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1. What is the requirement for Citrix server installation.

2. What is Datastore

3. What is Data collector

4. What is LHC

5. What is Client Lock Down

6. What is Printer terminology in Citrix

7. How to use datastore for database

8. What is the difference between all citrix versions

9. What are different load evaluators are available in Citrix

10. How to implement Policies in Citrix

11. What you will check when any user is not able to launch citrix application.

12. What is IMA

13. What is ICA and what are the advantage of ICA

14. What is Speed Screen

15. What are the query command in citrix

16. What are the different ports use in Citrix

17. How the licensing works in Citrix and difference in Citrix Licensing version wise

18. What are the console available to manage citrix server

19. What is WebInterface or Nfuse

20. What is citrix secure / access gateway and how its work

21. What are the difference between Win2K and 2K3 Terminal server.

22. What is the difference between 2k & 2k3 terminal server licensing

23. What is SBC

24. What is Printer driver replicationa and mapping

25. How to recover when Datastore failing

26. How to recover when IMA failing

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27. What is the requirement of Installation Manager and wht kind of extension its support.

28. What are the perameter of Resource Manager

Question 1: How does the race condition occur?

It occurs when two or more processes are reading or writing some shared data and the final result depends on who runs

precisely when.

Question 2: What is multiprogramming?

Multiprogramming is a rapid switching of the CPU back and forth between processes.

Question 3: Name the seven layers of the OSI Model and describe them briefly.

Physical Layer - covers the physical interface between devices and the rules by which bits are passed from one to another.

Data Link Layer - attempts o make the physical link reliable and provides the means to activate, maintain, and deactivate

the link.

Network Layer - provides for the transfer of information between end systems across

some sort communications network.

Transport Layer - provides a mechanism for the exchange of data between end system.

Session Layer - provides the mechanism for controlling the dialogue between applications

in end systems.

Presentation Layer - defines the format of the data to be exchanged between applications

and offers application programs a set of data transformation services.

Application Layer - provides a means for application programs to access the OSI environment.

Question 4: What is the difference between TCP and UDP?TCP and UDP are both transport-level protocols. TCP is designed to provide reliable

communication across a variety of reliable and unreliable networks and internets.

UDP provides a connectionless service for application-level procedures. Thus, UDP is basically

an unreliable service; delivery and duplicate protection are not guareented.

Question 5: What does a socket consists of?

The combination of an IP address and a port number is called a socket.

Q1. Name of seven layers in Open System Interconnection model.

A. They are Application, Presentation, Session, Transport, Network, Data link, and Physical.

Q2. What is the time complexity of matrix multiplication ?

void Mult_Matrix(matrix A, matrix B, matrix C)

{

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int i, j, k;

for ( i = 1; i < N; i++)

for ( j = 1; j < N; j++ )

{

C[i][j] = 0;

for ( k = 0; k < N; k++ )

C[i][j] = A[i][j]*B[k][j];

}

retrun;

}

A. The time comlexity of matrix mulitiplication is O(N^3)

Q3. What is the null pointer in C++ ?

A. The null pointer is a special C++ pointer value that can be used for any pointer that doesnt pointer anywhere. It can be

written as the constant NULL form stlib.h

Q4. What is the goal of the shortest distance algorithm ?

A. The goal is to completely fill the distance array so that for each vertex v, the value of distance[v] is the weight of the

shortest path from start to v.

Q5. What is the difference between an abstract class and an interface?

A.

An abstract class may have fields and some implemented methods.

An interface has no implementation; only constants and method declarations.

Can you be able to identify between Straight- through and Cross- over cable wiring?

Straight-through is type of wiring that is one to to one connection Cross- over is type of wiring which

those wires are got switchedWe use Straight-through cable when we connect between NIC Adapter and

Hub. Using Cross-over cable when connect

between two NIC Adapters or sometime between two hubs.

What is the significance of the IP address 255.255.255.255?

The limited broadcast address is utilized when an IP node must perform a one-to-everyone delivery on the

local network but the network ID is unknown.

What tool have you used to create and analyze packet captures?

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Network Monitor in Win2K / Win2K3, Ethereal in Linux, OptiView Series II (by Fluke Networks).

What is LDAP used for?

LDAP is a set of protocol used for providing access to information directories.

What is the difference between a domain local group and a global group?

Domain local groups grant permissions to objects within the domain in which the reside. Global groups

contain grant permissions tree or forest wide for any objects within the Active Directory

How do you set a default route on an IOS Cisco router?

ip route 0.0.0.0 0.0.0.0 x.x.x.x [where x.x.x.x represents the destination address]

What is a default gateway?

The exit-point from one network and entry-way into another network, often the router of the network.

What is Kerberos?

It is an authentication service developed at the Massachusetts Institute of Technology. Kerberos uses

encryption to prevent intruders from discovering passwords and gaining unauthorized access to files.

What is NVT (Network Virtual Terminal)?

It is a set of rules defining a very simple virtual terminal interaction. The NVT is used in the start of a

Telnet session.

What is silly window syndrome?

It is a problem that can ruin TCP performance. This problem occurs when data are passed to the sending

TCP entity in large blocks, but an interactive application on the receiving side reads 1 byte at a time.

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What is region?

When hierarchical routing is used, the routers are divided into what we will call regions, with

each router knowing all the details about how to route packets to destinations within its own

region, but knowing nothing about the internal structure of other regions.

What is traffic shaping?

One of the main causes of congestion is that traffic is often busy. If hosts could be made to

transmit at a uniform rate, congestion would be less common. Another open loop method to

help manage congestion is forcing the packet to be transmitted at a more predictable rate. This

is called traffic shaping.

What is packet filter?

Packet filter is a standard router equipped with some extra functionality. The extra functionality

allows every incoming or outgoing packet to be inspected. Packets meeting some criterion are

forwarded normally. Those that fail the test are dropped.

What is virtual path?

Along any transmission path from a given source to a given destination, a group of virtual

circuits can be grouped together into what is called path.

What is virtual channel?

Virtual channel is normally a connection from one source to one destination, although multicast

connections are also permitted. The other name for virtual channel is virtual circuit.

What is LLC?

LLC is Logical Link Control, one of two sublayers of the data link layer of OSI reference model,

as defined by the IEEE 802 standard. This sublayer is responsible for maintaining the link

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between computers when they are sending data across the physical network connection.

What is the difference between routable and non- routable protocols?

Routable protocols can work with a router and can be used to build large networks. Non-

Routable protocols are designed to work on small, local networks and cannot be used with a

router

What is MAU?

In token Ring , hub is called Multistation Access Unit(MAU).

Explain 5-4-3 rule?

In a Ethernet network, between any two points on the network ,there can be no more than five

network segments or four repeaters, and of those five segments only three of segments can be

populated.

What is the difference between TFTP and FTP application layer protocols?

The Trivial File Transfer Protocol (TFTP) allows a local host to obtain files from a remote host

but does not provide reliability or security. It uses the fundamental packet delivery services

offered by UDP.

The File Transfer Protocol (FTP) is the standard mechanism provided by TCP / IP for copying a

file from one host to another. It uses the services offer by TCP and so is reliable and secure. It

establishes two connections (virtual circuits) between the hosts, one for data transfer and

another for control information

What is the range of addresses in the classes of internet addresses?

Class A 0.0.0.0 - 127.255.255.255

Class B 128.0.0.0 - 191.255.255.255

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Class C 192.0.0.0 - 223.255.255.255

Class D 224.0.0.0 - 239.255.255.255

Class E 240.0.0.0 - 247.255.255.255

What is difference between ARP and RARP?

The address resolution protocol (ARP) is used to associate the 32 bit IP address with the 48 bit

physical address, used by a host or a router to find the physical address of another host on its

network by sending a ARP query packet that includes the IP address of the receiver. The

reverse address resolution protocol (RARP) allows a host to discover its Internet address when

it knows only its physical address.

What are the data units at different layers of the TCP / IP protocol suite?

The data unit created at the application layer is called a message, at the transport layer the data

unit created is called either a segment or an user datagram, at the network layer the data unit

created is called the datagram, at the data link layer the datagram is encapsulated in to a frame

and finally transmitted as signals along the transmission media.

What is ICMP?

ICMP is Internet Control Message Protocol, a network layer protocol of the TCP/IP suite used

by hosts and gateways to send notification of datagram problems back to the sender. It uses the

echo test / reply to test whether a destination is reachable and responding. It also handles both

control and error messages.

What is Protocol Data Unit?

The data unit in the LLC level is called the protocol data unit (PDU). The PDU contains of four

fields a destination service access point (DSAP), a source service access point (SSAP), a

control field and an information field. DSAP, SSAP are addresses used by the LLC to identify

the protocol stacks on the receiving and sending machines that are generating and using the

data. The control field specifies whether the PDU frame is a information frame (I - frame) or a

supervisory frame (S - frame) or a unnumbered frame (U - frame).

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Difference between bit rate and baud rate.

Bit rate is the number of bits transmitted during one second whereas baud rate refers to the

number of signal units per second that are required to represent those bits.

Baud rate = bit rate / N ?: where N is no-of-bits represented by each signal shift.

How Gateway is different from Routers?

A gateway operates at the upper levels of the OSI model and translates information between

two completely different network architectures or data formats.

What is passive topology?

When the computers on the network simply listen and receive the signal, they are referred to as

passive because they dont amplify the signal in any way. Example for passive topology - linear

bus.

What is NETBIOS and NETBEUI?

NETBIOS is a programming interface that allows I/O requests to be sent to and received from a

remote computer and it hides the networking hardware from applications.

NETBEUI is NetBIOS extended user interface. A transport protocol designed by microsoft and

IBM for the use on small subnets.

What is redirector?

Redirector is software that intercepts file or prints I/O requests and translates them into network

requests. This comes under presentation layer.

What is Beaconing?

The process that allows a network to self-repair networks problems. The stations on the network

notify the other stations on the ring when they are not receiving the transmissions. Beaconing is

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used in Token ring and FDDI networks.

What is terminal emulation, in which layer it comes?

Telnet is also called as terminal emulation. It belongs to application layer.

What do you meant by triple X in Networks?

The function of PAD (Packet Assembler Disassembler) is described in a document known as

X.3. The standard protocol has been defined between the terminal and the PAD, called X.28;

another standard protocol exists between hte PAD and the network, called X.29. Together,

these three recommendations are often called triple X.

What is SAP?

SAP: Service Access Point , Series of interface points that allow other computers to

communicate with the other layers of network protocol stack.

How does the browser know to go to a certain IP address when you enter a domain like

crackthecampus.com?

It searches through local DNS cache, if nothing is there, it queries the ISPs DNS server

What is Load balancing?

If the number of incoming clients requests exceeds the number of processes in a server class,

the TP Monitor may dynamically start new ones and this is called Load balancing

What is OLTP?

In the transaction server, the client component usually includes GUI and the server componentsusually consists of SQL transactions against a database. These applications are called OLTP

(Online Transaction Processing) OLTP Applications typically, Receive a fixed set of inputs from

remote clients. Perform multiple pre-compiled SQL comments against a local database.Commit

the work and Return a fixed set of results.

What is Message Oriented Middleware (MOM)?

MOM allows general purpose messages to be exchanged in a Client/Server system using

message queues. Applications communicate over networks by simply putting messages in the

queues and getting messages from queues. It typically provides a very simple high level APIs to

its services. MOMs messaging and queuing allow clients and servers to communicate across a

network without being linked by a private, dedicated, logical connection. The clients and server

can run at different times. It is a post-office like metaphor.

What is meant by Asymmetrical protocols?

There is a many-to-one relationship between clients and server. Clients always initiate the

dialog by requesting a service. Servers are passively awaiting for requests from clients.

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What is Groupware server?

Groupware addresses the management of semi-structured information such as text, image,

mail, bulletin boards and the flow of work. These Client/Server systems have people in direct

contact with other people.

What is Client/Server?

Clients and Servers are separate logical entities that work together over a network to

accomplish a task. Many systems with very different architectures that are connected together

are also called Client/Server.

What is a File server?

File servers are useful for sharing files across a network. With a file server, the client passes

requests for file records over nerwork to file server.

What are called Fat clients and Fat servers?

If the bulk of the application runs on the Client side, then it is Fat clients. It is used for decision

support and personal software.If the bulk of the application runs on the Server side, then it is Fat servers. It tries to minimize

network interchanges by creating more abstract levels of services.

What is Remote Procedure Call (RPC)?

RPC hides the intricacies of the network by using the ordinary procedure call mechanism

familiar to every programmer. A client process calls a function on a remote server and suspends

itself until it gets back the results. Parameters are passed like in any ordinary procedure. The

RPC, like an ordinary procedure, is synchoronous. The process that issues the call waits until it

gets the results.

Under the covers, the RPC run-time software collects values for the parameters, forms a

message, and sends it to the remote server. The server receives the request, unpack the

parameters, calls the procedures, and sends the reply back to the client. It is a telephone-like

metaphor.

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What are the building blocks of Client/Server?

The client ,The server and Middleware.

What is a TP Monitor?

There is no commonly accepted definition for a TP monitor. According to Jeri Edwards a TP

Monitor is an OS for transaction processing.

TP Monitor does mainly two things extremely well. They are Process management and

Transaction management.

They were originally introduced to run classes of applications that could service hundreds and

sometimes thousands of clients. TP Monitors provide an OS - on top of existing OS - thatconnects in real time these thousands of humans with a pool of shared server processes.

What are Super servers?

These are fully-loaded machines which includes multiprocessors, high-speed disk arrays for

intervive I/O and fault tolerant features.

What is a Web server?

This new model of Client/Server consists of thin, protable, universal clients that talk to superfat

servers. In the simplet form, a web server returns documents when clients ask for them by

name. The clients and server communicate using an RPC-like protocol called HTTP.

What is a Database Server?

With a database server, the client passes SQL requests as messages to the database server.

The results of each SQL command are returned over the network. The server uses its own

processing power to find the request data instead of passing all the records back to the client

and then getting it find its own data. The result is a much more efficient use of distributed

processing power. It is also known as SQL engine.

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What is an Object server?

With an object server, the Client/Server application is written as a set of communicating objects.

Client object communicate with server objects using an Object Request Broker (ORB). Theclient invokes a method on a remote object. The ORB locates an instance of that object server

class, invokes the requested method and returns the results to the client object. Server objects

must provide support for concurrency and sharing. The ORB brings it all together.

What is anonymous FTP and why would you use it?

Anonymous FTP enables users to connect to a host without using a valid login and password.

Usually, anonymous FTP uses a login called anonymous or guest, with the password usuallyrequesting the users ID for tracking purposes only. Anonymous FTP is used to enable a large

number of users to access files on the host without having to go to the trouble of setting up

logins for them all. Anonymous FTP systems usually have strict controls over the areas an

anonymous user can access.

What is a DNS resource record?

A resource record is an entry in a name servers database. There are several types of resource

records used, including name-to-address resolution information. Resource records aremaintained as ASCII files.

Explain the function of Transmission Control Block?

A TCB is a complex data structure that contains a considerable amount of information about

each connection.

What is virtual path?

Along any transmission path from a given source to a given destination, a group of virtual

circuits can be grouped together into what is called path.

What protocol is used by DNS name servers?

DNS uses UDP for communication between servers. It is a better choice than TCP because of

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the improved speed a connectionless protocol offers. Of course, transmission reliability suffers

with UDP.

What is External Data Representation?

External Data Representation is a method of encoding data within an RPC message, used to

ensure that the data is not system-dependent.

What is Brouter?

Hybrid devices that combine the features of both bridges and routers.

Explain 5-4-3 rule?

In a Ethernet network, between any two points on the network, there can be no more than five

network segments or four repeaters, and of those five segments only three of segments can be

populated.

What is REX?

Request to Exit (REX) - A signal that informs the controller that someone has requested to exit

from a secure area.

What are major types of networks and explain?

Server-based network.

Peer-to-peer network.

Peer-to-peer network, computers can act as both servers sharing resources and as clients using

the resources.

Server-based networks provide centralized control of network resources and rely on server

computers to provide security and network administration.

Explain the importance and use of each, Version, Culture and PublicKeyToken for an

assembly?

This three alongwith name of the assembly provide a strong name or fully qualified name to the

assembly. When a assebly is referenced with all three.

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PublicKeyToken: Each assembly can have a public key embedded in its manifest that identifies

the developer. This ensures that once the assembly ships, no one can modify the code or other

resources contained in the assembly.

Culture: Specifies which culture the assembly supports

Version: The version number of the assembly.It is of the following form

major.minor.build.revision.

How you will set the datarelation between two columns?

ADO.NET provides DataRelation object to set relation between two columns.It helps to enforce

the following constraints,a unique constraint, which guarantees that a column in the table

contains no duplicates and a foreign-key constraint,which can be used to maintain referential

integrity.A unique constraint is implemented either by simply setting the Unique property of a

data column to true, or by adding an instance of the UniqueConstraint class to the DataRelation

objects ParentKeyConstraint. As part of the foreign-key constraint, you can specify referential

integrity rules that are applied at three points,when a parent record is updated,when a parent

record is deleted and when a change is accepted or rejected.

What is source route?

It is a sequence of IP addresses identifying the route a datagram must follow. A source route

may optionally be included in an IP datagram header.

What is SLIP (Serial Line Interface Protocol)?

It is a very simple protocol used for transmission of IP datagrams across a serial line.

What is Proxy ARP?

It is using a router to answer ARP requests. This will be done when the originating host believes

that a destination is local, when in fact is lies beyond router.

What is OSPF?

It is an Internet routing protocol that scales well, can route traffic along multiple paths, and uses

knowledge of an Internets topology to make accurate routing decisions.

What is BGP (Border Gateway Protocol)?

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It is a protocol used to advertise the set of networks that can be reached with in an autonomous

system. BGP enables this information to be shared with the autonomous system. This is newer

than EGP (Exterior Gateway Protocol).

What is autonomous system?

It is a collection of routers under the control of a single administrative authority and that uses a

common Interior Gateway Protocol.

What is EGP (Exterior Gateway Protocol)?

It is the protocol the routers in neighboring autonomous systems use to identify the set of

networks that can be reached within or via each autonomous system.

What is IGP (Interior Gateway Protocol)?

It is any routing protocol used within an autonomous system.

What is Mail Gateway?

It is a system that performs a protocol translation between different electronic mail

delivery protocols

What is wide-mouth frog?

Wide-mouth frog is the simplest known key distribution center (KDC) authentication

protocol.

What are Digrams and Trigrams?

The most common two letter combinations are called as digrams. e.g. th, in, er, re

and an. The most common three letter combinations are called as trigrams. e.g.

the, ing, and, and ion.

What is silly window syndrome?

It is a problem that can ruin TCP performance. This problem occurs when data are

passed to the sending TCP entity in large blocks, but an interactive application on

the receiving side reads 1 byte at a time.

What is region?

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When hierarchical routing is used, the routers are divided into what we will call

regions, with each router knowing all the details about how to route packets to

destinations within its own region, but knowing nothing about the internal structure

of other regions

What is multicast routing?

Sending a message to a group is called multicasting, and its routing algorithm is

called multicast routing.

What is traffic shaping?

One of the main causes of congestion is that traffic is often busy. If hosts could be

made to transmit at a uniform rate, congestion would be less common. Another

open loop method to help manage congestion is forcing the packet to be

transmitted at a more predictable rate. This is called traffic shaping.

What is virtual channel?

Virtual channel is normally a connection from one source to one destination,

although multicast connections are also permitted. The other name for virtual

channel is virtual circuit.

What is logical link control?

One of two sublayers of the data link layer of OSI reference model, as defined by

the IEEE 802 standard. This sublayer is responsible for maintaining the link

between computers when they are sending data across the physical network

connection.

What is the difference between routable and non- routable protocols?

Routable protocols can work with a router and can be used to build large networks.

Non-Routable protocols are designed to work on small, local networks and cannot

be used with a router

What MAU?

In token Ring , hub is called Multistation Access Unit(MAU).

What is difference between baseband and broadband transmission?

In a baseband transmission, the entire bandwidth of the cable is consumed by a single signal. In

broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to

be sent simultaneously.

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What are the important topologies for networks?

BUS topology:In this each computer is directly connected to primary network cable in a singleline.

Advantages:Inexpensive, easy to install, simple to understand, easy to extend.

STAR topology:In this all computers are connected using a central hub.

Advantages:Can be inexpensive, easy to install and reconfigure and easy to trouble shoot

physical problems.

RING topology:In this all computers are connected in loop.

Advantages:All computers have equal access to network media, installation can be simple, and

signal does not degrade as much as in other topologies because each computer regenerates it

What is the difference between TFTP and FTP application layer protocols?

The Trivial File Transfer Protocol (TFTP) allows a local host to obtain files from a remote host

but does not provide reliability or security. It uses the fundamental packet delivery services

offered by UDP.The File Transfer Protocol (FTP) is the standard mechanism provided by TCP /

IP for copying a file from one host to another. It uses the services offer by TCP and so is reliable

and secure. It establishes two connections (virtual circuits) between the hosts, one for data

transfer and another for control information.

What are the data units at different layers of the TCP / IP protocol suite?

The data unit created at the application layer is called a message, at the transport layer the data

unit created is called either a segment or an user datagram, at the network layer the data unit

created is called the datagram, at the data link layer the datagram is encapsulated in to a frame

and finally transmitted as signals along the transmission media.

What are the different type of networking / internetworking devices?

Repeater:Also called a regenerator, it is an electronic device that operates only at physical

layer. It receives the signal in the network before it becomes weak, regenerates the original bit

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pattern and puts the refreshed copy back in to the link.

Bridges: These operate both in the physical and data link layers of LANs of same type. They

divide a larger network in to smaller segments. They contain logic that allow them to keep the

traffic for each segment separate and thus are repeaters that relay a frame only the side of the

segment containing the intended recipent and control congestion.

Routers:They relay packets among multiple interconnected networks (i.e. LANs of differenttype). They operate in the physical, data link and network layers. They contain software that

enable them to determine which of the several possible paths is the best for a particular

transmission.

Gateways:They relay packets among networks that have different protocols (e.g. between a

LAN and a WAN). They accept a packet formatted for one protocol and convert it to a packet

formatted for another protocol before forwarding it. They operate in all seven layers of the OSI

model.

What is Project 802?

It is a project started by IEEE to set standards to enable intercommunication between

equipment from a variety of manufacturers. It is a way for specifying functions of the physical

layer, the data link layer and to some extent the network layer to allow for interconnectivity of

major LAN

protocols.It consists of the following:

802.1 is an internetworking standard for compatibility of different LANs and MANs across

protocols.

802.2 Logical link control (LLC) is the upper sublayer of the data link layer which is non-architecture-specific, that is remains the same for all IEEE-defined LANs.

Media access control (MAC) is the lower sublayer of the data link layer that contains some

distinct modules each carrying proprietary information specific to the LAN product being used.

The modules are Ethernet LAN (802.3), Token ring LAN (802.4), Token bus LAN (802.5).

802.6 is distributed queue dual bus (DQDB) designed to be used in MANs.

What are the types of Transmission media?

Signals are usually transmitted over some transmission media that are broadly classified in to

two categories.

a)Guided Media:These are those that provide a conduit from one device to another that include

twisted-pair, coaxial cable and fiber-optic cable. A signal traveling along any of these media is

directed and is contained by the physical limits of the medium. Twisted-pair and coaxial cable

use metallic that accept and transport signals in the form of electrical current. Optical fiber is a

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glass or plastic cable that accepts and transports signals in the form of light.

b) Unguided Media: This is the wireless media that transport electromagnetic waves without

using a physical conductor. Signals are broadcast either through air. This is done through radio

communication, satellite communication and cellular telephony.

What is Bandwidth?

Every line has an upper limit and a lower limit on the frequency of signals it can carry. This

limited range is called the bandwidth

Difference between bit rate and baud rate.

Bit rate is the number of bits transmitted during one second whereas baud rate refers to the

number of signal units per second that are required to represent those bits.

baud rate = bit rate / N ,where N is no-of-bits represented by each signal shift.

What does the Mount protocol do ?

The Mount protocol returns a file handle and the name of the file system in which a requested

file resides. The message is sent to the client from the server after reception of a client'srequest.

What is anonymous FTP and why would you use it?

Anonymous FTP enables users to connect to a host without using a valid login and password.

Usually, anonymous FTP uses a login called anonymous or guest, with the password usually

requesting the user's ID for tracking purposes only. Anonymous FTP is used to enable a largenumber of users to access files on the host without having to go to the trouble of setting up

logins for them all. Anonymous FTP systems usually have strict controls over the areas an

anonymous user can access.

What is the Network Time Protocol?

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The Network Time Protocol is a protocol for synchronizing the clocks of computer systems over

packet-switched, variable-latency data networks. NTP uses UDP port 123 as its transport layer.

It is designed particularly to resist the effects of variable latency (Jitter).NTP is one of the oldest

Internet protocols still in use (since before 1985).

What is a pseudo tty?

In Unix, a pseudo terminal is a pseudo-device pair that provides a text terminal interface without

associated virtual console, computer terminal or serial port hardware. Instead, a process

replaces the role of the underlying hardware for the pseudo terminal session.For each pseudo

terminal, the operating system kernel provides two character devices: a master device and a

slave device.The master and slave devices, in their most common deployment, form an

association between a Unix shell and a terminal emulation program or some sort of network

server.The slave device file, which generally has a nomenclature of /dev/ttyp*, has theappearance and supported system calls of any text terminal. Thus it has the understanding of a

login session and session leader process (which is typically the shell program).The master

device file, which generally has a nomenclature of /dev/ptyp*, is the endpoint for communication

with the terminal emulator. It receives the control requests and information from the other party

over this interface and responds accordingly.

What is External Data Representation?

eXternal Data Representation (XDR) is an IETF standard from 1995 of the presentation layer in

the OSI model. XDR allows data to be wrapped in an architecture independent manner so data

can be transferred between heterogeneous computer systems. Converting from the local

representation to XDR is called encoding. Converting from XDR to the local representation is

called decoding. XDR is implemented as a software library of functions that is portable between

different operating systems and is also independent of the transport layer.

What is the difference between interior and exterior neighbor gateways?Interior gateways connect LANs of one organization, whereas exterior gateways connect the

organization to the outside world.

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What are 10Base2, 10Base5 and 10BaseT Ethernet LANs ?

10Base2An Ethernet term meaning a maximum transfer rate of 10 Megabits per second that

uses baseband

signaling, with a contiguous cable segment length of 100

meters and a maximum of 2 segments.

10Base5An Ethernet term meaning a maximum transfer rate of 10 Megabits per second thatuses baseband

signaling, with 5 continuous segments not exceeding 100

meters per segment.

10BaseTAn Ethernet term meaning a maximum transfer rate of 10 Megabits per second that

uses baseband

signaling and twisted pair cabling.

BOOTP helps a diskless workstation boot. How does it get a message to the network

looking for its IP address and the location of its operating system boot files ?

BOOTP sends a UDP message with a subnetwork broadcast address and waits for a reply from

a server that gives it the IP address. The same message might contain the name of the machine

that has the boot files on it. If the boot image location is not specified, the workstation sends

another UDP message to query the server

What protocol is used by DNS name servers ?

DNS uses UDP for communication between servers. It is a better choice than TCP because of

the improved speed a connectionless protocol offers. Of course, transmission reliability suffers

with UDP.

Which are the three types of routing tables ?

The three types of routing tables are fixed, dynamic, and fixed central. The fixed table must be

manually modified every time there is a change. A dynamic table changes its information based

on network traffic, reducing the amount of manual maintenance. A fixed central table lets a

manager modify only one table, which is then read by other devices. The fixed central tablereduces the need to update each machine's table, as with the fixed table. Usually a dynamic

table causes the fewest problems for a network administrator, although the table's contents can

change without the administrator being aware of the change.

What is source-route bridging algorithm ?

The source-route bridging (SRB) algorithm was developed by IBM and was proposed to the

IEEE 802.5 committee as the means to bridge between all LANs. SRBs are so named because

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they assume that the complete source-to-destination route is placed in all inter-LAN frames sent

by the source. SRBs store and forward the frames as indicated by the route appearing in the

appropriate frame field. Assume that Host X wants to send a frame to Host Y. Initially, Host X

does not know whether Host Y resides on the same LAN or a different LAN. To determine this,

Host X sends out a test frame. If that frame returns to Host X without a positive indication that

Host Y has seen it, Host X assumes that Host Y is on a remote segment. To determine theexact remote location of Host Y, Host X sends an explorer frame. Each bridge receiving the

explorer frame copies the frame onto all outbound ports. Route information is added to the

explorer frames as they travel through the internetwork. When Host X's explorer frames reach

Host Y, Host Y replies to each individually, using the accumulated route information. Upon

receipt of all response frames, Host X chooses a path based on some predetermined criteria.

Host X must select one of these two routes. The IEEE 802.5 specification does not mandate the

criteria that Host X should use in choosing a route, but it does make several suggestions,

including the following:

First frame received

Response with the minimum number of hops

Response with the largest allowed frame size

Various combinations of the preceding criteria

In most cases, the path contained in the first frame received is used.

What is Transparent Bridge ?

Transparent bridges were first developed at Digital Equipment Corporation (Digital) in

the early 1980s. Transparent bridges are so named because their presence and operation are

transparent to network hosts. When transparent bridges are powered on, they learn the

workstation locations by analyzing the source address of incoming frames from all attached

networks. For example, if a bridge sees a frame arrive on port 1 from Host A, the bridgeconcludes that Host A can be reached through the segment connected to port 1. Through this

process, transparent bridges build a table. The bridge uses its table as the basis for traffic

forwarding. When a frame is received on one of the bridge's interfaces, the bridge looks up the

frame's destination address in its internal table. If the table contains an association between the

destination address and any of the bridge's ports aside from the one on which the frame was

received, the frame is forwarded out the indicated port. If no association is found, the frame is

flooded to all ports except the inbound port. Broadcasts and multicasts also are flooded in this

way. Transparent bridges successfully isolate intrasegment traffic, thereby reducing the traffic

seen on each individual segment. This is called filtering and occurs when the source and

destination MAC addresses reside on the same bridge interface. Filtering usually improves

network response times, as seen by the user. The extent to which traffic is reduced and

response times are improved depends on the volume of intersegment traffic relative to the total

traffic, as well as the volume of broadcast and multicast traffic.

What is the basic difference between transparent bridges and source-route bridges

relative to the forwarding processes ?

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In a transparent bridged environment, bridges determine whether a frame needs to be

forwarded, and through what path based upon local bridge tables. In an SRB network, the

source device prescribes the route to the destination and indicates the desired path in the RIF.

What is Switched Multimegabit Data Service ?Switched Multimegabit Data Service (SMDS) is a high-speed, packet-switched, datagram-based

WAN networking technology used for communication over public data networks (PDNs). SMDS

can use fiber- or copper-based media. SMDS networks consist of several underlying devices to

provide high-speed data service. These include customer premises equipment (CPE), carrier

equipment, and the subscriber network interface (SNI). CPE is terminal equipment typically

owned and maintained by the customer. CPE includes end devices, such as terminals and

personal computers, and intermediate nodes, such as routers, modems, and multiplexers.

Intermediate nodes, however, sometimes are provided by the SMDS carrier. Carrier equipment

generally consists of high-speed WAN switches that must conform to certain network equipment

specifications. These specifications define network operations, the interface between a local

carrier network and a long-distance carrier network, and the interface between two switches

inside a single carrier network.

Where is SMDS Interface Protocol used ?

The SMDS Interface Protocol (SIP) is used for communications between CPE (Customer

premises equipment) and SMDS (Switched Multimegabit Data Service) carrier equipment. SIP

provides connectionless service across the subscriber network interface (SNI), allowing the

CPE to access the SMDS network.

What is Data-Link Switching ?Data-link switching (DLSw) provides a means of transporting IBM Systems Network Architecture

(SNA) and network basic input/output system (NetBIOS) traffic over an IP network. It serves as

an alternative to source-route bridging (SRB), a protocol for transporting SNA and NetBIOS

traffic in Token Ring environments that was widely deployed before the introduction of DLSw. In

general, DLSw addresses some of the shortcomings of SRB for certain communication

requirementsparticularly in WAN implementations. This chapter contrasts DLSw with SRB,

summarizes underlying protocols, and provides a synopsis of normal protocol operations. The

three primary functions of DLSw are :

The Switch-to-Switch Protocol (SSP) is the protocol maintained between two DLSw nodes or

routers.

The termination of SNA data-link control (DLC) connections helps to reduce the likelihood of

link layer timeouts across WANs.

The local mapping of DLC connections to a DLSw circuit.

What is Banyan VINES ?

Banyan Virtual Integrated Network Service (VINES) implements a distributed network operating

system based on a proprietary protocol family derived from the Xerox Corporation's Xerox

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Network Systems (XNS) protocols. VINES uses a client/server architecture in which clients

request certain services, such as file and printer access, from servers.

What is Enhanced Interior Gateway Routing Protocol ?

The Enhanced Interior Gateway Routing Protocol (EIGRP) represents an evolution from its

predecessor IGRP. This evolution resulted from changes in networking and the demands ofdiverse, large-scale internetworks. EIGRP integrates the capabilities of link-state protocols into

distance vector protocols. Additionally, EIGRP contains several important protocols that greatly

increase its operational efficiency relative to other routing protocols. One of these protocols is

the Diffusing update algorithm (DUAL). DUAL enables EIGRP routers to determine whether a

path advertised by a neighbor is looped or loop-free, and allows a router running EIGRP to find

alternate paths without waiting on updates from other routers. EIGRP provides compatibility and

seamless interoperation with IGRP routers. An automatic-redistribution mechanism allows IGRP

routes to be imported into EIGRP, and vice versa, so it is possible to add EIGRP gradually into

an existing IGRP network. Because the metrics for both protocols are directly translatable, they

are as easily comparable as if they were routes that originated in their own autonomous

systems (ASs). In addition, EIGRP treats IGRP routes as external routes and provides a way for

the network administrator to customize them.

Name the four key technologies that are used by EIGRP ?

EIGRP employs four key technologies, including neighbor discover/recovery, Reliable Transport

Protocol (RTP), Diffusing Update ALgorithm (DUAL) finite-state machine, and a modular

architecture that enables support for new protocols to be easily added to an existing network.

Why EIGRP is more efficient in operation than IGRP ?

Unlike most other distance vector routing protocols, EIGRP does not mandate a periodic update

of routing tables between neighboring routers. Instead, it employs a neighbordiscovery/recovery mechanism to ensure that neighbors remain aware of each other's

accessibility. As long as a router receives periodic hello packets from its neighbors, it can

assume that those neighbors remain functional. More importantly, it can assume that all of its

routes that rely upon passage through those neighbors remain usable. Thus, EIGRP is much

more efficient than conventional distance vector routing protocols because it imposes much less

overhead on routers and transmission facilities during normal operation.

What is Interior Gateway Protocol ?

IGRP is a distance vector Interior Gateway Protocol (IGP). Distance vector routing protocols

mathematically compare routes using some measurement of distance. This measurement is

known as the distance vector. Routers using a distance vector protocol must send all or a

portion of their routing table in a routing-update message at regular intervals to each of their

neighboring routers. As routing information proliferates through the network, routers can identify

new destinations as they are added to the network, learn of failures in the network, and, most

importantly, calculate distances to all known destinations.

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What is MAC address?

The address for a device as it is identified at the Media Access Control (MAC) layer in the

network architecture. MAC address is usually stored in ROM on the network adapter card and is

unique.

What is cladding?A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.


A gateway operates at the upper levels of the OSI model and translates information between

two completely different network architectures or data formats


When the computers on the network simply listen and receive the signal, they are referred to as

passive because they dont amplify the signal in any way. Example for passive topology - linear

bus.

What is SAP?

Series of interface points that allow other computers to communicate with the other layers of

network protocol stack.

What is subnet?

A generic term for section of a large networks usually separated by a bridge or router.

What is IP?

IP is Internet Protocol. It is the network protocol which is used to send information from one

computer to another over the network over the internet in the form of packets

Whats the meaning of ARP in TCP/IP?

The ARP stands for Address Resolution Protocol. The ARP standard defines two basic

message types: a request and a response. a request message contains an IP address and

requests the corresponding hardware address; a replay contains both the IP address, sent in

the request, and the hardware address.

What is data link layer in the OSI reference model responsible for?

Data link layer is located above the physical layer, but below the network layer. Taking raw data

bits and packaging them into frames. The network layer will be responsible for addressing the

frames, while the physical layer is reponsible for retrieving and sending raw data bits.

What is binding order?

The order by which the network protocols are used for client-server communications. The most

frequently used protocols should be at the top.

How do cryptography-based keys ensure the validity of data transferred across the

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network?

Each IP packet is assigned a checksum, so if the checksums do not match on both receiving

and transmitting ends, the data was modified or corrupted.

What is UTP?

UTP Unshielded twisted pair 10BASE-T is the preferred Ethernet medium of the 90s. It isbased on a star topology and provides a number of advantages over coaxial media.

It uses inexpensive, readily available copper phone wire. UTP wire is much easier to install and

debug than coax. UTP uses RG-45 connectors, which are cheap and reliable.

What is a router? What is a gateway?

Routers are machines that direct a packet through the maze of networks that stand between its

source and destination. Normally a router is used for internal networks while a gateway acts a

door for the packet to reach the outside of the internal network

What is Semaphore? What is deadlock?

Semaphore is a synchronization tool to solve critical-section problem, can be used to control

access to the critical section for a process or thread. The main disadvantage (same of mutual-

exclusion) is require busy waiting. It will create problems in a multiprogramming system, where

a single CPU is shared among many processes.

Busy waiting wastes CPU cycles.

Deadlock is a situation when two or more processes are waiting indefinitely for an event that

can be caused by only one of the waiting processes. The implementation of a semaphore with a

waiting queue may result in this situation

What is MAC address?

The address for a device as it is identified at the Media Access Control (MAC) layer in

the network architecture. MAC address is usually stored in ROM on the network adapter

card and is unique.

What is cladding?

A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.


A gateway operates at the upper levels of the OSI model and translates informationbetween two completely different network architectures or data formats


When the computers on the network simply listen and receive the signal, they are

referred to as passive because they dont amplify the signal in any way. Example for

passive topology - linear bus.

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What is SAP?

Series of interface points that allow other computers to communicate with the other

layers of network protocol stack.

What is subnet?

A generic term for section of a large networks usually separated by a bridge or router.

What is IP?

IP is Internet Protocol. It is the network protocol which is used to send information from

one computer to another over the network over the internet in the form of packets

Whats the meaning of ARP in TCP/IP?

The ARP stands for Address Resolution Protocol. The ARP standard defines two

basic message types: a request and a response. a request message contains an IPaddress and requests the corresponding hardware address; a replay contains both the

IP address, sent in the request, and the hardware address.

What is data link layer in the OSI reference model responsible for?

Data link layer is located above the physical layer, but below the network layer. Taking

raw data bits and packaging them into frames. The network layer will be responsible for

addressing the frames, while the physical layer is reponsible for retrieving and sending

raw data bits.

What is binding order?The order by which the network protocols are used for client-server communications.

The most frequently used protocols should be at the top.

How do cryptography-based keys ensure the validity of data transferred across

the network?

Each IP packet is assigned a checksum, so if the checksums do not match on both

receiving and transmitting ends, the data was modified or corrupted.

What is UTP?

UTP Unshielded twisted pair 10BASE-T is the preferred Ethernet medium of the 90s.

It is based on a star topology and provides a number of advantages over coaxial media.

It uses inexpensive, readily available copper phone wire. UTP wire is much easier to

install and debug than coax. UTP uses RG-45 connectors, which are cheap and

reliable.

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What is a router? What is a gateway?

Routers are machines that direct a packet through the maze of networks that stand

between its source and destination. Normally a router is used for internal networks while

a gateway acts a door for the packet to reach the outside of the internal network

What is Semaphore? What is deadlock?

Semaphore is a synchronization tool to solve critical-section problem, can be used to

control access to the critical section for a process or thread. The main disadvantage

(same of mutual-exclusion) is require busy waiting. It will create problems in a

multiprogramming system, where a single CPU is shared among many processes.

Busy waiting wastes CPU cycles.

Deadlock is a situation when two or more processes are waiting indefinitely for an event

that can be caused by only one of the waiting processes. The implementation of a

semaphore with a waiting queue may result in this situation

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