NW CH3 MANIUAL Flashcards
(20 cards)
How is it possible to send bits across
INCOMPATIBLE LANs and WANs?
Answer: This is possible through PROTOCOL SOFTWARE running on each host and router, which smooths out the differences between the different networks.
🔷 What is a Network Protocol?
What is the num for the Q
Num is 3
- A network protocol is a set of rules that devices follow to exchange information correctly.
- These rules are arranged in layers, forming a protocol stack (e.g., HTTP, TCP, IP).
- This modular design allows protocols to be developed, updated, and managed independently.
🔷 What is a Network Model?
What is the num for the Q
Num is 4
A network model describes:
- The architecture, components, and design used for communication between systems.
- How data moves from source to destination.
- Also called a protocol stack or protocol suite.
- Examples: OSI model, TCP/IP model.
A network portocol?
(i.e., set of rules) aims at governing how hosts and routers should coo erate when the transfer data from network to network.
What is and why network layering needed?
What is the number of this Q?
Network model👉Network protocol: rules are arranged in layers, forming a protocol stack (e.g., HTTP, TCP, IP). Protocol stack👉Comulative set of protocols to generating network layers or some n layer model
That protocol stack
- modular design
- each layer is distinct module and acts separtly in the communication -system
- **Most of networks operate on either a 5 or 7 Ia’yer protocol stack.
**
- Interfaces between each la er allow each layer to communicate with the layers directl above and below it.
- Layer n on one host carries a conversation” with its eer la er n on another host
✅** Reasons We Use Layering:**
1Modular Design:
Each layer handles one specific task (like addressing, error checking, routing, etc.). That makes it easier to design, troubleshoot, and update.
2Isolation of Functionality:
If one layer changes (e.g., you replace Wi-Fi with fiber optics), the other layers don’t need to change.
3**Interoperability:/ flexibility
**Different vendors can create devices or software that work together — because they all follow the same layered model.
4**Easier Development:
**Engineers can focus on just one layer rather than the whole system.
5**Example – Assembly Line Analogy:
**Like a car factory, each station (layer) adds or processes something before passing it on.
OSI Model – 7 Layer
Layer 7 – Application
Interface between user and network
Provides network services to applications (e.g., browsers, email)
Example protocols: HTTP, FTP, SMTP
PDU: Data
Example device: Application software (e.g., Zoom, Chrome)
Layer 6 – Presentation
Translates data formats (e.g., character encoding, encryption, compression)
Ensures data is in a usable format for the Application Layer
PDU: Data
Example: Encryption engines, codecs
Layer 5 – Session
Establishes, manages, and terminates sessions between applications
Controls communication synchronization and dialog
PDU: Data
Example: Session managers, APIs
Layer 4 – Transport
Breaks data into segments
Adds port numbers for application-specific routing
Ensures reliable delivery (TCP) or faster but unreliable delivery (UDP)
Firewalls filter based on transport protocols and ports
PDU: Segment
Example: TCP, UDP, Firewalls
Layer 3 – Network
Adds IP addresses to create packets
Determines the best path across networks using routing
Routes packets between different networks
PDU: Packet
Devices: Routers, Layer 3 switches, firewalls
Layer 2 – Data Link
Adds MAC addresses to form frames
Handles error detection for local transmission
Controls access to the physical medium
PDU: Frame
Devices: Switches, bridges, network interface cards (NICs)
Layer 1 – Physical
Transmits raw bits over the physical medium (cables, wireless, etc.)
Converts data into electrical, optical, or radio signals
Concerned with connectors, voltage, frequencies, and physical standards
PDU: Bits
Devices: Cables, hubs, Wi-Fi radios, network cards
Based on OSI Reference Model, Explain the Function of a Router
What is the number of this Q?
Num is 4
- A Router operates at the Network Layer (Layer 3) of OSI reference model.
- It is primarily responsible for routing data packets between
different networks.
- It uses IP addresses to determine the best path for a packet to travel from its source to its destination.
- Routers maintain routing tables that contain information about network paths and make forwarding decisions based on the destination IP adAess in the packet header
Based on OSI Reference Model, Diflerentiate
Between a Layer 2 Switch and a Layer 3 Switch
What is the number of this Q?
Num is 3 for each
Layer 2 Switch:
- It operates at the Data Link Layer of OSI reference model.
- It forwards traffic based on Media Access Control (MAC) addresses.
- It is used for connecting devices within the same local network se ent.
Layer 3 Switch:
- It operates at the Network Layer of OSI reference model.
- It performs routing functions based on IP addresses in addition to switching based on MAC addresses.
- It is used to route traffic between different VLANs within a larger network
Explain at Which OSI Model Layers Does a Firewall Operate
What is the number of this Q?
Num is 2
Firewalls operate at:
- Layer 3 (Network Layer), filtering traffic based on IP addresses, and
- Layer 4 (Transport Layer), filtering based on port numbers and protocols like TCP (Transmission Control Protocol) and UDP (User Datagram Protocol).
Segment (Transport Layer – Layer 4)
A segment is the data unit at the Transport Layer.
It includes:
- The original application data
- Transport layer headers (including source and destination port numbers)
Responsible for process-to-process communication.
Example device: Firewall (filters by port number)
Packet (Network Layer – Layer 3)
A packet is the data unit at the Network Layer.
It includes:
- The segment (from Transport Layer)
- Network layer headers (including source and destination IP addresses)
Responsible for host-to-host communication across networks.
Example devices: Router, Layer 3 switch, Firewall
Frame (Data Link Layer – Layer 2)
A frame is the data unit at the Data Link Layer.
It includes:
- The packet (from Network Layer)
- Data Link layer headers and trailers
- MAC addresses for source and destination
Responsible for node-to-node communication within the same local network.
Example device: Layer 2 switch
🔑 What is the OSI Model?
Num is 4
- OSI stands for Open Systems Interconnection.
- It’s a conceptual framework that standardizes how data is sent and received over a network.
- Developed by the International Standards Organization (ISO).
- It breaks communication into 7 layers, from the user’s application all the way to the physical medium.
🎯 Main goal of the OSI model?
To allow interoperability between different systems, so that devices and software from different vendors can work together.
✅ What is the TCP/IP Model?
TCP/IP stands for:
It’s a simplified, 5-layer model that maps roughly to the OSI model, It consists of 5 layers:
- The TCP/IP model is a practical framework used in real-world networking. The OSI model is educational, while TCP/IP is implementable and forms the backbone of the internet.
- Designed by the U.S. Department of Defense, not ISO.
TCP/IP model Layer 5 – Application Layer
بتضم التلاته في واحد
Layer 5 – Application Layer
Purpose:
Provides network communication services to user-level applications
- Equivalent to OSI Layers 5, 6, and 7 combined
Key Protocols:
- HTTP – Web communication(HyperText Transfer Protocol)
- FTP – File transfer
- SMTP – Sending email
- DNS – Domain resolution
- NNTP – Network News (Transfer Protocol)
- SNMP – Network management
Functions:
Direct interface with software applications
Responsible for data formatting, encryption, and session handling (merged from OSI)
TCP/IP model Layer 4 – Transport Layer
Layer 4 – Transport Layer
Purpose:
- Provides end-to-end communication between processes
- Responsible for segmentation, port addressing, and delivery method
Key Protocols:
UDP and TCP are transport level protocols responsible for deliver of a message between processes i.e., running programs).
TCP (Transmission Control Protocol):
- Reliable delivery (acknowledgments, retransmissions)
- Guarantees segments arrive in order and complete
UDP (User Datagram Protocol):
- Unreliable, faster delivery
- No guarantee of delivery or order
- Used where speed > accuracy (e.g., streaming)
Functions:
Segments data from applications
Adds port numbers to direct traffic to correct process
Works closely with firewalls for filtering by port/protocol
layer4 TL represented by TCP/IP by two protocols
Under layer 4 transport layer:
two protocol
TCP versus UDP
In tabular way
TCP/IP model
UDP and TCP are transport level protocols responsible for deliver of a message between processes i.e., running programs).
TCP
Secure
Connection-Oriented
Slow
Guaranteed Transmission
UBCA
RerM
FC
there was no space for Error checking DONOTFORGETIT
Used by critical application, Recorder machanisim, Flow control, and Error checking
TCP/IP model Layer 3 – Network Layer
Layer 3 – Network Layer
Purpose:
Moves packets from one host to another across networks
Adds IP addresses and selects the best routing path
Key Protocol:
IP (Internet Protocol) – Host-to-host delivery
Supporting Protocols:
ARP (Address Resolution Protocol) – Maps IP to MAC
RARP (Reverse ARP) – Maps MAC to IP
ICMP – Error reporting and ping
IGMP – Multicast management
Functions:
Handles logical addressing (IP)
Makes routing decisions
Communicates between routers and network devices
Components of an IP Address:?
Main Functions of an IP Address:?
🔹 What is an IP Address?
Components of an IP Address:?
Main Functions of an IP Address:?
Components of an IP Address:?
Main Functions of an IP Address:?
🔹 What is an IP Address?
Definition:
An Internet Protocol (IP) address is a device’s unique numeric identifier on a network.
Example:
192.168.5.10
Range per number:
Each section can be from 0–255
Components of an IP Address:
Network ID – Identifies the network portion
Host ID – Identifies the device within the network
Example:
IP Address: 192.168.3.16
Network ID: 192.168.3
Host ID: 16
Main Functions of an IP Address:
-
Naming Scheme:
Each host gets a unique IP address that follows a standardized format -
Delivery Mechanism:
IP organizes and routes data into packets
A packet contains:
Header: info like source/destination IPs, size, etc.
Payload: the actual data (e.g., website content, file data)
