Category: Interview Questions

1. What Is Switching?

The function of Switching is to Switch data packets between devices on the same network.

2. What Is Switch?

A Switch is a device which is used to connect multiple devices inside Local Area Network (LAN). Unlike hubs, switches examine each packet and process it accordingly rather than simply repeating the signal to all ports. Switches operate at Layer Two (Data Link Layer) of the OSI model.

3. What Is The Difference Between A Hub, Switch & Router?

Hub is designed to connect hosts to each other with no understanding of what it is transferring. When a Hub receives a packet of data from a connected device, it broadcasts that data packet to all other ports regardless of destination port. HUB operates at Layer 1 (Physical Layer).

Switch also connects hosts to each other like a hub. Switch differs from a hub in the way it handles packets. When a switch receives a packet, it determines what hosts the packet is intended for and sends it to that hosts only. It does not broadcast the packet to all the hosts as a hub does which means bandwidth is not shared and makes the network more effcient. Switch operates at Layer 2 (Data Link Layer).

Router is di􀃗erent from a switch or hub since its function is to route data packets to other networks, instead of just the local network. Routers operates at Layer 3 (Network Layer).

4. What Are The Functions Of A Switch?

The Switch performs three major functions:-

1. Address learning.
2. Packet forwarding/filtering.
3. Loop avoidance by Spanning Tree Protocol.

5. What Is Sub Interface?

To support ISL or 802.1Q routing on a Fast Ethernet interface, the router’s interface is divided into logical interfaces—one for each VLAN. These are called subinterfaces.

6. What Is A Broadcast Domain And A Collision Domain?

Broadcast Domain
– Broadcast is a type of communication, where the sending device send a single copy of data and that copy of data will be delivered to every other device in the network segment. A Broadcast Domain consists of all the devices that will receive every broadcast packet originating from any device within the network segment. All ports on a hub or a switch are by default in the same broadcast domain. All ports on a router are in the different broadcast domains and routers don’t forward broadcast.

Collision Domain
– is a network scenario where one particular device sends a packet on a network segment forcing every other device on that same segment to pay attention to it. At the same time, if a different device tries to transmit simultaneously, it will lead to a collision after which both devices must retransmit, one at a time. This situations is often in a hub environment, because each port on a hub is in the same collision domain. By contrast, Each port on a bridge, a switch or router is in a seperate collision domain.

7. Compare Hub And Switch With Respect To Broadcast And Collision Domain?

In Hub there is one collision domain and one broadcast domain.

In Switch there is multiple collision domain and one broadcast domain.

8. What Is A Mac Address Table And How A Switch Will Build A Mac Table?

To switch frames between LAN ports efficiently, the switch maintains an address table called MAC address Table or CAM Table (Content Addressable Memory Table). When the switch receives a frame, source MAC address is learned and recorded in the CAM table along with the port of arrival, VLAN and time stamp. The switch dynamically builds the MAC address table by using the Source MAC address of the frames received. Than this table is used by switch to determine where to forward trafic on a LAN.

9. How Switch Learns Mac Address?

When a frame reaches to the port of a switch, the switch reads the MAC address of the source device from Ethernet frame and compares it to its MAC address table (also known as CAM (Content Addressable Memory) table). If the switch does not find a corresponding entry in MAC address table, the switch will add the address to the table with the port number at which the Ethernet frame is received.

If the MAC address is already available in the MAC address table, the switch compares the incoming port with the port already available in the MAC table. If the port numbers are different, the switch updates the MAC address table with the new port number.

10. How Does Switch Performs Forwarding Function?

When a Layer2 Ethernet frame reaches a port on the Switch, it not only reads the source MAC address of the Ethernet frame as a part of learning function, but also reads the destination MAC address as a part of forwarding function. The destination MAC address is important to determine the port which the destination device is connected to.

As the destination MAC address is found on the MAC address table, the switch forwards the Ethernet frame via the corresponding port of the MAC address.

11. Explain Flooding?

If the destination MAC address is not found in the MAC address table, the switch forwards the frame out all of its ports except the port on which the frame was received. This is known as flooding.

1. What Are The Benefits Of Fibre Channel Sans?

Fibre Channel SANs are the de facto standard for storage networking in the corporate data center because they provide exceptional reliability, scalability, consolidation, and performance. Fibre Channel SANs provide significant advantages over direct-attached storage through improved storage utilization, higher data availability, reduced management costs, and highly scalable capacity and performance.

2. What Environment Is Most Suitable For Fibre Channel Sans?

Typically, fibre channel SANs are most suitable for large data centers running business-critical data, as well as applications that require high-bandwidth performance such as medical imaging, streaming media, and large databases. Fibre Channel SAN solutions can easily scale to meet the most demanding performance and availability requirements.

3. What Customer Problems Do Fibre Channel Sans Solve?

The increased performance of Fibre Channel enables a highly effective backup and recovery approach, including LAN-free and server-free backup models. The result is a faster, more scalable, and more reliable backup and recovery solution. By providing flexible connectivity options and resource sharing, Fibre Channel SANs also greatly reduce the number of physical devices and disparate systems that must be purchased and managed, which can dramatically lower capital expenditures. Heterogeneous SAN management provides a single point of control for all devices on the SAN, lowering costs and freeing personnel to do other tasks.

4. How Long Has Fibre Channel Been Around?

Development started in 1988, ANSI standard approval occurred in 1994, and large deployments began in 1998. Fibre Channel is a mature, safe, and widely deployed solution for high-speed (1 GB, 2 GB, 4 GB) communications and is the foundation for the majority of SAN installations throughout the world.

5. What Is The Future Of Fibre Channel Sans?

Fibre Channel is a well-established, widely deployed technology with a proven track record and a very large installed base, particularly in high-performance, business-critical data center environments. Fibre Channel SANs continue to grow and will be enhanced for a long time to come. The reduced costs of Fibre Channel components, the availability of SAN kits, and the next generation of Fibre Channel (4 GB) are helping to fuel that growth. In addition, the Fibre Channel roadmap includes plans to double performance every three years.

6. What Are The Benefits Of 4gb Fibre Channel?

Benefits include twice the performance with little or no price increase, investment protection with backward compatibility to 2 GB, higher reliability due to fewer SAN components (switch and HBA ports) required, and the ability to replicate, back up, and restore data more quickly. 4 GB Fibre Channel systems are ideally suited for applications that need to quickly transfer large amounts of data such as remote replication across a SAN, streaming video on demand, modeling and rendering, and large databases. 4 GB technology is shipping today.

7. How Is Fibre Channel Different From Iscsi?

Fibre Channel and iSCSI each have a distinct place in the IT infrastructure as SAN alternatives to DAS. Fibre Channel generally provides high performance and high availability for business-critical applications, usually in the corporate data center. In contrast, iSCSI is generally used to provide SANs for business applications in smaller regional or departmental data centers.

8. When Should I Deploy Fibre Channel Instead Of Iscsi?

For environments consisting of high-end servers that require high bandwidth or data center environments with business-critical data, Fibre Channel is a better fit than iSCSI. For environments consisting of many midrange or low-end servers, an IP SAN solution often delivers the most appropriate price/performance.

9. Name Some Of The San Topologies?

Point-to-point, arbitrated loop, and switched fabric topologies.

10. What’s The Need For Separate Network For Storage Why Lan Cannot Be Used?

LAN hardware and operating systems are geared to user traffic, and LANs are tuned for a fast user response to messaging requests.

With a SAN, the storage units can be secured separately from the servers and totally apart from the user network enhancing storage access in data blocks (bulk data transfers), advantageous for server-less backups.

11. What Are The Advantages Of Raid?

“Redundant Array of Inexpensive Disks”

Depending on how we configure the array, we can have the

• data mirrored [RAID 1] (duplicate copies on separate drives)
• striped [RAID 0] (interleaved across several drives), or
• parity protected [RAID 5](extra data written to identify errors).

These can be used in combination to deliver the balance of performance and reliability that the user requires.

12. What Is The Difference Between Raid 0+1 And Raid 1+0?

RAID 0+1 (Mirrored Stripped)

In this RAID level all the data is saved on stripped volumes which are in turn mirrored, so any disk failure saves the data loss but it makes whole stripe unavailable. The key difference from RAID 1+0 is that RAID 0+1 creates a second striped set to mirror a primary striped set. The array continues to operate with one or more drives failed in the same mirror set, but if drives fail on both sides of the mirror the data on the RAID system is lost. In this RAID level if one disk is failed full mirror is marked as inactive and data is saved only one stripped volume.

RAID 1+0 (Stripped Mirrored)

In this RAID level all the data is saved on mirrored volumes which are in turn stripped, so any disk failure saves data loss. The key difference from RAID 0+1 is that RAID 1+0 creates a striped set from a series of mirrored drives. In a failed disk situation RAID 1+0 performs better because all the remaining disks continue to be used. The array can sustain multiple drive losses so long as no mirror loses both its drives.

This RAID level is most preferred for high performance and high data protection because rebuilding of RAID 1+0 is less time consuming in comparison to RAID 0+1.

13. When Jbod’s Are Used?

“Just a Bunch of Disks”

It is a collection of disks that share a common connection to the server, but don’t include the mirroring, striping, or parity facilities that RAID systems do, but these capabilities are available with host-based software.

14. Differentiate Raid And Jbod?

RAID:
“Redundant Array of Inexpensive Disks”

• Fault-tolerant grouping of disks that server sees as a single disk volume
• Combination of parity-checking, mirroring, striping
• Self-contained, manageable unit of storage

JBOD:
“Just a Bunch of Disks”

• Drives independently attached to the I/O channel
• Scalable, but requires server to manage multiple volumes
• Do not provide protection in case of drive failure

15. What Is A Hba?

Host bus adapters (HBAs) are needed to connect the server (host) to the storage.

16. What Are The Advantages Of San?

• Massively extended scalability
• Greatly enhanced device connectivity
• Storage consolidation
• LAN-free backup
• Server-less (active-fabric) backup
• Server clustering
• Heterogeneous data sharing
• Disaster recovery – Remote mirroring
• While answering people do NOT portray clearly what they mean & what advantages each of them have, which are cost effective & which are to be used for the client’s requirements.

17. What Is The Difference B/w San And Nas?

The basic difference between SAN and NAS, SAN is Fabric based and NAS is Ethernet based.

SAN –
Storage Area Network

It accesses data on block level and produces space to host in form of disk.

NAS –
Network attached Storage

It accesses data on file level and produces space to host in form of shared network folder.

18. What Is A Typical Storage Area Network Consists Of – If We Consider It For Implementation In A Small Business Setup?

If we consider any small business following are essentials components of SAN

• Fabric Switch
• FC Controllers
• JBOD’s

19. Can You Briefly Explain Each Of These Storage Area Components?

Fabric Switch: It’s a device which interconnects multiple network devices .There are switches starting from 16 port to 32 ports which connect 16 or 32 machine nodes etc. vendors who manufacture these kind of switches are Brocade, McData.

20. What Is Fc Controllers?

These are Data transfer media they will sit on PCI slots of Server; you can configure Arrays and volumes on it.

21. What Is The Most Critical Component In San?

Each component has its own criticality with respect to business needs of a company.

22. How Is A San Managed?

There are many management software’s used for managing SAN’s to name a few

• Santricity
• IBM Tivoli Storage Manager.
• CA Unicenter.
• Veritas Volumemanger.

23. Which One Is The Default Id For Scsi Hba?

Generally the default ID for SCSI HBA is 7.

• SCSI-
  Small Computer System Interface
• HBA –
  Host Bus Adaptor

24. What Is The Highest And Lowest Priority Of Scsi?

There are 16 different ID’s which can be assigned to SCSI device 7, 6, 5, 4, 3, 2, 1, 0, 15, 14, 13, 12, 11, 10, 9, 8.

Highest priority of SCSI is ID 7 and lowest ID is 8.

25. How Do You Install Device Drivers For The Hba First Time During Os Installation?

In some scenarios you are supposed to install Operating System on the drives connected thru SCSI HBA or SCSI RAID Controllers, but most of the OS will not be updated with drivers for those controllers, that time you need to supply drivers externally, if you are installing windows, you need to press F6 during the installation of OS and provide the driver disk or CD which came along with HBA.

If you are installing Linux you need to type “linux dd” for installing any driver.

26. What Is Array?

Array is a group of Independent physical disks to configure any Volumes or RAID volumes.

27. Which Are The San Topologies?

SAN can be connected in 3 types which are mentioned below:

• Point to Point topology
• FC Arbitrated Loop ( FC :Fibre Channel )
• Switched Fabric

28. Which Are The 4 Types Of San Architecture Types?

• Core-edge
• Full-Mesh
• Partial-Mesh
• Cascade

29. Which Command Is Used In Linux To Know The Driver Version Of Any Hardware Device?

dmesg

30. How Many Minimum Drives Are Required To Create R5 (raid 5) ?

You need to have at least 3 disk drives to create R5.

31. Can You Name Some Of The States Of Raid Array?

There are states of RAID arrays that represent the status of the RAID arrays which are given below:

• Online
• Degraded
• Rebuilding
• Failed

32. Name The Features Of Scsi-3 Standard?

QAS:
Quick arbitration and selection

Domain Validation

CRC:
Cyclic redundancy check

33. Can We Assign A Hot Spare To R0 (raid 0) Array?

No, since R0 is not redundant array, failure of any disks results in failure of the entire array so we cannot rebuild the hot spare for the R0 array.

34. Can You Name Some Of The Available Tape Media Types?

There are many types of tape media available to back up the data some of them are:

• DLT:
  digital linear tape – technology for tape backup/archive of networks and servers; DLT technology addresses midrange to high-end tape backup requirements.
• LTO:
  linear tape open; a new standard tape format developed by HP, IBM, and Seagate.
• AIT:
  advanced intelligent tape; a helical scan technology developed by Sony for tape backup/archive of networks and servers, specifically addressing midrange to high-end backup requirements.

35. What Is Ha?

HA High Availability is a technology to achieve failover with very less latency. Its a practical requirement of data centers these days when customers expect the servers to be running 24 hours on all 7 days around the whole 365 days a year – usually referred as 24x7x365. So to achieve this, a redundant infrastructure is created to make sure if one database server or if one app server fails there is a replica Database or Appserver ready to take-over the operations. End customer never experiences any outage when there is a HA network infrastructure.

36. What Is Virtualization?

Virtualization is logical representation of physical devices. It is the technique of managing and presenting storage devices and resources functionally, regardless of their physical layout or location. Virtualization is the pooling of physical storage from multiple network storage devices into what appears to be a single storage device that is managed from a central console. Storage virtualization is commonly used in a storage area network (SAN). The management of storage devices can be tedious and time-consuming. Storage virtualization helps the storage administrator perform the tasks of backup, archiving, and recovery more easily, and in less time, by disguising the actual complexity of the SAN.

37. Describe In Brief The Composition Of Fc Frame?

Start of the Frame locator

Frame header (includes destination id and source id, 24 bytes/6 words)

Data Payload (encapsulate SCSI instruction can be 0-2112 bytes in length)

CRC (error checking, 4 bytes)

End of Frame (1 byte)

38. What Is Storage Virtualization?

Storage virtualization is amalgamation of multiple n/w storage devices into single storage unit.

39. What Are The Protocols Used In Physical/data Link And Network Layer Of San?

• Ethernet
• SCSI
• Fibre Channel

40. What Are The Types Of Disk Array Used In San?

• JBOD
• RAID

41. What Are Different Types Of Protocols Used In Transportation And Session Layers Of San?

• Fibre Channel Protocol (FCP)
• Internet SCSI (iSCSI)
• Fibre Channel IP (FCIP)

42. What Is The Type Of Encoding Used In Fibre Channel?

8b/10b, as the encoding technique is able to detect all most all the bit errors

43. How Many Classes Of Service Are Available In Fibre Channel?

7 Classes of service are available in Fibre Channel

Class-1: Dedicated connection between two communicators with acknowledgement of frame delivery.

In class 1 service, a dedicated connection source and destination is established through the fabric for the duration of the transmission. It provides acknowledged service. This class of service ensures that the frames are received by the destination device in the same order in which they are sent, and reserves full bandwidth for the connection between the two devices. It does not provide for a good utilization of the available bandwidth, since it is blocking another possible contender for the same device. Because of this blocking and necessary dedicated connection, class 1 is rarely used.

Class-2: connection less but provides acknowledgement

Class 2 is a connectionless, acknowledged service. Class 2 makes better use of available bandwidth since it allows the fabric to multiplex several messages on a frame-by-frame basis. As frames travel through the fabric they can take different routes, so class 2 service does not guarantee in-order delivery. Class 2 relies on upper layer protocols to take care of frame sequence. The use of acknowledgments reduces available bandwidth, which needs to be considered in large-scale busy networks.

Class-3: connection less and provides no notification of delivery

There is no dedicated connection in class 3 and the received frames are not acknowledged. Class 3 is also called datagram connectionless service. It optimizes the use of fabric resources, but it is now upper layer protocol to ensure that all frames are received in the proper order, and to request to the source device the retransmission of missing frames. Class 3 is a commonly used class of service in Fibre Channel networks.

Class-4: allows fractional bandwidth for virtual circuits

Class 4 is a connection-oriented service like class 1, but the main difference is that it allocates only a fraction of available bandwidth of path through the fabric that connects two N_Ports. Virtual Circuits (VCs) are established between two N_Ports with guaranteed Quality of Service (QoS), including bandwidth and latency. Like class 1, class 4 guarantees in-order delivery frame delivery and provides acknowledgment of delivered frames, but now the fabric is responsible for multiplexing frames of different VCs. Class 4 service is mainly intended for multimedia applications such as video and for applications that allocate an established bandwidth by department within the enterprise. Class 4 was added in the FC-PH-2 standard.

Class -5: Class 5 is called isochronous service, and it is intended for applications that require immediate delivery of the data as it arrives, with no buffering. It is not clearly defined yet. It is not included in the FC-PH documents.

Class-6: Provides multicast, dedicated connection with acknowledgment

Class 6 is a variant of class 1, known as multicast class of service. It provides dedicated connections for a reliable multicast. An N_Port may request a class 6 connection for one or more destinations. A multicast server in the fabric will establish the connections and get acknowledgment from the destination ports, and send it back to the originator. Once a connection is established, it should be retained and guaranteed by the fabric until the initiator ends the connection. Class 6 was designed for applications like audio and video requiring multicast functionality. It appears in the FC-PH-3 standard.

Class-F: used for switch to switch communication in the fabric.

Class F service is defined in the FC-SW and FC-SW-2 standard for use by switches communicating through ISLs. It is a connectionless service with notification of non-delivery between E_Ports used for control, coordination, and configuration of the fabric. Class F is similar to class 2; the main difference is that Class 2 deals with N_Ports sending data frames, while Class F is used by E_ports for control and management of the fabric.

44. What Are The Main Constraints Of Scsi In Storage Networking?

• Deployment distance (max. of 25 mts)
• Number of devices that can be interconnected (16)

45. What Is A Fabric?

Interconnection of Fibre Channel Switches

46. What Are The Services Provided By Fabric To All The Nodes?

• Fabric Login
• SNS
• Fabric Address Notification
• Registered state change notification
• Broadcast Servers

47. What Is The Difference Between Lun And Wwn?

LUN:
unique number that is assigned to each storage device or partition of the storage that the storage can support.

WWN:
64bit address that is hard coded into a fibre channel HBA and this is used to identify individual port (N_Port or F_Port) in the fabric.

48. What Are The Different Topologies In Fibre Channel?

• Point-to-Point
• Arbitrary Loop
• Switched Fabric Loop

49. What Are The Layers Of Fibre Channel Protocol?

• FC Physical Media
• FC Encoder and Decoder
• FC Framing and Flow control
• FC Common Services
• FC Upper Level Protocol Mapping

50. What Is Zoning?

Fabric management service that can be used to create logical subsets of devices within a SAN. This enables portioning of resources for management and access control purpose.

51. What Are The Two Major Classification Of Zoning?

Two types of zoning are:

• Software Zoning
• Hardware Zoning

52. What Are Different Levels Of Zoning?

• Port Level zoning
• WWN Level zoning
• Device Level zoning
• Protocol Level zoning
• LUN Level zoning

53. What Are The 5 States Of Arbitrary Loop In Fc?

• Loop Initialization
• Loop Monitoring
• Loop arbitration
• Open Loop
• Close Loop

54. How Does Fc Switch Maintain The Addresses?

FC Switch uses simple name server (SNS) to maintain the mapping table

55. What Is The Purpose Of Disk Array?

Probability of unavailability of data stored on the disk array due to single point failure is totally eliminated.

56. What Is Disk Array?

Set of high performance storage disks that can store several terabytes of data. Single disk array can support multiple points of connection to the network.

57. What Is Multipath I/o?

Fault tolerant technique where, there is more than one physical path between the CPU in the computer systems and its main storage devices through the buses, controllers, switches and other bridge devices connecting them.

58. What Is Raid?

Technology that groups several physical drives in a computer into an array that you can define as one or more logical drive. Each logical drive appears to the operating system as single drive. This grouping enhances the performance of the logical drive beyond the physical capability of the drives.

59. What Is Stripe-unit-size?

It is data distribution scheme that complement s the way operating system request data. Granularity at which data is stored on one drive of the array before subsequent data is stored on the next drive of the array. Stripe unit size should be close to the size of the system I/O request.

60. What Is Lun Masking?

A method used to create an exclusive storage area and access control. And this can be achieved by storage device control program.

61. What Is The Smallest Unit Of Information Transfer In Fc?

Frame

62. What Is Bad Block Reallocation?

A bad sector is remapped or reallocated to good spare block and this information is stored in the internal table on the hard disk drive. The bad blocks are identified during the media test of the HDD as well as during various types of read write operations performed during the I/O tests. Apart from the new generation of HDD comes with a technology called BGMS (background media scan) which continuously scans the HDD media for defects and maps them when the drive is idle (this is performed after the HDD is attached to the system).

63. What Are Two Types Of Recording Techniques On The Tapes?

• Linear Recording
• Helical Scan Recording.

64. What Is Snapshot?

A snapshot of data object contains an image of data at a particular point of time.

65. What Is Hsm?

Hierarchical storage management – An application that attempts to match the priority of data with the cost of storage.

66. What Is Hot-swapping?

Devices are allowed to be removed and inserted into a system without turning off the system.

67. What Is Hot-sparing?

A spare device is available to be inserted into the subsystem operation without having to remove and replace a device.

68. What Are Different Types Of Backup System?

• Offline
• Online
• Near Line

69. What Is The Different Between Mirroring, Routing And Multipathing?

• Redundancy Functions Relationships Role
• Mirroring Generates 2 ios to 2 storage targets Creates 2 copies of data
• Routing Determined by switches independent of SCSI Recreates n/w route after a failure
• Multipathing Two initiator to one target Selects the LUN initiator pair to use

70. Name Few Types Of Tape Storage?

• Digital Linear Tape
• Advanced Intelligent Tape
• Linear Tape Open

71. What Is A Sequence In Fc?

Group of one or more frames that encompasses one or more “information units” of a upper layer protocol.

Example:
It requires

• One sequence to transfer the command
• One or more sequence to transfer the data
• Once sequence to transfer the status.

72. What Is Exchange In Fc?

Exchange is to establish a relationship between 2 N_PORTs and then these two ports transfer data via one or more sequence within this relationship.

Example:
Exchange exist to transfer the command, data and the status of one SCSI task

73. Why Do We Need Login In Fc?

Port Login:
To exchange service parameters between N_Ports and N_Ports

Process Login:
To establish the SCSI operating environment between two N_PORTS

Fabric Login:
Similar to port login, FLOGI is an extended link service command that sets up a session between two participants. With FLOGU a session is created between an N_Port or NL_Port and the switch.

74. What Are The Different Types Of Clusters?

• High availability clusters
• High Performance Clusters
• Load Balancing Clusters.

75. What Are Three Levels Of Management In Storage?

• Storage Level Management
• Network Level Management
• Enterprise Level Management

76. What Are The Key Activities In San Management?

• Monitoring
• Configuring
• Controlling
• Troubleshooting
• Diagnosing

77. What Is The Difference Between Hba And Nic?

HBA => Host bus adapters are used in storage based traffic while NIC (Network Interface Cards are used in IP based LAN traffic.

78. What Is The Measuring Unit Of Data Activity?

Gigabits per second (Gb/ps)

79. What Are The Basic Storage Policies?

• Security and authentication
• Capacity, Content and quota management
• Quality of Service

80. What Is Bypass Circuitry?

A circuit that automatically removes the storage device from the data path (FC device out of FC AL loop) when signaling is lost (this signal is called port by-pass signal).

81. How Many Connections Are Possible In Fabric Topology?

2^24 (24 bit address to the port), and the largest possible fabric will have 239 interconnected switches.

82. What Is One Of The Constraints Of Using Storage Switch?

Latency

83. What Is The Difference Between Nas And San?

NAS:

• Cables used in the n/w
• n/w protocols (TCP/IP, IPx) and file sharing protocols (CIFS & NFS)
• Lower TCO
• Support heterogeneous clients
• Slow

SAN:

• High-speed connectivity such as FC
• Do not use n/w protocols because data request are not made over LAN
• Higher TCO
• Requires special s/w to provide access to heterogeneous clients
• Fast

84. What Is Jitter?

Jitter refers to any deviation in timing that a bit stream suffers as it traverses the physical medium and the circuitry on-board the end devices. A certain amount of deviation from the original signaling will occur naturally as serial bit stream propagates over fibre-optic or copper cabling.

85. What Is Ber/bit Error Rate?

Probability that a transmitted bit will be erroneously received is the measure of number of bits (erroneous) at the output of the receiver and dividing by the total number of bits in transmission.

86. What Is Wwpn?

WWPN is the 16 bit character that is assigned to the port, SAN volume controller uses it to uniquely identify the fibre channel HBA that is installed in the host system.

87. What Is Connection Allegiance?

Given multiple connections are established, individual command/response pair must flow over the same connection. This connection allegiance ensures that specific read or writes commands are fulfilled without any additional overhead of monitoring multiple connections and to see whether a particular request is completed.

88. What Is Burst Length?

The burst length is the number of bytes that the SCSI initiator sends to the SCSI target in the FCP_DATA sequence.

89. What Is Nas In Detail?

NAS or Network Attached Storage

“NAS is used to refer to storage elements that connect to a network and provide file

access services to computer systems. A NAS Storage Element consists of an interface or engine, which implements the file services, and one or more devices, on which data is stored. NAS elements may be attached to any type of network. When attached to SANs, NAS elements may be considered to be members of the SAS (SAN Attached Storage) class of storage elements.

A class of systems that provide file services to host computers. A host system that uses network attached storage uses a file system device driver to access data using file access protocols such as NFS or CIFS. NAS systems interpret these commands and perform the internal file and device I/O operations necessary to execute them.

Though the NAS does speed up bulk transfers, it does not offload the LAN like a SAN does. Most storage devices cannot just plug into gigabit Ethernet and be shared – this requires a specialized file server the variety of supported devices is more limited.NAS has various protocols established for such needed features as discovery, access control, and name services.

90. Briefly List The Advantages Of San?

SANs fully exploit high-performance, high connectivity network technologies

SANs expand easily to keep pace with fast growing storage needs

SANs allow any server to access any data

SANs help centralize management of storage resources

SANs reduce total cost of ownership (TCO).

ISCSI fundamentals

ISCSI is a protocol defined by the Internet Engineering Task Force (IETF) which enables SCSI commands to be encapsulated in TCP/IP traffic, thus allowing access to remote storage over low cost IP networks.

91. What Advantages Would Using An Iscsi Storage Area Network (san) Give To Your Organization Over Using Direct Attached Storage (das) Or A Fibre Channel San?

• iSCSI is cost effective, allowing use of low cost Ethernet rather than expensive Fibre architecture.
• Traditionally expensive SCSI controllers and SCSI disks no longer need to be used in each server, reducing overall cost.
• Many iSCSI arrays enable the use of cheaper SATA disks without losing hardware RAID functionality.
• The iSCSI storage protocol is endorsed by Microsoft, IBM and Cisco, therefore it is an industry standard.
• Administrative/Maintenance costs are reduced.
• Increased utilisation of storage resources.
• Expansion of storage space without downtime.
• Easy server upgrades without the need for data migration.
• Improved data backup/redundancy.

1. Can We Use Commit Inside The Trigger? If Not Then How Can We Save The Transaction Made By The Trigger?

Using pragma concept.

2. What Is The Difference Between “is” And “as” While Creating Procedure?

Both are equivalent. Just replacement of DECLARE keyword in declarative section.

3. What Is The Difference Between Stored Procedures And Stored Functions In Oracle?

Both(functions and Procedures) are the Oracle Objects that work explicitly towards database objects like Tables,Views.

The diff. b/t Stored Procedures and Functions:

1. The procedures doesn’t return values. whereas the function returns value.
2. The procedures accept more than one argument whereas the functions not.

4. How Can We Call Stored Procedures Inside Store Procedures?

Alter procedure CallAnotherProcedure as exec sp_helptext CallAnotherProcedure 

5. What Is Stored Procedure?

A stored procedure is a group of SQL statements that form a logical unit and perform a particular task. Stored procedures are used to encapsulate a set of operations or queries to execute on a database server. For example, operations on an employee database (hire, fire, promote, lookup) could be coded as stored procedures executed by application code. Stored procedures can be compiled and executed with different parameters and results, and they may have any combination of input, output, and input/output parameters.

6. Explain About The Process Which Takes Place To Execute A Stored Routine?

CREATE PROCEDURE and CREATE FUNCTION statement are used to create stored routine. It can act as a function or a procedure. A procedure can be called by using a call statement and pass output with the help of output variables. It can call other Stored routines and it can be called from the inside of a statement.

7. Explain About The Difficulties Faced By The Database Developer In Implementing Pre Compiled Statements?

There are many difficulties for implementing pre compiled statements because it should have all the arguments provided to it during compile time. It also depends upon the database and configuration. Performance also varies and it largely depends upon whether it is a generic query or user defined functions.

8. Where The Procedures Are Stored In Database?

A stored procedure is a subroutine available to applications accessing a relational database system. Stored procedures (sometimes called a proc, sproc, StoPro, or SP) are actually stored in the database data dictionary

9. How Many Types Of Stored Procedure?

Stored Procedure are of two types

1. user define stored procedure
2. System define Stored procedure.

10. Explain The Benefits Of Running Stored Procedure On A Database Engine?

Stored procedures can run directly run on a data base engine. In industries where automation is the key a stored procedure can run entirely on the data base provided to it and this runs on a specialized data base server. Network communication can be avoided. Also this procedure is useful for execution of complex SQL statements. 

11. What Is Cursors?

Cursors are supported by procedures, functions and triggers. Syntax of the cursors is embedded in SQL. Cursor should be declared before declaring handles. Before declaring cursors it is imperative to declare variables and conditions. 

12. State The Different Extensions For Stored Procedures?

 Most of the database systems have proprietary and vendor based extensions. Microsoft allows procedures to be written using Transact-SQL. Oracle calls its extension as PL/SQL. DB2 has its extension as PL/SQL. PL/pgSQL is the extension used by Postgre SQL and this allows users to have their own functional language such as pl/PHP and pl/Perl.

13. Does Storing Of Data In Stored Procedures Increase The Access Time? Explain?

Data stored in stored procedures can be retrieved much faster than the data stored in SQL database. Data can be precompiled and stored in Stored procedures. This reduces the time gap between query and compiling as the data has been precompiled and stored in the procedure. To avoid repetitive nature of the data base statement caches are used. 

14. How One Call Ddl Statement Using Stored Procedures In Oracle?

Yes, we can call DDL command using EXECUTE IMMEDIATE command

15. What Are External Procedures ? Why And When They Are Used?

External procedures are Extended stored procedures only. They let you create your own external routines in a programming language such as C. Extended stored procedures are DLLs that an instance of Microsoft SQL Server can dynamically load and run.Extended stored procedures run directly in the address space of an instance of SQL Server and are programmed by using the SQL Server Extended Stored Procedure API.

16. What Are The Uses Of Stored Procedure?

Stored procedures are often used for data validation and as access control mechanism. Logic applied in applications can be centralized and stored in applications. Complex procedures and functionalities which require huge amount of data processing and logic implementation access their data by procedures. Data is stored in these procedures and accessed by procedures.

17. What Is The Difference Between A User Defined Function And A Stored Procedure?

A user defined function and stored procedures are almost similar but there exists a difference between their implementation procedures in the code. Stored procedure needs to be invoked whereas a UDF can be used like any other statement. 

18. Explain About The Implementation Of Business Logic In Stored Procedures?

Stored procedures implement business logic into the database. It is embedded as API and this reduces the implementation of Logic code again explicitly. Implementation of business logic internally reduces the chances of data becoming corrupt.

19. Explain About Recursive Stored Procedures?

Recursive stored procedures are used for performing repetitive tasks. Recursive feature is disabled by default but can be activated by using the following command on the server max_sp_recursion_depth, also don?t forget to rename the system variable to a non zero variable.

20. State About The Security Aspects Of Stored Procedures?

Stored procedures should be written very carefully because they store complex and logical data. Security permissions should be very finely applied and this is possible by carefully written code. Permissions for client data should be set in such a manner that it could be accessible only by the client and the method of access should be according to the procedure laid down in the Stored procedures. 

21. If Get_product_name Is My Procedure Called In My Stored Procedure. Here In My Procedure I Am Passing A Value Directly But I Need To Pass The Value To The Procedure Dynamically. How It Is Possible?

By Dynamic sql.

22. Explain About The Implementation Of Stored Procedures?

Implementation of stored procedure varies for different databases and vendors. Stored procedures are very flexible and they can be implemented in variety of languages. Stored procedures written in non SQL languages may have a very little compatibility with SQL

23. Explain About The Return Statement?

A RETURN statement is used to terminate the execution of a stored function. This inturn returns a value of expr to the function caller. In a stored function there should be at least a single return statement. If there exists multiple functions it can have multiple exit points.

1. What Is An Infopath?

InfoPath is an XML based electronic forms development product.

2. What Are The Benefits Of Infopath 2007?

Prior to the introduction of Office 2007, the InfoPath client application, like other Office products, had to be installed on every user’s computer.

In order to develop and use a form:

1. The form had to be designed using InfoPath.
2. The resulting form template should be hosted in a network file share, or installed in individual user machines, or uploaded into a form library in SharePoint, from where users could fill the forms.
3. Filling up forms required InfoPath to be installed on the client machine.
4. Developing a connected InfoPath was complicated for end users.
5. Developers did not have an integrated development platform.
6. The product did not integrate with other Office products such as Word and Excel.

Benefits of Office 2007

This introduced a new server-side runtime to host InfoPath forms known as InfoPath Form Services.

The new capabilities include:

1. Ability to convert Word and Excel documents into InfoPath form templates.
2. With the help of InfoPath form services, a InfoPath form can be browser enabled.
3. The new InfoPath forms can be embedded in Outlook.
4. The form can be built once and rendered in different modes and devices, .i.e., Design Once.
5. Introduction of the document information panel. I.e., an InfoPath form that is hosted inside Word 2007 or PowerPoint 2007 can be used to edit document properties.
6. Introduction of logic inspector. The components which provide visual view of all the rules embedded in the form.
7. The new InfoPath forms can be published to content types.
8. Introduction of template parts, i.e., reusable code sections.
9. Introduction of an integrated development environment inside Visual Studio 2005 using Visual Studio Tools for Office.
10. The information right management can be used to protect sensitive data in the form.

3. What Is The Structure Of An Infopath Form Template?

The InfoPath form template (.xsn file) is actually a CAB file [can also be considered a zip file] containing the different component files of which InfoPath is built.

Following are some of the important files contained inside that CAB file:

1. ..xsf
2. ..xsl
3. ..xsd
4. ..dll
5. ..htm and other resource files.

4. What Are The Form View Files In Infopath? Or Xsl Files?

The .xsl file is the form view file that provides a way to represent different information, depending upon the runtime environment and other factors, including the security profile of end users. They are based on XML stylesheets that can be formatted depending upon the condition. [Conditional formatting is itself an inbuilt property of XSL.]

5. What Is An .xsd File In Infopath?

It is the form schema file of InfoPath. It determines the format of data that InfoPath recognizes.

6. Where Does Data Get Stored In An Infopath Form?

Data is stored in XML files.

7. Explain In Brief The Architecture Of Infopath Forms?

An InfoPath form template is actually a CAB File containing different component files.

Below is a list of files which forms part of an InfoPath template.

• .xsf file:
  A manifest file that describes the basic definition of other form files.
• .xsl file:
  Defines the transformation for data into different views.
• .xsd file:
  Defines the data source schema.
• .dll file:
  Carries the custom logic built into .NET or COM.
• .htm and other resource files:
  Custom HTML resource files and other resources for the form.

When a form template is uploaded using Administrative deployment, the template is stored in the content database of the site. Office Forms Services provide a server-runtime environment for InfoPath Forms Services. While running on the browser, all rules, validations, and calculations are executed in the browser using client-side script.

All business logic is executed on the server. So when a browser requests business logic execution, a post back is executed using low cost XMLHTTP. Formserver.aspx is an InfoPath Forms Services page that accesses the form’s data from the content database and renders it to the client.

8. What Are The Main Components Of Infopath Form Services That Are Responsible For Rendering The .xsn File On Browsers?

The InfoPath Form Services consists of four components that are responsible for rendering the .xsn file on browsers:

1. ASP.NET modules:
   Return HTML to the browser.
2. Infopath Form Services HTTP Handlers:
   Forward requests from IIS to the page generator.
3. Converter:
   Responsible for converting the .xsn file into .aspx pages.
4. Page generator:
   Communicates with internal data sources, and is responsible for processing postback data from the browser and maintaining session states.

9. What Is Logic Inspector?

Logic Inspector is a tool in InfoPath 2007 that shows all of the code dependencies for the form in a single dialog. Depending on how you access the Logic Inspector, you initially see either the overview pane or both the overview pane and the details pane.

10. What Are The Main Configuration Elements Of Infopath Form Services? Where Does The Server Level Configuration Elements Reside?

The InfoPath form services server-level configuration elements are located in SharePoint Central Administration.

11. How Many Sections Are There Inside The Infopath Form Services Element?

There are five sections:

1. Manage Form Templates
2. Configure InfoPath Services
3. Upload form templates
4. Manage Data Connection files
5. Manage the Web Service proxy

12. What Set Of Functions Can We Perform With The Help Of Manage Form Templates?

This section allows the administrator to perform the following actions:

1. Activate a form template to a site collection.
2. De-activate a form template from a site collection.
3. Quiesce a form template.
4. Remove a form template.

13. What Does Quiescing A Form Template Mean?

Quiescing is a process that takes the form templates offline gradually and prevents new sessions from being created. It allows existing sessions to be completed, thereby preventing data loss. When a form template is quiesced by the administrator, the form templates from all the site collections are taken offline.

14. What Are The Set Of Functions We Can Perform With The Help Of “configure Infopath Form Services”?

This page allows an Administrator to configure some of the basic settings for the InfoPath Form Services.

There are so many sections in the page, but the important of them are following:

1. User Browser-enabled form templates
2. Data connection time out
3. HTTP data connections
4. Cross domain access for User Form Templates
5. Form session states
6. Etc…

15. How Is Form Session State Maintained?

The InfoPath Form Services can maintain data in two modes:

1. SQL Server database:
   This approach is termed as using Session State Services.
2. ASP.NET view states stored in the client side: Termed form view.

Points to be noted:
The application needs to be associated with the Shared Service Provider.

16. When To Use Which Session State Mode?

Session State Service mode [SQL Server database] is recommended for low bandwidth users, as the form view states hamper the performance for low bandwidth. Whereas, Form View can be used for environments with small groups of users.

The administrator can also enter a value for the session data size allowed for Form View State. InfoPath Form Services will automatically revert to Session State Service when session data size exceeds the value associated with the form view mode.

17. What Is The Required Feature That Needs To Be Activated Within A Site Collection For Infopath Form To Work?

The feature called Office SharePoint Server Enterprise Site Collection Features must be activated within the site collection.

18. What Will Happen If “office Sharepoint Server Enterprise Site Collection Features” Is Not Activated?

It would require the InfoPath Client Application to be installed.

1. How Is The Ttl Field Used To Prevent Indefinite Looping Of Ip Datagrams?

The TTL field contains a counter value set by the source host. Each gateway that processes this datagram, decreases the TTL value by one. When the TTL value reaches zero, the datagram is discarded.

2. What Is The Byte Order Used For Transmitting Datagram Headers In The Tcp/ip Protocol Suite?

All the datagram headers in the TCP/IP protocol suite are transmitted in the “big endian” byte order. i.e. The most significant byte is transmitted first. This is also called as “network byte order”.

3. Why There Are Two Length Fields (ip Header Length, Ip Datagram Length) In The Ip Header?

The size of the IP header is not fixed. Depending on the IP options present, the size of the IP header will vary. A separate field for the IP header length is added, so that the destination system can separate the IP datagram header from the payload.

4. When Is A Datagram Considered Undeliverable?

If a datagram cannot be delivered to the destination host due to some reason, it is considered an undeliverable datagram.

5. What Is The Typical Value For The Ttl Field?

The typical value for a TTL field is 32 or 64.

6. Which Rfc Discusses The Type Of Service (tos) Field?

RFC 1349 discusses the Type Of Service (TOS) field.

7. What Is The Use Of The Time To Live (ttl) Field In The Ip Header?

The TTL field is used to limit the lifetime of a IP datagram and to prevent indefinite looping of IP datagrams.

Time To Live is used to limit the period of time of transmission of network technology that ba unit of data can experience before it should be discarded.

8. Tell Us Is The Datagram Identifier Field Unique For Each Ip Datagram?

Yes. The IP datagram identifier field is different for each IP datagram transmitted. The fragments of an IP datagram will have the same identifier value.

9. What Is The Spanning Tree Protocol Used For?

Spanning tree protocol is used to prevent looping of frames. Unlike IP, which has a TTL value field in the packet which is decremented every time the packet passes through a router and is dropped once the value reaches 0, the frame does not have any similar field. So if a scenario arises where a frame is looping in a switched environment, the frame would not automatically time out. The spanning tree protocol is used for preventing the looping.

10. How Many Root Bridges Can Be Available On A Stp Configured Network?

If the priority value of the two switches are same, which switch would be elected as the root bridge

The switch with the lowest mac-address value would be elected as the root bridge

11. How Many Designated Ports Can Be Available On A Root Bridge?

All ports on a root bridge is designated ports.

12. Is A Generic Ethernet Frame Modified When Stp Is Configured On The Network?

STP is a protocol. It has it’s own frame when configured. So it would not affect a generic ethernet frame on the network.

13. Is Stp Required To Be Configured When There Is Only One Switch Involved?

It is not required. STP is used to shutdown redundant links between switches to prevent loops.

14. Can Stp Be Configured On A Router?

STP can be configured only on switches and not on routers. STP is used to prevent frame looping

15. What Is Extended System Id?

The Extended System ID is utilized by spanning-tree to include the VLAN ID information inside 16-bit STP

16. What Is Root Port?

Once the Root Switch is elected, every other Switch in the network must select a single port on itself to reach the Root Switch. The port with the lowest root path cost (lowest cumulative cost to reach root switch) is elected as the root port and is placed in the forwarding state. Root Bridge will never have a Root Port.

17. What Is Path Cost Or Spanning Tree Path Cost Value?

The Spanning Tree Cost Value is inversely proportional to the bandwidth of the link and therefore a path with a low cost value is more preferable than a path with high cost value.
Link Bandwidth Cost Value

• 10 Gbps 2
• 1 Gbps 4
• 100 Mbps 19
• 10 Mbps 100

18. How Root Bridge Is Elected?

The bridge ID is used to elect the root bridge in the STP domain. This ID is 8 bytes long and includes both the priority and the MAC address of the device.

Switch with the lowest Bridge ID is elected as the Root bridge which means Switch with the lowest priority will become Root Bridge if two or more switches have same priority than switch with lowest mac address will become Root Bridge.

19. What Are Types Of Bpdu?

Two types of BPDU exist:-

1. Configuration BPDU
   – Used for Spanning-Tree Computation.
2. Topology Change Notification (TCN) BPDU
   – Used to announce changes in the Network Topology.

20. What Is The Destination Mac Address Used By Bridge Protocol Data Units (bpdus)?

Bridge Protocol Data Units (BPDUs) frames are sent out as at multicast destination MAC address

01:80:c2:00:00:00.

21. What Is Bpdu?

All the switches exchange information to select Root Bridge as well as for configuration of the network.

This is done through Bridge Protocol Data Unit (BPDU). Each switch compares the parameters in the BPDU that it sends to one neighbor with the one that it receives from another neighbor.

22. Explain Types Of Stp Port Roles?

1. Root port
   – The root port is always the link directly connected to the root bridge, or the shortest path to the root bridge. It is always on Non-Root Bridge.
2. Designated port –
   A designated port is one that has been determined as having the best (lowest) cost. A designated port will be marked as a forwarding port. It can be on both Root Bridge & Non Root Bridge. All ports of Root Bridge are Designated Port.
3. Forwarding port –
   A forwarding port forwards frames.
4. Blocked port –
   A blocked port is the port that is used to prevent loops. It only listens to BPDUs. Any port other than Root port & Designated port is a Block Port.

23. What Are Stp Timers And Explain Different Types Of Stp Timers?

STP uses three timers to make sure that a network converges properly before a bridging loop can form.

Hello timer – The time interval between Configuration BPDUs sent by the root bridge. It is 2 seconds by default.

Forward Delay timer – The time interval that a switch port spends in both the Listening and Learning states.

The default value is 15 seconds.

Max (Maximum) Age timer – Maximum length of time a BPDU can be stored without receiving an update. It can also be define as a time interval that a switch stores a BPDU before discarding it. It is 20 seconds by default.

24. What Are The Different Port States?

1. Disabled – A port in the disabled state does not participate in the STP.
2. Blocking – A blocked port does not forward frames. It only listens to BPDUs. The purpose of the blocking state is to prevent the use of looped paths.
3. Listening – A port in listening state prepares to forward data frames without populating the MAC address table. The port also sends and listens to BPDUs to make sure no loops occur on the network.
4. Learning – A port in learning state populates the MAC address table but doesn’t forward data frames. The port still sends and receives BPDUs as before.
5. Forwarding – The port now can send and receive data frames, collect MAC addresses in its address table, send and receive BPDUs. The port is now a fully functioning switch port within the spanning-tree topology.

25. How Stp Works?

STP chooses a Reference point (Root Bridge) in the network and calculates all the redundant paths to that reference point. Than it picks one path which to forward frames and blocks other redundant paths. When blocking hapeens, Loops are prevented.

26. What Is Stp And Redundant Links?

Spanning Tree Protocol (STP) is a protocol which prevents layer 2 loops. STP enables switches to become aware of each other so that they can negotiate a Loop-Free path through network.

In practical Scenario, Redundant links are created to avoid complete network failure in an event of failure of one link.

27. What Is Spanning Tree ?

Spanning-tree protocol is a protocol used in switching network to create a loop-free topology. STP is enabled by default on all VLANs on Catalyst switches. STP switches send BPDU’s (Bridge Protocol Data Units) to each other to form their topology databases. BPDU’s are sent out all ports every two seconds, are forwarded to a specific MAC multicast address: 0180.c200.0000. 

1. What Is Meant By Human Computer Interaction?

HCI (human-computer interaction) is the study of how people interact withcomputers and to what extent computers are or are not developed for successful interaction with human beings. A significant number of majorcorporations and academic institutions now study HCI.

2. What Is A Human Interaction?

Human Environmental Interactions can be defined as interactions between thehuman social system and (the “rest” of) the ecosystem. Human social systems and ecosystems are complex adaptive systems.

3. How Does The User Interact With The Computer?

Humans interact with computers in many ways; the interface between humans and computers is crucial to facilitating this interaction. Desktop applications, internet browsers, handheld computers, and computer kiosks make use of the prevalent graphical user interfaces (GUI) of today.

4. What Is Implicit Human Computer Interaction?

Implicit human computer interaction is an emerging research area of human computing. The implicit interaction system inputs from the understanding of users intention via automatic detecting and analyzing user actions. The output of the system is the adaptive service to the user.

5. What Is The Meaning Of Human Computer Interaction?

HCI (human-computer interaction) is the study of how people interact with computers and to what extent computers are or are not developed for successful interaction with human beings.
As its name implies, HCI consists of three parts: the user, the computer itself, and the ways they work together.

6. Why Hci Is Important?

Business and Industry. HCI is an important consideration for any business that uses computers in their everyday operation. HCI is especially important in the design of safety critical systems, such as, for example, those found in power plants, or air traffic control centers.

7. Why Is It Important To Have Human Interaction?

Social support and social interaction are one of the most important factors in predicting the physical health and well-being of everyone, ranging from childhood through older adults. Although social interaction is complex, I believe that it is vital to human health, both mentally and physically.

8. How Do You Interact With Other People?

Be respectful to everyone you interact with. Give them a chance to talk, don’t say or do anything insulting, respect their differences, and generally treat them the way that you would want to be treated. The most important part of interacting well with others is to listen to them.

9. What Are The Elements In Hci?

Hydrogen chloride, (HCl), a compound of the elements hydrogen and chlorine, a gas at room temperature and pressure.
A solution of the gas in water is called hydrochloric acid.

10. Where Is Hci Found In The Human Body?

Hydrochloric Acid (HCl) is produced by the stomach and has the job of breaking down proteins. If you make plenty of HCl, then the body can adequately digest protein. If not, protein digestion is compromised.

11. What Is A Bluetooth Hci?

L2CAP is used within the Bluetooth protocol stack. It passes packets to either the Host Controller Interface (HCI) or on a hostless system, directly to the Link Manager/ACL link. L2CAP’s functions include multiplexing data between different higher layer protocols.

12. What Is Design In Hci?

Human-computer interaction (HCI) has traditionally been the domain of engineering and psychology. Here, we approach it from the perspective of design.The goal of the human-computer interaction design (HCI/d) program is to teach you to think like a designer. Our approach is research-based, but never rigid.

13. What Is The Study Of Human Interaction?

Social behavior, a subset of human behavior, study the considerable influence of social interaction and culture. Human behavior is studied by the specialized academic disciplines of psychiatry, psychology, social work, sociology, economics, and anthropology.

14. What Is Human Social Interaction?

A social interaction is an exchange between two or more individuals and is a building block of society. Social interaction can be studied between groups of two (dyads), three (triads) and larger social groups. By interacting with one another, people design rules, institutions and systems within which they seek to live.

15. What Is The Hci?

HCI (human-computer interaction) is the study of how people interact with computers and to what extent computers are or are not developed for successful interaction with human beings. a significant number of major corporations and academic institutions now study HCI.