Capacity Planning
Content
Capacity Planning for Intern Int ernet et Serv Service ice Networks
Geof Huston NTW Track4
Issues TCP/IP T CP/IP Protocol Protocol Behavior Issues Usage Prole Capacit Gui!elines Gro"th #evels
Planning Issues
Un!erstan! the !o$ain o% operation
technical issues
$arket issues
co$petitive issues regulator regulat or issues
TCP/IP Protocol Issues T TCP/IP CP/IP
is N&T N&T a a 'o" !a$pe! protocol
en! to en! 'o" $anage$ent sli!ing "in!o" protocol a!aptive 'o" rate !esigne! to pro(e an! use $a) availa(le en! to en! (an!"i!th
onl li$ite! ( en! sste$ (ufering si*e
sste$ (ufers are getting larger as &+ ven!ors co$e to un!erstan! the pro(le$
(an!"i!th ) !ela
TCP/IP Protocol Issues TCP/IP Data Flow Rate Adaptation Steady State Available Bandwidth ,ate over'o" loa!ing into net"ork -ueues
e t a R w o l F t a a D
Time
TCP/IP Protocol Issues
No net"ork.(ase! 'o" control $echanis$ Net"ork.(ase! packet packet loss signals en! sste$s to collapse trans$ission "in!o" si*e aring "in!o" si*e allo"s a!aptive 'o" $etrics to a!apt to changing $a)i$u$ availa(le capacit +ustaine! insu0cient insu0cient capacit lea!s tto o congestion in!uce! collapse o% !ata throughput
TCP/IP Protocol Issues
1an si$ultaneous TCP TCP sessions interact "ith non.pre!ictive non.uni%or$ loa! 2%tp3//thu$per(ellcoreco$/pu(/!v"/sigco$56ps78 2%tp3//thu$per (ellcoreco$/pu(/!v"/sigco$56ps78
Peaks start to snchroni*e "ith each other Bufering evens out (ehave in!ivi!ual 'o"s9 (ut (ufers the$selves "ith 'uctuating loa! Bufering a!!s latenc
TCP/IP Protocol Issues TCP/IP efficiency effi ciency under und er congestion efficiency u nder cong estion load
t % u p h g u o r
Congestive Collapse . The sli!e to $iser an! packet loss
h T a % t a 3 3 D
33% Traffic Level
%
TCP/IP Protocol Issues T TCP CP
U:P.(ase! applications
vs U:P
Internet Phone9 i!eo9 Workgroup
U:P Issues
no 'o" control $echanis$
sustaine! use %orces prece!ence over TCP 'o"s increasing use o% 'o" (an!"i!th negotiate! protocols %or these applications 2,+P8
TCP/IP Protocol Issues
:a$ping net"ork capacit is not a !e$an! $anage$ent tool
Net"ork capacit $ust (e availa(le to $eet peak !e$an! levels "ithout congestion loss
Usage Profile T T"o "o
Business use prole p role
$a;or Internet use pr proles3 oles3 peak at <=>> . <?>> plateau <>>> . <@6>
,esi!ential !ial prole
peak at A>6> . A66> plateau <5>> . A4>>
Usage Profile
:istance proles <A #ocal < :o$estic Trunk @> International
T Tra0c ra0c
$i) !ue to3
:istance invisi(le applications "ithout user control :istance in!epen!ent user tarif
Capacity Guidelines
#ink Utilisation
Dverage "eekl tra0c level set to => o% availa(le (an!"i!th
Core net"ork capacit shoul! (e !i$ensione! accor!ing to aggregate access (an!"i!th
Link Usage Profile - optial
peak loa!ing less than <> ti$e
greater than => loa!ing %or => ti$e tra0c (ursting visi(le
Link Usage Profile - overloaded
5> peak loa!ing %or 4= ti$e ?> peak loa!ing %or ?> ti$e no (urst prole at peak loa!s i$(alance! tra0c 2i$port (ase!8
Link Usage Profile - saturated
visi(le plateau tra0c loa! signature signature s$all loa! increases cause "i!ening plateau
!verall Growt" Levels T T"o "o
gro"th pr pressures3 essures3
service! population
the changing Internet service $o!el
$ore net"ork.capa(le applications using $ore (an!"i!th
!verall Growt" Levels
Eor a constant service $o!el the gro"th curve "ill e)hi(it !e$an! saturation %!! $!! 3!! #!! "!! ! "
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!verall Growt" Levels
Eor a changing service $o!el the saturation point "ill $ove
1ore intense net"ork use ( increasingl sophisticate! applications "#!! "!!! &!!
Technology shift
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#ow to plan
Generate a $arket !e$an! $o!el
%orecast the nu$(er o% services in operation
e)isting services gro"th rate $arket capture level 2co$petitive position8
%orecast the average !e$an! per service
!ial access9 lease! line "e(9 %tp9 usenet caching tren!s ne" Internet services
#ow to plan
!e$an! $o!els are tpicall ver uncertain in!icators
high level o% uncertaint o% e)t e)ternaliti ernalities es highl !na$ic co$petitive position poorl un!erstoo! 2an! changing8 service !e$an! $o!el
#ow to plan
Eor"ar! e)trapo e)trapolation lation
assu$e e)isting tra0c %ollo"s a general gro"th $o!el %or"ar! e)trapolat the gro"th $o!el
Goo! %or short ter$ planning 2<A $onths8
Cannot %actor
latent !e$an! $arket price sensivit
Trend forecasting
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Planning
un!ertake !e$an! an! tren! %orecast $o!els
constantl revie" the $o!el against generate! usage !ata recognise that the larger the capacit ou nee! the longer the lea! ti$e to purchase it recognise that the (igger the purchase the greater the re-uire$ent %or capital
