Siemens employs the best and brightest people and empowers them to achieve the highest levels of performance. We look for well-rounded individuals who think outside the square and look to the future. For many of our roles, having the right qualifications is important, but we're equally interested in your personal skills, your experiences, and your values. We are looking for: People who are ambitious, team orientated and innovative thought leaders People who take on responsibility, act with integrity and have a quality orientation People who are customer-focused, clear communicators and problem solvers People who are dedicated to development and keen to make a difference
Transcript
Siemens employs the best and brightest people and empowers them to achieve the highest levels of performance.
We look for well-rounded individuals who think outside the square and look to the future.
For many of our roles, having the right qualifications is important, but we're equally interested in your personal skills,
your experiences, and your values.
We are looking for:People who are ambitious, team orientated and innovative thought leaders
People who take on responsibility, act with integrity and have a quality orientation
People who are customer-focused, clear communicators and problem solvers
People who are dedicated to development and keen to make a difference
The pie chart shows the distribution of New York market share by value of different computer companies in 2005.
The pie chart shows the distribution of New York market share by volume of different computer companies in 2005.
Number of units sold in 2005 in New York = 1,500
Value of units sold in 2005 in New York = US $1,650,000.
1. For the year 2005, which company has realised the lowest average unit sales price for a PC ?
A. Commodore B. IBM
C. Tandy D.
Cannot be determined
Answer & Explanation
Answer: Option D
Explanation:
Although it seems to be Commodore, the answer cannot be determined due to the fact that we are unaware of the break-up of the sales value and volume of companies compromising the other categories.
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2. Over the period 2005-2006, if sales (value-wise) of IBM PC's increased by 50% and of Apple by 15% assuming that PC sales of all other computer companies remained the same, by what percentage (approximately) would the PC sales in New York (value-wise) increase over the same period ?
A.16.1 %
B. 18 %
C. 14 % D. None of these
Answer & Explanation
Answer: Option A
Explanation:
If we assume the total sales to be 100 in the first year, IBM's sales would go up by 50% (from 28 to 42) contributing an increase of 14 to the total sales value.
Similarly, Apple's increase of 15% would contribute an increase of 2.1 to the total sales value. The net change would be 14 + 2.1 on 100. (i.e., 16.1%)
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3. In 2005, the average unit sale price of an IBM PC was approximately (in US$)
IBM accounts for 28% of the share by value and 10% of the share by volume.
28% of 1650000 = 28 x 1650000/100 = 462000
10% of 1500 = 10 x 1500/100 = 150
Therefore, average unit sale price = 462000/150 = 3080.
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Directions to Solve
The following pie-chart shows the sources of funds to be collected by the National Highways Authority of India (NHAI) for its Phase II projects. Study the pie-chart and answers the question that follow.
Sources of funds to be arranged by NHAI for Phase II projects (in crores Rs.)
1. Near about 20% of the funds are to be arranged through:
A. SPVS B.
External Assistance
C. Annuity D. Market Borrowing
Answer & Explanation
Answer: Option B
Explanation:
20% of the total funds to be arranged = Rs. (20% of 57600) crores
Rs. 11486 crores is the amount of funds to be arranged through External Assistance.
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2. If NHAI could receive a total of Rs. 9695 crores as External Assistance, by what percent (approximately) should it increase the Market Borrowing to arrange for the shortage of funds?
A. 4.5% B. 7.5%
C.6%
D. 8%
Answer & Explanation
Answer: Option C
Explanation:
Shortage of funds arranged through External Assistance
= Rs. (11486 - 9695) crores
= Rs. 1791 crores.
Increase required in Market Borrowing = Rs. 1791 crores.
Percentage increase required =
1791x 100 % = 5.98% 6%.
29952
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3. If the toll is to be collected through an outsourced agency by allowing a maximum 10% commission, how much amount should be permitted to be collected by the outsourced agency, so that the project is supported with Rs. 4910 crores?
4. What is the ratio between the number of students studying at post-graduate level from institutes S and the number of students studying at graduate level from institute Q?
A. 13 : 19 B. 21 : 13
C. 13 : 8 D.19 : 13
Answer & Explanation
Answer: Option D
Explanation:
Required ratio =
(21% of 24700)=
(21 x 24700)=
19.
(13% of 27300) 13 x 27300 13
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5. Total number of students studying at post-graduate level from institutes N and P is
A. 5601 B. 5944
C.6669
D. 8372
Answer & Explanation
Answer: Option C
Explanation:
Required number
= (15% of 24700) + (12% of 24700)
= 3705 + 2964
= 6669.
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Directions to Solve
Study the following pie-chart and the table and answer the questions based on them.
4. If in 1998, the population of villages Y and V increase by 10% each and the percentage of population below poverty line remains unchanged for all the villages, then find the population of village V below poverty line in 1998, given that the population of village in 1997 was 30000.
A. 11250 B.12760
C. 13140 D. 13780
Answer & Explanation
Answer: Option B
Explanation:
Population of village Y in 1997 = 30000 (given).
Let the population of village V in 1997 be v.
Then, 15 : 10 = 30000 : v v =30000 x 10
= 20000.
15
Now, population of village V in 1998 = 20000 + (10% of 20000) = 22000.
Population of village V below poverty line in 1998 = 58% of 22000 = 12760.
3. What percentage of the total investment is coming from either FII's or NRI's ?
A. 33 % B. 11 %
C.44 %
D. 22 %
Answer & Explanation
Answer: Option C
Explanation:
(33 + 11) = 44
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4. If the total investment other than by FII and corporate houses is Rs 335,000 crore, then the investment by NRI's and Offshore funds will be (approximately) ?
A.274,100
B. 285,600
C. 293,000 D. Cannot be determined
Answer & Explanation
Answer: Option A
Explanation:
Investment other than NRI and corporate houses is 33% = 335000. Also, investment by offshore funds and NRI's is equal to 27%.
Hence, 27 x 335,000/33 = 274 090.909
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5. If the total investment flows from FII's were to be doubled in the next year and the investment
flows from all other sources had remained constant at their existing levels for this year, then what would be the proportion of FII investment in the total investment into India Bonds next year (in US $ millions) ?
A. 40 % B.50 %
C. 60 % D. 70 %
Answer & Explanation
Answer: Option B
Explanation:
FII's currently account for 33 out of 100.
If their value is doubled and all other investments are kept constant then their new value would be 66 out of 133 = approximately equal to 50%
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Directions to Solve
The following pie chart shows the amount of subscriptions generated for India Bonds from different categories of investors.
Subscriptions Generated for India Bonds
6. What is the approximate ratio of investment flows into India Bonds from NRI's to corporate houses ?
PAPER : 3i INFOTECH TECHNICAL QUESTIONS (INTERVIEW)
Q7. What happens when the impedance of an electrical load is equal to the internal impedance of the power source?A. The source delivers minimum power to the loadB. The electrical load is shortedC. No current can flow through the circuitD. The source can deliver maximum power to the load
Q8. Why is impedance matching important?A. So the source can deliver maximum power to the loadB. So the load will draw minimum power from the sourceC. To ensure that there is less resistance than reactance in the circuitD. To ensure that the resistance and reactance in the circuit are equal
Q11. Why should core saturation of a conventional impedance matching transformer be avoided?A. Harmonics and distortion could resultB. Magnetic flux would increase with frequencyC. RF susceptance would increaseD. Temporary changes of the core permeability could result
Q12. What is one reason to use an impedance matching transformer?A. To reduce power dissipation in the transmitterB. To maximize the transfer of powerC. To minimize SWR at the antennaD. To minimize SWR in the transmission line
Q13. Which of the following devices can be used for impedance matching at radio frequencies?A. A transformerB. A Pi-networkC. A length of transmission lineD. All of these choices are correct
Q14. Which of the following describes one method of impedance matching between two AC circuits?A. Insert an LC network between the two circuitsB. Reduce the power output of the first circuitC. Increase the power output of the first circuitD. Insert a circulator between the two circuits
Q15. A two-times increase or decrease in power results in a change of how many dB?A. 2 dBB. 3 dBC. 6 dBD. 12 dB
Q16. How does the total current relate to the individual currents in each branch of a parallel circuit?A. It equals the average of each branch currentB. It decreases as more parallel branches are added to the circuitC. It equals the sum of the currents through each branch (Kirchoff's Current Law)D. It is the sum of the reciprocal of each individual voltage drop
How many did you get right out of 16? If you have a similar quiz and want users to test their knowledge or refresh old concepts, do share them with us!
This quiz / questions have been compiled by VU3PLP - An Active HAM (Amateur Radio Operator) from Bhuvaneshwar
Orissa. Rajesh also operates website for Orissa HAMS which provides details of amateur radio activity in Orissa.
68. There was a circuit given using three nand gates with two inputs and one output.Find the output.a) OR b) AND c) XOR d) NOT Ans: (a)
69. Iintegrated check value(ICV) are used as: Ans: The client computes the ICVand then compares it with the senders value.
70. When applets are downloaded from web sites , a byte verifier performs _________?Ans: Status check
71. An IP/IPX packet received by a computer using... having IP/IPX both how the packet Is handled. Ans: Read the, field in the packet header with to send IP or IPX protocol.
72. The UNIX shell ....a) does not come with the rest of the systemb) forms the interface between the user and the kernalc) does not give any scope for programmingd) deos not allow calling one program from with in anothere) all of the above Ans: (b)
73. In UNIX a files i-node ......?Ans: Is a data structure that defines all specifications of a file like the file size, number of lines to a file,
74. The very first process created by the kernal that runs till the kernal process is halts isa) init b) getty c) both (a) and (b) d) none of these Ans: (a)
75. In the process table entry for the kernel process, the process id value is(a) 0 (b) 1 (c) 2 (d) 255 (e) it does not have a process table entry Ans: (a)
76. Which of the following API is used to hide a windowa) ShowWindow b) EnableWindow c) MoveWindowd) SetWindowPlacemente) None of the above Ans: (a)
77. Which function is the entry point for a DLL in MS Windows 3.1a) Main b) Winmain c) Dllmain d) Libmain e) None Ans: (b)
78. The standard source for standard input, standard output and standard error is a) the terminal b) /dev/nullc) /usr/you/input, /usr/you/output/, /usr/you/error respectivelyd) None Ans: (a)
79. The redirection operators > and >>a) do the same function b) differ : > overwrites, while >> appendsc) differ : > is used for input while >> is used for outputd) differ : > write to any file while >> write only to standard outpute) None of these Ans: (b)
80. The command grep first second third /usr/you/myfilea) prints lines containing the words first, second or third from the file /usr/you/myfileb) searches for lines containing the pattern first in the files second, third, and /usr/you/myfile and prints themc) searches the files /usr/you/myfiel and third for lines containing the words first or second and prints themd) replaces the word first with the word second in the files third and /usr/you/myfilee) None of the aboveAns: (b)
Verbal :-
1. Depreciation: deflation, depression, devaluation, fall, slump2. Deprecate : feel and express disapproval, 3. Incentive : thing one encourages one to do (stimulus)4. Echelon : level of authority or responsibility5. Innovation : make changes or introduce new things6. Intermittent : externally stopping and then starting7. Detrimental: harmful8. Conciliation : make less angry or more friendly9. Orthodox: conventional or traditional, superstitious10. Fallible : liable to error11. Volatile : ever changing
12. Manifest: clear and obvious13. Connotation : suggest or implied meaning of expression14. Reciprocal: reverse or opposite15. Agrarian : related to agriculture16. Vacillate : undecided or dilemma17. Expedient : fitting proper, desirable18. Simulate : produce artificially resembling an existing one.19. Access : to approach20. Compensation: salary21. Truncate : shorten by cutting22. Adherence : stick23. Heterogeneous: non similar things24. Surplus : excessive25. Assess : determine the amount or value26. Cognizance : knowledge27. Retrospective : review28. Naive : innocent, rustic29. Equivocate : tallying on both sides, lie, mislead30. Postulate : frame a theory31. Latent : dormant, secret32. Fluctuation : wavering,33. Eliminate : to reduce34. Affinity : strong liking35. Expedite : hasten36. Console : to show sympathy37. Adversary : opposition38. Affable : lovable or approachable39. Decomposition : rotten40. Agregious : apart from the crowd, especially bad41. Conglomeration: group, collection42. Aberration: deviation43. Augury : prediction44. Creditability : ability to common belief, quality of being credible45. Coincident: incidentally46. Constituent : accompanying47. Differential : having or showing or making use of48. Litigation : engaging in a law suit49. Moratorium: legally or officially determined period of delay before fulfillment of the agreement of paying of debts.50. Negotiate : discuss or bargain51. Preparation : act of preparing52. Preponderant : superiority of power or quality53. Relevance : quality of being relevant54. Apparatus : appliances55. Ignorance : blindness, in experience56. Obsession: complex enthusiasm57. precipitate : speed, active58. corroborative: refutable59. obnoxious : harmless60. sanction: hinder
Q. Next they asked what preparations I have done for the interview.I told I have checked the BHEL's site and collected some information about it. Next I have prepared my area of interest i.e. Digital electronics. My 2nd area of interest was Microprocessors 8085 and they started with that.
Q. What do mean by 8085.I told it's the serial no. of the device given by the company Intel. But they were not satisfied and told it must have some meaning. I told may its 8 because it's a 8-bit processor and about other digits no idea.
Q. What is RISC/CISC?I answered RISC is reduced instruction set computing and CISC is complex instruction set computing.
Q. What's the difference between them?I told RISC is generally used for high speed switching operations and CISC is for general purpose like 8085.
Q. Do we use microprocessors nowadays?I told we generally go for microcontrollers these days.
Q. What are microcontrollers?I said it has memory inbuilt in it apart from microprocessor architecture.
Q. What do you think the CPU we use has microprocessor in it.I told it has but not only microprocessor. It has other components also.
Q. What do you think the other components are?The answer of this question doesn't click me there so I told no idea.
Q. What do think Pentium uses RISC or CISC?I was not sure with this so answered we can use RISC
4.What is the advantage of Win NT over Win 95
Ans. Robust and secure
17. B-tree (failure nodes at same level)
18. Dense index (index record appers for every search -key in file)
20.A program on swaping ( 10,5 )was given (candidate cannot recollect)
22.In which layer are packets formed ( in network layer )
23.heap ( priority queue )
24.copy constructor ( constant reference )
28. Irrevalent to unix command ( getty)
29.What is fork command in unix
Ans. System call used to create process
12. What method is used in Win95 in multitaskingAns. Non preemptive check18. Dense index (index record appers for every search -key in file)
24. copy constructor ( constant reference )28. Irrevalent to unix command ( getty)29. What is fork command in unixAns. System call used to create process
A moving coil meter is not used on an ac circuit because
a) It cannot read very small variations b) The direction of the deflection depends upon the direction of the current c) It is non linear d) It does not use the damping effect
Answer – b
The purpose of a switch is to open or close a circuit
a) In the event of a fault current b) Under load conditions c) Under overload conditions d) Automatically after a fault has been repaired
Answer – b
With a star-delta starter, the windings are brought out to a terminal box. The voltage applied to the windings at starting is
a) VL ÷ v3 b) VL x v3 c) VPhase ÷ v3
d) VPhase x v3
Answer – a
When the field windings of an electrical machine are not connected to its own armature, it is known as
a) Self- excited b) Polyphase c) Separately-excited d) Synchronous
Answer – c
If a motor is required to start against a large starting current, it is usual to use
a) Direct on line starter b) Face plate starter c) Step down centre tapped starter d) Rotor resistance starter
Answer – d
The usual method of insulating core laminations is
a) Low reluctance silicon steel b) Surface oxidization c) High frequency air cores d) Cellulose paper
Answer – b
One method of insulating windings is to use
a) Shelac b) High reluctance silicon steel c) Low frequency dust cores d) PVC
Answer – a
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TCP/IP
TCP/IP is actually a suite, or stack, of protocols that interconnect and work together to provide for reliable and efficient data communications across an internetwork. The major protocols of the TCP/IP suite are:
Transmission Control Protocol (TCP) User Datagram Protocol (UDP) Domain Name System (DNS) Internet Protocol (IP) Address Resolutions Protocol (ARP) File Transport Protocol (FTP) Simple Mail Transport Protocol (SMTP) Post Office Protocol (POP3) Interactive Mail Access Protocol (IMAP) Internet Control Message Protocol (ICMP) Routing Information Protocol (RIP) Open Shortest Path First (OSPF) Hypertext Transfer Protocol (HTTP) TCP/IP Utilities (PING, Telnet, IPCONFIG, ARP, and more)
How the TCP/IP Protocol Stack Maps to the OSI Model
* These are networking technologies that function at the Data Link and Physical layers. They aren't TCP/IP protocols or a part of the TCP/IP protocol stack.
Application Layer Protocols
FTP
FTP is a reliable, connection-oriented tool used to copy files from one computer to another over a TCP/IP network, such as the Internet of an intranet.
Another flavor of FTP is Trivial File Transfer Protocol (TFTP), which is an unreliable (maining delivery is not guaranteed) file trasfer protocol. Cisco reouters use TFTP to store and retrieve configuration files from a TFTP server.
Telnet
Telnet is a terminal emulation protocol used on TCP/IP-based networks to remotely log into a remote device to run a program or manipulate data. Telnet was originally developed for ARPAnet and is an inherent part of the TCP/IP communications protocol. In the Cisco world, Telnet is used to access and configure routers from remote locations.
Transport Layer Protocols
Network protocols are either connection-oriented or connectionless.
Connection-oriented protocols - require that a direct connection be established between two devices before data can begin to transfer between the devices. Packets are transferred using a prescribed sequence of actions that include an acknowledgment to signal when a packet arrives, and possibly resending the packet if there are errors. This method is reliable and, as a result of its reliability and the overhead involved, much slower than connectionless protocols. Connectionless protocols - are largely based on your faith in the technology. Packets are sent over the network without regard to whether they actually arrive at their destinations. There are no acknowledgments or guarantees, but you can send a datagram to many different destinations at the same time. Connectionless protocols are fast because no time is used in establishing and tearing down connections. Connectionless protocols are also referred to as best-effort protocols.
Connection-Oriented and Connectionless Protocols
Protocol Type
FTP Connection-oriented
IP Connectionless
IPX Connectionless
TCP Connection-oriented
UDP Connectionless
SPX Connection-oriented
Establishing a connection-oriented connection involves the process of setting up sequence and acknowledgment fields and agreeing upon the port numbers to be used. This is accomplished by a three-step handshake process that works like this:
Handshake one: Host 1 sends a synchronization message to Host 2 Handshake two: Host 2 acknowledges Host 1's synchronization message and sends back its own synchronization message. Handshake three: Host 1 acknowledges Host 2's synchronizattion message.
At this point, the connection is successfully established and the applications can begin transferring data.
Both TCP and UDP use port number to move information along to the application layer.
The registering body, IANA (Internet Assigned Numbers Authority), divides port numbers into three groups:
Well-known ports - are the most commonly used TCP/IP ports. These ports are in the range of 0 through 1023. These ports can be used only by system processes or privileged programs. Well-known ports are TCP ports but are usually registered to UDP services as well. Registered ports - are in the range of 1024 through 49151. Registered ports are used on most systems by user programs to create and control logical connections between proprietary programs. Dynamic (private) ports - are in the range of 49152 through 65525. These ports are unregistered and can be used dynamically for private connections.
Additional informaiton to know about port numbers:
Port numbers below 256 are assigned to public applications. Port numbers 256 - 1023 are assigned to companies for saleable applications Port numbers above 1023 are dynamically assigned in the host application Source and destination port numbers don't have to be the same
Well-Known Ports
Port Number Application
21 FTP
23 Telnet
25 SMTP
69 TFTP
80 HTTP
Transmission Control Protocol (TCP)
TCP is a connection-oriented reliable, delivery protocol that ensures that packets arrive at their destination error-free. Using TCP is similar to sending a registered letter. When you send the letter, you know for sure that it will get to its destination and that you'll be notivied that it got there in good condition.
What to know about TCP:
Connection-oriented Reliable transfer Error-checking Full-duplex transmission Flow control MultiplexingOn the Transport layer, packets are referred to as segments. The image below depicts the format of the TCP segment:
TCP Segment DescriptionField Lenght in Bits Purpose
Source port 16 The number of the calling port
Destination port 16 The number of the calling port
Sequence number 32 Used to ensure correct sequencing of data
Acknowledgment # 32 Sequence number of the next expected TCP octet
HLEN 4 Header lenght
Reserved 6 Set to zero
Code bits 6 Functions that set up and terminate the session
Window 16 Size of window sender can accept
Checksum 16 Sum of header and data fields (error correction feature)
Urgent Pointer 16 End of the urgent data
Option 0 or 32 Maximum TCP segment size
Data - Data from upper layers
User Datagram Protocol (UDP)
Remember that UDP is connectionless and unreliable.UDP Datagram
UDP Datagram Description
Field Size in Bits Purpose
Source port 16 The number of the calling port
Destination port 16 The number of the called port
Length 16 The length of the datagram
Checksum 16 Sum of header and data fields (error correction feature)
Data - Data from upper layers
Network Layer Protocols
A number of TCP/IP protocols operate on the Network layer of the OSI Model, including IP, ARP, RARP, BOOTP, and ICMP. Remember, the OSI Network layer is concerned with routing messages across the internetwork.
Internet Protocol (IP)
Where TCP is connection-oriented, IP is connectionless. IP provides for the best-effort delivery of the packets (or datagrams) that it creates from the setments it receives from the Transport layer protocols. The IP protocol provides for logical addressing on the Network layer.
The IP packet (or datagram) is variable length, and its format is shown below:
i. Spanning Tree Protocol
1. Spanning Tree Protocol (STP) IEEE Specification 802.1d is used to prevent routing loops. In Cisco Catalyst 5000 series switches, use BDPUs (Bridge Protocol Data Units) to determine the spanning tree topology. STP uses a Tree Algorithm (STA) to prevent loops, resulting in a stable network topology.
2. Following are the possible solutions for preventing routing loops.
1. Split Horizon - based on the principle that it is not useful to send the information about a route back in the direction from which the information originally came. 2. Poison Reverse - A router that discovers an inaccessible route sets a table entry consistent state (infinite metric) while the network converges. 3. Hold-down Timers - Hold down timers prevent regular update messages from reinstating a route that has gone bad. Here, if a route fails, the router waits a certain amount of time before accepting any other routing information about that route. 4. Triggered Updates - Normally, new routing tables are sent to neighboring routers at regular intervals (IP RIP every 30 sec / and IPX RIP every 60 sec). A triggered update is an update sent immediately in response to some change in the routing table. Triggered updates along with Hold-down timers can be used effectively to counter routing loops.
3. Spanning Tree Protocol (STP) is enabled on every port on Cisco switches, by default. It is preferred to leave it enabled, so that bridging loops don't occur. STP can be disabled selectively on any specific port by issuing the command:Switch (enable) set spantree disable <mod-number>/<port-number>.Ex: Switch (enable) set spantree disable 2/4The above command disables STP on port 4 of module 2.
4. All switches participating in STP exchange information with other switches in the network through messages, known as, Bridge Protocol Data Units (BDPUs). BDPUs are sent out at a frequency of 2 seconds on every port.
5. Internally, STP assigns to each bridge (or switch) port a specific role. The port role defines the behavior of the port from the STP point of view. Based on the port role, the port either sends or receives STP BPDUs and forwards or blocks the data traffic. The different port roles are given below:
1. Designated: One designated port is elected per link (segment).
The designated port is the port closest to the root bridge. This port sends BPDUs on the link (segment) and forwards traffic towards the root bridge. In an STP converged network, each designated port is in the STP forwarding state. The switch with the lowest cost to reach the root, among all switches connected to a segment, becomes a DP (Designated Port) on that switch. If the cost is tied (that is two or more switches have the same cost), the switch with the lowest bridge ID will have the DP (the switch on which DP is elected is called Designated Switch or Designated Bridge). Bridge ID: Priority + MAC address2. Root: A bridge can have only one root port. The root port is the port that leads to the root bridge. In an STP converged network, the root port is in the STP forwarding state. All bridges except the root bridge will have a root port. 3. Alternate: Alternate ports lead to the root bridge, but are not root ports. The alternate ports maintain the STP blocking state.4. Backup: This is a special case when two or more ports of the same bridge (switch) are connected together, directly or through shared media. In this case, one port is designated, and the remaining ports block. The role for this port is backup.
6. A switch, participating in Spanning-Tree protocol, passes through the following states:1. Blocked state: This is the initial state. All ports are put in a blocked state to prevent bridging loops. 2. Listen state: This is the second state of switch ports. Here all the ports are put in listen mode. The port can listen to frames but can't send. The period of time that a switch takes to listen is set by "fwd delay". 3. Learn state: Learn state comes after Listen state. The only difference is that the port can add information that it has learned to its address table. The period of time that a switch takes to learn is set by "fwd delay". 4. Forward state: A port can send and receive data in this state. Before placing a port in forwarding state, Spanning-Tree Protocol ensures that there are no redundant paths or loops.5. Disabled state: This is the state when the switch port is disabled. A switch port may be disabled due to administrative reasons or due to switch specific problems.
7. During the process of Spanning-Tree Protocol execution, Root switch (say, switch A) is elected first. Next, the switch closest to the root switch is selected. This switch is known as Designated switch or Parent switch (say switch B). The frames are forwarded to the root switch(A) through the designated switch(B). Now the lowest cost port on a switch (say switch C) is selected. This is known as the
Root port. A Root Port is the port on a switch that has the lowest cost path to the Root Bridge. All Non-Root Switches will have one Root Port. Here, switch B is the designated switch for switch C and switch A is known as the root switch for switch C. Note that switch C is connected to the root switch (A) through its designated switch (B).
8. During the process of Spanning-Tree Algorithm execution, some redundant ports need to be blocked. This is required to avoid bridging loops. To choose which port to use for forwarding frames, and which port to block, the following three components are used by the Spanning-Tree Protocol:
1. Path Cost: The port with lowest path cost is placed in the forwarding mode. Other ports are placed in blocking mode.2. Bridge ID: If the path costs are equal, then the bridge ID is used to determine which port should forward. The port with the lowest Bridge ID is elected to forward, and all other ports are blocked.3. Port ID: If the path cost and bridge ID are equal, the Port ID is used to elect the forwarding port. The lowest port ID is chosen to forward. This type of situation may arise when there are parallel links, used for redundancy.
9. When a bridge starts up, the bridge ID is set as root ID. That is, it considers itself as the root bridge. However, while exchanging BDPUs, if it comes across a BDPU that has a bridge ID lower than its own, then the bridge corresponding to the BDPU is considered as root bridge, and this information is propagated. The bridge ID consists of the following:
1. 2-byte priority: The default value on Cisco switches is 0X8000 (32,768), lower the priority, higher the chances of becoming a root bridge.2. MAC address: The 6 byte MAC address of the bridge. Lower the MAC address, higher the chances of becoming a root bridge. Note that, the bridge (or switch) with lowest value of 2-byte priority will become the root bridge. If the priority value is same, then the bridge with lowest value of 6-byte MAC address will become the root bridge.
10. The command "show spantree" includes information about the following:1. VLAN number2. Root bridge priority, MAC address3. Bridge timers (Max Age, Hello Time, Forward Delay)
ii. VLANS
Spanning Tree Overview
There can only be one Root Bridge. Root-Bridge ports are called 'Designated' and are set to send and
receive traffic (forwarding state). All other redundant links to the root bridge are shutdown.
Blocked ports still receive BPDUs. Convergence occurs when switches have transitioned to either
forwarding or blocking states. No other data is forwarded during this time.
Forward delay - Time taken for a switch to go from Listening to Learning (50 seconds default).
IEEE default priority = 32,768, this is true for all devices running STP IEEE version.
Port Fast Mode - Immediately brings a port from blocking to forwarding state by eliminating forward delays.
Bridges can only have one spanning tree instance compared to switches which can have many.
Bridge Protocol Data Units send confirmation messages using multicast frames.
STA - Spanning Tree Algorithm Spanning Tree Algorithm is used to calculate a loop-free path. All switch ports are in blocking mode to begin with. It takes
approx 30 seconds until packets can be forwarded. Step 1 : Elect Root Bridge - Lowest bridge priority, if there is a
tie then switch with lowest bridge IDStep 2 : Elect Root Ports - Locate redundant paths to root bridge; block all but on root. Root Path Cost is cumulative cost of path to root bridge. Ports directly connected to Root Bridge will be root ports, otherwise lowest root path cost used.Step 3 : Elect Designated Ports - Single port that sends and receives traffic from a switch to and from Root Bridge - Lowest cost path to Root Bridge.
Spanning Tree Protocol
The Spanning Tree Protocol was created by DEC (Digital Equipment Corporation) now Compaq. This is not compatible with the IEEE 802.1d version which Cisco use.
The Spanning Tree Protocol:
Prevents loops, loops cause broadcast storms Allows redundant links Resilient to topology changes STA (Spanning Tree Algorithm) - Used to calculate loop-free path
BPDUs (Bridge Protocol Data Units) are sent and received by switches in the network every 2 seconds (default) to determine spanning tree topology.Bridge Priority - Numerical value held by switches. All Catalyst switches are 32768Bridge ID = MAC AddressSpanning Tree
The spanning tree network protocol provides a loop free topology for
any bridged LAN. The Spanning Tree Protocol, which is also referred to as STP, is
defined in the IEEE Standard 802.1D. Spanning tree is based on
an algorithm invented by Radia Perlman while working for Digital Equipment
Corporation. STP is used in switched networks to prevent loops, and has been
standardized by IEEE 802.1D. As the name suggests, it finds a spanning
tree within the mesh network formed by the installer, whether purposefully
created or not, and disables the links not part of that tree. There are two different
standards of STP: IEEE and DEC. IEEE is the most common, and is recommended
to be the one used in a network. Problems can be caused in networks where both
standards of STP are implemented. It is likely that both standards will elect their
own root bridge and cause loops in the topology. The way in which both
standards handle Bridge Protocol Data Units (see below) also differs.
If more than one open path were to be active at once then there would be several
problems. First, a broadcast storm caused by broadcast packets looping between
switches would reduce available CPU resources and bandwidth (many modern
bridges can detect and limit the effects of this, although it usually still causes a
breakdown in connectivity). Second, the traditional source-based location system
(filtering database) used by switches would fail to operate correctly. However, a
good network design should include spare (redundant) links to provide an
alternate path if one fails. Hence the need for spanning tree in a switched
network.
[edit]Protocol operation
Elect a root bridge.
Find paths to root bridge.
Determine least cost (measured as sum of all traversed port costs) path to
11. Which of the following are primary duties of the OSI transport layer? (Choose two.)
path determination
end-to-end connectivity
flow control
security control
data representation
encryption of data
12. If an application uses a protocol that exchanges data without using windowing or flow
control and must rely on higher layer protocols for reliability, which protocol and transfer
methods are being used?
UDP, connection-oriented
UDP, connectionless
TCP, connection-oriented
TCP, connectionless
13. TCP is referred to as connection-oriented. What does this mean?
TCP uses only LAN connections.
TCP requires devices to be directly connected.
TCP negotiates a session for data transfer between hosts.
TCP reassembles the data steams in the order that it is received.
14. Which port numbers are commonly assigned for FTP use? (Choose two.)
19
20
21
22
15. hich Application layer protocol is widely used to support resolving host names to IP
addresses?
FTP
SMTP
SNMP
DNS
HTTP
WWW
CAT Reading Comprehension : Sample Passage
Read the passage given below and answer questions that follow based on the information
given in the passage
First AOL and Time Warner announced their intention to combine. Then came Time Warner/EMI and Tribune/ Times Mirror. Even more significant, however, has been the speculation that these mergers have caused: If these transactions are consummated, a large number of additional media mergers are expected. There is even the possibility of a nightmare scenario-a wave of media mergers so large that within a decade most of our information will be supplied by perhaps six of these huge conglomerates and a fringe of much smaller firms.
It's time to ask two critical questions. Is this kind of media oligopoly what we, as a society, want? And if not, can the antitrust laws effectively prevent the threatened merger wave? The answer to the first question is clear. We do not want a media oligopoly. The answer to the second question, however, is far less certain. We should distrust a media oligopoly because it would give undue control to a small number of individuals. This need not manifest itself in a price rise for the daily newspaper or AOL's monthly fee. Rather, it could consist of a change in editorial viewpoints, a shift in the relative prominence of links to certain websites or a decision not to cover certain topics, because they are not "newsworthy". These problems could exist without any improper intent on the part of the media barons. Even if they try to be fair and objective, they will necessarily bring their own worldview to the job. And in time some of these conglomerates may be controlled by people who are not fair or objective.
At first it might appear that the antitrust laws can be of little help in grappling with the issues presented by large media mergers. The anti-merger laws are commonly understood as protecting price competition, and a relatively small number of firms-to greatly oversimplify, let's say at most half a dozen-are normally thought to be enough to keep a market price-competitive. In industry after industry firms merge until there is only a handful left, and the antitrust enforcers are normally unable to do anything to prevent this. (In former years mergers were governed by an "incipiency" standard that prevented mergers and merger waves well before they would have led to very large or likely anti-competitive problems.) Even if a handful of firms are enough to insure effective competition in most industries, would six conglomerate media firms be sufficient for the diversity of viewpoints necessary to democracy? Would we be reassured if they could somehow guarantee that they would sell their magazines and Internet advertisements at competitive prices?
I am hopeful that the antitrust laws, if correctly and vigorously interpreted, are adaptable enough to meet this challenge. This is because antitrust is not exclusively about price. It is essentially about choice-about giving consumers a competitive range of options in the marketplace so that they can make their own, effective selection from the market's offerings. Consumers should be able to make their choices along any dimension important to them-including price, variety and editorial viewpoint.
Communications media compete in part by offering independent editorial viewpoints and an independent gatekeeper function. Six media firms cannot effectively respond to the demand for choice or diversity competition by extending their product lines, because new media products will inevitably bear, to some degree, the perspective of their corporate parent. For these reasons competition in terms of editorial viewpoint or gate-keeping can be guaranteed only by insuring that a media market contains a significantly larger number of firms than is required for price competition in other, more conventional markets.
It is unclear, however, whether this interpretation of the anti-trust laws will be applied by the enforcement agencies and the courts. What is needed, therefore, is a much more careful look at the challenges that will be raised by future media mergers.
This could best be accomplished if Congress created a Temporary Committee to Study Media Mergers and Media Convergence. This committee could include members of Congress; the heads of the Federal Trade Commission, the Federal Communications Commission and the
Justice Department's antitrust division; CEOs of media companies; and representatives of consumer groups. The committee would identify problems that may be caused by large media mergers and by media convergence. If the committee concludes that existing antitrust laws are inadequate, it should recommend to Congress that new anti-merger legislation be enacted. This may be the only way to prevent the nightmare scenario of a media oligopoly.
1. A wave of media mergers could
1. be a threat to democracy2. result in limiting editorial viewpoints3. result in misuse of certain laws4. both (1) and (2)5. none of the above
2. According to the passage, what could be the most significant outcome of media oligopoly?
1. An increase in the cost of newspapers2. The fact that in the long run, there will be a shift of power to people who might not be
balanced and fair in the way they deal with the media3. Certain websites may get more prominence than others4. There will be no competition among the newspapers5. There will soon exist only six media conglomerates
3. Which of the following statements, according to the author, are true
a. Half a dozen firms are enough to keep the market price - competitiveb. Half a dozen companies are not enough to provide a democratic mediac. Enforcement agencies may not interpret the ant-trust laws correctlyd. Half a dozen companies will be inadequate to meet the consumer demand for product
diversity
1. a, b2. a, b, c3. a, b, c, d4. b, c, d5. a, c, d
4. The current anti- trust laws
1. are not sufficient to deal with issues relating to large scale media mergers2. can prevent mergers from happening3. will be effective if properly interpreted4. favour a particular company or group of companies5. none of the above
5. To get a clear picture of the challenges posed by media mergers, the author recommends:>
1. creation of strict laws2. strengthening the enforcement agencies3. creation of a study committee by the congress4. none of the above5. all of the above
Click for Correct answers and explanations to the answers.
1. The author talks about the necessity of diversity of viewpoints being essential for democracy. Therefore, a lack of it could be a threat to democracy. So (1) can be inferred. Choice (2) is clearly mentioned in the passage. Choice (3) cannot be inferred from the passage. Choice (4) is the correct answer.
2. In the last line of the third paragraph, the author voices the contents of choice (2) as the serious threat to medial oligopoly. While the author refers to the possibility of only six conglomerates, he uses the number six figuratively and not factually. Choice (2).
3. In the third paragraph, the author answers that media mergers may not results in prices increasing. Statement (a) is mentioned. In the same paragraph, he clearly puts forth the case that the oligopoly will not be able to provide a democratic media. And in the sixth paragraph, the author mentions statement (c) and (d). Choice (3) is correct.
4. In the first line of the fifth paragraph, the author mentions that the existing anti trust laws, if interpreted properly, are adequate to meet the media merger challenge. Choice (3).
5. The last paragraph of the passage provides a clear suggestion. Choice (3) is correct.
Question 1. For the word given at the top of the table, match the dictionary definitions on the left (A, B, C, D) with their corresponding usage on the right (E, F, G, H). Out of the four possibilities given in the boxes below the table, select the one that has all the definitions and their usages correctly matched.
1. BILL
Dictionary definition Usage
A. A written statement showing how much money you own someone for the goods or services you have received
E. The bill was passed in the parliament with a wafer thin margin.
B. Written document containing a proposal for a new law
F. They were arrested for willfully mutilating 100 rupee
bills.
C. A list of event and performers at a concert, show, movie, etc.
G. Settling bills is an unsetting chore.
D. Paper money as in bank note H. Cats has been topping the bill in Broadway for over ten years.
(1) (2) (3) (4)
A G A H A F A G
B H B G B G B E
C E C E C H C H
D F D F D E D F
Questions 2 to 4. For each of the words below, a contextual usage is provided. Pick the word from the alternatives given that is most inappropriate in the given context.
2. TEMPORAL: Do not get tempted by these temporal pleasures. They do not last long.
(1)
Eternal
(2)
Immortal
(3)
Everlasting
(4)
Ephemeral
3. FATUOUS: He is far too sensible to have done a fatuous thing like this.
(1)
Stupid
(2)
Intelligent
(3)
Inane
(4)
Foolish
4. MACABRE: The office wore a macabre look on Friday after the company downsized its staff strength.
(1)
Grisly
(2)
Tropical
(3)
Gruesome
(4)
Lugubrious
Question 5. Sentences given in this question, when properly sequenced form a coherent paragraph. Each sentence is labeled with a letter. Choose the most logical order of sentences from among the four given choices to construct a coherent paragraph.
5.
A. One of the solutions provided by this calculator was the Torpedo Track Angle, the gyro angle to be applied to the torpedoes. This angle was relative to the direction the bow would be facing when the fish was fired.
B. The advantage of this was that the bow didn't necessarily have to be pointed towards the target.
C. During the attack, estimated target speed, course and range were fed into a mechanical angle solver ("fruit machine") which was also provided with the submarine's gyro heading.
D. Torpedo spread was achieved by maintaining a steady course (of the submarine) and varying the gyro angle firing interval (time between firing) for each fish.
