if the count falls to zero.

13. What is meant by integrated layer processing in RTP?

In TCP/IP each layer processed sequentially, whereas in integrated layer processing, adjacent layers are tightly coupled and they function parallely.

14. What is the function of RTP relays and give its types?

A relay operating at a given protocol layer is an intermediate system that acts as both a destination and a source in a data transfer.

15. What is the function of mixer and translator in RTP?

Mixer: It is source of synchronization. It receives stream of RTP packets from one or more sources. Combines these streams and forwards a new RTP packet stream to one or

more destinations.

Translator: It produces one or more outgoing RTP packets for each incoming packets. It change the format of the data that suite to transfer from one domain to another.

16. What is wild card filter style?                 Nov/Dec 2008

Wild card filter style specifies single resource reservation to be shared by all senders to this address. This style is represented in the form WF(*{Q}) where asterisk represent wild card sender and Q is flows pet.

17. RSVP is receiver initiated rather than sender initiated.why?

            RSVP is receiver initiated reservation, each member in multicast may require different resources to be reserved, depending on QoS it need.

18. State whether RTP is transport layer protocol or an application layer

            RTP is used as transport layer protocol for real time application

19. what is forward equivalence class in MPL’s network?

            A group of IP packets that are forwarded in the same manner is called forward equivalence class.

20. What is advantages of label switching?

            1. It improves performance and provide different QoS

            2. It also speed up IP packet forwarding process

            3. Reduces delay and improve overall throghput

21. What does RTCP provide to the sources?

            1. QOS and congestion control

            2. Identification

            3. Session time estimation

            4. Session control

22. What is the use of translator in RT P?

It produces one or more outgoing RTP packets for each incoming packets. It change the format of the data that suite to transfer from one domain to another.

23. What is wild card filter style?

            It specifies a single resource reservation to be shared by all senders to this address.

24. What are the characteristics of RSVP?

1.     Unicast and multicast

2.     Simplex

25. What are the concepts of data flow in RSVP

            1. session

            2. Flow specification

            3. Filter specification

26. Classify reservation attributes

            1. Shared

            2. Distinct

27. Mention the characteristics of MPLS.   Apr/May 2008

            1. connection oriented QOS support

            2. Traffic engineering

            3. Virtual private network

            4. Multi protocol support

28. What are the parameters for FEC to determine packets

            1. Source/destination IP address

            2. Source/destination port number

            3. IP protocol ID

            4. Differentiated service code point

            5. IPV6 flow label

29. Write the topology of LSPS

            1. Unique ingress and unique egress LSR

            2. Unique egress and multiple Ingress LSR

            3. Multiple egress LSRS for unicast traffic

30. State the terminology of MPLS             Apr/May 2012

            1. Label merging

            2. Frame merging

            3. label swapping

            4. Label switched Hop

31. List the application of TCP`                   Apr/May 2013

            1. Audio and video conferencing

            2. Live video distribution

3. shared workshops

4. Telephony

32. what are the two protocol used to design RTP?

            1. RTP data transfer protocol

            2. RTP control protocol

33. What are the two key concept of RTP protocol

      Architecture?

            1. Application level framing

            2. Integrated layer processing

34. Define session

            A session is logical association among two or more RTP entities that is maintained for the duration of data transfer

35. How the session is defined?

            1. RTP port number

            2. RTCP port number

            3. Participant IP addresses

36. What are the four functions performed by RTCP

            1. QOS and congestion control

            2. Identification

            3. session size

            4. Session control

37. Define label merging

            The replacement of multiple incoming labels for a particular FEC with a single outgoing label

38. Define frame merging

            Label merging when its applied to operation over frame based media

39. Define Label swapping

            The basic operation of looking up an incoming label to determine the outgoing label and farwarding is called label swapping

40. Define label switched Hop

            The hop between two MPLS nodes on which forwarding is done using labels.

PART-B

1.     Explain the design goal and the characteristics of RSVP protocol                                       Apr/May 2008

2.     Explain data flow and working mechanism of RSVP

                                                            Nov/Dec 2013

3.     Explain the types of reservation style of RSVP in detail

4.     Explain the characteristics and operation of MPLS

Nov/Dec 2012

5.     Explain label stacking and label format in MPLS

6.     Explain route selection and label distribution protocol in detail                                          Apr/May 2012

7.     Explain RTP protocol architecture in detail Nov/Dec 2009

8.     Explain RTP data transfer protocol in detail

9.     Explain RTP control protocol in detail Apr/May 2010