Networking Exam Review PDF

Networking Exam Review Monday, December 2, 2024 1:15 PM Network Components Host Roles ○ Hosts/End Devices: Originate/receive data on the network. ▪ Every computer on a network is a host/end device ○ Servers: Computers that provide info...

Networking Exam Review Monday, December 2, 2024 1:15 PM Network Components Host Roles ○ Hosts/End Devices: Originate/receive data on the network. ▪ Every computer on a network is a host/end device ○ Servers: Computers that provide info to end devices (ex, email, web, file) ○ Clients: computers that send requests to the servers to retrieve info. Peer-to-Peer ○ Devices can act as both client and server ○ Suitable for small setups ▪ Advantages; Easy to set up, less complex, lower cost and used for simple tasks. ▪ Disadvantages: No centralized administration, not as secure, not scalable and slower performance. Network Device and Media ○ End Devices: Devices that participate directly in network communication (ex. Pcs, phones) ○ Intermediary Devices: Devices that manage traffic and interconnects end devices(e.g routers, switches) ○ Media: Physical connections like cables or wires ▪ Metal Wires within cables: Uses electrical pulses ▪ Glass or plastic fibers within cables: Uses pulses of light ▪ Wireless transmission: Uses modulation of specific frequencies of electromagnetic waves Network Representation and Topologies Topology Diagram ○ Physical: Shows device location and connections ○ Logical: Displays the flow of data. Common Types of Networks By Size: ○ Small/Home (SOHO) to worldwide (internet) ○ LAN (local) vs WAN (wide geographical area) ▪ LAN: A network infrastructure that spans a small geographical area Interconnects end devices in a limited area Administered by a single organization or individual Provide high-speed bandwidth to internal devices. ▪ WAN: A network infrastructure that spans a wide geographical area Interconnects LANs over wide geographical area Typically administered by one or more service providers Typically provide slower speed links between LAN's The Internet ○ The internet is a worldwide collection of LANs and WANs ▪ LANs Are connected to each other using WANs ▪ WANs may use copper wires, fiber, optic cables, and wireless transmissions. ○ IETF, ICANN and IAB are groups that were developed to help maintain the structure in the internet. Intranet Vs Extranet Intranet: Private collection of LANS and WANS internal to an organization that is meant to be accessible only to the organization members or others with authorization. Extranet: an organization may use an external to provide secure access to their network for individuals who work for a different organization that need access to their data on their network. Internet Connections Internet Access Technologies ○ Home Options: Cable, DSL, cellular, satellite, dial up. Connection Description Cable high bandwidth, always on, internet offered by cable television service providers. DSL high bandwidth, always on, internet connection that runs over a telephone line. Cellular uses a cell phone network to connect to the internet. Satellite major benefit to rural areas without Internet Service Providers. Dial-up telephone an inexpensive, low bandwidth option using a modem. ○ Business Options: Dedicates leased lines, Ethernet WAN, VPNs ▪ Require: Higher bandwidth Dedicated connections Managed services Type of Connection Description Dedicated Leased Line These are reserved circuits within the service provider’s network that connect distant offices with private voice and/or data networking. Ethernet WAN This extends LAN access technology into the WAN. DSL Business DSL is available in various formats including Symmetric Digital Subscriber Lines (SDSL). Satellite This can provide a connection when a wired 0 solution is not available. The Converging Network ○ Carry Multiple services on one link, including: ▪ Voice ▪ Video ▪ data ○ Converged networks can deliver data, voice and video over the same network infrastructure. The network infrastructure uses the same set of rules and standards. Reliable Networks ○ There are four basic characteristics that the underlying architectures need to address to meet user expectations: ▪ Fault Tolerance: Limits the impact of a failure by limiting the number of affected devices. Multiple paths are required for fault tolerance Reliable networks provide redundancy by implementing a packet switched network ○ Packet switching splits traffic into packets that are routed over a network. ○ Each packet could theoretically take a different path to the destination. ○ THIS IS NOT POSSIBLE FOR CIRCUIT SWITCHED NETWORKS WITH ESTABLISH DEDICATED CIRCUITS. ▪ Scalability: Can expand quickly and easily to support new users and applications without impacting the performance of services to existing users. Essentially expansion without performance loss ▪ Quality of Service (QoS): Primary mechanism used to ensure reliable delivery of content for all users. With QoS, the router can easily manage the flow of data and voice traffic (ex. Live video without breaks and pauses) ▪ Security: 2 main types of network security ○ Network Infrastructure security: ▪ Protects physical devices from unauthorized access ○ Information Security: ▪ Protects data transmitted over the network ○ Goals of network Security ▪ Confidentiality: Only intended recipients can read the data ▪ Integrity: Assurance that data has not been altered during transmission ▪ Availability: Timely and reliable access to the data for authorized users. Network Trends ○ Recent Trends: ▪ Networks must adapt to new technologies and user devices ▪ Key trends include Bring Your Own Device (BYOD) ○ Users can use their personal devices ○ Provides flexibility and access to information Online collaboration ○ Collaborate and work with others over the network on joint projects. ○ Tools like cisco WebEx enable joint projects and instant communication Video communications ○ Video calls enhance communication regardless of location. Cloud computing ○ Stores files or backup data and applications on internet servers ○ Allows access from any device, anywhere ○ Types of Clouds ▪ Public Clouds: Available to the public, often pay per use ▪ Private Clouds: For specific organizations (ex. Government) ▪ Hybrid Clouds: Combination of public and private clouds ▪ Custom Clouds: Tailored for specific industries. ○ Technology Trends in the Home: ▪ Integrates technology into everyday appliances for interconnectivity. (smart techology/appliances) ▪ Example: Ovens communicating with calendars for meal timing. ○ Powerline Networking: ▪ Connects devices to LAN using electrical outlets ▪ Useful where data cables or wireless communications are not viable. ▪ Using a standard powerline adapter, devices can connect to the LAN wherever there is an electrical outlet by sending data on certain frequencies. ○ Wireless Broadband: ▪ Connects homes and small businesses to the internet using cellular technology. ▪ Common in rural areas, provided by Wireless Internet Service Providers (WISPs) WISP is an ISP that connects subscribers to designated access points or hotspots. ▪ Uses the same cellular technology used by a smart phone. ▪ An antenna is installed outside the house providing wireless or wired connectivity for devices in the home. Network Security ○ Network Security Threats ▪ Network Security is crucial for all network sizes. ▪ Must take the environment into account, while balancing data security with quality of service. ▪ Securing a network involves many protocols, technologies, devices, tools, and techniques in order to secure data and mitigate threats. ▪ External Threats Viruses, worms, Trojan horses Spyware and adware Zero-day attacks Threat Actor attacks Denial of service attacks Data interception and theft Identity theft ▪ Internal Threats: Lost or stolen devices Accidental misuse by employees Malicious employees ○ Security Solutions ▪ Use multiple layers of security solutions ▪ Network security components for home or small office network: Antivirus and antispyware software should be installed on end devices Firewall filtering used to block unauthorized access to the network. ▪ Larger Networks: Dedicated firewall systems Access control lists (ACL) Intrusion prevention systems (IPS) Virtual private networks (VPNs) 1.9: The IT Professional ○ CCNA Certification (Certifies Network Associate) ▪ Validates foundational technology knowledge Module 3: Protocols and Models 3.1: The Rules ○ Communication Fundamentals: ▪ Networks can vary in size and complexity ▪ There are 3 elements to any communication Source (Sender) Destination (Receiver) Channel (Media) - Provides for the path of communications to occur. ○ Communication Protocols: ▪ Protocols. are the rules that govern how communication occurs ○ Rule Establishment ▪ Individuals must use established rules or agreements to govern the conversation. ▪ Protocol Requirements: An identified sender and receiver Common language and grammar Speed and timing of delivery Confirmation or acknowledgment requirements ○ Network Protocol Requirements ▪ Common computer protocol requirement Message encoding ○ The process of converting information into format suitable for transmission. ○ Decoding: Reverses this process to interpret the information. Message formatting and encapsulation ○ Messages must adhere to specific formats based on ▪ Types of message ▪ Channel used for delivery Message size ○ Messages are converted to bits for transmission ○ Bits can be encoded into patterns of light, sound, or electrical impulses. ○ The destination host must decide the signals to interpret the message. Message timing: ○ Flow Control: Manages data transmission rate and defines how much information can be sent and the speed at which It can be delivered. ○ Response Timeout: Manages how long a device waits for a reply from the destination. ○ Access Method: Rules for when messages can be sent ○ Collision Management: Protocols may prevent or recover from message collisions(when more than one device sends traffic at the same time and the messages become corrupt) Message delivery options ○ Unicast: One to one communication ○ Multicast: One to many communication ○ Broadcast: One to all communication (Not used in ipv6) ○ Anycast: Additional delivery option for ipv6 Node Icon ○ The node Icon (circle) represents all devices in a network 3.2: Protocols ○ Network Protocol Overview ▪ Define a common set of rules ▪ Implementation: Can be in software or hardware or both ▪ Protocols have their own Function Format Rules ○ Network Protocol functions ▪ Devices use agreed-upon protocols to communicate, which may have multiple functions ○ ▪ ○ Protocol Interaction ▪ Networks require the use of several protocols ▪ Each protocol has its own function and format 3.3: Protocol Suites ○ Network Protocol Suites: ▪ Protocols must be able to work with other protocols Protocol suite: ○ A group of inter-related protocols necessary to perform a communication function. ○ The protocols are viewed in terms of layers ▪ Higher Layers – Focus on application and user services ▪ Lower Layers – concerned with moving data and provide service to upper layers ○ Evolution of Protocol Suites ▪ Common Protocol Suites The Protocol Suite (TCP/IP) ○ The most common and maintained by the Internet Engineering Task Force (IETF) Open Systems Interconnection (OSI) protocols: ○ Developed by the International Organization for Standardization (ISO) and the International Telecommunications Union (ITU) AppleTalk ○ Proprietary suite release by Apple Inc. Novell NetWare: ○ Proprietary suite developed by Novell Inc. ○ TCP/IP Protocol Example: ▪ Operates at application, transport and internet layers ▪ Common LAN protocols ▪ include ethernet and WLAN ○ TCP/IP Protocol Suite ▪ Used by the internet and includes many protocols: ▪ The TCP/IP is: An open standard protocol suite that is available to the public and can be used by nay vendor A standards-based protocol suite that is endorsed by the networking industry and approved by a standards organization to ensure interoperability. ▪ ○ TCP/IP Communication Process ▪ A web server encapsulates and sends a webpage to a client, which then de- encapsulated it for the browser. 3.4: Standards Organizations ○ Open Standards Encourage: ▪ Interoperability ▪ Competition ▪ Innovation ○ Standards organizations are ▪ Vendor-neutral ▪ Non-profit organizations ▪ Established to develop and promote concept of open standards ○ Internet Standards ▪ ▪ Internet Society (ISOC): Promoted open internet development ▪ Internet Architecture Board (IAB): Responsible for the management and development of internet standards. ▪ Internet Engineering Task Force IIETF): Developed, updated and maintains internet and TCP/IP technologies. ▪ Internet Research Task Force: Focused on long-term research related to the internet and TCP/IP protocols. ▪ Standards organizations involved with the development and support if TCp/IP: ▪ Internet Corporation for Assigned Names and Numbers (ICANN): Coordinates IP address allocation and domain management. ▪ Internet Assigned Numbers Authority (IANA): Manages IP address allocation and protocol indentifier for ICANN. ▪ ○ Electronic and Communication Standards ▪ Institute of Electrical and Electronics Engineers (IEEE) ▪ dedicated to creating standards in power and energy, healthcare, telecommunications, and networking. ▪ Electronic Industries Alliance (EIA): ▪ develops standards relating to electrical wiring, connectors, and the 19-inch racks used to mount networking equipment ▪ Telecommunications Industry Association (TIA) ▪ develops communication standards in radio equipment, cellular towers, Voice over IP (VoIP) devices, satellite communications, and more. ▪ International Telecommunications Union Telecommunication Standardization Sector (ITU-T) ▪ defines standards for video compression, Internet Protocol Television (IPTV), and broadband communications, such as a digital subscriber line (DSL). x 3.5: Reference Models ○ The Benefits of Using a Layered Model ▪ Two layered models to describe network Operations: ▪ Open System Interconnection (OSI) Reference Model ▪ TCP/IP Reference Model ▪ ▪ The benefits include assist in protocol design, foster competition, prevent tech or capability changes in one layer from affecting other layers. And provide a common language to describe networking functions and capabilities. ○ The OSI Reference Model ○ ○ The TCP/IP Reference Model ○ OSI vs TCP/IP ▪ The OSI model divides network access and application layers into multiple layers. ▪ The TCP/IP does not specify which protocols to use when transmitting over a physical medium. ▪ OSI layers 1 and 2 discuss the necessary procedures to access the media and physical means to send data over a network. 3.6: Data Encapsulation: ○ Segmenting Messages: ▪ Segmenting: Breaking messages into smaller units. ▪ Multiplexing: Combining multiple streams of segmented data. ▪ Benefits of segmenting data: ▪ Increases speed: Large data can be sent without blocking the link. ▪ Increases efficiency: Only failed segments need retransmission. ○ Sequencing: ▪ Numbering segments for proper reassembly ▪ TCP – Responsible for sequencing the. individual segments. ○ Protocol data Units (PDUs) ▪ Encapsulation: Adding protocol information to data ▪ PDU's change names as they move through layers: ▪ Data (Data Stream) ▪ Segment ▪ Packet ▪ Frame ▪ Bits (Bit Stream) ○ Encapsulation Example: ▪ Encapsulation is a top down process where each layer processes and passes data down to the next level. ▪ This process is repeated by each layer until it is sent out as a bit stream. ▪ Example: ○ Data is de-encapsulated as it moves up the stack. ○ When a layer completes its process, that layer strips off its header and passes it up to the next level to be processed. This is repeated at each layer until it is a data stream that the application can process. 1. Received as Bits (Bit Stream) 2. Frame 3. Packet 4. Segment 5. Data (Data Stream) ○ 3.7: Data Access ○ Addresses ▪ Both data link and network layers use addressing to deliver data from sourve to destination ▪ Network layer source & destination Address: Responsible for delivering the IPpacket from original source to the final destination. ▪ Data link layer source & Destination address: Responsible for delivering the datalink frame from one network interface card (NIC) to another NIC on the same network. ▪ ○ Logical Addresses ▪ The IP packet contains two IP addresses: ▪ Sender's address ▪ Receiver's address ▪ These addresses may be on the same link or remote ▪ An Ip address contains 2 parts: ▪ Network portion (IPv4) or Prefix (IPv6) ○ Left most part of the address which indicates the network group. ○ Each LAN and WAN will have the same network portion ▪ Host Portion (IPv4) or interface ID (IPv6) ○ The remaining part identifies a specific device within that group. ○ This portion is unique for each device on the network. ○ ○ Devices on the Same Network ▪ Devices on the same network have the same network portion on the IP address ▪ Example: ▪ PC1: 192.168.1.110 ▪ FTP Server: 192.168.1.9 ▪ ○ Role of the Data Link Layer Addresses: Same IP Network ▪ When devices are on the same Ethernet network, the data link frame will use the actual MAC address of the destination NIC. ▪ Mac addresses are physically embedded into the Ethernet NIC and are local addressing. ▪ Source MAC address: Originator's address ▪ Destination MAC address: Address of the destination NIC on the same link as the source. ▪ ○ Devices on a Remote Network ▪ When the destination is not on the same LAN, the process involves routing through different networks. ○ Role of the Network LAyer Addresses ▪ When the source and destination have different network portions, they are on different networks. ▪ PC1 – 192.168.1 ▪ Web Server – 172.16.1 ○ Role of the Data Link Layer Addresses: Different IP Networks ▪ When the final destination is remote, Layer 3 provides Layer 2 with the local default gateway IP address (router address). ▪ The default gateway (DGW) is the router's IP address that connects the LAN to other networks. ▪ All devices on the LAN must know this address to communicate outside their local network. ▪ Local Addressing: Data link addressing is local and includes source and destination addresses for each link. ▪ Mac Addressing for first segment ▪ : ▪ Source: AA-AA-AA-AA-AA-AA (PC1) ▪ Destination: 11-11-11-11-11-11 (Router - Default Gateway) ▪ ○ Data Link Addresses: ▪ Since data link addressing is local addressing, it will have a sourceand destination for each segment oe hop of thejournye to the destination. ▪ The MAC addressing for the first segment is: ▪ Source - (PC1 NIC) sends frame ▪ Destination - (First Router – DGW interface) recieves frame. ▪ ▪ Second Hop: ▪ Source: (First Router- exit interface) sends frame ▪ Destination: (Second Router) recieves frame ▪ Last Segment: ▪ Source: (Second Router- exit interface) sends frame ▪ Destination: (Web Server NIC) recieves frame ▪ Key Point: The packet (Layer 3 IP addressing) remains unchanged, while the frame (Layer 2 MAC addressing) changes at each hop. MODULE 4: PHYSICAL LAYER 4.1: Purpose of the Physical Layer ○ Physical Connection: Establishes a wired of wireless connection to a network ○ Network Interface Card: Connects devices to the network; can have multiple NIC's ○ Data transmission: Transports bits across network media and encodes frames for transmission. ▪ This is done as it accepts a complete frame frpm the Data Link Layer and encodes it as a series of signals that are transmitted to the local media. ▪ The next device in the path to the destination receives the bits and re-encapsulates the frame, then decides what to do with it. 4.2: Physical Layer Characteristics ○ Physical Layer Standards ○ ▪ Physical Components: Hardware devices, media, and connectors. ▪ Standards specify the design and functionality of these components. ▪ Encoding: Converts bits into recognizable formats. ▪ Signaling: Represents bit values on the medium. ▪ Represents bit values "1" and "0" on the medium. ▪ Types of signaling based on medium: ○ Electrical Signals: Over copper cable. ○ Light Pulses: Over fiber-optic cable. ○ Microwave Signals: Over wireless. ○ Bandwidth ▪ Definition: Capacity of a medium to carry data. ▪ Digital Bandwidth: Measures the amount of ▪ data flow in bits per second. ▪ Influenced by: ▪ Physical media properties. ▪ Current technologies. ▪ Laws of physics. ○ ○ Bandwidth Terminology: ▪ Lantency: Amount of time, including delays, for data to travel from one give point to another. ▪ Throughput: The measure of transfer of bits across over a given period of time. ▪ Goodput: the measure of usable data transferred over a given period of itme ▪ Goodput = Throughput – overhead 4.3: Copper Cabling ○ Most common type of cabling in networks ▪ Advantages ▪ Inexpensive ▪ Easy to install ▪ Low resistance to electrical current flow ▪ Limitations ▪ Attenuation: Signal, weakens over long distance ▪ Interference(can distort and corrupt the data signals): ○ Electromagnetic Interference (EMI) ○ Radio Frequency Interference (RFI) ○ Crosstalk ▪ Mitigations: ▪ Adhere to cable length limits to reduce attenuation ▪ Use metallic shielding and grounding to mitigate EMI and RFI ▪ Twisting wire pairs together to reduce crosstalk ○ Types of Copper Cabling ▪ Unshielded Twisted Pait (UTP) ▪ Most common networking media ▪ Terminated with RJ-45 connectors ▪ Intercinnects hosts with intermediary devices ○ Key Characteristics ▪ Outer jacket for protecting ▪ Twisted pairs reduce interference ▪ Color-coded insulation for identification. ▪ ▪ Shielded Twisted Pair (STP) ▪ Better noise protection than UTP. ▪ More expensive and harder to install. ▪ Terminated with RJ-45 connectors. ▪ Interconnects hosts with intermediary ▪ ○ Key Characteristics: ▪ Outer jacket for protection. ▪ Braided or foil shield for EMI/RFI protection. ▪ Color-coded insulation for identification. ▪ ▪ Coaxial Cable ▪ Consists of: ○ Outer cable jacket ○ Woven copper braid for shielding ○ Flexible plastic insulation ○ Copper conductor for signal transmission ▪ Commonly used in: ○ Wireless installations ○ Cable internet installations 4.4: UTP Cabling ○ Properties of UTP Cabling ▪ Has 4 pairs of colour coded twisted copper wired in a plastic sheath. ▪ No sheildinf is used ▪ Crosstalk Mitigation ▪ Cancellation: Each wire in a pair of wires uses opposite polarity. One wire is negative, the other wire is positive. They are twisted together and the magnetic fields effectively cancel each other and outside EMI/RFI. ▪ Variation is twists: Different twist rates help prevent crosstalk. ○ UTP Cabling Standards and Connectors ▪ Standards established by TIA/EIA (e.g., TIA/EIA-568) - 58 standarizes elements like: ▪ Cable types ▪ Cable Lengths ▪ Connectors ▪ Cable Termination ▪ Testing Methods ▪. ▪ Electrical standards by IEEE (e.g., Category 3, 5, 5e, 6). ▪ RJ-45 Connector: Used for terminating UTP cables. ▪ Cable Types ▪ Straight-through: Connects different devices. ▪ Crossover: Connects similar devices. 4.5 Fiber-Optic Cabling ○ Properties of Fiber-Optic Cabling ▪ Less common due to cost but ideal for specific scenarios. ▪ Transmits data over long distances at high bandwidth. ▪ Immune to EMI/RFI and less susceptible to attenuation. ▪ Made of thin glass strands using light pulses for data transmission. ○ Types pf Fiber