1. ECEN5553 Telecom Systems Dr
ECEN5553 Telecom Systems Dr. George Scheets Week #7 Read [11a] "More Signs Point to Cyberattack" thru [11d] "How to Hijack a Journal" [12a] "Browse at Your Own Risk" [12b] "The Data Brokers: Selling Your Personal Info" [13a] "Bitcoin Busts" [13b] "Hacking Your Phone" [13c] "How Strangers can Hack the Phone in your Pocket" 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)
41 %

3. 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.

4. 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.

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

6. 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)

7. 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

8. 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

9. 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

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

11. 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

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

13. 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)

14. 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.

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

16. 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)

17. 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

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

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

20. 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

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

22. 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

23. 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

24. 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

25. 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

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

27. 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

28. 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.

29. Frame Relay Backbone Trunks Leased Line FR Switch Frame Relay ‘Cloud’
Aware
Leased Line
FR Switch
Frame Relay ‘Cloud’
Full Duplex Trunks use StatMux & Packet Switching

30. Frame Relay Format I/O Decision based on DLCI & Look-up Table.
up to 8, FR
Header FR
Trailer IP
TCP
Data + Padding
I/O Decision based on DLCI & Look-up Table.
Header & Trailer usually swapped out.
Look Up Table Format:
DLCI ww received on port x?
Output on port y with DLCI zz.

31. Frame Relay Customer Cost
Port Speed (a.k.a. Port Connection Speed)
Line speed of attachment to carrier network
For each Virtual Circuit
Distance (not all carriers charged for this)
CIR (bit rate carrier seeks to guarantee)
Full Duplex (same CIR in each direction)
Simplex (different CIR's in each direction)

32. Ex) Frame Relay Corporate Connectivity
Detroit
VC, OKC - Detroit
Carrier Frame
Relay Network
OKC
(Hub)
VC, NYC - OKC
NYC
Router
Local Carriers dedicate bandwidth to our use.
Carrier provides random Packet Switched
StatMux connectivity via VC’s.

33. Ex) Frame Relay with Internet
Detroit
ISP
VC, OKC - Detroit
Carrier Frame
Relay Network
OKC
VC, NYC - OKC
NYC
Router
Local Carriers dedicate bandwidth to our use.
Carrier provides random Packet Switched
StatMux connectivity via VC’s.

34. Frame Relay
End-to-End Delay Internet ≈ Frame Relay > equivalent sized Leased Line Network
Cost Tendency Internet < Frame Relay < equivalent sized Leased Line Network

35. Worldwide Frame Relay Revenues
Sources:
Data Communications
Network World Business Communications
Network Strategy Partners
Wavesmith Networks
$17B in 2006
Declining.
$6.25B ‘98
$8.00B ‘99
$10.5B ‘00
$12.7B ‘01
$0.08B ‘93
$15.4B ‘02
$21B ‘04
$16.7B ‘03
$0.23B ‘94
$0.65B ‘95
$1.28B ‘96
$3.87B ‘97

36. U.S. Frame Relay Service Sprint Verizon AT&T Shut Down
As of 2 January 2009 no new FR customers
As of 1 February 2013 Existing customers cannot make changes Existing customers cannot renew service
AT&T
Still supporting current customers
Turning off system 30 April 2016
Source:
&

37. Internet Service Provider Backbone
Trunks
Leased Line B C
ISP Router
ISP ‘Cloud’
Full Duplex Trunks use StatMux & Packet Switching

38. THEN: ISP using Frame Relay VC's for Trunk Connections
Router
FR Trunks
FR VC C
Leased Line
ISP Trunk
FR Switch B
Frame Relay ‘Cloud’

39. NOW: ISP using Leased Lines for Trunk Connections
Router
Trunks C
Circuit
Leased Line
ISP Trunk
Cross Connect
Circuit Switched
TDM B

40. NOW: ISP using Light Waves for Trunk Connections
Router
Trunks C
Circuit
Fiber Optics
ISP Trunk
Optical Switch B

41. Frame Relay Backbone A
Trunks
Leased Line B C
FR Switch

42. THEN: FR using Leased Lines for Trunk Connections
FR Switch A
Trunks C
Circuit
Leased Line
ISP Trunk
Cross Connect B

43. Recently: Frame Relay using MPLS VC's for Trunk Connections
ISP Router
FR Switch
ISP Trunks
MPLS VC C
Leased Line
FR Trunk B
ISP ‘Cloud’

44. Frame Relay as a Corporate Backbone...
More Secure than the Commodity Internet
Can move a lot of data rapidly (if you pay for proper CIR and burst rate)
Is marginal for moving time sensitive traffic
Generally Cheaper for data than Leased Lines Fewer access lines required Backbone has higher Carrying Capacity

45. Frame Relay QoS DE bit used by FR switches to police network
Traffic > CIR enters switch in a 1 second interval? Marked DE
If you are behaving and other users exceed their CIR’s and FR switch becomes congested then other users’ traffic gets dumped 1st your traffic is protected.
Helps shelter you from behavior of others

46. Commodity Internet Performance
Number of
dropped packets
Average Delay for
delivered packets
0% %
Trunk Offered Load

47. Frame Relay Performance
Number of
dropped packets*
Average Delay for
delivered packets
0% %
Trunk Offered Load
*Dashed: If we are transmitting at > CIR Solid: Provided we are transmitting at < CIR
Some protection from behavior of others.
Internet priorities provide somewhat similar effect.

48. Ex) Frame Relay More Secure than Internet
Detroit
ISP
PVC, OKC - Detroit
Carrier Frame
Relay Network
Company X
OKC
PVC, NYC - OKC
NYC
Company X
Cannot access us thru FR net.
Router
Can get at us thru Internet.

49. ATM 7 Application 6 Presentation 5 Session TCP 4 Transport TCP
3 Network IP
2 Data Link ATM
1 Physical

50. ATM Widely deployed in mid-90's
Touted as the Network of the Future
Chops all traffic into fixed size 53B cells
5B overhead
48B traffic
Compromise
Data folks wanted larger size
Voice folks wanted smaller size

51. Layer 3-7 information AAL Overhead
ATM Cell Format
ATM
Header
Layer 3-7 information AAL Overhead
Carrier ATM Core Header includes:
28 Bits of Addressing Information
3 Bit Payload Type (Priorities)
1 Bit Cell Loss Priority (similar to FR DE bit) 8 Bits Header Error Control

52. StatMux ATM Version 1 empty (53B slots) 2 1 3 empty time 1
Different channels use all of
the frequency some of the time,
at random, as needed.
frequency 1
empty (53B slots) 2
Can
also
use
TDM. 1 3
empty
time 1

53. ATM uses Cell Switching
MULTIPLEXING
StatMux
TDM
FDM
Circuit
SWITCHING
Packet
Cell X X
ATM uses Cell Switching

54. ATM Used Virtual Circuits No Error Checking of payload
Needs fiber on long haul
Designed to move all types of traffic
Reduces size of physical plant
Eases maintenance problems
Unless system crashes!

55. Three reasons to consider ATM in the 1990's...
Your network is moving mixed traffic
You get a good deal $$$$
You need sheer SPEED
This was the case on carrier networks

56. ATM on the carrier backbone...
Your network is moving mixed traffic
yes in 90's (voice & data)
not so true in early 00's (data)
becoming true in late 00's (data & video)
becoming not so true in early 10's (video)
You need sheer SPEED
yes in 90's, not true now
You get a good deal $$$$
competitive in 90's, R&D has stopped

57. StatMux/TDM, Cell Switched Network, Full Duplex Trunks.
ATM Backbone
Trunks
Cell
Aware
Leased Line
ATM Switch
StatMux/TDM, Cell Switched Network, Full Duplex Trunks.

58. ATM at the desktop... Your network is moving mixed traffic
No. Moving mostly data.
You need sheer SPEED
No. Ethernet is fast enough.
You get a good deal $$$$
No. Ethernet is cheaper.

59. Virtual Circuit Set Up MPLS, Frame Relay, ATM, Carrier Ethernet
Client requests connectivity from Carrier
Provides endpoints
Specifies Service Level Agreement desired
Carrier arranges for connectivity to POP
Routing algorithm determines path through network
Appropriate Switches Notified
Look Up Tables Updated

60. ATM VC Classes of Service
Constant Bit Rate (CBR)
Leased Line emulation
Fixed Rate voice & video
Variable Bit Rate- Real Time (VBR-RT)
Interactive, variable rate, voice & video
Variable Bit Rate- non Real Time (VBR-nRT)
Non-Interactive, variable rate, voice & video
Available Bit Rate (ABR)
Data traffic needing guaranteed bandwidth
Unspecified Bit Rate (UBR)
Data traffic flying standby

61. ATM VC Classes of Service
Delivery
Rate
Constant
Variable
Delivery
Delay
Low
High
Ability to
Burst
None
A Lot
CBR
VBR-RT
VBR-nRT
ABR
UBR
Cost Hi
Low
Priority Hi
Low

62. The Internet Viewpoint in the 90's
ATM's
Ability to nail down paths (VC's)
Ability to prioritize traffic (5 CoS)
Ability to reserve switch resources
Trunk BW & Switch Buffer Space
Too Complex!!
Internet
Simpler technique is way to go
Treat all traffic the same

63. Today: Internet starting to look a lot like ATM
Ability to nail down paths (MPLS)
Ability to prioritize traffic (DiffServ)
Not used on Commodity Internet
Used on carrier VoIP networks
Used for some intra-corporate traffic
Ability to reserve switch resources
Not used on Internet
Scalable version of RSVP needed

64. Switched Network Carrying Capacities
Capacity
Packet Switch
StatMux
Cell Switch
StatMux
Circuit Switch
TDM
0% Bursty % Bursty
100% Fixed Rate % Fixed Rate
Offered
Traffic Mix

65. OSU Campus Network ('95 - '01) OneNet OC-3, then OC-12 Trunks
802.3
LAN
LAN
OC-3, then
OC-12
Trunks
802.3
LAN
802.3
LAN
ATM Switch
LAN
LAN
ATM-Ethernet
Switch

66. OSU Campus Network (> 2001)
OneNet
Ethernet
Switch
802.3
LAN
LAN
1 Gbps
Ethernet
802.3
LAN
802.3
LAN
Routers
LAN
LAN

67. OSU Campus Network (2007) OneNet Ethernet Switch 1 &10 Gbps Ethernet
802.3
LAN
LAN
1 &10 Gbps
Ethernet
802.3
LAN
802.3
LAN
Routers
LAN
LAN

68. OSU Campus Network (2015) OneNet Ethernet Switch 10 & 20 Gbps Ethernet
802.3
LAN
LAN
10 & 20 Gbps
Ethernet
802.3
LAN
802.3
LAN
Routers
LAN
LAN

69. ATM Bombed at the desktop (LAN) Succeeded on the WAN
Most Carrier Networks now Decommissioned
Still in use on some ADSL access networks
RIP

70. Carrier Leased Line Backbone
Trunks
Byte
Aware
Leased Line
Cross-Connect
TDM, Circuit Switched Network, Full Duplex Trunks.
Access lines mostly attach to routers, FR
switches, TD Muxes, & cross connects of other carriers.

71. WAN Connectivity Options
Leased Line Network
Switches are byte aware
I/O decisions on a byte-by-byte basis
Could be considered a "Layer 1.5" device
Circuit…
Dedicated resources
Routing thru system determined in advance
… is assigned trunk BW via TDM
BW required is based on peak input rates
Pricing a function of distance & peak rate

72. Internet Service Provider Backbone
Trunks
Packet
Aware
Leased Line
Router
StatMux, Packet Switched Network, Full Duplex Trunks.
Access lines mostly attach to corporate routers
& routers of other ISP’s.

73. WAN Connectivity Options
Internet
Switches are packet aware
I/O decisions use Layer 3 Internet Protocol address
Datagrams …
Each packet individually routed
…are assigned trunk BW via StatMux
BW required based more so on average input rates
Commodity Internet
Pricing a function of connection size
SLA Enabled Internet (Corporate Use)
Pricing a function of connection size, MPLS VC (size, DiffServ priority), & maybe distance

74. Frame Relay Backbone Trunks Leased Line FR Switch FR Frame Aware
StatMux, Packet Switched Network, Full Duplex Trunks.
Access lines mostly attach to routers.

75. WAN Connectivity Options
Frame Relay Network
Switches are frame aware
I/O decisions use Layer 2 Frame Relay address
Virtual Circuit…
Routing through system determined in advance
… is assigned trunk BW via StatMux
BW required based more so on average input rates
Pricing function of peak rate & CIR
May be distance independent
Hard to find now.

76. ATM Backbone Trunks Leased Line ATM Switch Cell Aware
StatMux/TDM, Cell Switched Network, Full Duplex Trunks.
Replaced by the Internet & Carrier Ethernet.

77. LAN Backbone Trunks Access Line Ethernet Switch Ethernet Frame Aware
StatMux, Packet Switched Network, Full/Half Duplex Trunks.
Access lines mostly attach to PC's, servers, & printers.
Trunks attach to Ethernet Switches, & routers.

78. Ethernet MAN/WAN
LAN
802.3
LAN
Carrier
Ethernet
LAN
802.3
LAN
802.3
LAN
LAN
Routers
LAN
Carrier Switches would only see 9 Router MAC addresses

79. Ethernet MAN/WAN
LAN
802.3
LAN
Carrier
Ethernet
LAN
802.3
LAN
802.3
LAN
LAN
LAN
Carrier switches would see all PC MAC addresses. Potentially too many!

80. Carrier Ethernet Feed Ethernet Frames to Carrier Carrier Network 802.3
LAN
802.3
LAN
Carrier
Network
LAN
802.3
LAN
802.3
LAN
LAN
LAN
Feed Ethernet Frames to Carrier

81. Carrier Ethernet Use Internet MPLS VC's Ethernet on Access Lines ISP
LAN
802.3
LAN
ISP
LAN
802.3
LAN
802.3
LAN
LAN
LAN
Use Internet MPLS VC's Ethernet on Access Lines

82. Carrier Ethernet Feed Ethernet Frames to Carrier Carrier Network 802.3
LAN
802.3
LAN
Carrier
Network
LAN
802.3
LAN
802.3
LAN
LAN
LAN
Feed Ethernet Frames to Carrier

83. Carrier Ethernet
LAN
Carrier
Ethernet
Switches
802.3
LAN
LAN
802.3
LAN
802.3
LAN
LAN
LAN
Use Provider Backbone Bridging Ethernet on access lines.

84. 802.3 Ethernet Packet Format
Bytes:
MAC
Destination
Address
MAC
Source
Address IP
TCP
Data + Padding
CRC

85. PBB Carrier Ethernet Packet (Simplified)
Bytes:
Carrier MAC
Destination
Address
Carrier MAC Source
Address
Carrier VLAN
Tag
MAC
Destination
Address
MAC
Source
Address IP
TCP
Data + Padding
CRC
Carrier Edge switches prepend customer Ethernet frames with provider frames.
# Carrier MAC addresses = # Carrier edge switches

86. PBB Carrier Ethernet WAN/MAN
LAN
LAN
Ethernet
Switch
LAN E1
LAN
LAN
LAN
LAN
LAN
LAN
Every Carrier Switch is an Edge Switch here.
Edge Switches learn MAC addresses of serviced end devices. E1 must learn Yellow & Orange MAC & VLAN addresses.

87. PBB Carrier Ethernet Switching (Simplified)
Unicast packet arrives with unknown customer destination MAC address
Source Carrier Edge Switch Examines Customer VLAN tag & source MAC address Maps to Carrier VLAN tag Carrier Edge Switch MAC address Appends Carrier Header
Destination Carrier Edge Switch Examines & Removes Carrier Header Forwards based on Customer MAC address

88. PBB Carrier Ethernet Switching (Simplified)
Broadcast packet arrives
Source Carrier Edge Switch Examines Customer VLAN tag & source MAC address Maps to Carrier VLAN tag Carrier Edge Switch MAC address(es) Appends Carrier Header Selectively Floods
Destination Carrier Edge Switch(es) Examines & Removes Carrier Header Forwards based on Customer VLAN