ECEN5553 Telecom Systems
Dr. George Scheets Week #7
Read
[14a] "IPv6: A Catalyst and Evasion Tool for Botnets"
[14b] "Segmenting for security"
[15a] "All Quiet on the Internet Front"
[15b] "DARPA: Nobody's Safe on the Internet"
[17a] "Rapidly Recovering from the Catastrophic
Loss of a Major Telecommunications Office"
[17b] "How IT Leaders Can Best Plan For
Disaster"
Outline 7 October 2015, Lecture 22 (Live)
No later than 14 October (Remote DL)

due 7 October (local)
14 October (remote)
29 %

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

Frame Relay Format
3 20 20 up to 8,146 3
FR
Header
IP TCP Data + Padding
FR
Trailer
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.

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)

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

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

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

Worldwide Frame Relay Revenues
Sources:
Data Communications
Network World
Business Communications
Network Strategy Partners
Wavesmith Networks
$17B in 2006

U.S. Frame Relay Service
 Sprint
 Shut Down
 Verizon
 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: http://www.verizonenterprise.com/external/service_guide/reg/cp_frame_relay.htm
& http://techcaliber.com/blog/?p=1100

Internet Service Provider Backbone
A
C
ISP Router
B
ISP ‘Cloud’
Full Duplex Trunks use StatMux & Packet Switching

THEN : ISP using Frame Relay
VC's for Trunk Connections
A
ISP
Router
C
FR
VC
FR Switch
Frame Relay ‘Cloud’
B

NOW : ISP using Leased Lines for Trunk Connections
A
ISP
Router
C Circuit
Cross Connect
Circuit Switched
TDM
B

NOW : ISP using Light Waves for Trunk Connections
A
ISP
Router
C Circuit
Optical Switch
B

Frame Relay Backbone
A
C
FR Switch
B

THEN : FR using Leased Lines for Trunk Connections
FR Switch
A
C Circuit
Cross Connect
B

NOW : Frame Relay using
MPLS VC's for Trunk
Connections
A ISP Router
C
FR Switch
MPLS
VC
B
ISP ‘Cloud’

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

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

Commodity Internet Performance
Number of
dropped packets
Average Delay for
delivered packets
0% 100%
Trunk Offered Load

Frame Relay Performance
Number of
dropped packets*
Average Delay for
delivered packets
0% 100%
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.

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

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

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

ATM Cell Format
5 48
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

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

MULTIPLEXING
StatMux TDM FDM
Circuit
Packet
Cell
X X
ATM uses Cell Switching

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!

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

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

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

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.

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

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

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

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

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

ATM Hookups
 Customer Viewpoint:
WAN see Frame Relay, MPLS
 Carrier Viewpoint:
 See Frame Relay, MPLS
 2.5 Gbps were fastest trunks available
 Traffic Policing
 Somewhat similar to Frame Relay
 VBR & ABR Cells marked as compliant or not
 Switch Congested? Drop UBR, then non-compliant VBR & ABR

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

OSU Campus Network ('95 - '01)
OneNet
802.3
LAN
802.3
LAN
802.3
LAN
ATM Switch
ATM-Ethernet
Switch
LAN
LAN
LAN

OSU Campus Network (> 2001)
OneNet
802.3
LAN
Ethernet
Switch
802.3
LAN
802.3
LAN
Routers
LAN
LAN
LAN

OSU Campus Network (2007)
OneNet
802.3
LAN
Ethernet
Switch
802.3
LAN
802.3
LAN
Routers
LAN
LAN
LAN

OSU Campus Network (2015)
OneNet
802.3
LAN
Ethernet
Switch
802.3
LAN
802.3
LAN
Routers
LAN
LAN
LAN

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

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

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

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

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

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

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
 Being replaced by Internet & Carrier Ethernet.

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

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

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

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

Carrier Ethernet
802.3
LAN
LAN
802.3
LAN
Carrier
Network
LAN
802.3
LAN
 Feed Ethernet Frames to Carrier
LAN
LAN

Carrier Ethernet
802.3
LAN
LAN
802.3
LAN
Carrier
Network
LAN
802.3
LAN
 Feed Ethernet Frames to Carrier
LAN
LAN

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

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

802.3 Ethernet Packet Format
Bytes: 6 6 2
MAC
Destination
Address
MAC
Source
Address
20 20 6-1460 4
IP TCP Data + Padding CRC

PBB Carrier Ethernet Packet (Simplified)
Bytes: 6 6 2 6 6 2
Carrier MAC
Destination
Address
Carrier
MAC Source
Address
Carrier
VLAN
Tag
MAC
Destination
Address
MAC
Source
Address
20 20 6-1460 4
IP TCP Data + Padding CRC
 Carrier Edge switches prepend customer
Ethernet frames with provider frames.
 # Carrier MAC addresses = # Carrier edge switches

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

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

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

Carrier Ethernet Status
 2009 U.S. Market Revenue $1.5 Billion
 2010 $3.2 Billion
 2013 $5.5 Billion
 2016 $11.1 Billion (projected)
 2018 $13 Billion (projected)
 Backhaul from wireless cell sites a major growth area source: www.accedian.com
www.telecompetitor.com

MAN/WAN Connectivity Options
 Carrier Ethernet
 Carrier Switches are Ethernet frame aware
 PBB I/O decisions based on Layer 2 Ethernet Address
 IP/MPLS I/O decisions based on MPLS tag
 Virtual Circuits can be used
 StatMux
 BW required based more so on average input rates
 Pricing function of peak rate, CIR, priority, and maybe distance
 On the way in.
 21st century version of Frame Relay

Carrying Capacity
Line Speed
Active Idle
Application Traffic Overhead
Carrying Capacity = Traffic(bps) /Line Speed(bps)
Goodput = Application Traffic Carried (bps)

Queue Length
 100,000,000 bps output trunk
 100,000,001 bps average input
 Average Input rate > Output rate
 Queue Length builds up
(without bound, in theory)

Queue Length
 100,000,000 bps output trunk
 99,999,999 bps average input
 Average Input rate < Output rate
 Queue Length not infinite...
...but very large

Queue Length @ 100% Load
Output capacity = 7 units
Input = 7 units on average (two dice rolled)
 t1: input = 4, output = 4, queue = 0
 t2: input = 5, output = 5, queue = 0
 t3: input = 4, output = 4, queue = 0
 t4: input = 7, output = 7, queue = 0
 t5: input = 11, output = 7, queue = 4
 t6: input = 10, output = 7, queue = 7

 t7: input = 6, output = 7, queue = 6 t8: input = 5, output = 7, queue = 4
 t9: input = 8, output = 7, queue = 5
 t10: input = 11, output = 7, queue = 9
This queue will tend to get very large over time.

Queue Length @100% Load
Will tend to increase w/o Bound.
 3
4000 queue 2000
0
0
0
0
2

10
5
3
2000 queue 1000
0
0
0
0
4

10
5
2

10
5
6

10
5
4

10
5
8

10
5
6

10
5
1

10
6
 6
8

10
5
1

10
6
 6

"Die Roll" Queue Lengths
 3
4000
101% Load
100% Load queue 2000
99% Load, Average Queue = 44.46
0
0
0
0
2

10
5
4

10
5
6

10
5
8

10
5
1

10
6
 6

Real vs Artificial Trace
10 Seconds
Real Traffic 10 Seconds
Artificial M/M/1 Traffic
Source: Willinger et al, "Self-Similarity through High Variability",
IEEE/ACM Transactions on Networking, February 1997.

Real vs Artificial Trace
100 Seconds
Real Traffic 100 Seconds
Artificial M/M/1 Traffic

Real vs Artificial Trace
16.7 Minutes
Real Traffic 16.7 Minutes
Artificial M/M/1 Traffic

Real vs Artificial Trace
167 Minutes
Real Traffic 167 Minutes
Artificial M/M/1 Traffic

Real vs Artificial Trace
27.78 Hours
Real Traffic 27.78 Hours
Artificial M/M/1 Traffic

Self Similar Behavior

Infinite Length Queue
(Classical StatMux Theory)
Probability of
dropped packets
Average Delay for
delivered packets
0% 100%
Trunk Offered Load

Finite Length Queue
(Real World StatMux)
Probability of
dropped packets
Average Delay for
delivered packets
0% 100%
Trunk Offered Load
You could fully load StatMux trunk lines... but your customers would be screaming at you due to lousy service.

Switched Network
Carrying Capacity
 Line Speed : Traffic injection speed
 Efficiency : Ability to use that Line Speed

Throughput : bps of traffic (+ overhead) moved

= Efficiency * Line Speed

Carrying Capacity : Ability to usefully use Line Speed

Accounts for packet overhead

Accounts for inability to fully load trunk lines with
StatMux'd traffic & still have a usable connection

Goodput: bps of application traffic moved
 = Carrying Capacity * Line Speed

Carrying Capacity
Line Speed
Active
Traffic
Idle
Overhead
Carrying Capacity = (%Trunk Load) * (%Traffic)
= Traffic(bps) /Line Speed(bps)