Network Management(2).ppt

8/9/2019 Network Management(2).ppt

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Network ManagementConcepts and Practice

Author: J. Richard Burke

Presentation by ShuPing !in


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"ut#ine

Network Components

"$er$iew o% Network Management


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Communication Architecture

A communication architecture integrates

many protoco#s and the so%tware that

imp#ements them. &hese parts can be de$e#oped

independent#y o% one another as #ong as the

de$e#opers adhere to the standard

inter%aces between them.


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"S' Re%erence Mode#


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"S' Re%erence Mode#

&he mode# does not speci%y how to imp#ementthe %unction in each #ayer.

&he %unctions in each #ayer are de%ined byprotoco#( which are imp#emented in so%tware. &he so%tware in each #ayer pro$ides ser$ices

to the #ayer abo$e it.

!ayering concept simp#i%ies the de$e#opmentprocess and a##ows impro$ements o% so%twarein one #ayer without a%%ecting other #ayers.


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Physica# !ayer

&his #ayer de%ines the e#ectrica#( mechanica#(

%unctiona# speci%ications %or hardware that

connects a de$ice to the network. Physica# #ayer standards wou#d speci%y

Connector)s si*e and shape

+,act number o% pins &he signa#s that can be used to those

pins


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-ata !ink !ayer

&his #ayer speci%ies the procedures in order

to achie$e re#iab#e pointtopoint trans%er o%

in%ormation between two de$ices. -ata #ink #ayer can be di$ided into two

sub#ayers.

!ogica# !ink Contro#

Medium Access Contro#


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-ata !ink !ayer cont)d/

CSMA0C- is imp#emented in +thernet.

CSMA means that a computer waits unti#

there is no signa# %rom any other computeron !AN be%ore transmitting a message.

C- reduces the probabi#ity that a co##ision

wi## occur by backo%% its transmission.

Bridge is a typica# de$ice working on data

#ink #ayer.


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Network !ayer

&his #ayer pro$ides the mechanisms %or

transporting a packet %rom the source

networks to the destination network. Packets are messages constructed by the

network #ayer and higher #ayers.

A router is ca##ed a network #ayer de$ice

because it is contro##ed by protoco#s up to

and inc#uding the network #ayer.


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&ransport !ayer

&ransport #ayer pro$ides reliableand

unreliabletransport protoco#s.

&he re#iab#e protoco#( which is ca##ed the&ransport Contro# Protoco# &CP/( pro$ides

the mechanisms that enab#e endtoend

re#iabi#ity.

&CP accomp#ishes this by the use o%

automated acknow#edgement and

automated retransmissions.


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&ransport !ayer cont)d/

&he unre#iab#e transport protoco#( which is

ca##ed the 1ser -atagram Protoco# 1-P/(

p#aces no constrains on the network. Beste%%ort de#i$ery %rom the source de$ice to

the destination de$ice is a## that is re2uired.

1-P is used when speed is o% the essence

and the e%%ort spent on ensuring re#iabi#ity is

not coste%%ecti$e.


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Session !ayer

&he Session #ayer pro$ides the mechanisms

necessary to open and c#ose mu#tip#e #ogica#

connections between processes on di%%erentPCs.

&hese #ogica# connections are ca##ed

session.

Many #ogica# connections can use the same

physica# connection.


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Presentation !ayer

&his #ayer pro$ides a commonrepresentation o% data trans%erred betweenpeer app#ication #ayer entities on di%%erentstations.

Abstract synta, notation.one ASN.3/ %ormatis use%u# %or app#ication #ayer.

4owe$er( the #ayers be#ow the presentation#ayer use a %ormant ca## trans%er synta,. &he presentation #ayer trans#ates between

ASN.3 and trans%er synta,.


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App#ication !ayer

Common App#ication Ser$ice +#ements

pro$ide ser$ice genera##y use%u# to a $ariety

o% app#ication programs pro$ided by$endors.

Speci%ic App#ication Ser$ice +#ements

ser$ice the additiona# needs o% particu#ar

app#ication programs.


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5rames

5rame construction App#ication program makes a re2uest.

&he re2uest is passed to the appropriateapp#ication#ayerentity.

&he app#ication#ayerentity constructs anApp#ication #ayer protoco# data unit P-1/.

&he App#ication #ayer P-1 is then passedto the appropriate presentation#ayerentity. &his entity constructs aPresentation #ayer P-1.


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5rames cont)d/

P-1s continue to be constructed and

passed to the #ayers be#ow. &his process

continues unti# the Network #ayer P-1 isrecei$ed by the -ata !ink #ayer.

&he %rame is construct in the -ata !ink

#ayer. &he Network !ayer P-1 is

encapsu#ated in a -ata !ink #ayer headerand trai#er.


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5rames cont)d/


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&CP0'P Protoco# Stack


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6orkstations

6orkstations typica# make use o% the

ser$ices o% a## #ayers o% a protoco# stack

because they process the re2uests o%app#ication programs %or in%ormation on

ser$ers.

Ser$er is #ike workstation making use o% a##

#ayers o% the protoco# stack.


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Repeater

Repeater amp#i%ies the signa# between

segments and e,tends the #ength o% a !AN.

Repeaters are used on 37BAS+8 and37BAS+9 !ANs.


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4ubs

A hub is a repeater with many input andoutput ports.

+$ery transmission recei$ed by the hub onone port is amp#i%ied and retransmitted outo% a## other ports.

4ub do not e,amine in%ormation in any %ie#d

o% the %rame. Repeaters and hubs are consider a Physica#

#ayer de$ice.


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Bridges

&ransparent bridge di$ides a !AN into segments that use the

same media access contro# speci%icationand it contro#s what tra%%ic is passedbetween segments.

uses bridge tableto #earn which de$ices

are on which segments. &rans#ating bridges connects networks using

di%%erent MAC #ayer speci%ications.


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Bridges cont)d/

+rrors and co##isions that take p#ace on one

segment are not propagated to de$ices on

the other segment. &he use o% switches rather than bridges is

commonp#ace today.


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Switches

A switch is a mu#tiport bridge.

Switches are typica##y con%igured to %orward

incoming %rames to outgoing ports based ondestination MAC addresses associated with

those ports in the switch tab#e.

Switches a#so can be con%igured to drop

%rames based on MAC destination or to

redirect %rames to other MAC address.


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Switches cont)d/

4igher #ayers o% the protoco# stack are now

being imp#emented in switches.

!ayer switch a#so can %unction #ike router.


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Routers

Router reads the Network #ayer header in

packet to %ind the destination network

address and then #ooks up the address inrouting tab#e.

&he routing tableis a #ist o% mappings o%

network addresses to ports that wi## get the

packet to the destination networks by thebest means.


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Routers cont)d/

Routing tab#e


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"ut#ine

Network Components

Overview of Network Management


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Network Management

Jobs o% network management in ear#y day

Attaching PCs and ser$er to a !AN using

Network 'nter%ace Cards N'Cs/ 'nsta##ing protoco# stacks

Con%iguring N'C '0" addresses and interrupts

so as not to con%#ict with other N'C se#ections.

1sing Ping app#ication to ensure that a##de$ices on the network cou#d communicate

with one another


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Network Management cont)d/

Access contro#

&he manager might write a script %or the

ser$er to contro# access to in%ormation onit.

&he script wou#d pro$ide access to dri$es(

%o#ders or %i#es that use or group o% users

needed. 'nsta## a print ser$er to manage the print

;obs %rom each o% the PCs.


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Network Management cont)d/

Network con%iguration

'% the networks were to be di$ided into subnets(

then a bridge wou#d be used to connect them.

&he manager wou#d con%igure a routing tab#e toenab#e connecti$ity according to network

address( subnet address and subnet mask.

5ina##y( insta##ing user app#ications on PCs is

necessary %or inter%acing correct#y with "S.


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Maintenance

A%ter con%iguring primary network

ingredients( here comes the maintenance.

Networkperformanceis not optimi*ed( therewi## be so%tware and hardware %ai#ures and

network resources wi## change.

&he manager is re2uired to make estimates

o% the network capacity.

&here was a need %or minima# security.


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Maintenance cont)d/

New work management has di$ided intospecia#ties nowadays.

Administration Backing up ser$ers Maintaining security 'nsta##ing "S and app#ications

Network engineer Be responsib#e %or the hea#th o% the

network and its a$ai#abi#ity to user.


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NetworkBased Management As network has grown #arger and more

comp#icated( network manager needed to %indmore e%%icient way to determine and contro# thestate o% network.

Some protoco#s cou#d be used by networkmanager to remote#y contro# de$ices. Simp#e Network Management Protoco#

SNMP/ Management 'n%ormation Base M'Bs/ Network Management Systems NMS/


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Network Management Protoco#

Stack

Management Station and Management

Agent.


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Network Management

+,amp#e

Step 3 NMS ca##s %or the ser$ice o% the management process

Step 8

the management process ca## the program theimp#ements network management protoco#.

Step NMP constructs a re2uest packet to the program on

the management agent. Step

At the management station the program that

imp#ements the NMP recei$es the response packet. Step ?

&he management process passes the re2uested$a#ue to the app#ication program.

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Network Management(2).ppt