Informacion Networking

7/23/2019 Informacion Networking

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Layer 5 – Session Layer

• The sesión layer manages sesión establishment, maintenance andtermination betweeg network devices.

• Example when yo! log on and log o" • This layer controls the name and address database #or the $S• %et&'$S (%etwork &asic 'np!t $!tp!t System) is a protocol that *orks

at this layer

Layer + – resentation Layer

• This layer translates the data #ormat #rom sender to receiver in thevarios $ses that may be !sed

• resentation Layer concepts incl!de car-cter code conversión, datacompression, and data encryption

• edirectors work on this layer, s!ch as mapped betwork drives thatenable a comp!ter to /ccess 0le shares on a remote comp!ter

Layer 1 – /pplication Layer

• Serves as the window #or !sers and application processes to /ccessnetworkservices

• This layer is where message creation begins• End2!ser protocols s!ch as 3T , S4T , Telnet and /S work at this

layer• This layer is not the application itsel#, b!t the protocols that are

initiated by this layer

Layer rotocol evice1 3T , 6TT , $ 7, S4T 8ateway+ 9ompression,

Encryption%:/

5 Logon:Logo" %:/; T9 , < %:/7 ' , '94 , / , ' o!ters= >?=.7, >?7.5 %'9s, switches,

bridges, */ s@ @??&/SE2T 6!bs, atch anels,

A;5 Backs

T9 4odel

The T9 :' model is similar to the $S' model

This model is composed o# only #o!r layers

Layer escriptio rotocols/pplication Layer e0nes T9 :'

application protocols6TT , Telnet, 3T



Transport Layer rovidescomm!nication sesiónmanagement

T9 , < , T

'nternet Layer ackages and ro!tesdata

' , '94 , / , /

%etwork 'nter#ace etails how data isphysically sent tro!ghthe network

Ethernet, Token ing,3rame elay

OSI Model TCP Model

/pplication Layer /pplication Layerresentation Layer

Session Layer Transport Layer Transport Layer

%etwork Layer 'nternet Layerata Link Layer %etwork /ccess Layerhysical Layer

Twisted2pair cable

The most commonly !sed cable type in local -rea networks

elatively easy to work with, Cexible, eDcient, and #ast

9ontains wight wires gro!ped into #o!r twisted pairs, typically orange, 8reenand &rown

The twisted wires red!ce crosstalk and inter#erence

Twist pair categories

Twist2pair cables are categori ed according to the #rec!ency at which theytransmit signals and their data trans#er rate

9able type Speed9ategory 7 (9at27) @? 4bps9ategory 5 (9at25) @?? 4bps9ategory 5e (9at25e) @?? 4bps and @???4bpsF9ategory + (9at +) @???4bpsF

Types o# patch cables

Straight thro!gh cable

4ost common type o# patch cable



<sed to connect a comp!ter to a central connecting device like a switch

9rossover cable

<sed to direct connect similar devices witho!t the !se o# a h!b

4 ' and 4 '2G ports

4Hdi!m dependent inter#ace (4 ') is a type o# Ethernet port connection!sing twisted pair cabling

3or comp!ter to comm!nicate with other devices, the wires have to crosssomewhere

'nstead o# !sing crossover cables to connect comp!ters to central

connecting devices s!ch as switches, these central connecting devices areeI!ipped with 4 '2G ports (mHdi!m dependent inter#ace crossover) whichtake care o# the cross

/tten!ation the I!antity o# in#ormation reaching the receiver as comparedto the transmitted I!antity o# in#ormation

4eas!red in decibels (d&)

/ccording to the 'EEE >?=.7, twisted2pair cables can be r!n @?? meters&eyond this the signal degrades to s!ch a point that it cannot be interpretedby the destination host.

/ signal repeater, a h!b, or switch can be !sed i# a cable needs to be r!n#arther

'nter#erence anything that disr!pts or modi0es a signal that is travelingalong a wire

Electrical so!rces

Lights

Electrical o!tlets

4otors

/ppliances

9opper2based cables and network devices sho!ld be kept away #rom theseelectrical devices and cables i# at all posible



9rosstalk

*hen the signal that is transmitted on one copper wire o# pair o# wirescreates and !ndesired e"ect on antoher wire or pair o# wires

*hen it comes to twisted2pair cabling, crosstalk is broken down into twocategories

%ear end crosstal (%EGT) occ!rs when is meas!red inter#erence btween twopairs in a single cable, meas!red on the cable end nearest the transmitter

3ar end crosstalk (3EGT) occ!rs when there is similar inter#erence, meas!redat the cable end #arthest #rom the transmitter.

Shielded twisted2pair (ST ) cables

Stp cables have an al!min!m shield inside the plastic Backet that s!rro!ndsthe pairs o# wires

3iber optic cables

Transmits light (photons) instead o# electricity over glass or plastic J0bersK

ery good #or high2speed, high2capacity data transmission d!e to lack o#atten!ation

Single2mode

4eant to carry a single ray o# light2one ray o# light, one mode

This type o# cable is normally !sed #or higher2bandwith, longer2distancer!ns, generally @?2>?km

4ore expensive eI!ipment

4!lti2mode

9able with a larger 0ber core, capable o# carrying m!ltiple rays o# light

This type o# cable is !sed #or shorter distance r!ns, !p to +?? meters

Tho!gh m!ch shorter tan single mode diber r!ns, this is still six times thedistance o# twisted2pair cable r!ns.

Less expensive eI!ipment

*ireless /ccess oint



/ wireless /ccess point (*/ ) enables wireless devices to connect to a wirednetwork

/ wireless ro!ter can also acts as a ro!ter, 0rewall, and ' proxy

*ireless modes

There are several di"erent methods to connecto to a wireless network

'n#raestr!ct!ra – the mode !sed when wireless clients connect to and area!thenticated by a wireless /ccess point

/d2hoc – !sed when all o# the clients comm!nicate directly each other

$ther wireless devices

*ireless repeater

<sed to extende the coverage o# a wireless network

*ireless bridge

/ wireless bridge is similar to a wireless repeater, b!t the bridge canconnect di"erent >?=.@@ standards togetherM this is know as bridge mode

'EEE >?=.@@ Standard ata trans#er rate(4ax.)

3reI!ency

>?=.@@a 5; 4bps 58h>?@.@@b @@ 4pbs =.;8h>?=.@@g 5; 4bps =.;8h>?=.@@n +?? 4bps =.;8h and 5 8h>?=.@@ac >++.1 4bps 58h

*ireless encryption options

*ireless encryptionprotocol

escription Encryption Level (keySi e)

*E *ired EI!ivalentrivacy

+;2bit

* / y * /= *'20 rotected /ccess =5+2bit TN' Temporal Ney 'ntegrity

rotocol@=>2bit

/ES /dvanced EncryptionStandar

@=>2, @O=2 and =5+2bit

Service Set 'denti0er (SS')

*hen !tili ing in#raestr!ct!ra mode, the base !nit (normally a */ ) will be

con0g!red with a service set identi0er (SS' )



The SS' is the name o# the wireless network, and it is broadcast over theairwaves

*hen clients want to connect to the */ , they can identi#y it by the SS'

3or sec!rity, the SS' can be hidden #rom p!blic discovery

' v;

'nternet rotocol versión ; (' v;) is the #o!rth versión o# the 'nternetrotocol and the 0rst versión to be widely deployed

' v; is a #reI!ently !sed comm!nications protocol and is one o# the coreprotocols #or the 'nternet

' resides on the network layer o# the $S' model

' /ddresses

' addresses consist o# #o!r octets (>2bits), each between ? and =55.

Examples incl!de

@=.5.=;.=

@=1.?.?.@

@O=.@+>.7.5;=?>.7=.5+.=7=

'n order #or an ' address to #!nction, there m!st be a properly con0g!red 'address and compatible s!bnet mask

To connect to the 'nternet (or any remote network), yo! will also need a8ateway address and – optionally – a %S server address



Loopback testing

The range #or class / is ?2@=1

The @=1 network n!mber isnt !sed by hosts as a logical ' address instead,this network is !sed #or loopback ' addresses, allowing #or testing

<sable addresses<sable addresses are always going to be two less than the mathematicalamo!nt

The 0rst and last addresses cannot be !sed

3or network @1=.=;.7.x

The ? (in binary) #or the host address is the entire network

@1=.=;.7.?

The @s (in binary) #or the host address is the broadcast address

@1=.=;.7.=55

9lass and 9lass E are not !sed by reg!lar hosts

9lass is !sed #or what is known as m!lticasting2transmitting data tom!ltiple comp!ters (or ro!ters)

9lass E was reserved #or #!t!re !se, b!t this has given way to ' v+ instead

'p conCicto

' conCicts occ!r when two devices have been assigned the same ' address



*indows Error there is an ' address conCicto with another system on thenetwork

'# there ir an ' address conCicto, the devices will have problems sendingand receiving data

/ ' '/

/ ' / is an acronym #or /!tomatic rivate ' /ddressing

't !ses a single 9lass & network n!mber @+O.=5;.?.?

'# a *indows client cannot get an ' address #rom a 69 server and has notbeen con0g!red statically, it will a!to2assign a n!mber on this network

e#a!lt 8ateway and %S server

3or a device to comm!nicate on the internet, a de#a!lt 8ateway and %Sserver m!st be assigned

e#a!lt 8ateway – rovides a de#a!lt ro!te #or T9 :' hosts to !se whencomm!nicating with hosts on remote networks. The 0rst ' address o# thedevice that a client comp!ter will look #or when attempting to gain acceso!tside the local network

%S Server – The server that provides name resol!tion o# domain names to' addresses

/ssociate the name to the adress



%etwork /ddress Translation

rovides a method #or translating ' v; addresses o# devices on one networkinto ' v; addresses o# devices on a di"erent network

%/T was developed to provide a temporary sol!tion to the ' v; address

iss!eEnables one address space (private) to be re2maped to another addressspace, or perhaps re2mapped to a single p!blic ' address











































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Informacion Networking

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