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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. DSL10. Cable Modems11. LANS & MANS
Homework Last Week
Engineering GroupNetwork Planning and Design
Operations GroupNOC
Network Operations
I & M GroupNetwork Installation
and Maintenance
Network
Fault TT
Installation
Performance & Traffic Data
New Technology
ManagementDecision
Users
TT Restoration
Configuration Data
InternetCentralManager
Centralized Architecture
CentralDatabase
Homework Centralized Arch
Engineering GroupNetwork Planning and Design
Operations GroupNOC
Network Operations
I & M GroupNetwork Installation
and Maintenance
Network
Fault TT
Installation
Performance & Traffic DataLatency, Capacity & Avail-ability summaries
New Technology
ManagementDecision
Users
TT Restoration
Configuration Data
Accounting Management Data Security Management Data
Internet
NetworkManagementServer
Hierarchial Architecture
DBMS
NetworkManagementClient
NetworkManagementClient
NetworkManagementClient
Internet
ReplicationComm
Distributed Architecture
DBMSDBMSDBMS
DBMS
Physical/Data Link/Network/ Layers?
Response time of a transaction:RT = (i) N(i) S(i)
N(i) = Number of times service i is needed S(i) = Time needed for completion of service i
Server i utilization:U(i) = A(i) S(i)
A(i) = Arrival rate of requests for service i
Queue length at server i:
Q(i) = U
Ui
i
()
()1
Homework-P 1 of 3
A company has a corporate network which consists of fiveEthernet LANs connected to a mainframe through 56 KBpslines. Each LAN has about 20 workstations which generate one message per second. Each message is 1000 bytes (8bits per byte). Most workstations interact with each other on their LANs with only 20% of the messages being sent to themainframe. The messages sent to the mainframe access a corporate database which services 50 I/O per second. Howmuch of a congestion problem exists on the LAN, the WAN and the mainframe database.
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.
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.
Decibells & Logarithms
Converting watts to dB (or milliwatts to dBm): 10 log10 1000 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 = 103.5 = 3162.3 watts
Note: There’s a point between the 3 & 5.
Decibells & Logarithms
dBW Watts -3 .5 0 1 3 2 6 4 9 8 10 10 20 100 30 1000 40 10000
Physical Layer
Nyquist1. 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?
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?
Noise
T = SNT = System Noise Temperature
No = Noise Density = kT, where k is Boltzmann’s Constant (-228.6 dBw)
N = Noise Power = kTB, where B is bandwidth.
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.
Transmission Lines
. Transmission Line Impedance:
Zo = LC = Induc ce
Capaci ce
tan
tan =E
Ii
i = IncidentVoltage
IncidentCurrent
Transmission Lines
Impedance mismatches (impedance of load does not equalimpedance of the line) result in a standing wave ratio (how muchenergy is reflected back to the transmitter).
Transmission Line Standing Wave Ratio:
SWR = E
Emax
min = I
Imax
min = Z
Zmax
min
Transmission Line Connector Distortion
Normal Power Level: - 120 dBmProblem Power Level +/- 10 dB
Linear Non-Linear
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)
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 channelB - 64 Kbps digital PCM channel for voice or dataC - 8 or 16 Kbps digital channelD - 16 Kbps digital channel for out of band signallingE - 64 Kbps channel for internal ISDN signallingH - 384, 1536, or 1920 Kbps digital channel
Basic Rate = 2B + 1D (the nominal 128 frequently used in homes)Primary Rate = 23 B + 1D
Integrated Services Digital Network (ISDN) Standard
TE 1 ISDN Terminal
TE 1 ISDN Telephone
Non-ISDN Terminal
TA
S
S
S
R
ISDN PBX
NT1 ISDNExchange
T U
R, S, T & U are CCITT defined reference PointsTA is terminal adapter
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
Digital Subscriber Line (DSL) Standard Services
Type DSL SpeedAsymmetric DSL 1.5 to 8 Mbps to user
16 to 640 Kbps to networkHigh-data-rate DSL 1.544 Mbps to and from userSingle-line DSL 768 Kbps full duplex on a pairRate-adaptive DSL 1.5 to 8 Mbps to user
16 to 640 Kbps to network(can adjust speeds)
Consumer DSL 1 Mbps to user16 to 128 Kbps to network(does not include splitter)
ISDN DSL Basic ISDN rateVery-high-data-rate DSL 13 to 52 Mbps to user
1.5 to 6 Mbps to network
DSL Rates (using 24 gauge wire)
Connection Max Data Rate Distance LimitADSL 1.5-8 Mbps downstream 12-18 K feet
Up to 1.544 Mbps upstream
HDSL T1 - 1.544 Mbps (4 wire) 12,000 feet
IDSL 144 Kbps (symmetric) 18,000 feet (36 w rptr)
SDSL T1 - 1.544 Mbps (2 wire) 11,000 feet
VDSL 13-52 Mbps downstream 1-4.5 K feet 1.5-2.3 Mbps upstream Up to 34 Mbps Symmetric
R-ADSL 1.5-8 Mbps downstream 12-18 K feet Up to 1.544 Mbps upstream
DSL Network Configuration
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
0-4 KHz 25KHz 200KHz 1.1MHz
To Network To User
Cable Modem DSL Access
Cable Modem Access
0
10
20
30
40
50
Mill
ion
Lin
es
1998 1999 2000 2001 2002 2003 2004
DSL Market
DSL Roll-Out
TeleChoice
1999 2000 2001 2002 2003 2004 2005
50
40
30
20
10
0
Mil
lion
s of
Lin
es
Simplified xDSL Architecture
PSTN
Fast Packet
Internet
Local Loop
Splitter
Voice Switch
DSLAM
ISPRouter
The transparent network …
Ideally, the network is transparenttransparent — the end user simply wants to get information to or from a remote location
Applicatione-business
Content ProviderEnterprise Host
End UserBusiness orResidential
…isn’t really so transparent
But today’s reality is that the transparent network is a complex value chaincomplex value chain of individual networks
NSPNSPNSPNSPNSPNSPNSPNSP
LECLECLECLEC
NAPNAPNAPNAP
BackboneBackboneBackboneBackbone
BackboneBackboneBackboneBackbone
BackboneBackboneBackboneBackbone
BackboneBackboneBackboneBackboneTransportTransportTransportTransport TransportTransportTransportTransport
E-businessE-businessE-businessE-business
LECLECLECLEC
ConsumerResidentialBusiness
Applicatione-business
Content Provider
Applicatione-business
Content Provider
PSINetPSINetPSINetPSINet
AOLAOLAOLAOL
XYZXYZXYZXYZ
The Value Chain
ConsumerResidentialBusiness
Applicatione-business
Content Provider
SBCSBCSBCSBC
SprintSprintSprintSprint
GTEIGTEIGTEIGTEI
New EdgeNew EdgeNew EdgeNew Edge
UUNetUUNetUUNetUUNetWilliamsWilliamsWilliamsWilliams QwestQwestQwestQwest
eBayeBayeBayeBay
The players in this value chain have many names and may be linked in different configurations
GTEGTEGTEGTE
Applicatione-business
Content Provider
PSINetPSINetPSINetPSINet
AOLAOLAOLAOL
XYZXYZXYZXYZ
The Value ChainConsumerResidentialBusiness
Applicatione-business
Content Provider
Applicatione-business
Content Provider
SBCSBCSBCSBC
SprintSprintSprintSprint
GTEIGTEIGTEIGTEI
New EdgeNew EdgeNew EdgeNew Edge
UUNetUUNetUUNetUUNetWilliamsWilliamsWilliamsWilliams QwestQwestQwestQwest
eBayeBayeBayeBay
These value chains are held together by very thin threadsthin threads of linkages between legacy operations support systems (OSSs) and a lot of manual processesmanual processes
GTEGTEGTEGTE
Serving CO
Who Fixes The Network?
Hub office
DSLAM
ADM
DWDM
Internet
DWDM
ATMNetwork
VerizonILEC Verizon ILEC
Worldcom
VerizonAdvanced
Data Verizon Advanced Data
VerizonAdvanced
Data
AOL
AOL
ADM
ADM
ADM
LEC NAP LEC NAP
BackboneNAPNSPApplicatione-business
Content Provider
Providers Ask Two Pivotal Questions
Is the network service up Is the network service up
and running properly?and running properly?
If it’s not, where’s the If it’s not, where’s the problemproblem
and how do we fix itand how do we fix it??
LEC
The Answer...
Providers must tightly link their operations with their trading trading partnerspartners through integratedintegrated service assurance service assurance
NAP
NSP
Service Assurance Market
Test & Measurement
Test & Measurement
OperationsSupportSystems
OperationsSupportSystems
Service AssuranceService AssuranceService AssuranceService Assurance
• $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
* RHK Estimates
Service Assurance Activities
Monitor SLAsMonitor SLAs
ReportReport
Allocate ResourcesAllocate Resources
Determine SLA ViolationsDetermine SLA Violations
TestTest
Isolate Root CauseIsolate Root Cause
Detect Alarms/EventsDetect Alarms/Events
Detect Performance/Traffic ProblemsDetect Performance/Traffic Problems
Decide RepairDecide Repair
Network “Communication” is Key
Need to provide service information within and between networks
LEC
NAP
NSP
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
Outsourcing Net Mgt
PerformanceIT Net Mgt Service
iNOC Imonitor
HCL Technologies
iNOC Services
NetProactive Services Remote
Infrastructure Management
IT Bdgt 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-
Outsourcing Net Mgt
Company Name Service Name Svc Yrs Sales Per Yr EmployeesHCL Technologies iNOC Services 3 $336M 8748America
iNOC IMonitor 3 $4.8M 30
NetProactive Remote 4 $500K 28Services Infrastructure
Management
PerformanceIT PerformanceIT 6 $10M 100 Network MgtService