n read 2.3, 2.5 n problems 1.6, 2.6, 2.8 n quiz #1, lecture 12, 4 february u open book & notes u...
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Read 2.3, 2.5 Problems 1.6, 2.6, 2.8 Quiz #1, Lecture 12, 4 February
Open book & notes Calculators are allowed No Smart Phones
ECEN4533 Data CommunicationsLecture #4 14 January 2013Dr. George Scheets
ECEN4533 Data CommunicationsLecture #4 14 January 2013Dr. George Scheets
Read 3.1 Ignore Probability Equations until Review
Scan Design Problem #1 Problems 2.7, 3.1, 3.2 Quiz #1
Lecture 12, 4 February (Live) < 11 February (Async Distance Learning)
Extra Credit (up to 20 points) Find errors in text or solutions.
ECEN4533 Data CommunicationsLecture #5 16 January 2013Dr. George Scheets
ECEN4533 Data CommunicationsLecture #5 16 January 2013Dr. George Scheets
Read 3.2 Problems 3.9, 3.10 Quiz #1
Lecture 12, 4 February (Live) < 11 February (Async Distance Learning)
Design #1 due 1 February (Live) 8 February (Async DL) Late = -1 per working day
No Class next Monday
ECEN4533 Data CommunicationsLecture #6 18 January 2013Dr. George Scheets
ECEN4533 Data CommunicationsLecture #6 18 January 2013Dr. George Scheets
PSTN Call SequencingPSTN Call Sequencing User Dials Number Routing Protocol Determines path thru network Affected Core Switches notified
Time Slots reserved to support callTime Slot = 1 byte every 1/8000 th second for 64 Kbps
Switches continuously move bytes arriving on input time slot(s) to appropriate output line and time slot(s)
User “sees” dedicated nailed up bandwidth Source TCP opens logical connection with Sink
Packets transferred, logical connection closed Switch resources released when user hangs up
ISDN connection using PSTNISDN connection using PSTN
Long Distance & Local Carriers dedicate 64 Kbps to our use (Circuit Switching).
node c
PSTNetwork
Nailed up Circuit
PC
node a
PC
Carrier PSTN NetworkCarrier PSTN Network
1
3PSTN Switch
TrunksAccess LinePC
PC
Switches move bytes from input to output.Bytes get moved at line speeds.Trunk capacity is dedicated.
Moving Traffic with PacketsMoving Traffic with Packets Layer 7 Application Word Perfect
2,920B file to move Layer 6 Presentation Windows API Layer 5 Session TCP Layer 4 Transport TCP
Maximum TCP Segment Size assumed to be 1460B(Parameter in Windows Registry)
Chops file into 2 x 1460B packets, adds 20B TCP Header to each Layer 3 Network IP
Adds 20B IP Header to each packet Layer 2 Data Link Undefined
Adds 10B Layer 2 Header to each frame Layer 1 Physical Undefined
Wired PhoneWired Phone
CO CO
AnalogVoice
Digital Bit Stream(1's & 0's) @ 64 Kbps
Generally analog from phone to CO One twisted Pair
At Central Office Filtered (BW about 3.5 KHz) Analog Voltage is Sampled 8,000 times/second Rounded off to 1 of 256 possible voltages Converted to a fixed length 8 bit code word
AnalogVoice
Ex) InternetEx) Internet
Local connection dedicates 64 Kbps to our use. ISP provides connectivity on a random, as needed, basis.
Location a
Location b
ISP Network
PC
PC
Internet Service Provider BackboneInternet Service Provider Backbone
1
3Router
TrunksAccess Line
Routers move packets from input to output.Packets get full trunk line speed.Trunk capacity shared randomly, as needed.
PC
PC 64 Kbps
45 Mbps
Internet Call SequencingInternet Call Sequencing Assuming an "Always On" 64 Kbps connection...
Similar to DSL or Cable Modem (but slower) ... Logical connections opened between end devices
TCP (Layer 5). Routers do not monitor!! Router I/O decisions based on Layer 3 IP address
Best match found in Look-Up Table Router Tables updated independently of traffic
‘Hello’ packets exchanged every 10 seconds with adjacent routers
More detailed routing information (who is connected to whom) exchanged intermittently
Router determines best output port, generally for blocks of hierarchical IP addresses
Moving Traffic with PacketsMoving Traffic with Packets Layer 7 Application Word Perfect
2,920B file to move Layer 6 Presentation Windows API Layer 5 Session TCP Layer 4 Transport TCP
Maximum TCP Segment Size assumed to be 1460B(Parameter in Windows Registry)
Chops file into 2 x 1460B packets, adds 20B TCP Header to each Layer 3 Network IP
Adds 20B IP Header to each packet Layer 2 Data Link Undefined
Adds 10B Layer 2 Header to each frame Layer 1 Physical Undefined
Ex) ATMEx) ATM
Local Carriers dedicate 64 Kbps to our use. IXC provides random connectivity on an as-needed basis.
Location a
locationc
Carrier ATM Network
VC, a to/from c
PC
PC
ATM BackboneATM Backbone
ATM Switch
TrunksAccess Line
Switches move cells from input to output.Cells get full trunk line speed.Trunk capacity shared randomly, as needed.
ATM Call SequencingATM Call Sequencing End device requests logical connection Routing Protocol determines path thru network Affected Core Switches notified
Look-Up table updated to show proper output port where specific input cells should be placed
Switch resources (bandwidth, buffer space) reserved as appropriate
User appears to see dedicated nailed up bandwidth Path is known as a Virtual Circuit
TCP opens logical connection with far site Packets transferred, TCP logical connection closed
Switch resources released when user finished
Moving Traffic with ATM CellsMoving Traffic with ATM Cells Layer 7 Application Word Perfect
2,920B file to move Layer 6 Presentation Windows API Layer 5 Session TCP Layer 4 Transport TCP
Maximum Segment Size assumed to be large, say 64 KB 2,920B file not segmented. Adds 20B TCP Header
Layer 3 Network IP Adds 20B IP Header
Layer 2 Data Link ATM Adds 8B padding & 8B SAR Trailer. Chops into 2976/48 = 62 cells (53 byte cell size). Adds 5B ATM
header to each cell. Layer 1 Physical Undefined
Internet Packet FormatInternet Packet Format
Traffic
?? 20 20 0-1460 ??
IP TCPLayer 2 Header
Layer 2 Trailer?
Probably originated or passed through an Ethernet.
Internet Protocal v4Internet Protocal v4
TOS
TTL
Source Address
Destination Address
4 Bytes
802.3LAN
LAN
OSU Campus Network (> 2001)OSU Campus Network (> 2001)
Routers
1 GbpsEthernet
OneNetEthernetSwitch
802.3LAN
802.3LAN
LAN
LAN
OSU 2009 Internet ConnectivityOSU 2009 Internet Connectivity
Example TracertExample Tracert
Handy site for figuring out who owns IP addresses:www.arin.net(has links to databases covering other regions)
Traceroute to WWW.CISCO.COMTraceroute to WWW.CISCO.COM
4 Internal OSU-Stillwater routers 3 OneNet routers (all in Tulsa?) 5 Cogent Communications routers
te4-3.ccr01.tul01.atlas.cogentco.com te2-2.mpd01.dfw01.atlas.cogentco.com
1 Akamai Technologies (Hosting Service) (3:30 pm, 12Sept11, rtt = 8 msec, 12 routers)
Traceroute to WWW.TULSA.COMTraceroute to WWW.TULSA.COM 4 Internal OSU-Stillwater routers 3 OneNet routers (Tulsa?) 4 Cogent Communications routers
te4-4.1052.ccr01.tul01.atlas.cogentco.com te0-2-0-7.ccr22.dfw01.atlas.cogentco.com
1 Global Crossing router GigabitEthernet2-3.ar2.HOU1.gblx.net
4 Routers in Houston te2-5.dsr01.hstntx2.networklayer.com
The Planet server (hosting service) (3:55 pm, 12Sept11, rtt = 14 msec, 16 routers)
# Routers not necessarily f(distance)# Routers not necessarily f(distance)
Launched 14 September 2011, 2 miles from OSU campus 1 Scheets' home router 5 SBC (now AT&T) & AT&T routers
dist2-vlan50.okcyok.sbcglobal.net ggr6.dlstx.ip.att.net
3 Cogent Communications routers te3-2.ccr01.tul01.atlas.cogentco.com
3 ONENET routers Probably in Tulsa, maybe Oklahoma City
3 Oklahoma State routers (11:19 am, 14Sept11, rtt = 71 msec, 15 routers)
Fall 2007 Weird Route Seen by StudentTulsa to OSU Stillwater
Fall 2007 Weird Route Seen by StudentTulsa to OSU Stillwater
Tracert launched from Tulsa, hitAtlantaWashington, D.C.IllinoisKansas CityTulsaOklahoma CityOSU Stillwater
Internet Protocal v6Internet Protocal v64 Bytes
Flow Label
Destination Address
Source Address
Hop Limit
RedNeckNet ISPRedNeckNet ISP
Salina
Joplin
Stillwater
Lubbock
Dallas
Little Rock
RedNeckNet VoIPRedNeckNet VoIP
Full MeshN(N-1)/2 Connections
RedNeckNet VoIPRedNeckNet VoIP
Bus5 Connections
RedNeckNet VoIPRedNeckNet VoIP
Star5 Connections
GradingGrading Real World:
1 team gets full credit Everyone else gets a zero
Partial credit Awarded on Quizzes & Tests NOT AWARDED ON DESIGN PROJECTS!
Real world designs don't get partial credit Either Work or They Don't
Double check your work!!! Use a spreadsheet
StatMuxStatMuxfrequency
tim
e
1
3
1
2
Different channels use all of the frequency some of the time,at random, as needed.
CDMCDMfrequency
tim
eDifferent channels use all of the bandwidth all of the time.
Channels use different codes. Other channels cause noise-like interference.
CDMA: 3D ViewCDMA: 3D View
code #1
code #2
code #3
frequency
time