1. ECEN5553 Telecom Systems Dr
ECEN5553 Telecom Systems Dr. George Scheets Week 6 Readings: Read [8] "IPv6: A Catalyst and Evasion Tool for Botnets" Read [9a] "DARPA: Nobody's Safe on the Internet" [9b] "Could You Fall for a Scam?" [9c & d] Two Network World articles Read [10] "The Real Story of Stuxnet" Exam #1: No later than 23 September (Remote DL) Outline: Lecture 22, 5 October (Live) No later than 12 October (Remote DL) Exam #2: 24 October (Live & Local DL) No Later than 31 October (Remote DL)

2. Outlines Received due 5 October (local) 12 October (remote)
14 %

3. Exam #1 Grading Lost points? No comments? → Insufficient info provided
Rule of Thumb: "X" point question needs > "X" facts
Lost points? Comments? Your score ≈ % correct
Not happy with your score? Did you…
Start studying at the last minute?
Read assigned articles?
Answer the question asked?
Use the space provided?
Leave the instructor with impression you could've said more
There is plenty of time to Recover
365 points remain to be claimed

4. Traditional Videoconferencing
384 Kbps fixed
rate output (video + audio)
Camera
Codec
Dedicated Bandwidth Network:
Circuit Switched TDM
times/sec
*State Owned Fiber *ISDN
Audio
Video
Codec

5. rate output (video + audio)
2002 Videoconferencing V2.0
384 Kbps fixed
rate output (video + audio)
Now > 784 Kbps
Packet Switched
StatMuxed
Prioritized
*State Owned Fiber
This is technique being
used in this class for
video to & from Tulsa &
Stillwater.
Camera
Codec
Audio
Video
Codec

6. Internet Video Streaming
The Internet
Quality of
Received Stream
depends on:
(1) Size of your
pipe.
(2) Internet
congestion.
(3) Server congestion.
Disk Drive PC

7. Internet Video Streaming
Disk Drive
Stillwater
Video Server
generates
packets.
Fairly steady generation if server not swamped.
Rate depends on pipe size.

8. Internet Video Streaming
Disk Drive
Video Server
Packets exit at an irregular rate.
Random delays.
Non-Dedicated Bandwidth (Packet Switched, Stat Muxing)

9. ISP Routes can be Roundabout
Launched 30 January 2007, 2 miles from OSU campus
1 Dr. Scheets' home router
6 SBC routers
adsl dsl.okcyok.sbcglobal.net
ex2-p11-0.eqchil.sbcglobal.net
7 Level3 routers
Te-3-2.Chicago1.Level3.net
kscymo2wcx010-pos9-0-oc48.wcg.net
tulsok6wcx2-pos11-0-oc48.wcg.net
5 ONENET routers
at least 1 in Oklahoma City
3 Oklahoma State routers
Using DiffServe, End-to-End
performance on
this 22 router path ...

10. ISP Routes can be Roundabout
Launched 5 September 2008, 2 miles from OSU campus
1 Scheets' home router
4 SBC routers
adsl dsl.okcyok.sbcglobal.net
bb1-g1-0-2.rcfril.sbcglobal.net
1 Equinix router
1 Transitrail router
onenet.chcgil01.transitrail.net
3 ONENET routers
at least 1 in Oklahoma City
4 Oklahoma State routers
rtt = 55 msec
...may be worse
than End-to-End
performance on
this 14 router path when not using DiffServ.

11. Internet Service Provider Network
LAN PC
Trunks
Leased Line
Router
LAN
Corporate sites using Internet as WAN.
Can pay ISP extra $$ →
Traffic between sites gets preferential treatment. PC

12. Interactive VOICE & VIDEO over the commodity INTERNET (Best Effort, No Priorities)
Is not ready for Prime Time
Delay & Quality problems difficult to solve under the current system...
...although throwing Bandwidth at the problem will alleviate
Has a place for the user whose main concern is $$$$ or convenience

13. Internet Service Provider Network
LAN PC
Trunks
Leased Line
Router
LAN
Routers operate at Layers 1-3.
PC’s operate at Layers 1-7.
Routers do not monitor opening of TCP
Logical Connections. RSVP would change this. PC

14. Multi-Protocol Label Switching
Enables Virtual Circuits
End-to-End Paths nailed down
Traffic Engineering Easier
Resource Reservation Easier
Seeing fairly widespread ISP deployment

15. Internet QoS
Most every ISP is installing or testing one or more of following...
DiffServ
MPLS
Resource Reservation capability
Pricing structure to reflect different QoS
... but they are not yet widely deployed.
As a result, currently the Commodity Internet remains mostly
Best Effort, FIFO Routing

16. Thinking of moving large amounts of high quality, time sensitive traffic over the Commodity Internet?
Check back in 2-3 years when...
Priorities Enabled (IPv6 and/or DiffServ)
Resources Guaranteed (Resource Reservation Protocol (RSVP) or equivalent is deployed)
Flat rate pricing is gone

17. The Internet Is... A superb information source A good marketing tool
Sometimes difficult to separate wheat from chaff
IEEE Communications or Proceedings
Peer Reviewed
IEEE Spectrum
Reviewed by editor
Jane Doe's Web site
Reviewed by Jane Doe
A good marketing tool

18. The Internet Is... a Security Nightmare
Any-to-Any connectivity is both strength and weakness
Tracert yields Router IP Addresses
Could Telnet or HTTP to many. Password?
Espionage
Read “The Cuckoo’s Egg” by Cliff Stoll
Former #1 on New York Times Best Seller
Recommended by Dr. Scheets’ Mom

19. The Internet Is... a Security Nightmare
Bad things have been out there for years
Viruses, Worms, Trojans, Denial of Service, etc.
November 2, 1988 Internet Worm
Network shut down for 2-3 days
Took advantage of
Unix buffer overflow problems
Poor password choices
Stuxnet Worm
State sponsored?
Seemed to target Iran's nuclear bomb program

20. The Internet Is... a Security Nightmare
TCOM5223 Information Assurance Management
TCOM5233 Applied Information Systems Security
TCOM5243 Information Technology Forensics
“Remember, when you connect with another computer, you're connecting to every computer that computer has connected to.”
Dennis Miller, Saturday Night Live

21. Pros of Using the Internet
Any-to-Any Connectivity
It’s Inexpensive (save $$$$)
Tons of valuable information available
Excellent marketing/sales tool

22. Cons of Using the Commodity Internet
Any-to-Any Connectivity puts all attached machines at risk
Slightly higher risk of Theft of Traffic
Tons of Worthless Information Available
No QoS guarantees or Guaranteed Bandwidth May have trouble rapidly moving large files May have trouble reliably moving time sensitive traffic
WARNING: SECURITY HAZARD!

23. 802.3 Ethernet Packet Format
Bytes:
MAC
Destination
Address
MAC
Source
Address
Data +
Padding
IPv6
TCP
CRC

24. Connectionless vs. Connection Oriented
Connectionless * Packet delivery may be out of order * Packet delivery NOT guaranteed * Packets may be mangled * End User’s responsibility to fix any problems
Connection Oriented * Packet delivery in order * Packet delivery usually guaranteed

25. IP is Connectionless
up to 1,460 IP
TCP
Data + Padding
I/O decisions based on IP address & look-up table.
Tables updated independent of traffic.

26. Wide Area Connectivity Options
Leased Line (a.k.a. Private Line) Network
Switches are byte aware
Circuit is assigned trunk BW via TDM
BW required is based on peak input rates
Route through system determined in advance.
Pricing function of distance & peak rate
Most expensive connectivity option
Highest quality connectivity option

27. Leased Line Usage U.S. Revenues still around $34 Billion in 2009
Drop in Corporate
Increase in wireless backhaul
$30 Billion in 2014
Shift is to Internet Services
source: Insight Research

28. Switched Ethernet LAN's
Edge
Router PC
Leased Lines
Switched
Hub PC
100, 1,000 Mbps PC
10/100 Mbps PC
Switched
Hub PC
Switched
Hub PC PC

29. Ex) Corporate Leased Line Connectivity
Detroit
Leased Line
320 Kbps
Carrier Leased
Line Network
OKC
128 Kbps
256 Kbps
NYC
Telecom Carriers
dedicate 320, 128, and 256 Kbps links for
our sole use via Circuit Switching.
Router

30. Ex) Corporate Leased Line Connectivity
Detroit
384 Kbps
Carrier Leased
Line Network
OKC
NYC
320 Kbps
From/To
OKC
DET
NYC -
144 76 88 28
112 34
Router

31. How will company connect to Internet?
Configuration
Every site connect locally?
All sites connect thru, say, OKC?
Type of connection
Leased Line
DSL?
Cable Modem?
Other?

32. Ex) Internet thru OKC Detroit ISP Leased Line Carrier Leased
Line Network
OKC
NYC
Traffic matrix should expand to include
ISP. Faster line speeds likely required.
Router

33. Ex) Internet thru OKC Detroit ISP 640 Kbps Carrier Leased OKC
NYC
Carrier Leased
Line Network
Router
ISP
640 Kbps
From\To
OKC
DET
NYC
ISP -
144 76 60 88 28 50
112 34 40
110
100 90
How big should the pipe
to the ISP be?
300 Kbps is outbound from ISP
> 640 Kbps circuit needed.

34. Ex) Internet thru OKC Detroit ISP 576 Kbps 640 Kbps Carrier Leased OKC
Line Network
OKC
448 Kbps
NYC
From\To
OKC
DET
NYC
ISP -
144 76 60 88 28 50
112 34 40
110
100 90
Router
Need to bump size of other
2 pipes.
194/186 NYC → 448 Kbps
278/166 DET → 576 Kbps

35. WAN Design (Link Reduction)
Start with Traffic Matrix
Examine Full Mesh
Consider eliminating lightly used links
Reroute affected traffic
Compare costs at each iteration

36. WAN Connectivity Options
Internet
Routers are packet aware
Datagrams are assigned trunk BW via StatMux
BW required based more so on average input rates
Each packet individually routed
MPLS enabled networks can use Virtual Circuits
Pricing a function of connection size
& Possibly QoS if MPLS and/or DiffServe used

37. Ex) Commodity Internet Corporate Connectivity
Detroit
ISP Network
OKC
NYC
Router
Local Carriers dedicate bandwidth
to our use. ISP provides random Packet Switched
StatMux connectivity via datagrams.

38. Ex) Commodity Internet Corporate & Internet Connectivity
Detroit
576 Kbps
ISP Network
OKC
640 Kbps
448 Kbps
NYC
Router
From/To
OKC
DET
NYC
ISP -
144 76 60 88 28 50
112 34 40
110
100 90
310/280 OKC → 640 Kbps
194/186 NYC → 448 Kbps
278/166 DET → 576 Kbps

39. Ex) IP with QoS Corporate & Commodity Internet Connectivity
Detroit
576 Kbps
MPLS VC, OKC - Detroit
Internet Service
Provider Network
OKC
768 Kbps
448 Kbps
MPLS VC, NYC - OKC
NYC
From/To
OKC
DET
NYC
ISP -
144 76 60 88 28 50
112 34 40
110
100 90
Detroit & NYC: No change.
OKC: Port Speed must be bumped to
relay Detroit ↔ NYC corporate traffic.

40. Leased Line at OKC ↔ ISP Inbound Det→OKC 88 Det→NYC 28 NYC→OKC 112
Outbound
OKC→Det 144
OKC→NYC 76
OKC→ISP 60
Det →NYC 28
NYC → Det 34
Inbound
Det→OKC 88
Det→NYC 28
NYC→OKC 112
NYC→Det 34
ISP → OKC 110
From/To
OKC
DET
NYC
ISP -
144 76 60 88 28 50
112 34 40
110
100 90
Total Outbound = 342 Kbps
Total Inbound = 372 Kbps
Leased Line Size > 744 Kbps
Leased Line = 768 Kbps minimum.

41. Carrier Leased Line Network
Trunks
Byte
Aware
Leased Line
Cross-Connect
Carrier reserves BW from pool for our use.
Ex) For a 384 Kbps connection, Cross-Connects assign 6 byte sized TDM time slots 8000 times/second = 6*8*8000 = 384 Kbps.

42. Internet Service Provider Backbone
Trunks
Packet
Aware
Leased Line
Router
ISP Routers assign BW for our use on Random,
as needed basis via StatMux & Packet Switching.

43. Internet Service Provider Network
LAN PC
Trunks
Leased Line
Router
LAN
Corporate customers might attach
via Edge Router & Leased Lines. WS

44. Internet (Inside the Cloud)
Infinite Buffers
"OK" so long as Average Offered Input Rate < Output Line Speed
Internet
Router
100 Mbps Trunk
?? Mbps Connections
P(Access Line is Active) = 10%
How many access lines can this switch support?
100 Mbps/154 Kbps = 649 (theoretically)

45. Internet (Inside the Cloud)
Negligible Buffers
OK so long as Instantaneous Offered Input Rate < Output Line Speed
Internet
Router
100 Mbps Trunk
?? Mbps Connections
P(Access Line is Active) = 10%
How many access lines can this switch support?
With 404 users, 99.99% sure Input Rate < Line Speed

46. Bounds on Packet Switch Carrying Capacity 100 Mbps Trunk, 1
Bounds on Packet Switch Carrying Capacity Mbps Trunk, 1.54 Mbps Inputs with 154 Kbps average loads
Lower Upper 90% % % %
Instantaneous
Input < Line
Speed
Where switch
could operate
Where switch
probably operates

47. Queue Size: Correlated vs Uncorrelated Identical Loads (traffic carried/line speed)
mean(queue)=135.6
The negligible
buffer analysis
does not
account for long
term bursts.
Correlated: Long Term Bursts
mean(queue)=32.80
Real world switches
have finite buffers.
Required size to
prevent dropped
packets depends on
length of burst.
Uncorrelated: Random Input

48. Carrier Leased Line Network
LAN PC
Trunks
Byte
Aware
Leased Line
Cross-Connect
LAN
Corporate customers might attach
via Edge Router & Leased Lines. WS

49. Leased Lines (TDM) 2 1 Leased Line Cross-Connect 1 23 2 1
Leased
Line
Cross-Connect 3 2 1 3 2 1
TDM time slots are moved from input to output
TDM switch is not "packet aware"
Time slots are allocated whether or not there is any traffic on them

50. Circuit Switched connections waste bandwidth for bursty traffic.
NYC
to OKC
1.54 Mbps Line Speed
146 Kbps Average
time
Idle Time >> Active Time

51. Leased Lines (Inside the Cloud)
Example
Leased
Line
Cross-Connect
100 Mbps Trunk
?? Mbps Connections
P(Access Line is Active) = 10%
How many access lines can this switch support?
64 (100% input bps < trunk bps)

52. Given 100 Mbps of Bandwidth...
Mbps Circuit Switched TDM Customers with Kbps average load & % availability
Mbps Packet Switched StatMux Customers with Kbps average load & % availability
64 x 154 Kbps =
9.856 Mbps
404 x 154 Kbps =
62.22 Mbps
More Bursty Data Traffic can be moved
with the Packet Switched StatMux network.

53. Switched Network Carrying Capacities
Capacity
Packet Switch
StatMux
Circuit Switch
TDM
0% Bursty % Bursty
100% Fixed Rate % Fixed Rate
Offered Load

54. Network Cost... Can be spread over 64 Leased Line customers
Can be spread over 404 Internet customers
The Internet Is a Packet Switched StatMux network Largely hauling bursty data traffic Effectively hauling bursty data traffic Inexpensive (compared to a Leased Line)

55. Internet Performance Trunk Offered Load
This type of plot valid for all
real world full duplex
statistically multiplexed switches:
Ethernet, Internet, Frame Relay
Number of
dropped packets
Average Delay for
delivered packets
0% %
Trunk Offered Load

56. Internet Performance Effect of priorities
Average Delay for
low priority packets
Average Delay for all
delivered packets
high priority packets
0% %
Trunk Offered Load

57. Internet Performance Effect of priorities
Number of
low priority drops
Number of dropped packets
high priority drops
0% %
Trunk Offered Load

58. Internet Backbone Engineering
Option A) Deploy ‘best effort’ Routers Rapidly Deploy Trunk Bandwidth Keep Trunks Lightly Loaded
Delays will be small
Dropped packets will be few
Quality fine for all traffic

59. Backbone Engineering: Option A
Number of
dropped packets
Average Delay for
delivered packets
0% %
Keep Trunks Lightly Loaded

60. Internet Backbone Engineering
Option B) Deploy more complex QoS enabled Routers Deploy fewer, more heavily loaded Trunks Give preferential treatment to interactive Voice/Video
Option A seems to be preferred today

61. Backbone Engineering: Option B High Priority delay at 50% Load = Delay for all traffic at 20% Load
Average Delay for
low priority packets
Average Delay for all
delivered packets
high priority packets
0% %
Heavier Trunk Load

62. Frame Relay ANSI Standard covering OSI Layer 2 Accessed by Routers
Derived from X.25 Protocol Dumps almost all error checking
Requires fiber on the long haul
Uses Virtual Circuits (VC’s) VC differs from Datagram Path thru network set up in advance Requires Carrier intervention

63. Frame Relay 1st Commercial Deployment 1990
WilTel → Worldcom→ bankrupt → Verizon
Cheaper alternative to Leased Lines
Faster alternative to X.25
Internet a small network in 1990
Academia
Military
Some commercial traffic
See CUCKOO'S EGG to get a flavor

64. Frame Relay 7 Application 6 Presentation 5 Session TCP 4 Transport TCP
3 Network IP
2 Data Link Frame Relay
1 Physical

65. Frame Relay
Committed Information Rate (CIR) Is a Quality of Service Guarantee "Guaranteed" minimum Bandwidth Should be set > average traffic during appropriate peak period
Port Connection Speed a.k.a. Port Speed or Burst Speed Bandwidth you can burst to provided network capacity exists. Set = Bit Rate of Access Line

66. Frame Relay Packet Format
Data + Padding
up to 8, IP
TCP FR
Header
Trailer
Header includes 10 bit Data Link Connection
Identifier (DLCI) - Locally Unique (FR ports) Trailer includes 2 byte CRC Sequence that only checks Header
I/O decisions based on FR address & look-up table.