CS2060 -HIGH SPEED NETWORKS PART-A UNIT I -HIGH SPEED NETWORKS

CS2060 - HIGH SPEED NETWORKS

PART-A UNIT I - HIGH SPEED NETWORKS

1.Define ISDN? The integrated services digital network is to provide a unique user network

interface(UNI) for the support of the basic set of narrow band(NB) services that is voice and low speed data thus providing a narrowband integrated access.

2.What are the features of an ISDN? Standard user network interface (UNI). Integrated digital transport. Service integration. Intelligent network services.

3.What is constant bit rate(CBR)? CBR is used to provide circuit emulation services. The corresponding bandwidth

allocated on the peak of the traffic sources so that a virtually loss free communication service is obtained with prescribed targets of cell transfer delay(CTD) and cell delay variation(CDV).

4.What is available bit rate(ABR)? It is used to support data traffic sources. In this class a minimum bandwidth can be

required by the source that is guaranteed by the network. The service is supported with the guarantee of CLR or CTD.

5.What is unspecified bit rate(UBR)? It is used to support data sources willing to use just the capacity left available by all the

other without any objective on CLR and CTD. 6.Define ATM adaptation layer(AAL)?

A collection of standardized protocols that provide services to higher layers by adapting user traffic to a cell format.

7.Define AAL1(AAL type 1)? An AAL used for the transport of constant bit rate (CBR) traffic (ie. Audio and video)

and for emulating TDM based circuits. 8.Define AAL2(AAL type2)?

An AAL used for supporting time dependent variable bit rate (VBR-RT) connection oriented traffic (ie. packetized video and audio).

9.What is AAL3/4(AAL type 3 and 4)? An AAL used for supporting both connectionless and connection oriented variable bit

rate (VBR) traffic. It is also used to support SMDS. 10.What is AAL5(AAL type5)?

The most common AAL type used for the transport of data packets. 11.Define ATM?

A broadband switching and multiplexing, connection-oriented, high performance and cost effective integrated technology for supporting BISDN services.

12.What are the features of SDH? Provision of single worldwide transmission network. Easy multiplexing and demultiplexing. Flexibility in adapting internal signal structure. Provision of operation and maintenance functions.

www.Vidyarthiplus.com


13.What are the layers present in SDH?

Circuit layer. Path layer. Transmission layer.

14.Give the SDH multiplexing elements? Container, virtual container, tributrary unit, tributrary unit group , administrative unit,

administrative unit group, synchronous transport module . 15.What is meant by floating mode of multiplexing?

Pointer information allows a VC to float within it’s TU is called mode of multiplexing. 16.What are the elements present in VC?

A VC consists of a Container and the path overhead processed in the SDH multiplexer. 17.What are the functions of a tributrary unit group?

It performs the function of assembling together several TU’s without further overhead. 18.What is path overhead?

The header needed to perform the functions at the path layer is path overhead. 19.What is the need for plesiochronous digital hierarchy?

The need is to develop a step-by-step hierarchical multiplexing in which higher level multiplexing are needed.

20.What is SS7? SS7 defines the signaling network features and the protocol architecture of the common

channel signaling used in ISDN. 21.What is common channel signaling?

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.

22.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. 23.Define cell sequence integrity?

It is the characteristic of virtual channel to preserve sequence of transmitted cells. 24.What is the purpose of cell loss priority bit in ATM cell format?

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 within the network.

25.What are the AAL services? 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.

26.What are the two types of sublayer used in ATM adaptation layer? Convergence sub layer. Segmentation and Reassembly sub layer.

27.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.



28.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.

29.Define fabric in fiber channel communication. The fiber channel communication network consists of one or more switching elements

which are collectively called as fabrics. 30.Define collision domain?

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

31.Define DTE? 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: terminals, personal computers, routers, and bridges. 32.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.

33.What is Virtual channel? 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.

34.What are the benefits of ATM? 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.

35.What are the Requirements of Wireless LAN? Throughput. Number of nodes. Connection to backbone. Service area. Battery power consumption. Transmission robustness and security.

36.What are IEEE 802.11 Services? Association. Reassociation. Disassociation. Authentication. Privacy.



37.What are the functions of AAL5?

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).

38.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. 39.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.

40.What are the topologies used in Fiber channel? Switched topology. Point-to-point topology. Arbitrated loop topology.

UNIT II - CONGESTION AND TRAFFIC MANAGEMENT

1.Define switch? A switch is simply a box with some number of ports that different devices such as

workstations, routers and other switches attach to. 2.What are the techniques available to accomplish switch path control?

Address learning. Spanning tree. Broadcast and discover. Link state routing. Explicit signaling.

3.Define VLAN? VLAN is a broadcast domain whose members use LAN switching to communicate as if

they shared the same physical segment. 4.What are the uses of VLAN?

VLAN are useful for administrative, security and broadcast control. 5.What are the two internal forwarding techniques used in LAN switch?

Cut through Store and forward

6.What is cut through forwarding? A switch being to forward the packet as soon as the destination address is examined and

verified. The forwarding of the first path of the packet can begin even as the remainder of the packet is being read into the input port switch buffers.

7.What are the advantages of using twisted pair star LAN? Two wire system is susceptible to crosstalk and noise. A twisted pair can pass relatively wide range of frequencies. Attenuation is in the range of 20db/mile at 500 KHz. Transmission is not affected by interference.



8.What are the properties of VC connections?

Each VC is identified by a VC identifier. Cells belonging to the single message follow the same VC. Cells remain in the original order till they reach the destination.

9.What are the advantages of VLAN? Configuration. Security. Network efficiency. Broadcast containment.

10.How the Broadcast containment is possible in VLAN? A properly configured and operational VLAN should prevent or minimize broadcast

leakage from one VLAN to another. 11.What is meant by tag control information (TCI)?

The TCI consists of a three bit user priority field that is used to indicate the frames priority as it is forwarded through swithes supporting the IEEE 802.1P specification.

12.What is the need for the canonical format indicator(CFI)? The one bit CFI indicates if the MAC address information is in canonical format.

13.Why switching is so popular? Switching technologies offer much greater performance and capacity at much lower

price. Advances in silicon are placing more networks processing on expensive chips which prices down and boosts performance by orders of magnitude over older software based processing.

14.What is meant by LAN switching? LAN switching is used to move data packets between workstations on the same or

different segments. 15.What is meant by VAN switching?

VAN switching takes the form of a virtual connection that is provisioned between two end points such as a pair of routers.

16.What are the properties of switching? Operate at layer2 and below of any protocol stack. Performed in hardware.

17.Define switch forwarding? The information available in the data packet and maintained in the switch enables the

switch to rapidly move data packets from an input port to an output port. 18.What is the need for broadcast and discover technique?

It is commonly used in LAN switching and bridging to locate switched path through the network.

19.Define spanning tree explorer(STE)? If the spanning tree is in place the explorer packet may be opt to follow the spanning tree

path to the destination is called as STE. 20.What is the need for the connection identifier(CI)?

CI contained in the packet is used to determine the output port .CI is also called as label. 21.Define all routers explorer(ARE)?

If the explorer packet is flooded throughout the entire network is called as ARE.



22.Difference between multi-server queue and multiple single server ?

S.no Multi-server queues Multiple single sever queues 1. It has less waiting time Waiting time is more since there are many

single servers. 2. It has infinite populations and

infinite queue size Population and queue size is less and have significant impact on performance

23.Define Kendall's notation? The notation is given by X/Y/N where

X refers to the distribution of interarrival times Y refers to the distribution of service times N refers to the number of server

24.Define mean residence time? The average number of item residence in a system ,including the item being served(if

any) and the item waiting(if any),is r ; and the average time that an item spends in the system ,waiting and being served , is Tr; referred as mean residence time.

25.List some of the common distributions made? G, general distribution of interarrival times or service times. GI, general distribution of interarrival times with restriction that interarrival times are

independent. M, negative exponential distribution. D, deterministic arrivals or fixed length service.

26.Why Queuing Analysis? Option 1: Will wait and see what happens. Option 2: Analyst may take the position impossible to project future demand and degree

of certainty. Option 3: Use of an Analytic model. Option 4: Use of Simulation model.

27.List some of the model characteristics? The characteristics are

Item population. Queue size. Dispatching discipline.

28.List the assumption made on input and output? The assumptions made on input are,

Arrival time. Service time. Number of servers.

The assumptions made on output are, Items waiting. Waiting time. Items queued. Residence time.

29.What is the objective of congestion control? The objective of congestion control is to maintain the number of packets within the

network below the level at which performance falls off dramatically.



30.Difference between implicit congestion and explicit congestion?

S.no Implicit congestion Explicit congestion 1. It deals with discard and delay It deals with binary rate and

credit 2. Mainly used for connectionless or datagram

configurations such as IP based internet It takes place in two direction forward and backward

31.Define Backpressure? Backpressure is of limited use they can be applied in logical connections used for

connection oriented network, X.25 based packet switching network. 32.Define Choke packet?

Choke packet is control packet generated at a congested node and transmitted back to a source node to restrict traffic flow.

Example: ICMP (Internet Control Message Protocol) and Source quench. 33.List the congestion control mechanism in packet switching networks?

Send a control packet from congested node to some oral source nodes. Rely on routing information. Make use of an end-to-end probe packet. Allow a packet switching nodes to add congestion information to packets as they go by.

34.List the objectives of frame relay congestion control Minimize frame discard. Create minimal network additional traffic. Maintain, with high probability and minimum variance. Be simple to implement. Distribute network resource fairly among users.

35.What is Discard Strategy? Discard Strategy deals with the most fundamental response to congestion; when

congestion becomes severe enough, the network is forced to discard frames. 36.What is Congestion Avoidance?

Congestion Avoidance is used at onset of congestion to minimize the effect on the network. Explicit signaling mechanism from the network that will trigger the congestion avoidance .

37.What is Congestion recovery? Congestion recovery procedures are used to prevent network collapse in the face of

severe congestion. These procedure are typically initiated when the network begun to drop frames due to congestion.

Example: LAPF or TCP. 38.What is committed information rate (CIR)?

Committed information rate is a rate, in bits per second that the network agrees to support for a particular frame-mode connection. It is vulnerable to discard in the event of congestion.

39.Define BECN? Backward explicit congestion notification (BECN) notifies the user that congestion

avoidance procedures should be initiated where applicable for traffic in the opposite direction of the received frame. It indicates that frames user transmits on this logical connection may encounter congested resources.



40.Define FECN?

Forward explicit congestion notification (FECN) notifies the user that congestion avoidance procedures should be initiated where applicable for traffic in the same direction of the received frame. It indicates that frames user transmits on this logical connection, has encountered congested resources.

41.What is network response and user response? Network response is necessary for frame handler to monitor its queuing behavior. Here

the choice is based on end user. User response is determined by the receipt of BECN or FECN .The simplest procedure is to use BECN because other one is complex.

42.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. 43.what are the characteristics of queuing process?

Arrival pattern Service pattern Number of server System capacity Queue discipline

44.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. 45.What are the Congestion-Control Mechanisms? 1.Backpressure

Request from destination to source to reduce rate. Useful only on a logical connection basis. Requires hop-by-hop flow control mechanism.

2.Policing Measuring and restricting packets as they enter the network.

3.Choke packet Specific message back to source. Example: ICMP Source Quench.

4.Implicit congestion signaling Source detects congestion from transmission delays and lost packets and reduces flow.

46.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.

47.What is meant by BECN? 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.



48.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.

49.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.

50.What are the Considerations for Traffic Management in Congested Network? Fairness. Quality of Service. Reservations.

51.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.

52.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 53.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.

54.Define access rate? 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. 55.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.

56.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



57.Compare single server and multi server queue.

S.no Single server model Multi server model 1. Congestion statistics for this

model are : M/M/1, M/D/1, M/G/1 Congestion statistics for this model is : M/M/N

2. Arrival rate=λ Arrival rate for each server=λ/N 58.What is meant by traffic intensity in queuing analysis?

Traffic intensity, ρ = λ/µ =Arrival rate/Service rate 59.Write Little’s formula.

ρ = λTs r = λTr w = λTw

UNIT III - TCP AND ATM CONGESTION CONTROL

1.Define non blocking? If an input output connection between an arbitrary idle inlet and outlet can be established

by the network independent of the network state at setup time is called as non blocking. 2.Define blocking?

If atleast one I/O connection between an arbitrary idle inlet and outlet cannot be established by the network owing to internal congestion due to the already established I/O connections is called as blocking.

3.What are the types of non blocking network? Strict sense non-blocking. Wide sense non-blocking. Rearrangeable non-blocking.

4.What is the cost index of a cross bar network? The cost index that is the number of cross points for a cross bar network is C=N^2.

5.What is meant by full connection? If each matrix in stage i(i=1,2,………s-1) is connected to all the matrices in stages i-1and

i+1 is called as full connection. 6.What is meant by partial connection?

If each matrix in stage i(i=1,2……….s-1) is not connected to all the matrices in stages i-1 and i+1 is called as partial connections.

7.When two network are said to be isotropic? Two network are said to be isotropic, if after relabelling the inlets, outlets and the

matrices of the first network with the respective labels of the second network, first network can be made identical to the second network by moving it’s matrices and correspondingly it’s attached links.

8.When the two network are said to be topologically equivalent? Two network are topologically equivalent if an isomorphism holds between the

underlying graphs of the two network. 9.Define packet self routing property?

Each switching element(SE) is capable of routing autonomously the received packets to their destinations. such feature is known as self routing property.



10.What are the four types of network permutations in banyan network?

h-shuffle. h-unshuffle. Butterfly permutation. Identity Permutation.

11.What is h-shuffle permutation? The h-shuffle permutation consist in a circular left shift by one bit position of the h+1

least significant bit of the inlet address. 12.What is h-unshuffle permutation?

The h-unshuffle permutation consist in a circular right shift by one bit position of the h+1 least significant bit of the inlet address.

13.What are the two banyan network properties? Buddy property. Constrained reachablity property.

14.What are the two algorithms to build merging networks? Odd-even merging. Bitonic merging.

15.Define Circular Bitonic Sequence? Circular Bitonic Sequence is a sequence obtained shifting circularly the elements of a

bitonic sequence by an arbitrary number of positions K. 16.What is slepian-Duguid theorem?

A three stage network is rearrangable if and only if r2>max (n, m). 17.Define partially self routing?

If packet self routing takes place only in the position of the network then it is called as partially self routing.

18.What are the four basic technique available for a partial connection multistage network?

Vertical replication (VR). Vertical replication coupled with horizontal replication. Link dilation. EGS network.

19.What is the need for call processing? Call processing whose task is to receive from the input port controller(IPC) the virtual

call request and to apply the appropriate algorithm to decide whether to accept or refuse the call.

20.Distinguish between blocking and non blocking network? S.no Blocking network Non-blocking network 1. If an I/O connection between an

arbitrary idle inlet and the outlet can be established by the network independent of the network state at set up time is called as non blocking.

If at least one I/O connection between an arbitrary idle inlet and the outlet cannot be established by the network owing to internal congestion due to the already established I/O connection is called as blocking.

21.What are retransmit policies used in TCP traffic control? First only. Batch. Individual.



22.State the condition that must be met for a cell to conform.

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.

23.What are the mechanisms used in ATM traffic control to avoid congestion condition? Resource management. Connection admission control. Usage parameter control. Traffic shaping.

24.What are the TCP congestion control mechanisms? Retransmission Timer Management. Window Management.

25.What are the Three Techniques to calculate retransmission timer (RTO). RTT Variance Estimation. Exponential RTO Backoff. Karn’s Algorithm.

26.What is reactive congestion control? 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.

27.What are the requirements for ATM Traffic and Congestion Control? 1.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.

2.Congestion control tools from these technologies do not work in ATM. 28.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.

29.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.

30.What is meant by cell insertion time and allowed cell rate? 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. 31.Define Behavior Class Selector (BCS).

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.

32.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.



33.What is meant by Open Loop Control and Closed Loop Control?

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.

34.What are the accept policies used in TCP traffic control? In-order policy. In-window policy.

35.What are the techniques of Window management? Slow start. Dynamic window sizing on congest. Fast retransmit. Fast recovery. Limited transmit.

36.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. 37.Two techniques to reduce the transmission of useless cells?

Partial packet discard. Early packet discard.

38.What are the QoS parameters? Peak to peak cell delay variation. Maximum cell transfer delay. Cell loss ratio.

39.What is Buffer Management? 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.

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

called self clocking.

UNIT IV – INTEGRATED AND DIFFERENTIATED SERVICES 1.What are the types of Queuing?

Input Queuing. Output Queuing. Shared Queuing.

2.What are the three parameters used to describe the switching fabric performance? Switch throughput. Average packet delay. Packet loss probability.

3.Define switch throughput? It is defined as the probability that a packet received on an input link is successfully

switched and transmitted by the addressed switch output.



4.What is maximum throughput? The maximum throughput also referred as the switch capacity indicates the load carried

by the switch for an offered load =1. 7. 5.What is packet loss probability?

Probability that a packet received at a switch input is lost due to buffer overflow (0<p<=1).

6.What are the internal protocols available to enable the downstream transmission of packets?

Backpressure. Queue loss.

7.What is back pressure? Signals are exchanged between switching elements in adjacent stages so that the generic

SE can grant a packet transmission to its upstream SE’s only within the current idle buffer capacity.

8.What are the types of back pressure? Gobal back pressure. Local back pressure.

9.Define local back pressure? The number of buffer places that can be filled in the generic SE in stage i at slot t by

upstream SE’s is simply given by the number of idle positions at the end of slot t-1. 10.Define global back pressure?

The number of buffer places that can be filled in the generic SE in stage i at slot t by upstream SE’s is simply given by the number of idle positions at the end of slot t-1 increased by the number of packets that are going to be transmitted by the SE in the slot.

11.Define input queuing? Cells addressing different switch outlets are stored at the switch input interface as long as

there conflict-free switching through the inter connection network is possible. 12.Define output queuing?

Multiple cells addressing the same switch outlet are first switched through the interconnection network and then stored in the switch output while waiting to be transmitted downstream.

13.What is shared queuing? The queuing capability shared by all switch input and output interfaces is available for all

cells that cannot be switched immediately to the desired switch outlet. 14.What are the blocks involved in an N×M ATM switch?

N input port controller. Non blocking interconnection network. M output port controller.

15.What are the assumptions made in an input queuing? Bi>0,Bo=Bs=0 and K=1.

16.What are the algorithms involved for an input queuing? Three phase algorithm. Ring reservation algorithm.

17.What are the phases present in three phase switch? probe phase. Acknowledgement phase. data phase.



18.What is signal latency in a network? The number of bit times it takes for a signal to cross the network is called signal latency.

19.Why combined input and output queuing is necessary? The combined architecture adopt a k-non blocking self routing multistage structure where

the shared queue is removed. The virtual queue, input and output queue are mutually independent discrete time systems. In this queuing technique the number of cells entering the virtual queues in a slot approaches infinity and the queue joined by each cell is randomly and independently selected.

20.What is the assumption made in an output queuing? Bo>0, Bi=Bs=0 and Output speed up K>1.

21.What is cross bar tree switch? Cross bar tree switch consists of a set of N planes each inter connecting a switch inlet to

all the N output concentrators. 22.What is the assumption made in a shared queuing?

Bs>0,Bi=Bo=0 and K=1. 23.What is the need for an delay network in the starlite switch?

The recirculation or delay network of size P×P acts as a distributed shared buffer and feeds back to the routing network up to P=N Bs packets that could not be switched in the preceding slot.

24.What are the blocks involved in a trap network? Marker. Running adder winner. Running adder loser. Concentrator.

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

26.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.

27.Define Delay Jitter. The delay jitter is the maximum variation in delay experienced by packets in a single

session. 28.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.

29.What is meant by guaranteed service? Flows that are reserving resources are provided with guaranteed service. The service

provides assured capacity levels. 30.Define global synchronization.

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.



31.What are the design goals of RED algorithm? Congestion avoidance. Global synchronization avoidance. Round on average queue length.

32.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. 33.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.

34.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. 35.Define DS boundary node.

A DS node that connects one Ds domain to the node in another domain. 36.Define DS interior node.

A node in DS domain, which is not the boundary node is called Ds interior node. 37.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.

38.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.

39.What is meant by integrated services? 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 within the domain to provide a particular QOS guaranteed.

40.What is average packet delay? The average number of slots it takes for a packet received at a switch inlet to cross the

network and thus to be transmitted downstream by the addressed switch outlet (T=1).

UNIT V – PROTOCOLS FOR QOS SUPPORT 1.Define ARP?

A TCP/ IP protocol used for resolving local network addresses by mapping a physical address to an IP address is called ARP.

2.What are the classes in IP addressing? Overlay model Peer model.

3.What are applications of Address resolution server? Maintains a table/cache of LAN or network layer addresses and associated ATM

addresses. Maintains responds to queries for information from associated clients.



4.Define ATMARP? ATMARP is a protocol and message formats that enable a client to request and receive

resolution of a destinations IP address with an ATM address from an ATMARP server so that the client may establish an SVC to the destination.

5.What are the functions of ATMARP client? Queries the ATMARP sever for address mappings and caches responses. Establish SVCs to other devices on the same LIS

6.What is the need for ATMARP server? Maintains a table of IP/ATM mappings Responds to queries from ATMARP client Run on a standalone device or in a route server or router.

7.Define IP? A networking protocol for providing a connectionless service to the higher transport

protocol. 8.Define IP switch

A device or system that can forward IP packets at layer three and possesses a switching component that enables packets to be switched at layer two as well.

9.What is the function of an IP switch? IP switch decides which packet will be forwarded at layer three and which will be

switched at layer two and then to redirect some or all packets over a layer two switched path.

10.Define logical address group? A collection of hosts and routers connected to a physical NBMA network that is capable

of establishing a short cut path with host and routers on different subnets. 11.Define LIS?

An IP subnet consisting of ATM attached devices that share a common address prefix and can communicate with each using ATM PVCs or SVCs.

12.What is the need for classical IP? A protocol is developed for IP over ATM networks so that common applications can be

supported in an ATM environment. The main issues for the transport of IP over ATM are packet encapsulation and the address resolution.

13.Define cell loss priority? A 1-bit field in the ATM cell header that corresponds to the loss priority of a cell.

14.What is Multicast address Resolution Server? An address resolution protocol that resolves IP multicast group address with ATM

addresses so that IP multicast can operate on top of an ATM network. 15.Define IP multicast?

IP network provides a service in which packets addressed to a group address are delivered by routers to those networks with group members. A group membership protocol (IGMP) is used by hosts to tell routers which multicast group they wish to join/leave and the routers run a multicast routing protocol to build a delivery tree from source’s network out to all networks that have group members.

16.What is non Broadcast Multi-access Network? A network that consists of devices attached to a common intrastructure but does not have

any native broadcast capability. 17.What is payload?

IT is a part of ATM cell. It contains the actual information carried and occupies 48 bytes.



18.What is mean by peer model? This model occurs when the network forwarding nodes operate on a single topology. This

model supports a single IP topology and a single IP topology and a single IP address space.

19.Define topology driven IP switching? on the presence of entries in a

routing table. Examples are ARIS and Tag switching. 20.List out the properties of IPV6?

An IP switching solution that builds a shortcut path based

128 bit address)

s. verlay model?

ocols at IP and ATM and user network interfaces.

of ATM attached endpoints that use the same MARS server to

s a point to multipoint VC that is routed at the MARS and

as an intermediate point between the MARS senders and the receivers. It is

of time that the information is contained in the Client

each intermediate router maintain state information

nt resources to be reserved

ade to the router by a particular destination, the router considers

pecifies 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 is Reserve Specification, T spec is Traffic Specification.

Improved addressing structure ( Improved security and authentication Simplified header format Flexible support for option

21.What are the characteristics of O Uses separate addressing Runs separate routing prot Requires address resolution between IP Uses virtual IP switches

22.What is MARS cluster? A cluster is a group

register their group membership information with and to receive group membership updates from.

23.Define cluster control VC? The cluster control VC i

branches out to all cluster members. It is used by the MARS server to distribute group membership.

24.What is MCS? MCS serves

responsible for registering its ATM address along with the IP multicast group address. 25.Define Holding time in NHRP?

Holding time is the amount Information Element (CLE) is considered valid.

26.What is meant by soft state in RSVP? RSVP use connectionless approach,

about nature of flow, that will be refreshed by end system at predetermined amount of time. This is called soft state.

27.Why receiver is responsible to initiate reservation in RSVP? Each member (destination) in multicast may require differe

depending on QOS it needs. So it is therefore better for receiver to make resource reservation.

28.Define session in RSVP? Once a reservation is m

this as a session and allocates resources for the life of that session. Session is defined by Destination IP address, IP protocol identifier, Destination port.

29.Define flow specification in RSVP. The flow specification of RSVP s



30.Define filter specification in RSVP. Filter spec in RSVP defines the set of packets or flow, for which a reservation is

requested. Filter spec is defined by Source address, UDP/TCP source port. le used in RSVP?

frame merging? coming labels for a particular equivalent

s called label merging. operation over frame based media,

. S.

ess edge in MPLS domain?

called ingress edge. omain is called egress

ching and routing packets on the basis of which a label has been added to each

to zero.

ghtly coupled and they function parallely.

forwards a new RTP packet stream to one or

31.What are the types of reservation sty Wild card filter reservation style. Fixed filter reservation style. Shared explicit reservation style.

32.What is meant by label merging and Label merging: The replacement of multiple in

class with a single outgoing label i Frame merging: Label merging, when it is applied to

then it is called as frame merging. 33.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

34.Define Label switched hop in MPL The hop between two MPLS nodes on which forwarding is done using labels is called

label switched loop. 35.What is meant by ingress edge and egr

Ingress edge: Label switched router through which packets from internet router enters into MPLS domain is

Egress Edge LSR: LSR through which packets leaves the MPLS dedge.

36.Define Label switched router in MLPS An MPLS network consists of a set of nodes called label switched router (LSR) capable

of switpackets.

37.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 falls38.What is meant by integrated layer processing in RTP?

In TCP/IP each layer processed sequentially, whereas in integrated layer processing, adjacent layers are ti

39.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. 40.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 andmore 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.



PART-B .Explain the network evolution through ISDN to BISDN?

LAN. Unique user network interface (UNI

features of an ISDN? Explain ISDN in detail?

(AAL) in detail?

ing techniques in detail?

h path control in detail?

earrange able network? ion network.

ing technique in detail? itch. n switch.

g technique in detail?

ail? ch.

ut shared queing techniques in detail?

1

). Broad band NB ISDN services.

2.What are the Standard user network interface(UNI). Integrated digital transport. Service integration. Intelligent network services.

3.Explain ATM Adaptation Layer AAL1 (AAL type1). AAL2 (AAL type2). AAL3/4(AAL types 3 and 4). AAL5 (AAL types 5).

4.Explain the switch forward Types. Operation. Advantage and Disadvantage.

5.Explain switc Types. Operation. Advantage and Disadvantage.

6.Explain the r Full connect Partial connection network.

7.Write short notes on the network which satisfies Self routing property? Banyan network. Construction. Explanation.

8.Explain the input queu Three phase sw Ring reservatio Example.

9.Explain the output queuin Knock out switch. Example.

10.Explain the shared queuing technique in detail? Starlite switch. Example.

11.Explain the input output queing techniques in det Three phase swit

12.Explain the inp Three phase switch. Starlite switch. Example.



13.Explain the output shared queing techniques in detail? itch.

Example.

riven. M address?

. protocol.

tocol? tion Protocol.

in detail? Cs.

olution protocol.

addressing model used in IP switching?

hput. et delay.

Sunshine sw

14.Explain the IP switching types? Flow driven. Topology d

15.Explain the concept of IP over AT CLIP protocol Address resolution

16.Explain the concept of Next-Hop Resolution Pro Next-Hop Resolu Address resolution protocol. Example.

17.Explain the concept of multicasting Multicasting using VC and MA Address res Example.

18.Explain IPV6 over ATM? IPV4 evolution. IPV6.

19.Briefly explain the types of Overlay model. Peer model.

20.Give the performance analysis of various queued switches? Maximum throug Average pack Packet loss probability.



CS2060 -HIGH SPEED NETWORKS PART-A UNIT I -HIGH SPEED NETWORKS

Documents

Transcript of CS2060 -HIGH SPEED NETWORKS PART-A UNIT I -HIGH SPEED NETWORKS