1. Agenda 1. QUIZ 2. HOMEWORK LAST CLASS 3. HOMEWORK NEXT CLASS
4. dBs, NYQUIST & SHANNON
5. NOISE
6. TRANSISSION LINES
7. FIBER
8. ISDN
9. DSL
10. Cable Modems
11. LANS & MANS

2. Homework Last Week Network Engineering Group Network Planning
Users
Management
Decision
Configuration Data
New Technology
Performance & Traffic Data
TT Restoration
Engineering Group
Network Planning
and Design
Operations Group
NOC
Network Operations
I & M Group
Network Installation
and Maintenance
Fault TT
Installation

3. Centralized Architecture
Manager
Internet
Central
Database

4. Homework Centralized Arch
Network
Users
Management
Decision
Configuration Data
New Technology
Performance & Traffic Data
Latency, Capacity & Avail-
ability summaries
TT Restoration
Engineering Group
Network Planning
and Design
Operations Group
NOC
Network Operations
I & M Group
Network Installation
and Maintenance
Fault TT
Installation
Accounting Management Data
Security Management Data

5. Hierarchial Architecture
Network
Management
Server
Network
Management
Client
Internet
DBMS
Network
Management
Client
Network
Management
Client

6. Distributed Architecture
DBMS
Internet
Replication
Comm
DBMS
DBMS
DBMS

7. Physical/Data Link/Network/ Layers?

8. Homework-P 1 of 3
A company has a corporate network which consists of five
Ethernet LANs connected to a mainframe through 56 KBps
lines. Each LAN has about 20 workstations which generate
one message per second. Each message is 1000 bytes (8
bits per byte). Most workstations interact with each other on
their LANs with only 20% of the messages being sent to the
mainframe. The messages sent to the mainframe access a
corporate database which services 50 I/O per second. How
much of a congestion problem exists on the LAN, the WAN
and the mainframe database.

9. Homework P 2 of 3
An Advise To The Lovelorn database operates on a T-1 line.
The average input is 1000 bytes of questions. The average
output has 1Million bytes of answers. Database processing
time averages 3 seconds. What is the total response time if
you assume 8 bits per byte.

10. Homework P 3 of 3 Ping ns1.bangla.net. How many packets were lost?
What was the response time?
Now do a trace rout and see how many hops it takes to get
to get to ns1.bangla.net.

11. Decibells & Logarithms
Converting watts to dB (or milliwatts to dBm):
10 log watts = 30 dBw
Converting dB to watts (or dBm to milliwatts):
30 dBw = log-1, or log-1 (3) or 10 raised
to the 3rd power = 103 = 1000 watts
35 dBw = = watts
Note: There’s a point between the 3 & 5.

12. Decibells & Logarithms
dBW Watts

13. Physical Layer
Wire & Fiber

14. Nyquist
1. Nyquist: The maximum practical data rate (samples) per channel.
Max R = 2 H log2 V
Logarithmic function to the base 2: For each # V, log V = the exponent to which 2 must be raised to produce V. Then if V = 16, the log2 of V = 4. If V = 2, the log2 of V = 1.
Then what is the maximum practical data rate for BPSK signal on a line with a bandwidth of 3000 Hz?
What is the maximum practical data rate for a QPSK
signal on a line with a bandwidth of 3000 Hz?

15. Shannon Shannon: The maximum theoretical data rate per channel.
Max R = CBW x log2 (1 + S/N)
[CBW = H in Nyquist Theorem]
Then what is the maximum practical data rate for signal with a 30 dB S/N on a line with a bandwidth of 3000 Hz?

16. Noise T = SNT = System Noise Temperature
No = Noise Density = kT, where k is Boltzmann’s Constant ( dBw)
N = Noise Power = kTB, where B is bandwidth.

17. Transmission Lines
We understand transmission lines by oversimplifying them:
a. Lump all resistances into a single large resistance.
b. Lump all inductances into a single large inductance.
c. Lump all capacitances into a single large capacitance.
d. Lump all conductance (leakage) into a single large conductance.
e. Assume perfectly uniform construction and perfect symmetry so it
looks exactly the same from both ends.
f. Lump all of the above into a simple impedance network and
assume stability.

18. Transmission Lines

19. Transmission Lines
Impedance mismatches (impedance of load does not equal
impedance of the line) result in a standing wave ratio (how much
energy is reflected back to the transmitter).

20. Transmission Line Connector Distortion
Normal Power Level: dBm
Problem Power Level +/- 10 dB
Linear
Non-Linear

21. Fiber Optics
Attenuation: Light loss due to both scattering and absorption.
Absorption: The amount of light loss due to its conversion to heat.
Scattering: The disappearance of light due to its leaving the core of
of a fiber.
Chromatic dispersion: The tendency of a fiber to cause slightly
differing wavelengths of emitted light to travel through
the fiber at different speeds.
(See Handout)

22. Integrated Services Digital Network (ISDN) Standard
1. A major TELCO attempt to integrate voice and non-voice services.
2. Integrated multiple channels interleaved with time division multiplexing.
A - 4 KHz analog telephone channel
B - 64 Kbps digital PCM channel for voice or data
C - 8 or 16 Kbps digital channel
D - 16 Kbps digital channel for out of band signalling
E - 64 Kbps channel for internal ISDN signalling
H - 384, 1536, or 1920 Kbps digital channel
Basic Rate = 2B + 1D (the nominal 128 frequently used in homes)
Primary Rate = 23 B + 1D

23. Integrated Services Digital Network (ISDN) StandardU
NT1
ISDN
Exchange S
TE 1 ISDN Terminal S
ISDN PBX
TE 1 ISDN Telephone R TA
Non-ISDN Terminal
R, S, T & U are CCITT defined reference Points
TA is terminal adapter

24. Digital Subscriber Line (DSL) Standard
Drivers:
ISDN didn’t capture significant market share for TELCOs
Higher speed applications require new technologies
Users want to stay connected longer
High cost of converting infrastructure
Telephone lines weren’t designed to provide simultaneous
digital and analog services
Competition from satellite (e.g., DirectTV/Direct PC) & cable
industry

25. Digital Subscriber Line (DSL) Standard Services
Type DSL Speed
Asymmetric DSL 1.5 to 8 Mbps to user
16 to 640 Kbps to network
High-data-rate DSL Mbps to and from user
Single-line DSL 768 Kbps full duplex on a pair
Rate-adaptive DSL 1.5 to 8 Mbps to user
(can adjust speeds)
Consumer DSL 1 Mbps to user
16 to 128 Kbps to network
(does not include splitter)
ISDN DSL Basic ISDN rate
Very-high-data-rate DSL 13 to 52 Mbps to user
1.5 to 6 Mbps to network

26. DSL Rates (using 24 gauge wire)
Connection Max Data Rate Distance Limit
ADSL Mbps downstream K feet
Up to Mbps upstream
HDSL T Mbps (4 wire) ,000 feet
IDSL Kbps (symmetric) ,000 feet (36 w rptr)
SDSL T Mbps (2 wire) 11,000 feet
VDSL Mbps downstream K feet
Mbps upstream
Up to 34 Mbps Symmetric
R-ADSL Mbps downstream K feet

27. DSL Network Configuration

28. Asymmetric DSL Characteristics
Uses frequency division multiplex occupying spectrum above voice
Principal modulation scheme is Discrete multitone (DMT), a
quadrature amplitude modulation coding technique developed by
Bell Labs (ANSI T1.413 standard)
Can be mapped into higher layer protocol mechanisms that can
include IP frames or ATM cells
Can interface to Simple Network Management Protocol (SNMP)
for operations, administration and management
To Network
To User
0-4 KHz 25KHz KHz MHz

29. Cable Modem DSL Access

30. Cable Modem Access

31. DSL Roll-Out Millions of Lines TeleChoice50 40 30 20 10
Millions of Lines
TeleChoice

32. Simplified xDSL Architecture
Voice Switch
PSTN
ISP
Router
Local Loop
Fast Packet
Splitter
This is a very basic view of how DSL works.
The customer’s phone line is connected to a splitter. Coming in, the splitter separates your line between voice and data. Going out, it combines the two out to your local loop and into your central office.
The circuit is split again, and the voice channel goes to a voice switch and out to the public telephone network.
The data channel is connected to a device called a DSLAM, which is a DSL access multiplexer. DSLAMs take traffic from multiple DSL lines and combines them and sends it to a fast packet network, typically an ATM network.
The data streams are switched to a gateway router and on to your internet service provider, who provides you with internet access.
DSLAM
Internet

33. The transparent network …
Application
e-business
Content Provider
Enterprise Host
End User
Business or
Residential
Ideally, the network is transparent — the end user simply wants to get information to or from a remote location

34. …isn’t really so transparent
Application
e-business
Content Provider
Consumer
Residential
Business
E-business
LEC
LEC
NSP
NAP
NSP
Backbone
Transport
Transport
Application
e-business
Content Provider
But today’s reality is that the transparent network is a complex value chain of individual networks

35. The Value Chain
Application
e-business
Content Provider
Consumer
Residential
Business
eBay
GTE
SBC
New Edge
PSINet
AOL
Sprint
Williams
UUNet
XYZ
Qwest
Application
e-business
Content Provider
GTEI
The players in this value chain have many names and may be linked in different configurations

36. The Value Chain
Consumer
Residential
Business
Application
e-business
Content Provider
eBay
GTE
SBC
New Edge
PSINet
AOL
Sprint
Williams
UUNet
XYZ
Qwest
Application
e-business
Content Provider
GTEI
These value chains are held together by very thin threads of linkages between legacy operations support systems (OSSs) and a lot of manual processes

37. Who Fixes The Network? Application e-business Content Provider NSP NAP
Backbone
AOL
Verizon
Advanced
Data
Worldcom
DWDM
DWDM
Internet
AOL
Verizon
ILEC
Verizon
Advanced
Data
Verizon ILEC
Verizon Advanced Data
Serving CO
Hub office
ADM
ADM
ATM
Network
DSLAM
ADM
ADM
LEC
NAP
LEC
NAP

38. Providers Ask Two Pivotal Questions
Is the network service up
and running properly?
If it’s not, where’s the problem
and how do we fix it?

39. The Answer...
NSP
LEC
NAP
Providers must tightly link their operations with their trading partners through integrated service assurance

40. Service Assurance Market
Operations
Support
Systems
$3.5B* in 2000 $8.4B* in 2004
Growing at 25%
Includes OSS software, services, and remote probes
Key players: Spirent Communications, Telcordia, Lucent, Acterna (TTC/WWG), Micromuse
Test & Measurement
Service Assurance
* RHK Estimates

41. Service Assurance Activities
Monitor SLAs
Report
Allocate Resources
Determine SLA Violations
Test
Isolate Root Cause
Detect Alarms/Events
Detect Performance/Traffic Problems
Decide Repair

42. Network “Communication” is Key
LEC
NSP
NAP
Need to provide service information within and between networks

43. Outsourcing Net Mgt
IT Spending averages 3% of revenue & revenue is down
No outsourcer will meet all the needs of your business or agency
The annual cost of 9 networking and 6 help desk staffers averages $1.08 million (including benefits)
Four vendors investigated that cost approximately $350,000 to $500,000
Worth while thoughts:
Double check special requests (what, who, when, where, how)
Lay-offs hurt you and the outsourcer
Willingness to accept fines or reimbursement is a big deal
Block & Level the SLA vs. the network

44. Outsourcing Net Mgt IT B dg t Reduction 30% 4 5 3 1 Svce-level Mgt 30%
PerformanceIT
iNOC
HCL
NetProactive
Net Mgt
Imonitor
Technologies
Services
Service
iNOC
Remote
Services
Infrastructure
Management
IT B dg
t Reduction
30% 4 5 3 1
Svce-level Mgt 30% 5
4.5 3 3
Other Costs 20% 5 4 4 3
Operations 10% 4 4 5 3
Reporting 10% 5 4 5 4
Total Score 100%
4.60
4.45
3.60
2.50
Grade A A - B - C -

45. Outsourcing Net Mgt
Company Name Service Name Svc Yrs Sales Per Yr Employees
HCL Technologies iNOC Services $336M
America
iNOC IMonitor $4.8M
NetProactive Remote $500K
Services Infrastructure
Management
PerformanceIT PerformanceIT $10M
Network Mgt
Service