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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)
Outlines
Received
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
Carrier Frame
Relay Network
OKC
(Hub)
Router
Local Carriers dedicate bandwidth to our use.
Carrier provides random Packet Switched
StatMux connectivity via VC’s.
NYC
Ex) Frame Relay with Internet
Detroit
ISP
Carrier Frame
Relay Network
OKC
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
$17B in 2006
Declining.
Sources:
Data Communications
Network World
Business Communications
Network Strategy Partners
Wavesmith Networks
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
C
ISP
Router
FR
VC
FR Switch
Frame Relay ‘Cloud’
B
NOW: ISP using Leased Lines
for Trunk Connections
A
C
ISP
Router
Circuit
Cross Connect
Circuit Switched
TDM
B
NOW: ISP using Light Waves
for Trunk Connections
A
C
ISP
Router
Circuit
Optical Switch
B
Frame Relay Backbone
A
C
FR Switch
B
THEN: FR using Leased Lines
for Trunk Connections
A
C
FR Switch
Circuit
Cross Connect
B
NOW: Frame Relay using
MPLS VC's for Trunk
Connections
ISP Router
A
FR Switch
C
ISP ‘Cloud’
MPLS
VC
B
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%
Trunk Offered Load
100%
Frame Relay Performance
Number of
dropped packets*
Average Delay for
delivered packets
0%
Trunk Offered Load
100%
*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
Detroit
ISP
OKC
Carrier Frame Company X
Relay Network
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
ATM
Header
48
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.
SWITCHING
MULTIPLEXING
StatMux
TDM
X
X
FDM
Circuit
Packet
Cell
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 $$$$
 You need sheer SPEED
 This
was the case on carrier networks
ATM on the carrier backbone...
 Your
network is moving mixed traffic
 yes
in 90's (voice & data)
 not so true in early 00's (data)
 becoming true in late 00's (data & video)
 becoming not so true in early 10's (video)
 You
need sheer SPEED
 yes
 You
in 90's, not true now
get a good deal $$$$
 competitive
in 90's, R&D has stopped
ATM Backbone
Cell
Aware
ATM Switch
StatMux/TDM, Cell Switched Network, Full Duplex Trunks.
ATM at the desktop...
 Your
 No.
 You
Moving mostly data.
need sheer SPEED
 No.
 You
network is moving mixed traffic
Ethernet is fast enough.
get a good deal $$$$
 No.
Ethernet is cheaper.
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
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
Hi

CBR

VBR-RT

VBR-nRT
ABR
UBR
Low


Delivery
Rate
Priority
Constant
Hi
Low
Variable
Delivery Ability to
Delay
Burst
Low
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
 Treat
technique is way to go
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% Fixed Rate
Offered
Traffic Mix
100% Bursty
0% Fixed Rate
OSU Campus Network ('95 - '01)
OneNet
802.3
LAN
802.3
LAN
802.3
LAN
LAN
ATM Switch
ATM-Ethernet
Switch
LAN
LAN
OSU Campus Network (> 2001)
802.3
LAN
Ethernet
Switch
OneNet
802.3
LAN
802.3
LAN
LAN
Routers
LAN
LAN
OSU Campus Network (2007)
802.3
LAN
Ethernet
Switch
OneNet
802.3
LAN
802.3
LAN
LAN
Routers
LAN
LAN
OSU Campus Network (2015)
802.3
LAN
Ethernet
Switch
OneNet
802.3
LAN
802.3
LAN
LAN
Routers
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
 I/O
are packet aware
decisions use Layer 3 Internet Protocol address
 Datagrams
 Each
 …are
 BW

packet individually routed
assigned trunk BW via StatMux
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
 I/O
are frame aware
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
 May
 Being
function of peak rate & CIR
be distance independent
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
802.3
LAN
LAN
Carrier
Ethernet
LAN
802.3
LAN
Routers

Carrier Switches would only
see 9 Router MAC addresses
LAN
LAN
Ethernet MAN/WAN
802.3
LAN
802.3
LAN
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
802.3
LAN
LAN
Carrier
Network
LAN
802.3
LAN

Feed Ethernet Frames to Carrier
LAN
LAN
Carrier Ethernet
802.3
LAN
802.3
LAN
LAN
Carrier
Network
LAN
802.3
LAN

Feed Ethernet Frames to Carrier
LAN
LAN
Carrier Ethernet
802.3
LAN
LAN
ISP
802.3
LAN
LAN
802.3
LAN

Use Internet MPLS VC's
Ethernet on Access Lines
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
MAC
Destination
Address
6
2
MAC
Source
Address
20
20
6-1460
4
IP
TCP
Data + Padding
CRC
PBB Carrier Ethernet Packet (Simplified)
Bytes: 6
6
2
Carrier MAC
Carrier
Carrier
Destination MAC Source VLAN
Address
Address
Tag

6
6
2
MAC
MAC
Destination Source
Address 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
LAN
LAN
Ethernet
Switch
E1
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.
34000
3.40910
queue5  j2000
0
0
0
0
2 10
4 10
5
5
6 10
8 10
5
j 5
1 10
6
110
5
6
32000
1.98310
queue5  j1000
0
0
0
0
2 10
5
4 10
5
6 10
5
j 5
8 10
5
1 10
6
110
6
"Die Roll" Queue Lengths
101% Load
34000
3.40910
100% Load
queue5  j2000
99% Load, Average Queue = 44.46
0
0
0
0
2 10
5
4 10
5
6 10
5
j 5
8 10
5
1 10
6
110
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%
Trunk Offered Load
100%
Finite Length Queue
(Real World StatMux)
Probability of
dropped packets
Average Delay for
delivered packets
0%
Trunk Offered Load
100%
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)