Networking Notes for Interview.doc

8/13/2019 Networking Notes for Interview.doc

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NETWORK ESSENTIAL

Network:The physical connection of computers or 2 or more computers connected together

called Network.

Networking:sharing the resources within a N/W.

Share Resources:Hardware & Software

Require:Media

Media: its a communication path through which signal will pass.

Internet:connection number of network.

NETWORK SIZES

LAN: connection of 2 or more location within a single location.

CAN: connecting a N/W within a Single campus.

MAN:is a largecomputer network that usually spans a city or a large campus.

WAN: is acomputer network that covers a broad area (i.e., any network whose communications

links cross metropolitan, regional, or national boundaries)

Server:who always gives the resources.

Peer:who acts as both client and server.

Client:who always request for the resources.

There are 2 models

1) Work group or peer to peer model

2) Server based model or ( Client model) or (domain model)

Operating system

1) Client operating system2) N/W operating system

Client operating system such as: N/W operating system such as:1) Windows 98 1) server 20002) NT- Workstation 2) NT server3) 2000 Professional 3) Linux and Netware & windows 2003
http://en.wikipedia.org/wiki/Computer_networkhttp://en.wikipedia.org/wiki/Computer_networkhttp://en.wikipedia.org/wiki/Computer_networkhttp://en.wikipedia.org/wiki/Computer_network


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Work group or peer to peer model

Disadvantage:

No centralize deviceNo centralized data base

Advantage:Sharing the information

Reduce the cost

Its an independent

Server based model or (Client or Server model) or (domain model)

Disadvantage:

It will depends on server

Cost is expensive

Only local user will be loginIf server fails the whole N/W is fail.

Advantage:Data Centralization

Security

Effective PermissionSingle Platform to manage whole network

User can login to any computer and access their resources any time and much more

Basic components of N/W

Media, NIC, Protocols

N/W Card: is also called LAN orTransceiver.

Multiple home pc:aPC which is having more the one PC.

PXE:Pre-execution Environment and it is an Integrated IC.

Using PXE we can make client & connect to the server.

Different types of N/W card

1) ARC NET 2) TOKEN RING 3) ETHERNET

TOPOLOGY:The wave in which the Computers are connected is known as topology.

There are 2 types of topology

1) Physical topology: the physical structure of a N/W.

2) Logical topology: it defined the dataflow with in a N/W.

ETHERNET:its a physical address or MAC address


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Advantages

Easy to implement and extend.

Easy to install.

Well-suited for temporary or small networks not requiring high speeds (quick setup).

Cheaper than other topologies. Cost effective; only a single cable is used.

Easy identification of cable faults.

Reduced weight due to fewer wires.

Disadvantages

Limited cable length and number of stations.

If there is a problem with the cable, the entire network breaks down.

Maintenance costs may be higher in the long run.

Performance degrades as additional computers are added or on heavy traffic (shared

bandwidth). Proper termination is required (loop must be in closed path).

Significant Capacitive Load (each bus transaction must be able to stretch to most distant

link).

It works best with limited number of nodes.

Slower data transfer rate than other topologies.

Only one packet can remain on the bus during one clock pulse

Difficult to troubleshoot.

Star topology

Star networksare one of the most commoncomputer networktopologies.In its simplestform, a star network consists of one centralswitch,hub or computer,

Its Fig2 looks like: Physical is always star, Logical is always Bus

Fig2: Star Topology

It requires centralized Device (HUB, SWITCH) UTP cable

No need for Termination
http://en.wikipedia.org/wiki/Computer_networkhttp://en.wikipedia.org/wiki/Network_switchhttp://en.wikipedia.org/wiki/Network_hubhttp://en.wikipedia.org/wiki/Network_hubhttp://en.wikipedia.org/wiki/Network_switchhttp://en.wikipedia.org/wiki/Computer_networkhttp://en.wikipedia.org/wiki/Computer_network


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Disadvantages

The cable require is becomes more

Cost will be more or high

If centralize device fails, the whole N/W will fail.

AdvantageStatus LEDsTroubleshooting easy

If the one pc fails the rest of the PCs will participate

We can extend the N/W.

RING TOPOLOGY

A ring network is anetwork topology in which each node connects to exactly twoother nodes, forming a single continuous pathway for signals through each node - a

ring. Data travels from node to node, with each node along the way handling every

packet.

Require Token ring, Ethernet

1) CDDI:copper distributed data interface2) FDDI:Fiber distributed data interface3) IBMToken Ring

Cables:UTP cable & Fiber optic cable

Fig3: Ring topology

Advantages

Very orderly network where every device has access to the token and the opportunity to

transmit

Performs better than a star topology under heavy network load

Can create much larger network usingToken Ring

Does not require network server to manage the connectivity between the computers

Disadvantage

One malfunctioning workstation or bad port in the MAU can create problems for the

entire network

Moves, adds and changes of devices can affect the network
http://en.wikipedia.org/wiki/Network_topologyhttp://en.wikipedia.org/wiki/Token_Ringhttp://en.wikipedia.org/wiki/Token_Ringhttp://en.wikipedia.org/wiki/Network_topology


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Network adapter cards and MAU's are much more expensive thanEthernet cards and

hubs

Much slower than an Ethernet network under normal load

MESH TOPOLOGY

The value of fully meshed networks is proportional to the exponent of the number of

subscribers, assuming that communicating groups of any two endpoints, up to and

including all the endpoints.

The physical fully connected mesh topology is generally too costly and complex forpractical networks, although the topology is used when there are only a small number of

nodes to be interconnected.

All the pc are connected together

It support fault toleranceRequire UTP cable

Fig4: Mesh Topology

HYBRID TOPOLOGY

Hybrid networks use a combination of any two or more topologies in such a way that the

resulting network does not exhibit one of the standard topologies (e.g., bus, star, ring, etc.). Forexample, a tree network connected to a tree network is still a tree network, but two star networks

connected together exhibit a hybrid network topology. A hybrid topology is always producedwhen two different basic network topologies are connected. Two common examples for Hybridnetwork are:star ring networkandstar bus network

A Star ring network consists of two or more star topologies connected using amultistation access

unit (MAU) as a centralized hub.

A Star Bus network consists of two or more star topologies connected using a bus trunk (the bus

trunk serves as the network's backbone).

Fig5: Hybrid Topology

Advantage: The dissimilar topology can be connected.
http://en.wikipedia.org/wiki/Ethernethttp://en.wikipedia.org/wiki/Media_Access_Unithttp://en.wikipedia.org/wiki/Media_Access_Unithttp://en.wikipedia.org/wiki/Media_Access_Unithttp://en.wikipedia.org/wiki/Media_Access_Unithttp://en.wikipedia.org/wiki/Ethernet


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To building a N/W

Combi card: -An N/W card which has more than 1 type of connector is called combi card.

Require: -Nodes, Media, NIC, Drivers

Drivers: -it is software which makes the H/W to function properly.

Plug-N- Play: -is a feature in which it automatically detects the hardware &try to load the resources.

In order to support P-N-P

1) Os Must support2) Bios must have P-N-P compatible3) The hardware & drivers have P-N-P compatible (Plug & play)

Protocol: -is a set of rules which governs how the system will communicate n/w. or it is a common

language used by the system for the communicating B/W each other protocol& Protocol is software

Protocol stack: -A collection of protocol it is require for in order to provide task.

TCP/IP: - Transmission control protocol. It is routable protocol.

IPX/SPX: - internetworking packet exchange // Sequential Packet exchange. It is routable protocol.

NET BIOS: - Net basic input output system. It is Non- routable protocol.

Adopter: -it is a card is connected to one of the slot.

Ping: -Packet Internet Grapher.

OSI MODEL

OSI: -open system interface or interconnected.

OSI model is known as Reference model & how the data will flow in the media this is done by OSI

model.

It is designed in 1977 the organization ISO.

ISO: -International organization for standardization.

Reference model has 7 layers &each layer is performed its own task.

Each subtask has one layer, the Dividing a subtask is known as task.


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OSI Model have 7 Layers

Application Layer 7thLayer 7TH& 6TH& 5THlayer is also

known as MESSAGES

It is a Top most layer

Presentation Layer 6thLayer

Session Layer 5thLayer

Transport Layer 4thLayer 4thlayer is also known as

SEGMENTS

It is a medal most layer

Network Layer 3rdLayer 3rdlayer is also known as

PACKETS

It is a medal most layer

DataLink Layer 2ndLayer 2NDlayer is also known as

FRAMES

It is a lower most layer

Physical Layer 1STLayer 1st layer is also known as

BITS

It is a lower most layer

Physical

P

DataLink

D

Network

N

Transport

T

Session

S

Presentation

P

Application

A

Please do Not through sars piazza awave

Application Layer

: - is a layer at which the users interact with the network.

Protocols used by the application layer: FTP=21& 20, TFTP=69, HTTP=80, SNMP= , NMTP=

Presentation Layer

It takes the presenting the data to the user or application layer.

Presentation layer helps in compression, Encryption, code formatting

Protocols used by the Presentation layer: BMP, AUI, WAV, MPEG, DOC. & TEXT MODE: ASCIE,EBCDIC, and JPEU.


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Session Layer

Which helps establish a session like user logon, exchanging dialogues, alerting, and authentication

Which helps in build a session & teardown a session.

Before sending the data the session must establish

It helps in sending multiple sessions.(At a time a single pc sending so many files, web pages, printer o/p)

Before sending the data 1stit contacts the transport layer.

Protocols: NFS: - N/W file system. RPC: - Remote processor call. SQL: - structure query language.

Transport Layer

It helps in flow control & Error control & segmenting, Multiplexing, Reliable & Unreliable services.

Converting data into segments, 3way handshake, and connection management.

Segment: -is it a part of a message. Which helps in connection management.

Segmenting: - The process of dividing the large number of messages in to small blocks of data is known

as segmenting.

Flow control: -in order to flow of data.

Which maintain the flow of data transfer B/W the PC-PC.

Sequential numbering: -which helps in the rearrange the data at the destination.

Disadvantage: - there is no sequential number.

Advantage: - speed will increase.

Example: - there is 2 systemshave 100mbps & 2 systemshave 10mbps {100 mbps has adjusted to

10mbps}.

Connection Management: -it is for connection oriented or TCP. Before sending any data the 3way handshake must establish.


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Example: - 3 Way Hand Shake

Comp 1 Comp2

_________ SYNC _______________________

SYNC/ACKNOWNLEDGEMENT

ACKNOWNLEDGEMENT

FLOW OF SEGMENT (OR) CONTROL

Connection Management

1) Connection establishment2) Dataflow3) Connection termination

Flow Control

How the segments will flow

Example: -

Sender Receiver

Flood /over flowing the data

Flow of controls uses 2 methods to avoide the over flow of data.

1) Windowing: it avoids the overflow of data.2) Ready or not Ready

C2C1

10 segments 8 segments


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1) Ready or not ReadyExample: -

Sender Receiver

1-2-3-14-20-25

Not Ready

Ready

Here there is no proper negotiating between devices.

2) WindowingSegments 1-50 Segments 1-50

DYNAMIC NEGOCIATION

Negotiation: they will talk each other means source and destination.

It will fix window size it is become slow

The destination is not over flow.

Error control

CONNECTION ORIENTED CONNECTION LESS

TCP (Transmission control protocol) UDP (User Datagram Protocol)

Slow Fast

Reliable Non-Reliable

It will work with acknowledgement It will not work with acknowledgement

It uses 3way hand shake It wont use 3way hand shake

Ex:FTP Ex:DNS

Reliable: - the data losses are avoided and there is no data loss.

Error control done at Transport layer.

Multiplexing

1-50 segments 10 segments

Sender Receiver


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Network Layer

Which helps in routing, Brouter, Layer 3 switch & it will converts segments to packets.

Packets are also known as datagram. Packets consisting of source and destinationIP address.

Error checking done at N/W layer.

N/W is a logical&most of the important task will be done at the N/W &Transport Layer.

The function of N/W layer routing [Route discovery or Route selection]

Routing: -is a device which used for routing & the process of transferring the packets from one network

to another network is known as routing.

Each Router maintains a table known as routing table.

All ways switches check the MAC address.

Router: - is used to connect 2 different networks.

Device Addressing

Logical: - Ip address

Physical: - MAC address

Where the router acts as a gateway B/W the N/Ws.

Hop count: -The one pass through a N/W or router is known as a Hop Count.

Routing table: -routers maintain a table known as routing table. Which helps the packets to reach itsdestination.

Data-Link Layer

Data link layer helps in MAC addressing & Error checking.

Frame consists of Trailer, Data, and CRC

Header: -consists of source and destination MAC address

Data: -consisting actual data to send the destination.

CRC: -It is consists the Error checking.

Error checking is used to know whether the data is altered this error checking is done at the destinationend where as it is send by the source end.


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Example:-Frame works

1) After sending a frame it waits for some time.2) If it receives (-ve) acknowledgement it will retransmit once again.3) If it receives (+ve) acknowledgement it will transmit the next frame4) No acknowledgement (+ve) or (-ve) it wait for some time & it transmit the same frame once

again.

Parity checking: -is also used for error checking.1) Even Parity 2) Odd Parity

MACaddress is also known as Hardware (or) physical address.

It is 12 digit Hexa-decimal numbersEx: -0A-12-09-BC-08-F3

IEEE: -Divide a 12digit decimal into 2

1st6 digit 2nd6 digit

It is given by IEEE & It is given by other company

OUT: - organization unique identify

1stdigit has to be same and another 6digit we can change that number.

In data link layer has 2 sub layers

1) Logical link control (LLC)2) MAC

Binding: -the process of linking the protocol to a NIC is known as binding or The process of interfacingthe LAN drivers with protocols is knows as BINDING.

Data Link devices:-Bridge & Layer-2-switch.

Protocols: -1) 802.3 2) 802.2 3) SAP/SNAD 4) FRAME RELAY 5) HDLC 6) PPP 7) SDLA

LAN protocols: 802.3, 802.2, SAP/SNAD, Frame relay

WAN protocols: HDLC, PPP, SDLA


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DHCP

Dynamic Host Configuration Protocol

Installed DHCP in to Windows 2000 & 2003 & 2008 server is called DHCP server.

The range of IP address is created depending on the number of clients.

The range of IP address must use the same class & same N/W ID which is used for Windows 2000 &2003 & 2008 server& it is one time configuration.

If the server fails the IP address will fail.

DHCP port number= 67&68

Release the Existing IP address IPCONFIG / RELEASE

Renew the existing IP address IPCONFIG / RENEW

Auto private IP address (APIPA)

Whenever the client request & no response from the DHCP server the client will automatically generateda class B IP address of its own.

To configure DHCP at the Client end

1) Install DHCP in the machine running with server2) Configure server

(a) Give the scope of IP address[Starting & ending range]

(b) Specify the lease period

Note: - [DHCP will assign the IP address to clients on lease basis]

(c) At the client end(a) Select local area N/W & enable

Obtain an IP address automatically

DHCP service

StartSettingsControl PanelAdd/Remove windows componentsN/Wing servicesDHCP


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Configuring a DHCP Scope

Log on administrator

The DHCP Server provides:

1) Default gateway address2) Domain Name3) Service server addresses4) WINS server addresses5) NETBIOS name resolution type.

TITLE: DHCP Options Supported by ClientsFrom the Network Administration group, start DHCP Manager.

The DHCP Manager window appears.

1) Under DHCP Servers, select *Local Machine*

Local Machine indicates that you are configuring the local DHCP server, and not a remoteDHCP server.

2) From the Scope menu, choose Create.

The Create Scope dialog box appears.3) Complete the scope configuration.

The DHCP server cannot be a DHCP client. It must have a static IP address, subnet mask,and default gateway address. You also have the option of assigning an exclusion range orspecific excluded addresses as well as lease duration and a name.4) Choose OK when done.5) Choose Yes to activate the scope.

The DHCP Manager window appears with the new scope added. Notice the yellow light bulbnext to the IP address. This indicates an active scope.6) Close the DHCP Manager

TCP/IP Models

Application Also known as Application, Presentation, Session

Transport Layer Also known as Transport

Internet Also known as NetworkNetwork Also known as Data link, Physical


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802 Projects

IEEE: -it is designed 1980 Feb standard for LAN &WAN&it has 12 standards.

1) 802.1 LAN/MAN Management2) 502.2 LLC sub layer3) 802.3 CSMA/CD [ Ethernet]4) 802.4 Token Passing5) 802.5 IBM Token Ring6) 802.6 DQDB [Distributed Queue dual bus]7) 802.7 Broad band N/W8) 802.8 Fibre optic9) 802.9 ISDN10)802.10 LAN/WAN security11)802.11 wireless communication12)802.12 Demand priority or 100VG anylan

Media access

1) Contention methoda) CSMA/CA & it is used in Apple talc Network

b) CSMA / CD & it is user in Ethernet Network2) Token passing

a) Token Ring & FDDI network3) Demand priority

CSMA/CA: - Carrier sense multiple access / collision avoidance.

CSMA/CD: - Carrier sense multiple access / collision detection.

Contention Method

In contention method whenever the nodes whats to send a data 1stits sense the carrier whenever thecarrier is found free it will transmit the data. When 2 systems sense the media at the same time & if it free

they will transmit and collision will occur in a Network.

Before sending the data C1C4 sense the carrier or media or check to know whether the carrier free.

CSMA/CD

Hub always logically Bus & physically Star.

Switch always physical star & Logical Ring

In Ethernet always the data flows in Bidirectional.Ex:-2 pcsfrom C1to C4& C2C1aretransferring the data at a time.


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Disadvantage: - the collision will occur when 2 pcs transmitted the data at a time.

In this method all the system contender to transmit the data.

Whenever the number of nodes increases the collision will occurs data is avoided performance willdecreases.

Ethernet network designed by HAWAI.

CSMA/CA

Anode wishing to transmit data has to first listen to the channel for a predetermined amount of time todetermine whether or not another node is transmitting on the channel within the wireless range. If the

channel is sensed "idle," then the node is permitted to begin the transmission process. If the channel issensed as "busy," the node defers its transmission for a random period of time. Once the transmission

process begins, it is still possible for the actual transmission of application data to not occur.

In this method it wont send the data 1

st

, 1

st

it will send the signal.

TOKEN PASSING

In telecommunication,token passingis achannel access method where a signal called a tokenis passedbetween nodes that authorize the node to communicate. The most well-known examples aretoken ringandARCNET.

In case of token passing each system will get an opportunity to transmit the data here the token will begenerated. The system which is having the token can transmit the data.

In this token passing method the collision are avoided because the data flows in always one direction &

more number of systems will simultaneously transmit the data.

The Ring Designed by IBM international business machine.

DEMAND PRIORITY PROTOCOL

Require demand priority switches. Demand priority is the media access control protocol defined in theIEEE 802.12 draft standard. It is called 100VG-anyLAN by HP. various techniques are used to ensurefaitness of access for all nodes and to guarantee access time for individual nodes. Round robin selection

procedures are used to give each node an equal opportunity to transmit data. Two priority levels areprovided so that time-critical traffic such as interactive video, audio and multimedia can be given priority

service with guaranteed low delay. A bandwidth allocator can be introduced to control the amount of

bandwidth each application can use.

These techniques make demand priority able to accommodate multimedia applications with guaranteed

performance levels, while allowing normal traffic to use the remaining bandwidth in a fair manner.
http://en.wikipedia.org/wiki/Node_(networking)http://en.wikipedia.org/wiki/Telecommunicationhttp://en.wikipedia.org/wiki/Channel_access_methodhttp://en.wikipedia.org/wiki/Token_ringhttp://en.wikipedia.org/wiki/ARCNEThttp://en.wikipedia.org/wiki/ARCNEThttp://en.wikipedia.org/wiki/Token_ringhttp://en.wikipedia.org/wiki/Channel_access_methodhttp://en.wikipedia.org/wiki/Telecommunicationhttp://en.wikipedia.org/wiki/Node_(networking)


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NETWORKING DEVICES

1) Hub2) Switch3) Router

HUB

Hub is a device & also known as Concentrator

There are 3 types of hub

1) Passive Hub 2) Active Hub 3) Intelligent Hub

Active Hub

1) External power supply2) Statuss LEDs

3) The signal become strong4) Amplification5) No MAC address6) The administrator check the status of LEDs

Passive Hub

1) The signals become weaken.2) No amplification its just act likes a connector which helps how the system will

communicate.

3) No amplification4) No status LEDs

Intelligent Hub

1) It will check the status of the frame2) The time requirement is more3) Status of LEDs4) Amplification5) Its have own power supply

SWITCH

There are 3 types of switch

1) Store & forward 2) Cut through 3) Fragment free

Store & forward

1) Before sending the data it will check the source and destination MAC address2) It is slow3) It is Reliable&It will check the CRC.[ cyclic Redundancy check]


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Cut through

1) It wont check the CRC2) It will check the destination & Amplify3) It will faster4) It wont check the error

5) Non-Reliable

Fragment free

1) It will check 1st64 bytes of data2) There is128bytes3) In 64 bytes any error will be their it wont send the data for the destination.4) Once a switch off the MAC table it will erase & its temporary memory & when the MAC table

will take some time & its refresh.5) Reliable

IP ADDRESSING

It is a logical or layer 3 addresses.It is a 32 bit address. It is an Ip 4 version. Each block is known as fieldor octet. Each field size is 8 bit.

8 bits 8 bits 8 bits 8 bits

Range & Classes of IP address

Class A 1 to126 [127 is a Loop back address& it is used for troubleshooting or it is checking forTCP/IP stack]

Class B128 to 191

Class C192 to 223

Class D224 to 239 & Class E240 to 254 [255 is a Broadcast address]

Without sub netting IP address has 2 parts

1) N/W part 2) Host part

With subneting IP address has 3 ports

1) N/W part 2) Host part 3) Subneting


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To Built N/W

Whenever all computer must have same ID [Identification] &all computers must different host ID.

Subneting:- The process of dividing large N/Ws into small N/W is known as subneting.

Subnet Mask:- which is used to differentiate the Host part from a N/W part.

Class N/W Host No. of N/W No. of Host Subneting

A 1 3 126 1, 67, 77, 214 Class A

255.0.0.0

B 2 2 16, 384 65, 534 Class B

255.255.0.0

C 3 1 20, 97, 152 254 Class C

255.255.255.0D Multicast

address

E Researchpurpose

0 for N/W address / Default Routing

127 for loop back address

255 Broadcast addresses

(.)Dotperiod is used to separate the field.

Note: - While addressing a Host using an IP address the part should not consist of all Zeros or all ones.

Note: - Where all Zeros represent network address where all ones represent broadcast address.

For a given 2 N/W addresses are always lost

For Class A2 to the power of 24-2=22

For Class B2 to the power of 16-2 =14

For Class C2 to the power of 8-2=6

The host part should consist of 0s & 1s.


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Private address

Class A: 10.0.0.0 [1 N/W is reserved for private]

Class B: 172.16.0.0 to 172.16.0.31 [16 N/W is reserved for private]

Class C: 192.168.0.0 to 192.168.255.0 [256 N/W is reserved for private]

Class C Subneting

Mask

bitsSubnet Mask # of Host # of N/Ws

/24 255.255.255.0 2 to power of 8 256-2=254

/25 255.255.255.128 2 to power of 7 128-2=126

/26 255.255.255.192 2 to power of 6 64-2=62

/27 255.255.255.224 2 to power of 5 32-2=30

/28 255.255.255.240 2 to power of 4 16-2=14

/29 255.255.255.248 2 to power of 3 8-2=6/30 255.255.255.252 2 to power of 2 4-2=2

Example:-

200.10.10.0/282to the power of 4Total Network address=16 Host: (16-2=14 from each network)

Subnet Mask: 255.255.255.240

Network

address

Host address Range Broadcast

address

200.10.10.0 200.10.10.1 to 200.10.10.14 200.10.10.15200.10.10.16 200.10.10.17 to 200.10.10.30 200.10.10.29

200.10.10.48 200.10.10.33 to 200.10.10.46 200.10.10.47

200.10.10.64 200.10.10.49 to 200.10.10.62 200.10.10.63

200.10.10.80 200.10.10.65 to 200.10.10.78 200.10.10.79

200.10.10.96 200.10.10.81 to 200.10.10.94 200.10.10.95

200.10.10.112 200.10.10.97 to 200.10.10.110 200.10.10.111

200.10.10.128 200.10.10.113 to 200.10.10.126 200.10.10.127

200.10.10.144 200.10.10.129 to 200.10.10.142 200.10.10.143

200.10.10.160 200.10.10.145 to 200.10.10.159 200.10.10.159

200.10.10.176 200.10.10.161 to 200.10.10.174 200.10.10.175

200.10.10.192 200.10.10.177 to 200.10.10.190 200.10.10.191

200.10.10.208 200.10.10.193 to 200.10.10.206 200.10.10.207200.10.10.224 200.10.10.209 to 200.10.10.222 200.10.10.223

200.10.10.240 200.10.10.225 to 200.10.10.238 200.10.10.239

200.10.10.254 200.10.10.241 to 200.10.10.254 200.10.10.255


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Class B Subneting

Host

bits

Subnet Mask Host Network

/16 255.255.0.0 2 the power of 16

65536-2= 65534

/17 255.255.128.0 2 the power of 1532768-2= 32766

/18 255.255.192.0 2 the power of 14 16384-2= 16382

/19 255.255.224.0 2 the power of 138192-2= 8190

/20 255.255.240.0 2 the power of 124096-2= 4094

/21 255.255.248.0 2 the power of 112048-2= 2046

/22 255.255.252.0 2 the power of 101024-2= 1022

/23 255.255.254.0 2 the power of 9512-2= 510

/24 255.255.255.0 2 the power of 8

256-2= 254

/25 255.255.255.128 2 the power of 7

128-2= 126

/26 255.255.255.192 2 the power of 664-2= 62

/27 255.255.255.224 2 the power of 532-2= 30

/28 255.255.255.240 2 the power of 416-2= 14

/29 255.255.255.248 2 the power of 28-2= 6

/30 255.255.255.252 2 the power of 134-2= 2


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Example:-

175.10.0.0/202 to the power of 4Total Network address=16 Host: (16-2=14 from each network)

Network address Host address Range Broadcast

address Range175.10.0.0 175.10.0.1 to 175.10.14.254 175.10.15.255175.10.16.0 175.10.16.1 to 175.10.30.254 175.10.31.255

175.10.32.0 175.10.32.1 to 175.10.46.254 175.10.47.255

175.10.64.0 175.10.48.1 to 175.10.62.254 175.10.63.255

175.10.80.0 175.10.64.1 to 175.10.78.254 175.10.79.255

175.10.96.0 175.10.80.1 to 175.10.94.254 175.10.95.255

175.10.112.0 175.10.96.1 to 175.10.110.254 175.10.111.255

175.10.128.0 175.10.112.1 to 175.10.126.254 175.10.127.255

175.10.144.0 175.10.128.1 to 175.10.142.254 175.10.143.255

175.10.160.0 175.10.144.1 to 175.10.158.254 175.10.159.255

175.10.176.0 175.10.160.1 to 175.10.174.254 175.10.175.255

175.10.192.0 175.10.176.1 to 175.10.190.254 175.10.191.255175.10.208.0 175.10.192.1 to 175.10.206.254 175.10.207.255

175.10.224.0 175.10.208.1 to 175.10.222.254 175.10.223.255

175.10.240.0 175.10.224.1 to 175.10.238.254 175.10.239.255

175.10.254.0 175.10.240.1 to 175.10.254.254 175.10.255.255


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Class A Subneting

Host

bits

Subnet Mask Host / Subnet Host/Network

/8 255.0.0.0 2 the power of 24

16777216-2= 16777214

/9 255.128.0.0 2 the power of 23

8388608-2= 8388606

/10 255.192.0.0 2 the power of 22

4194304-2= 4194302

/11 255.224.0.0 2 the power of 21

2097152-2= 2097150

/12 255.240.0.0 2 the power of 20

1048576-2= 1048574

/13 255.248.0.0 2 the power of 19

524288-2= 524286

/14 255.252.0.0 2 the power of 18

242144-2= 242142

/15 255.254.0.0 2 the power of 17

131072-2= 131070

/16 255.255.0.0 2 the power of 16

65536-2= 65534

/17 255.255.128.0 2 the power of 1532768-2= 32766

/18 255.255.192.0 2 the power of 1416384-2= 16382

/19 255.255.224.0 2 the power of 138192-2= 8190

/20 255.255.240.0 2 the power of 124096-2= 4094

/21 255.255.248.0 2 the power of 112048-2= 2046

/22 255.255.252.0 2 the power of 101024-2= 1022

/23 255.255.254.0 2 the power of 9512-2= 510

/24 255.255.255.0 2 the power of 8

256-2= 254


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/25 255.255.255.128 2 the power of 7

128-2= 126

/26 255.255.255.192 2 the power of 664-2= 62

/27 255.255.255.224 2 the power of 532-2= 30

/28 255.255.255.240 2 the power of 416-2= 14

/29 255.255.255.248 2 the power of 28-2= 6

/30 255.255.255.252 2 the power of 14-2= 2

Example:-

10.0.0.0/23 2 to the power of 15Total Network address=768 Host: (2 to the power of 9 =512host

from each network)

Network address Host address Broadcast

address10.0.0.0 10.0.0.1 to 10.0.1.254

10.0.2.1 to 10.0.1.254

10.0.4.1 to 10.0.1.254

10.0.6.1 to 10.0.1.254

10.0.8.1 to 10.0.1.254

10.0.10.1 to 10.0.1.254

10.0.12.1 to 10.0.1.254

10.0.14.1 to 10.0.1.25410.0.16.1 to 10.0.1.254

10.0.18.1 to 10.0.1.254

10.0.20.1 to 10.0.1.254


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DEVELPOMENT OF TCP/IP

Require: -Media convertor, MSAU, Repeaters

MSAU: - Multi Station Access Unit

Signal Generator: - It separates the signal& Noise..

--------------------------------

MSAU: - it is used for IBM Token Ring.

Repeaters: - It is a physical layer of OSI Model.

Drawback of Repeaters: - it will amplify the signals known as repeaters

Media convertor: - It is a small box & it is a device which converts input fibre optic cable to cable to fibreoptic cable & output fibre optic cable to converting to the UTP cable is known as media convertor.

Connect the Fibre optic cable requires: -

1) SC: - Subscriber connector2) ST: - Straight trip3) Patch cards

Advantages of Fibre optic cable

1) Cheap: - Fiber optic cables cost less than copper wire, making optical cables a more economicalchoice when transmitting data over large distances.

2) Secure: - Fiber optic cables offer more secure communications because they are highly resistantto tapping, radio frequency interference and jamming. The United States Department ofDefense has been using fiberoptics for secure communications for more than 25 years.

3) Low Attenuation: - Fiber optics experience very little data loss, even over long distances,

because light travels through the fiber without experiencing attenuation or a loss of intensity over

time.

4) Space Saver: - A single fiber optic cable can carry significantly more data than a single electrical

cable, which saves space within a building or other small space.

5) Low Attenuation: - Fiber optics experience very little data loss, even over long distances,because light travels through the fiber without experiencing attenuation or a loss of

intensity overtime.

PC1 PC2
http://www.ehow.com/facts_5147482_advantages-fiber-optic-cable.htmlhttp://www.ehow.com/optics/http://www.ehow.com/facts_5147482_advantages-fiber-optic-cable.htmlhttp://www.ehow.com/optics/http://www.ehow.com/facts_5147482_advantages-fiber-optic-cable.html


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802.6 DQDB {Distributed Queue Dual-bus}

It is a distributed multi-accessnetwork.

a. Supports integratedcommunications using a dual bus and distributed queuing,b. Provides access tolocal ormetropolitan area networks

c. Supports connectionless data transfer,connection-oriented data transfer, andisochronouscommunications, such as voice communications.

802.2 LLC Sub layer {Link link control}

The Logical Link Control (LLC) data communication protocol layer is the upper sub-layer of theData

Link Layer (which is itself layer 2, just above thePhysical Layer)in the seven-layerOSI reference model.It providesmultiplexing andflow control mechanisms that make it possible for several network protocols(IP,IPX)to coexist within a multipoint network and to be transported over the same network media.

The LLC sub-layer acts as an interface between the Media Access Control (MAC) sub layer and the

network layer.It is the same for the various physical media (such as Ethernet,token ring,andWLAN).

As theEther type in anEthernet II framing formatted frame is used to multiplex different protocols on topof the Ethernet MAC header it can be seen as LLC identifier.

802.7 Broad band N/W

The IEEE Broadband Technical Advisory Group, chartered to develop standards for definition of a

broadband cable plant design and establish guidelines for LAN construction within a physical facilitysuch as a building. This standard has been withdrawn.

An IEEE standard for a broadband local area network (LAN) using coaxial cable. This standard was

developed for cable Internet companies.

802.11 wireless communication

A WirelessLocal Area Network (WLAN) links two or more devices using some wireless distributionmethod (typically spread-spectrum or OFDM radio), and usually providing a connection through anaccess point to the wider internet. This gives users the mobility to move around within a local coveragearea and still be connected to the network.

Wireless LANs have become popular in the home due to ease of installation, and the increasing

popularity of laptop computers. Public businesses such as coffee shops and malls have begun to offer

wireless access to their customers; sometimes for free. Large wireless network projects are being put upin many major cities:New York City,for instance, has begun a pilot program to cover all five boroughsof the city with wirelessInternet access.
http://en.wikipedia.org/wiki/Accesshttp://en.wikipedia.org/wiki/Telecommunicationhttp://en.wikipedia.org/wiki/Local_area_networkhttp://en.wikipedia.org/wiki/Metropolitan_area_networkshttp://en.wikipedia.org/wiki/Telecommunication_connectionhttp://en.wikipedia.org/wiki/Isochronoushttp://en.wikipedia.org/wiki/Protocol_(computing)http://en.wikipedia.org/wiki/Data_Link_Layerhttp://en.wikipedia.org/wiki/Data_Link_Layerhttp://en.wikipedia.org/wiki/Physical_Layerhttp://en.wikipedia.org/wiki/OSI_modelhttp://en.wikipedia.org/wiki/Multiplexinghttp://en.wikipedia.org/wiki/Flow_controlhttp://en.wikipedia.org/wiki/Internet_Protocolhttp://en.wikipedia.org/wiki/IPXhttp://en.wikipedia.org/wiki/Media_Access_Controlhttp://en.wikipedia.org/wiki/Network_layerhttp://en.wikipedia.org/wiki/Ethernethttp://en.wikipedia.org/wiki/Token_ringhttp://en.wikipedia.org/wiki/Wireless_LANhttp://en.wikipedia.org/wiki/Ethertypehttp://en.wikipedia.org/wiki/Ethernet_II_framinghttp://en.wikipedia.org/wiki/Wirelesshttp://en.wikipedia.org/wiki/Spread_spectrumhttp://en.wikipedia.org/wiki/OFDMhttp://en.wikipedia.org/wiki/Laptophttp://en.wikipedia.org/wiki/New_York_Cityhttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/New_York_Cityhttp://en.wikipedia.org/wiki/Laptophttp://en.wikipedia.org/wiki/OFDMhttp://en.wikipedia.org/wiki/Spread_spectrumhttp://en.wikipedia.org/wiki/Wirelesshttp://en.wikipedia.org/wiki/Wirelesshttp://en.wikipedia.org/wiki/Ethernet_II_framinghttp://en.wikipedia.org/wiki/Ethertypehttp://en.wikipedia.org/wiki/Wireless_LANhttp://en.wikipedia.org/wiki/Token_ringhttp://en.wikipedia.org/wiki/Ethernethttp://en.wikipedia.org/wiki/Network_layerhttp://en.wikipedia.org/wiki/Media_Access_Controlhttp://en.wikipedia.org/wiki/IPXhttp://en.wikipedia.org/wiki/Internet_Protocolhttp://en.wikipedia.org/wiki/Flow_controlhttp://en.wikipedia.org/wiki/Multiplexinghttp://en.wikipedia.org/wiki/OSI_modelhttp://en.wikipedia.org/wiki/Physical_Layerhttp://en.wikipedia.org/wiki/Data_Link_Layerhttp://en.wikipedia.org/wiki/Data_Link_Layerhttp://en.wikipedia.org/wiki/Protocol_(computing)http://en.wikipedia.org/wiki/Isochronoushttp://en.wikipedia.org/wiki/Telecommunication_connectionhttp://en.wikipedia.org/wiki/Metropolitan_area_networkshttp://en.wikipedia.org/wiki/Local_area_networkhttp://en.wikipedia.org/wiki/Telecommunicationhttp://en.wikipedia.org/wiki/Accesshttp://en.wikipedia.org/wiki/Access


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802.10 Local Area Network / Wide Area Network

1. Un-patched servers

Server systems used within the corporate network, both ones exposed to the internet, and internalservers that have no direct connection to the internet represent a potential major security risk.

While most IT departments would claim that they are diligent about applying patches as soon as theyare available, this risk has to be taken very seriously as even large companies (Microsoft for example)

have failed to patch all servers in a timely manner, leading to disruption of internal network traffic byWorms like Code Red and its variants. (Particularly at risk are internal servers that may be neglected

because they dont connect directly to the internet)

2. Un-patched client software

Many common and freely available internet client applications, in particular Internet Explorer,Outlook Express, and Outlook contain security vulnerabilities that may be exploited by a large number ofvariations on Worm or Viral code. Many of the variations will slip past anti-virus software for several

days before anti-virus software makers add their signatures to their software.

Many of these threats can be negated by making sure that all web browsing and e-mail software is

regularly updated with all available security patches.

In the particular case of e-mail attachments, the single most dangerous and common security threattoday, Using Microsoft Outlook 2000 patched to at least service release 2 and having the extended

attachment security option installed completely blocks all executable content in email attachments.Microsoft Office XP includes the dangerous attachment blocking automatically.

It should be noted that no version of Microsofts free Outlook Express offers effective blocking of

dangerous attachments and users of Outlook Express should therefore have an up to date anti-virus utilityinstalled on their system in addition to training on what attachments are safe to open.

3. Insecure peer to peer file sharing

Individual users computers often have file and printer sharing turned on, allowing files to be copied

directly between computers within an office. While this is very convenient and often essential toworkgroup productivity, care must be taken when deciding what folders to share.

Workstation computer operating systems generally offer much less security than server operating

systems. Network aware worms and viruses may take advantage of unprotected shared folders to spreadfrom machine within a LAN. To prevent the possible spread of viruses between computers the root folder,

program folders, and operating system folders should never be shared.

Only folders containing data files should be shared, and confidential data that must be shared should

be stored on a server where more security is available.

4. Insecure passwords

When possible, any resources shared on a network should be protected by allowing access only with a

valid user name and password combination. Passwords should be difficult to guess, and not shared or leftin plain sight (i.e. stuck to the monitor.)

A strong password policy allows access to resources to be restricted as needed, to working hours, and

an individuals access to confidential data can be disabled immediately upon termination.


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Protecting the Network

Being aware of the above threats and following the guidelines above will provide a reasonable level of

safety for a corporate network, but additional steps are usually taken to further reduce security risks.

Firewalls and Network Address Translation

Most networks have the added security of a hardware or software firewall that blocks and discards anytraffic coming into the network that is not expected. Computers behind the firewall usually are assignedspecial IP (Internet Protocol) addresses that cannot be routed over the internet.

Network address translation is performed by a gateway router or proxy server (often integrated withthe firewall) that allows computers with non-routable addresses to make requests from the internet.

There is no way that unsolicited traffic from the internet can de directed to a computer with a non-routable address unless the firewall/router etc. has been specifically programmed to pass traffic to a

particular server (a web or mail server for example) behind the firewall.

Unfortunately a firewall cannot prevent hostile applications running on individual workstations (suchas Trojans, Viruses, and Worms) from opening security holes from inside a network, as the traffic can

appear to be perfectly normal.Programs like Zone Alarm (which has a free version) try to identify suspicious outgoing traffic, but

these need to be installed on each individual workstation and may be of limited usefulness because of a

large number of false alarms.

The Bottom Line

Even If all of the above suggestions are followed to the extreme, there is still the chance thatsomething can get past even the best planned network security; the internet will never be completely safe.

These suggestions should in most cases limit potential damage to a single computer. The failure tofollow these suggestions, in particular allowing unsafe peer to peer file sharing with inadequate or non-existent passwords could allow a hostile application to spread to a large number of computers

Expand

1 FAT File Allocation Table2 LAN/N/W Local Area Network3 WAN Wide Area Network

4 CAN Campus Area Network

5 MAN Metropolitan Area Network

6 NIC Network Interface Card

7 UTP Unshielded Twisted Pair

8 STP Shielded Twisted Pair

9 PXE Pre-Execution Environment

10 MAC Media Access Control

11 IBM International Business Machine

12 AWG American Wire Gauge

13 CDDI Copper Distributed Data Interface

14 FDDI Fibre Distributed Data Interface

15 TPI Twisted Per Inch

16 EMI Electro Magnetic Interface

17 AUI Attachment Unit Interface


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18 FDM Frequency Division Multiplexing

19 TCP/IP Transmission Control Protocol/Internet Protocol

20 IPX/SPX Internetworking packet Exchange/Sequential Packet Exchange

21 NEUI Net Extend User Interface

22 BNC British Novell Connector

23 OSI Open System Interconnector Interface24 ISO International Standardization For Organization

25 UDP User Datagram Protocol

26 IP Internet Protocol

27 DHCP Dynamic Host Configuration Protocol

28 INIC Internet Network Information Centre

29 ARCN Attachment Resources Computing Network

30 LTAP Local Talk Access Protocol

31 TTAP Token Talk Access Protocol

32 PAP Print Access Protocol

33 ATDSP Apple Talk Data Steam Protocol

34 ATSP Apple Talk Session Protocol

35 DGDP Data Gram Delivery Protocol36 ZIP Zone Information Protocol

37 RTMP Routing Table Management Protocol

38 ATTP Apple Talk Transmission Protocol

39 NNTP Network News Transmission Protocol

40 FQDN Fully Qualified Domain Name

41 WINS Windows Internet Name Service

42 DNS Domain Name System Or Service

43 POP Post Office Protocol

44 HTML Hyper Text Markup Language

45 HDLC High Level Data Link Control

46 SDLC Sequential Data Link Control47 PPP Point To Point Protocol

48 SLIP Serial Line Internet Protocol

49 CLP Command Line Interface

50 IOS Internetworking Operating System

51 HAL Hardware Abstraction Layer

52 NDS Novell Directory Service

53 ADS Active Directory Service

54 RAS Remote Access Service

55 CSN Client Services Netware

56 GSN Gateway Services Netware

57 LLC Logical Link Control

58 APIPA Auto Private Internet Protocol Address59 CSMA/CA Carrier Sense L=Multi Access/Collision Avoidance

60 CSMA/CD Carrier Sense Multiple Access/Collision Detection

61 QOS Quality Of Services

62 MAU Multistation Access Unit

63 PIG Packet Internet Grapher

64 IEEE Institute Of Electrical And Electronics Engineering

65 NLSP Netware Link State Protocol


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66 OSPP Open Shortest Path Protocol

67 RIP Routing Information Protocol

68 SPF Shortest Path First

69 DQDB Distributed Queue Data Bus

70 ISDN Internet Service Digital Network

71 ST Straight Trip

72 SC Subscriber Connector

73 DOD Department Of Defense

74 ARPA Advance Research Project Agency

75 FTP File Transfer Protocol

76 SMTP Simple Mail Transfer Protocol

77 TFP Trivial File Transfer Protocol

78 HTTP Hyper Tie Transfer Protocol

79 ARP Address Resolution Protocol

80 RARP Reverse Address Resolution Protocol

81 ICMP Internet Control Message Protocol

82 SNMP Simple Networking Manage Protocol

83 FPN File & Printer Netware84 CSN Client Service Netware

85 GSN Gateway Service Netware

86 RPC Remote Processor Call

87 DCE Data Communication Equipment

88 BRI Binary Rate Interface

89 ASC Anolog Switch Connection

90 DSC Digital Switch Connection

92 TDM Time Division Multiple

93 ATM Asynchronous Transfer Mode

94 MC Microsoft Challenge

95 RADUI Remote Authentication Dial In User Service

96 SLIP Serial Line Internet Protocol97 CHAP Challenge Handshake Authentication Protocol

98 EAP Extensible Authentication Protocol

99 PAP Password Authentication Protocol

100 L2TP Layer 2 Tunneling Protocol

101 BAP Bandwidth Allocation Protocol

102 PPTP Point To Point Tunneling Protocol

103 SMART Self Monitoring Analysis Receiving Transceiver

104 TDRM Time Domain Reflect meter

105 CHSAP Challenge Hand Shake Authentication Protocol


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ACTIVE DIRECTORY SERVICES

An active directory is a directory structure used on Microsoft Windows based computers and servers tostore information and data about networks and domains

Work group

In workgroup model with a single user account user can login from only from that local user system

where the account is created but he cant login from all the system.

In work group model only local users can be created

Note:Administrator built in user& Administrators built in group

Converting workgroup model to Domain Model


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Server act like a

1) Stand-alone server2) Member server3) Domain controller

4) Additional domain controller

Standalonealone server

Standalone servers are independent of domain controllers on the network. They are not domain membersand function more like workgroup servers. In many cases a standalone server is configured with aminimum of security control with the intent that all data served will be readily accessible to all users.

Member server

Member servers

A member server is a computer that:

Runs an operating system in the Windows 2000 Server family or the Windows Server 2003

family.

Belongs to a domain.

Is not a domain controller.A member server does not process account logons, participate in Active Directory replication, or storedomain security policy information.

Member servers typically function as the following types of servers: file servers, application servers,

database servers, Web servers, certificate servers, firewalls, and remote access servers. For more

information about server roles, seeServer roles.

The following security-related features are common to all member servers:

Member servers adhere to Group Policy settings that are defined for the site, domain, or

organizational unit.

Access control for resources that are available on a member server.

Member server users have assigned user rights.

Member servers contain a local security account database, the Security Accounts Manager(SAM).

Domain controller

Domain controllersA domain controller is a computer that:

Runs an operating system in the Windows 2000 Server family or the Windows Server 2003family.
http://technet.microsoft.com/en-us/library/cc756962(WS.10).aspxhttp://technet.microsoft.com/en-us/library/cc756962(WS.10).aspx


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Uses Active Directory to store a read-write copy of the domain database, participate inmultimaster replication, and authenticate users.

Domain controllers store directory data and manage communication between users and domains,including user logon processes, authentication, and directory searches. Domain controllers synchronizedirectory data using multimaster replication, ensuring consistency of information over time.

Additional domain controller

If you already have one domain controller in a domain, you can add additional domain controllers to the

domain to improve the availability and reliability of network services. Adding additional domaincontrollers can help provide fault tolerance, balance the load of existing domain controllers, and provide

additional infrastructure support to sites.

More than one domain controller in a domain makes it possible for the domain to continue to function if adomain controller fails or must be disconnected. Multiple domain controllers can also improve

performance by making it easier for clients to connect to a domain controller when logging on to thenetwork. You can add additional domain controllers over the network or from backup media.

Before adding domain controllers you should thoroughly understand Active Directory and therequirements necessary to set up additional domain controllers in an existing domain

The command used to install active directory services

DCPROMOto Install Domain Controller Promote

DCPROMOto Demote or Uninstall

Points

1) Active directory services to a standalone server will convert to a domain control

2) To convert standalone server to domain controller install ADS

Before installing ADS

A) The system must have at least one partition formatted with NTFS 5.0

B) The N/W card has been configured properly.

3) In standalone server we can create the local user can be created

4) By converting standalone server to domain controller you cannot create local users

5) To login from the clients end to a domain controller connect the clients or joint the clients to amember of domain controller.

6) ADScan be installed only on windows 2000, 2003 server family. It cannot be installed on 2000 orXP Professional.

7) In 2000 or XP professional only local users can be created.

8) When I connect the standalone server to a member of domain controller it will become MemberServer.

9) From the member server. The administration can be done but the directory will be updated indomain controller not the member server


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10)Disjoining the member server from a domain controller will convert to a standalone server.

11)The process of transferring the database from one system to another system called Replication.

12)To support the fault tolerance creates one additional domain controller where it will keep anadditional copy of directory database.

13)The database updated in the domain controller will be replicated to Additional DomainController.

Points

a) When I connect between 2 different parent by default there is no relational ship.

b) In this case users in one domain cannot authenticate in the other domain & users in the otherdomain cannot authenticate in this domain.

c) In this case user has to manually establish the relationship. This relationship is known asTRANSITIVE TRUST

d) NON TRANSTIVE TRUSTestablish by in one way.e) B/W parent & child domain by default a 2way trust relationship will establish by default this

is known as Transitive Trust.Means users in one domain can authenticate in the otherdomain & users in the other can authenticate in this domain because both the domains are

Trusting B/W each other.

A one way Non Transitive Trust

Pc1 Pc 2 Pc 3 Trusted Pc1 Pc 2 Pc 3 Trusting

In this Trust one domain has to be configured as Trust Domain. (Where the user account are their)

and the other domain has to be configured as Trusting Domain.

HOD.COM STAFF.COM


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In the one way Non Transitive Trust as shown in the above figure users in the MD domain canauthenticate in the Staff.com domain but users in the Staff.com domain cannot authenticate in the

MD.com.The arrow indicates Trusted to Trusting.

Parent Domain

Schema

A schema is a set of rules which defines the tree structure.

A collection of tree are Known as Forest.

By default name of the active directory database NTDS


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PROFILE

Profile: user desktop environment

Profile is divided by 2 types

1) Software profile

2) Hardware profile

Local profile:Stored in the C:\Documents and Settings\username folder. The profiles file is

NTUSER.DAT in the directory called by the user's name.

Drawback: the user is not getting the same desktop in the other system whenever you login.

Mandatory profile:Which discards any changes the user makes to their profile at logoff time, can be

implemented by modifying the name of the user profile file from ntuser.dat to ntuser.man. The ntuser.ini

file is used to set up the user roaming profile components that are not copied to the server. The

ntuser.dat.log file is used for ntuser.dat file recovery in the case of an error. Additional folders in thec:\documents and settings\username folder are: Desktop, Start Menu, My Documents, and Cookies.

User can change the desktop

Roaming Profile:Stored on an NT server and downloaded to the computer that the user logs onto. This

way the same user's profile can be available on any machine.

It is profile which will be updated in the Domain controller.

Disadvantage:in roaming profile whenever the user logoff the changes will be updated

Drawback:background changes are updated.


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RAID

(Redundant Array of Independent Disks)

BASIC DYNAMIC

Manufacture Disk Not available

Partition Volume

Support all OS 2000 family

Convert basic to dynamic Disk Cantconvert

Simple Volume:The process of extending the size within a single drive is known as simple volume.

We can create volumes after converting basic disks to dynamic mini single disk & up to 32 disks is

required. In simple volume we can extend the volumes as much as possible with in the disk region.

Simple volume is not fault tolerance.

Spanned volume:after upgrading as dynamic from the basic disk we can create spannedvolume

We can extend the size of a volume by utilizating the free spaces from more than 1 Disk.

At start writing the 1stdisk & later on finishing that it goes to 2ndhard disk.

Data will be written one after another

It wont support fault tolerance

Cant extend system partition further.

Only NTFS partition can be extended

Uneven size of space from different disks can be put together & create a volume.

If any 1 disk fails the whole disk will crush.

RAID 0 OR Stripe Volume

It requires mini-2 HDD & Maxi -32HDD

On this volume we can have an even space from all the disks & put together & create a volume. It will

take the least space from the disk & create a volume.

Data will be written simultaneously in the entire disk at a time.& it can be extended.

It will uses for even sizes and performance.

Disadvantage:It wont support fault tolerance.There is no Redundancy


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RAID 1 ORMirroring & Duplexing Volume

In order to create Mirroring 2HDD mini & maxi 2HDD & we should combine the HDD of having

same R P M (Rotation per Minute).

After creating mirrored volume data will be automatically copied as its on the other disks.

If we cannot 2 HDD in a particular IDE then it becomes Mirroring. In case one HDD from to IDE 0 &

one HDD from IDE-1 then it becomes Duplexing.

It support fault tolerance.

RAID 5 ORStripping with parity Volume

It require mini 3 HDD Maxi=32 HDD

It supports fault tolerance here also only even space of all the disks may be clubbed.

In this method 67% of the data may be written in the entire disk & 33% of the space will be resources for

the parity information.

In this method we can break the Mirroring that makes 2 separate volumes & there will be no fault

tolerance. & we can remove disk that makes it will remove whole disk.

Bridge

HUB HUB

pc1 2 3 4 5 6 7 pc1 2 3 4

Port 1 Port 2

A network bridge, also known as a layer 2 switch, is a hardware device used to create a connection

between two separate computer networks or to divide one network into two. Both networks usually usethe same protocol;Ethernet is an example of a protocol. Network devices include, but are not limited to,

Personal Computers (PCs), printers, routers, switches and hubs. Devices connected to a network via anEthernet adapter card have what is known as a Media Access Control (MAC) address, also called a

physical or hardware address. It is this address that uniquely identifies a device to a bridge that can thendetermine to which network the device is connected.

The principal function of a networkbridge is to forward data based on the MAC address of the sendingand receiving devices. This operation helps to eliminate what are known as collision domains. One way ofdefining a collision domain is a network in which one device, also called a node, and forces every otherdevice to listen when it is transmitting data packets. Another definition states that a collision domain

exists when two or more devices attempt to transmit information at the exact same time. Networks

Bridge
http://www.wisegeek.com/what-is-a-computer.htmhttp://www.wisegeek.com/what-is-ethernet.htmhttp://www.wisegeek.com/what-are-personal-computers.htmhttp://www.wisegeek.com/what-is-pcs.htmhttp://www.wisegeek.com/what-is-pcs.htmhttp://www.wisegeek.com/what-are-personal-computers.htmhttp://www.wisegeek.com/what-is-ethernet.htmhttp://www.wisegeek.com/what-is-a-computer.htm


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running Carrier Sense Multiple Access/Collision Detection (CSMA/CD) should, intheory,be protectedfrom collisions occurring, but CSMA/CD can fail.

Whenever collisions occur, the efficienttransmission of data packets is greatly compromised. The more

devices that are on a network trying to transmit data, the greater the chance for a collision to occur. Anetwork bridge can be used to segment one network into two, thereby reducing the number of devices

competing for transmission privileges. For example, if network A has 20 devices, there is the likelihoodthat two or more of them will attempt to transmit data at the same time and cause a collision. If a network

bridge is added, it can split network A into networks A and B of 10 devices each.

Once the network bridge is incorporated, it will begin to "listen" to the transmission of data performed bydevices on the two networks. It accomplishes this by recording the MAC address of the devices in a tablethat it automatically generates without being programmed to do so. When the first device transmits data,

the network bridge will add its MAC address to what is known as a forwarding table for future reference.The bridge also looks at the MAC address of the destination or receiving device. If it does not appear in

its table, the bridge will broadcast the data packet to all devices on both networks to locate the intendeddestination.

Forwarding tables are not instantly built, rather the network bridge has to wait until it receives a

transmission from a device before it can learn its MAC address. MAC addresses of receiving devices alsohave to be learned via broadcast, a search for the location of the destination. Once the destinationresponds, its address is also added to the forwarding table of the network bridge. Eventually, all MAC

addresses will be captured and data packets will be efficiently routed straight to their destination. Thiswill happen without all devices having to listen to one transmitting device.

When the sending and receiving devices are on the same network, no forwarding of data packets takes

place. If they are on opposite networks, the bridge will forward the information. The prevention ofcollisions is not the only advantage of using bridges; they also are used to control the flow of informationto maintain privacy. When a device transmits, it is seen by the bridge as a MAC address that belongs to

one of two separate networks, and if the sending and receiving devices are on the same network, the datawill not be forwarded. This is one way anetwork administrator might maintain privacy of information.

Features of bridge

Which isolates 2 different collision domains.

Which will doubles the bandwidthIt reduces the traffic

Disadvantage

In bridge all the ports must have the same N/W ID. Whereas using router we cannot different N/Ws.

Advantage

Different types of N/Ws can be connected like

1) Ethernet with token ring

2) Token ring with Ethernet.
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This is possible because bridge acts like a translator.

Which accept the frame from an Ethernet n/w translated into a format that will be understood by the token

ring n/w & (Viceversa)

DIFFERENCE BETWEEN BRIDGE AND ROUTER

BRIDGE ROUTER

1 Built table based on MAC address Built table based on the network

address

2 All the ports must have the same network number It can connect different network

number

3 Unknown address will be forward It will filter the unknown address

4 Forward the broad cast address It wont forward the broadcastaddress

DIFFERENCE BETWEEN BRIDGE AND SWITCH

BRIDGE SWITCH

1 Switch mode: store & forward Store & forward

2 Duplexing: Function in only duplexing Function in both duplexing &fullduplexing

3 FPS: Switch will have more FPS(50,000) >1 Million

4 Ports: (2 TO 16) 100

The bridge will forward the unknown addresses to all the other ports from where it receives the frame.

Bridge uses a protocol spanning tree protocol. (STP)

Spanning tree protocol: is set of rules which dynamically select the path by communicating with the

bridges when the bridges are connected in parallel to provide the redundancy.