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

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

Centralized Architecture Manager Internet Central Database

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

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

Distributed Architecture DBMS Internet Replication Comm DBMS DBMS DBMS

Physical/Data Link/Network/ Layers?

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.

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 Wire & Fiber

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?

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 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).

Transmission Line Connector Distortion Normal Power Level: - 120 dBm Problem 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 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

Integrated Services Digital Network (ISDN) Standard U 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

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 Speed Asymmetric DSL 1.5 to 8 Mbps to user 16 to 640 Kbps to network High-data-rate DSL 1.544 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

DSL Rates (using 24 gauge wire) Connection Max Data Rate Distance Limit ADSL 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

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 To Network To User 0-4 KHz 25KHz 200KHz 1.1MHz

Cable Modem DSL Access

Cable Modem Access

DSL Roll-Out Millions of Lines TeleChoice 50 40 30 20 10 Millions of Lines TeleChoice 1999 2000 2001 2002 2003 2004 2005

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

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

…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

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

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

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

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?

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

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

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

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

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 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 -  

Outsourcing Net Mgt Company Name Service Name Svc Yrs Sales Per Yr Employees HCL Technologies iNOC Services 3 $336M 8748 America iNOC IMonitor 3 $4.8M 30 NetProactive Remote 4 $500K 28 Services Infrastructure Management PerformanceIT PerformanceIT 6 $10M 100 Network Mgt Service