NET 101 - Midterm

Page 1: Fiber Optic Basics

Fiber Optic Installation

  • Fiber is installed in HDPE pipes buried 1 meter deep.

  • HDPE pipes are protected with sand and brick lining.

  • Fiber roles typically extend up to 2 km.

  • Fiber cables are spliced using jointing techniques.

  • Faults in fiber, such as cuts, are identified using an OTDR (Optical Time Domain Reflectometer).

Transmission Impairments in Fiber-Optic Cables

Dispersion

  • Resulting in pulse broadening where light spreads as it travels.

  • Material Dispersion: This is affected by the type of dopants used in the core glass.

  • Modal Dispersion: Different modes of light propagate at different speeds.

Scattering

  • Caused by imperfections in the glass fiber during manufacturing, especially when heated.

Absorption

  • Occurs due to atomic resonance in the glass structure, which can absorb certain wavelengths of light.

Bending Losses

  • Results from improper installation of fiber cables.

Page 2: Joining Fibers

Fiber Joining Techniques

Splice

  • Permanently welds, glues, or fuses two ends of a fiber cable.

Connectors

  • Create non-permanent joints for easy disconnect.

Couplers

  • Split the fiber signal into multiple directions.

Fiber Types

  • Splicing single-mode fibers is more challenging compared to multimode fibers.

Construction of a Fiber-Optic Cable

  • A typical fiber-optic cable consists of:

    • One or more fibers

    • Coating

    • Buffer tube

    • Strength member

    • Outer jacket

  • Loose Buffer: Allows for fiber movement. Often used in outdoor installations.

  • Tight Buffer: Features a small diameter and smaller bend radius; suitable for indoor installations.

Page 3: Types of Fiber

Single Mode Fiber

  • Core diameter of 2 to 8 μm.

  • Designed to carry only a single light ray.

Multimode Fiber

  • Core diameter ranges from 50 to 200 μm.

  • Designed to carry multiple light rays at once.

  • Step-index vs Graded-index: Multimode is generally less expensive and easier to terminate, but has lower capacity and efficiency than single mode.

Fiber Construction

  • Light travels through the inner layer (core) and is confined by the outer layer (cladding).

  • Standard sizes exist; for example, a fiber denoted as 62.5/125 means a core diameter of 62.5 μm and a cladding diameter of 125 μm.

Page 4: Fiber-Optic Cable Transmission

Digital Signal Transmission

  • Fiber-optic cables transmit digital signals as light pulses.

  • Optical carriers are classified based on their transmission capacities.

  • Attenuation measured in dB/km ranges between 0.2 to 2.0 dB/km.

Fiber Patch Cords & Pigtails

  • Pigtails: Connectors on one side, usually spliced to terminate fibers.

  • Patch Cords: Connectors on both sides; used to connect switches to fiber cables.

Page 5: Fiber Optic Connectors

Functionality

  • Fiber optic connectors are used to terminate fibers and connect to other fibers or equipment.

Infrastructure Components

  • Components of a fiber optic cabling infrastructure include:

    • Fiber cables

    • Fiber pigtails

    • Fiber connectors

    • LIU (Light Interface Unit)

    • Couplers

    • Fiber patch cords.

Page 6: Making Connections - Steps

Connection Steps

  1. Strip the cable end.

  2. Untwist the wire ends.

  3. Arrange wires.

  4. Trim wires to the appropriate size.

  5. Attach the connector.

  6. Conduct a check.

  7. Crimp the connection.

  8. Test the final wire for correct termination of the 8 wires.

Testing Equipment

  • WAVETEK is used for testing the capabilities of connections.

Page 7: Patch Panel Termination

Patch Panel Setup

  • Patch panel allows for termination and connecting with a punchdown in the back.

  • Patch cords plug into the front.

  • I/O & Faceplates: Faceplates can be mounted on walls or raceways. They can provide either single or dual information outlets to network connectivity.

Page 8: Key Elements of Wiring

Types of Wiring

  1. Backbone Wiring: Connects the Telecommunications Room (TR) to the equipment room and between buildings.

  2. Horizontal Wiring: Connects work areas to termination in the TR.

  3. Work Area Wiring: Connects user stations to outlets.

Advantages of Structured Wiring

  • Enhances efficient, cost-effective wiring layouts.

  • Standardized layouts facilitate detection and isolation of problems.

  • Ensures compatibility with future equipment and applications.

Page 9: Structured Wiring Overview

Definition

  • Structured wiring refers to a cabling system that adheres to strict installation standards, which enhances the integrity of the cabling system and reduces the need for re-cabling with new applications.

Infrastructure Components

  • Mounted and permanent.

  • Facilitates easier patching for maintenance.

Page 10: UTP Cable Types and Characteristics

Cat5e Cable

  • Data capacity of 1000 Mbps, suitable for runs up to 90 meters.

  • Uses solid-core cables for structural installations and stranded cables for patch cables.

  • Terminated with RJ-45 connectors.

UTP Categories

  • Overview includes various categories and their data rates:

    • Category 1: Voice only (Telephone)

    • Category 2: Data to 4 Mbps (Localtalk)

    • Category 3: Data to 10 Mbps (Ethernet)

    • Category 4: Data to 20 Mbps (Token ring)

    • Category 5: Data to 100 Mbps (Fast Ethernet)

    • Category 5e: Data to 1000 Mbps (Gigabit Ethernet)

    • Category 6: Data to 2500 Mbps (Gigabit Ethernet).

Page 11: UTP Characteristics & Testing

Characteristics

  • Unshielded Twisted Pair (UTP): consists of twisted pairs of insulated conductors covered by an insulating sheath.

EIA/TIA Cable Testing Standards

  • Required tests for every cable tester include:

    • Length

    • Wire map

    • Attenuation.

Page 12: Patch Cable vs. Cross Connect

Patch Cables

  • A straight-through type of twisted-pair or fiber optic jumper cable.

  • Used for connecting network devices like computers to hubs or distribution panels.

Crossover Cables

  • Cross the transmit and receive pairs (orange and green pairs) in a standard Ethernet connection.

  • Used directly to connect two Ethernet devices together.

Page 13: UTP Cables Overview

T-1 Cable

  • Often referred to as DS-1, consists of 2 pairs of UTP 19 AWG wire.

  • Can carry either voice or data traffic, with a bandwidth of 1.54 Mbps.

  • Fractional T-1s sold in increments of 64 kbps.

CAT 7 Cable

  • Rated at 600 Mbps with individually shielded twisted pairs.

Page 14: CAT 5 & CAT 6

CAT 5 Cable

  • Data rate of 100 Mbps; used for 100BaseT Ethernet and 155 Mbps ATM.

CAT 5E and CAT 6

  • Backwards compatible with CAT 5. CAT 6 provides at least double the bandwidth of CAT 5.

  • Bi-directional dual duplex transmission scheme requires using all four pairs simultaneously for 1000Base-T transmission.

Page 15: Coaxial Cable Overview

Structure

  • Composed of a central wire surrounded by insulation and a grounded shield of braided wire.

Applications

  • Primarily used for CATV due to its high bandwidth of nearly 1 GHz.

  • Also used for long-distance transmission with low attenuation and noise levels.

Page 16: 10Base2 and 10Base5 Cables

10Base2 Cable

  • Also known as Thin Ethernet or Thinnet; operates at 10 Mbps.

  • Maximum cable length is 200 meters; uses baseband transmission with BNC connectors.

10Base5 Cable

  • Also known as Thick Ethernet or Thicknet; maximum data transfer speed is 10 Mbps with a maximum cable length of 500 meters.

Page 17: Coax Cable Types

Types

  1. Thick Coax (10Base5)

  2. Thin Coax (10Base2)

Types of Copper Cables

  • Includes Coaxial cables, Unshielded Twisted Pair (UTP), and Shielded Twisted Pair (STP).

  • Cost varies based on materials and manufacturing processes involved.

Page 18: Transmission Medium Overview

Definition

  • The physical path through which data travels from transmitter to receiver.

Types

  1. Copper Cable: The oldest and most common transmission medium; cheap.

  2. Optical Fiber: Increasingly used for high-speed applications.

Cabling Specifications

  • Includes standards and regulations by IEEE 802 and ANSI/EIA/TIA 568.

Page 19: Required Tools for Making Connections

Tools

  • Required for assembling cables include:

    • Cat5e Cable

    • RJ45 Connectors

    • Cable Stripper

    • Scissors

    • Crimping Tool

    • Punching Tool (for patch panels and Information Outlets).

Page 20: OSI Model Introduction

Overview

  • The OSI model was established in 1947 and is dedicated to standardizing international network communications. It represents a layered architecture.

  • Topics include:

    • Layered Architecture

    • Peer-to-Peer Processes

    • Encapsulation.

Page 21: OSI Model Layers

7 Layers of the OSI Model

  1. Application

  2. Presentation

  3. Session

  4. Transport

  5. Network

  6. Data Link

  7. Physical.

Page 22: Functions of OSI Model Layers

Layer Functions

  1. Application Layer: Provides access to network resources.

  2. Presentation Layer: Translates, encrypts, and compresses data.

  3. Session Layer: Manages sessions between applications.

  4. Transport Layer: Ensures reliable message delivery and error recovery.

  5. Network Layer: Delivers packets from source to destination.

  6. Data Link Layer: Organizes bits into frames and delivers them.

  7. Physical Layer: Transmits bits over a medium; provides mechanical and electrical specifications.

Page 23: TCP/IP Protocol Suite Overview

Structure Comparison to OSI Model

  • TCP/IP protocol suite consists of four layers: host-to-network, internet, transport, and application.

  • Compared to OSI, it can also be understood as having five layers: physical, data link, network, transport, and application.

  • Key topics include:

    • Physical and Data Link Layers

    • Network Layer

    • Transport Layer

    • Application Layer.

Page 24: Addressing in TCP/IP

Types of Addresses

  • Four types of addresses are used in TCP/IP:

    • Physical Addresses

    • Logical Addresses

    • Port Addresses

    • Specific Addresses.

Page 25: Relation of Layers and Addresses

Layer and Address Correspondence

  • In TCP/IP, each layer works with specific types of addresses:

    • Application Layer processes specific addresses.

    • Transport Layer uses port addresses.

    • Network Layer uses logical addresses.

    • Data Link Layer uses physical addresses.

Requirements for Communication

  • Cooperative action is necessary for proper communication among different systems.

Page 26: Protocol Architecture Overview

Break Down of Data Transfer Tasks

  • Task of data transfer is modularized for efficiency.

    • Example: file transfer could include modules for application, communication service, and network access.

Real World Example

  • Philosopher-translator-secretary architecture model delineates communication functions efficiently.

Page 27: Simplified File Transfer Architecture

Modules Overview

  1. File Transfer Application Layer: Commands and file data.

  2. Communications Service Module: Ensures reliable transfer, error detection.

  3. Network Access Module: Handles actual data transfer to networks.

Key Principles

  • Layered structure and protocol stack allow for service exchange between layers independently.

Page 28: General Three Layer Model

Application Protocols

  • Different applications (email, file transfer, etc.) connect through defined protocol layers.

  • The network access layer manages communication with network hardware.

Data Exchange Methods

  • Different switching techniques such as circuit switching, packet switching must be abstracted from upper layers.

Page 29: Transport Layer Functions

Data Exchange Reliability

  • The transport layer provides reliable data exchange, ensuring packets arrive correctly sequenced.

  • Independent of the application type and network used.

Addressing Requirements

  • Unique network addressing for each computer and unique application addressing within multitasking computers (Service Access Points or SAPs).

Page 30: Protocol Architectures and Networks

Service Access Points

  • Applications operate with specific service access points or ports.

Protocol Data Units (PDU)

  • User data moves through layers, headers are added/removed, forming a Protocol Data Unit.

Page 31: Transport Layer & Network PDU

Fragmentation in Transport Layer

  • Each fragment of data adds a transport header for destination, sequence, and error detection.

Network PDU

  • Adds network header which includes destination network addresses and optional facilities.

Page 32: Standard Protocol Architectures

Approaches to Standardization

  • OSI Reference Model vs TCP/IP Protocol Suite. OSI defined but not widely adopted while TCP/IP became a prevalent standard.

OSI Model Description

  • Comprises a layered approach, ensuring independence and efficiency in communication protocols.

Page 33: OSI Reference Model Elements

Layer Functions

  • Each layer's function depends on the next lower layer's performance; changes in one do not affect others.

Elements of Standardization

  • Key factors include protocol specifications, data formats, service definitions, and addressing schemes.

Page 34: OSI Layers Overview

Layer Functions

  1. Physical Layer: Specifies physical interface characteristics.

  2. Data Link Layer: Responsible for error detection, control, and managing the link layer protocols.

  3. Network Layer: Handles routing, switching, and network-related protocols.

Page 35: OSI Layers Continued

Definitions of Layers

  1. Transport Layer: Guarantees end-to-end data guarantees.

  2. Session Layer: Controls dialogues and handles communication direction.

  3. Presentation Layer: Deals with data formatting, compression, and encryption.

  4. Application Layer: Provides support for diverse applications and services.

Page 36: TCP/IP Protocol Suite Overview

Usage and Development

  • Widely adopted prior to the OSI model due to its foundation on projects such as ARPANET. The TCP/IP model does not strictly adhere to a specific layer structure.

Layer Roles in TCP/IP

  • Simplifies understanding of communication without needing to assign roles to each layer as it relies heavily on protocol functions, especially TCP, IP, and their respective application protocols.

Page 37: Network Access and Physical Layers in TCP/IP

Layer Functions

  • These layers focus less on structure in TCP/IP; primarily concerns with connecting to networks for transmitting IP packets.

Internet Layer Functionality

  • Implements internetworking protocols with a point-to-point approach.

Page 38: Transport Layer Protocols

Functions of Transport Protocols

  • Different protocols exist in the transport layer for reliable connection (TCP) and efficient delivery without guarantees (UDP).

IP Protocol

  • Serves as the core of the TCP/IP suite, with two versions (IPv4 and IPv6) co-existing for diverse applications.

Page 39: TCP/IP Protocol Suite Details

TCP Overview

  • Reliable connection providing flow control, error detection, includes segments in its data unit called TCP segments.

UDP Overview

  • Lightweight, end-to-end protocol with minimum overhead; does not guarantee delivery or sequence stability in packets.

Page 40: Protocol Units in TCP/IP

Data Units Description

  • Application data is encapsulated in IP datagrams and TCP or UDP segments, which include headers indicating relevant protocol information.

Page 41: Common Protocols in the TCP/IP Suite

Overview of Protocols

  • Includes application protocols like HTTP, FTP, SMTP, as well as other important protocols like BGP, DNS, and more.

Page 42: Internetworking Strategies

Definition and Structure

  • An interconnected network formed from multiple subnetworks allowing devices within each to communicate.

  • Routers serve as intermediaries to pass packets across different protocol types.

Router Functions

  • Support diverse protocols for inter-communication and handle differences such as segment sizes and addressing to ensure seamless data transfer.

Page 43: Actions of the Sender

Steps for Data Preparation

  1. Prepare the data using specific application protocols.

  2. Ensure common data formats are used for compatibility.

  3. Segment, duplicate, fragment, and frame data for transmission through the respective communication layers.

Page 44: Receiver Action Process

Steps Once the Signal Reaches

  1. Incoming signals are processed layer by layer, confirming the integrity of data throughout.

  2. Finally, the application prepares any required transformations such as decompression before data delivery.

Page 45: Importance of Standards

Advantages of Interoperability

  • Standards facilitate communication between devices of varied manufacturers, promoting a large market while ensuring quality and efficiency in services.

Page 46: IETF Organization Structure

Functionality

  • Voluntary group structured by areas such as security and routing that develop and maintain networking standards.

Documentation Process

  • Uses Internet Drafts as temporary documents, leading to formal RFCs which outline standards and practices.

Page 47: Internet Standards Track Process

Steps for Protocol Standardization

  1. Internet Draft

  2. Proposed Standard

  3. Draft Standard

  4. Internet Standard

  • Requires consensus and operational experience.

Page 48: Analog and Digital Signals

Definitions

  • Analog Data: Continuous information with infinite variability.

  • Digital Data: Represents information with discrete values.

Page 49: Signal Comparisons

Time vs. Domain Representation

  • Visual comparison between analog signals (smooth, continuous) and digital signals (distinct spikes).

Page 50: Periodic Signals

Types of Periodic Analog Signals

  • Composite signals can be broken into multiple frequencies and can change based on amplitude and other characteristics.

Page 51: Frequency and Time Relationships

Definitions

  • Describes the relation of frequency to waveform changes over time.

Page 52: Importance of Composite Signals

Use in Data Communications

  • Composite signals are essential; they require decomposition into sine waves for proper analysis and function.

Page 53: Fourier Analysis

Signal Bandwidth

  • Defines composite signals and harmonic contributions.

Page 54: Fourier Series Representation

Utilization

  • Fourier series facilitate the representation of periodic signals in terms of sine and cosine components.

Page 55: Examples of Fourier Series

Signal Representation

  • Illustrates the breakdown of complex waveforms into periodic components for analysis.

Page 56: Fourier Transform

Process Overview

  • Fourier Transform analyzes the frequency domain characteristics of nonperiodic signals.

Page 57: Time-limited and Band-limited Signals

Definitions

  1. Time-limited signals: Have defined duration.

  2. Band-limited signals: Have frequency restrictions.

Page 58: Baseband Transmission

Characteristics

  • Baseband transmission allows digital signals' shape preservation only with adequate bandwidth channels.

Page 59: Signal Impairments

Causes of Signal Impairment

  • These include attenuation, distortion, and noise, affecting the integrity of the received signals.

Page 60: Measurement of Attenuation

Concept

  • Represents energy loss in signals over distance, with amplifiers compensating for decay.

Page 61: Distortion and Noise

Definitions

  • Distortion: Results from phase alterations among different signal frequencies.

  • Noise Types: Includes thermal noise and impulse noise from external sources.

Page 62: Signal Quality Measurement

SNR Importance

  • The Signal to Noise Ratio indicates system quality, balancing strength against noise power.

Page 63: Capacity of Transmission Systems

Bandwidth and Error Rate

  • System capacity is determined by signal levels, bandwidth, and channel quality, following relevant theoretical models.

Page 64: Shannon's Theorem

Capacity Calculation

  • Provides the upper limit of data transmission capacity in noisy environments, defining the relationship between bandwidth and signal quality.

Page 65: Propagation and Transmission Delays

Delay Definitions

  • Outlines how propagation speed and transmission size impact the overall latency of network communications, emphasizing the bandwidth-delay product.