Introduction EECS 325/425 Michael Rabinovich
[email protected]
Introduction
Logistics
Lecture time: Wed/Fri 9:00-10:15am !!ice hours: Wednesda"s 1:00-#:00$m or b" a$$ointment %lin 50&' (rading:
)ome*or+s: #5, .o be turned in on the due date FR class verdue home*or+ loses 10, o! value once $ast due and !urther 10, ever" # hours %including *ee+ends etc2' )ome*or+ not acce$ted once acce$ted once it3s over &# hours $assed due
4roects: #0, Midterm: #0, Final: 65,
.e7t: 8urose and Ross om$uter ;et*or+s: a to$-do*n a$$roach2 < th dition ourse in!ormation/documents: lac+board Introduction
8e" =dvice: e Resource!ul>
?I learned ever"thing !rom the boo+2@ Atud" grou$s !!ice hours .=s Whatever *or+s>
Atud" grou$s:
8 to discuss home*or+/$roect 8 to e7$lain a home*or+ solution to each other … as long as no one takes notes with them from discussion! Introduction
Bnderstanding om$uter ;et*or+s
What ha$$ens *hen I clic+ on this lin+C htt$://cnn2com
= number o! com$uters across the countr" are involved
)undreds o! +ilob"tes travel thousands o! miles
)andled b" doDens o! rela" devices
= number o! $rotocols *or+ together: )..4 E;A BE4 .4 I4 (4 A4F =R4 thernet WiFi
= number o! com$anies get involved
The course oecti"e# a $eak ehind the scene%
Introduction
ourse bectives
4rovide basic overvie* o! the net*or+ing area
Internet $rotocol stac+ 4rotocol e7am$les at a$$lication trans$ort net*or+ and lin+ la"ers Internet hierarch" addressing routing algorithms
4re$are !or in-de$th stud" in selected areas (ain initial e7$erience in creating net*or+ a$$lications (et e7$osure to lo*-level net*or+ $rogramming ;ot a vocational course>
Introduction
Eisclaimer:
.hese lecture notes are based heavil" on the slides $rovided b" the authors o! the boo+2 =ll material $rovided b" the authors should be considered as belonging to their co$"right: G 199nterprise access networks %>thernet' institutional link to ISP /Internet1 institutional router Ethernet switch
institutional mail. web ser2ers
t&picall& !se in companies, !niversities, etc "# 0bps, "##0bps, "Cbps, "#Cbps transmission rates toa&, en s&stems t&picall& connect into >thernet switch Intro!ction
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Wireless access networks
share wireless access network connects en s&stem to ro!ter
via base station aka “access point”
wireless LAs:
within b!iling %"## (t' E#*5""bFg %Wi2i': "", 67 0bps transmission rate
wie-area wireless access
provie b& telco %cell!lar' operator, "#’s km between " an "# 0bps 8C, 7C: ?>
to Internet to Internet Intro!ction
"-"E
.he ;et*or+ ore
mesh o! interconnected routers the !undamental uestion: ho* is data trans!erred through netC circuit s*itching: dedicated circuit $er call: tele$hone net $ac+et-s*itching: data sent thru net in discrete ?chun+s@ Introduction
;et*or+ ore: ircuit A*itching nd-end resources reserved !or ?call@
lin+ band*idth s*itch ca$acit" dedicated resources: no sharing circuit-li+e %guaranteed' $er!ormance call setu$ reuired Introduction
;et*or+ ore: ircuit A*itching net*or+ resources %e2g2 band*idth' divided into ?slices@
slices allocated to calls resource slice idle i! not used b" o*ning call %no sharing'
dividing lin+ band*idth into ?slices@ !reuenc" division time division
Introduction
ircuit A*itching: FEM and .EM E3ample7 6DM
' users fre4uenc5 time
!DM
fre4uenc5 time
Introduction
;et*or+ ore: 4ac+et A*itching each end-end data stream divided into $ac+ets $ac+ets !rom di!!erent users share net*or+ resources each $ac+et uses !ull lin+ band*idth resources used as needed and*idth division into ?slices@ Eedicated allocation Resource reservation
resource contention: aggregate resource demand can e7ceed available ca$acit" congestion: $ac+ets ueue *ait !or lin+ use store and !or*ard: $ac+ets move one ho$ at a time
;ode receives com$lete $ac+et be!ore !or*arding
Introduction
4ac+et A*itching: Atatistical Multi$le7ing 10 Mb/s thernet
=
statistical multi$le&ing
125 Mb/s ueue o! $ac+ets *aiting !or out$ut lin+
E
Aeuence o! = K $ac+ets does not have !i7ed $attern shared on demand statistical multi$le&ing 2 .EM: each host gets same slot in revolving .EM !rame2 Introduction
4ac+et s*itching versus circuit s*itching 4ac+et s*itching allo*s more users to use net*or+>
1 Mb/s lin+ each user:
100 8b/s *hen ?active@ active 10, o! time
; users
circuit-s*itching:
10 users
1 Mb$s lin+
$ac+et s*itching:
*ith 65 users $robabilit" N 10 active less than 2000 Introduction
4ac+et s*itching versus circuit s*itching Is $ac+et s*itching a ?slam dun+ *innerC@
(reat !or burst" data resource sharing sim$ler no call setu$ 7cessive congestion: $ac+et dela" and loss $rotocols needed !or reliable data trans!er congestion control ;o guaranteed $er!ormance P: )o* to $rovide circuit-li+e behaviorC band*idth guarantees needed !or audio/video a$$s Introduction
4ac+et-s*itching: datagram and virtual circuit net*or+s
(oal: move $ac+ets through routers !rom source to destination datagram net*or+:
destination address in $ac+et determines ne7t ho$ 4ath ma" change !rom one datagram to another Routers !orget about a datagram a!ter !or*arding to ne7t ho$
virtual circuit net*or+:
each $ac+et carries tag %virtual circuit IE' tag determines ne7t ho$ !i7ed $ath determined at call setu$ time remains the same thru call routers maintain $er-call state Introduction
;et*or+ .a7onom" .elecommunication net*or+s
4ac+et-s*itched net*or+s
ircuit-s*itched net*or+s
FEM
.EM
EM
;et*or+s *ith Qs
Eatagram ;et*or+s
Introduction
