Lo Unit I 2.Packet switched network 3.

Explain in detail about protocol layers and their service models

1.Expalin in detail about network core? A packet-switched network is a type of computer network in which data is divided
Network Core into smaller, manageable chunks called packets. These packets are individually In computer networks, protocol layers are organized sets of rules and func onali es that
routed through the network based on des na on addresses contained within them. enable communica on between devices. These layers follow a structured approach to
1. Defini on and Importance handle different aspects of network communica on, ensuring that complex tasks are
Here are key points that could be covered in a 5-mark explana on of a packet-
The network core is the central part of a telecommunica ons switched network: broken down into manageable components.
network responsible for rou ng and forwarding data efficiently and 1. **Defini on and Concept**: Start by defining what a packet-switched network is. 1. **Physical Layer**: This is the lowest layer of the OSI model and deals with the physical
transmission of data bits over a communica on channel. It defines the electrical,
reliably. It ensures that data packets are delivered across the Men on that it's a type of digital network in which data is transmi ed in discrete
mechanical, and procedural aspects of transmi ng raw data signals over physical media
network with minimal delay and high throughput. This core units called packets. Unlike circuit-switched networks, where a dedicated
such as copper wires, fiber op cs, or wireless channels.
communica on path is established for the en re dura on of the communica on, 2. **Data Link Layer**: The data link layer provides reliable node-to-node communica on,
infrastructure is cri cal for maintaining the overall performance and packet-switched networks dynamically route packets of data through the network handling error detec on and correc on in the physical layer’s transmi ed bit stream. It is
stability of the network. based on available network resources and des na on addresses. responsible for framing data into frames, ensuring data integrity, and managing access to
2. Key Components 2. **Packet Structure**: Explain the structure of a packet. Each packet typically the physical medium.
• Core Routers and Switches: These devices handle the bulk consists of a header sec on (containing control informa on such as source and 3. **Network Layer**: The network layer facilitates communica on between different
des na on addresses, sequencing, error detec on) and a payload sec on (actual networks by handling rou ng, addressing, and logical addressing (such as IP addresses). It
of data traffic, ensuring efficient rou ng and high-speed data data being transmi ed). determines the best path for data to travel from the source to the des na on across
transfer across the network. 3. **Rou ng and Switching**: Describe how packets are routed through the mul ple network nodes.
• High-Capacity Links: Fiber op c cables and other high- network. When a source device wants to send data to a des na on device, the data 4. **Transport Layer**: The transport layer ensures reliable data transfer between devices
is divided into packets. Each packet is then routed independently through the and handles end-to-end error recovery and flow control. It segments data received from
capacity transmission media are used to interconnect core devices, the session layer into smaller units for transmission and reassembles them at the
network. Routers and switches within the network use algorithms and protocols (like
enabling long-distance and high-bandwidth data transmission. IP rou ng protocols) to determine the best path for each packet towards its des na on.
3. Example des na on. 5. **Session Layer**: The session layer establishes, manages, and terminates sessions (or
connec ons) between applica ons on different devices. It allows two devices to
Consider an Internet Service Provider (ISP) network. The core 4. **Advantages**: Highlight the advantages of packet-switched networks:
communicate over a network by providing synchroniza on and checkpoin ng of data
network of the ISP connects mul ple regional networks and data - **Efficiency**: They can u lize network resources more effec vely by dynamically
exchange.
rou ng packets based on current network condi ons. 6. **Presenta on Layer**: The presenta on layer is responsible for data transla on,
centers. For instance, when a user in New York accesses a website - **Scalability**: Packet-switched networks are generally more scalable as they can encryp on, and compression to ensure that data sent by the applica on layer of one
hosted in California, the data packets travel through the ISP’s core handle varying amounts of traffic without requiring dedicated resources for each system can be read by the applica on layer of another. It formats data in a way that is
network, u lizing high-speed core routers and fiber op c links to communica on. understandable to the applica on layer.
traverse the distance quickly and efficiently. - **Flexibility**: They support various types of traffic (voice, video, data) and can **Service Models in Protocol Layers**: Each layer in the OSI model provides specific
adapt to different types of network topologies. services to the layer above it while u lizing services from the layer below. This interac on
4. Significance in Real-World Applica ons 5. **Examples and Applica ons**: Provide examples of packet-switched networks, follows two primary service models:
The core network’s efficiency impacts various services, such as video such as the Internet (based on TCP/IP protocols), Ethernet LANs, and modern cellular - **Connec on-oriented service**: This model ensures reliable data delivery by
streaming, online gaming, and cloud compu ng, where high-speed networks (which use packet-switching for data transmission). establishing a dedicated connec on before transmi ng data. It guarantees that data will
and reliable data transmission are crucial. A robust core network 6. **Challenges**: Briefly discuss challenges associated with packet-switched arrive in the correct order and without errors, using mechanisms like acknowledgment and
networks, such as packet loss, latency varia on, and the need for protocols to retransmission.
ensures that users experience minimal latency and high-quality manage packet delivery and error detec on/recovery. - **Connec onless service**: In this model, data is sent without first establishing a
service. By covering these points, you can provide a comprehensive explana on of packet- dedicated connec on. It is typically faster but less reliable than connec on-oriented
switched networks suitable for a 5-mark answer in a computer networks context. service.These service models dictate how data is handled and delivered between devices at
Each point contributes to a deeper understanding of how data is transmi ed and each layer of the OSI model, ensuring efficient and reliable communica on across diverse
This detailed explana on covers the essen al aspects of the network environments. Each layer’s protocols and services collec vely enable the complex
managed in such networks.
network core, emphasizing its defini on, components, and real- func onality of modern computer networks, suppor ng everything from simple web
world applica on browsing to intricate global communica ons.

Unit II 5. Explain the web and HTTP 6.FTP

4. Explain in detail about principles of network applica ons In computer networks, the World Wide Web (WWW) and the Hypertext Transfer Protocol FTP (File Transfer Protocol) is a standard network protocol used for transferring files
In computer networks, network applica ons are so ware programs that use the network (HTTP) are founda onal components that facilitate the exchange of informa on and between a client and a server on a computer network. Here’s an explana on of FTP in
to perform tasks such as exchanging emails, browsing websites, or accessing remote files. resources across the Internet. Here’s an explana on of the web and HTTP: computer networks:
The principles underlying network applica ons are crucial for understanding how these 1. **World Wide Web (WWW)**: - **Defini on**: The World Wide Web is a system of 1. **Defini on**: - FTP is a protocol that defines how files should be exchanged between
applica ons interact with each other and with the underlying network infrastructure. interconnected hypertext documents accessed via the Internet. It allows users to view and computers over a TCP/IP network, such as the Internet.
Here’s an explana on of the principles of network applica ons: interact with text, images, videos, and other mul media content. - It operates on a client-server model where one computer acts as the FTP client ini a ng
1. **Client-Server Model**: - **Principle**: The web operates on the client-server model, where web browsers requests, and another as the FTP server responding to those requests.
- **Defini on**: This model defines roles in network applica ons where one device (the (clients) request web pages and resources from web servers. These web pages are typically 2. **Working Principle**: - **Client-Server Interac on**:
client) requests services or resources from another device (the server). wri en in Hypertext Markup Language (HTML) and may include other resources such as - The FTP client connects to the FTP server typically on port 21 (the default control port)
- **Principle**: Clients ini ate requests for services, such as retrieving a web page or CSS (Cascading Style Sheets), JavaScript, and mul media files. using TCP/IP.
downloading a file, while servers respond to these requests by providing the requested - **Key Components**: - **Uniform Resource Locator (URL)**: A URL is a web address - Once connected, the client can request to download (retrieve) files from the server or
resources. This model allows for scalable and efficient resource sharing across networks. that iden fies the loca on of resources on the web. It consists of a protocol (e.g., HTTP, upload (store) files to the server.
2. **Peer-to-Peer Model**: - **Defini on**: In contrast to the client-server model, the HTTPS), domain name (e.g., www.example.com), and specific resource path. - **Authen ca on**:
peer-to-peer (P2P) model allows individual devices (peers) to act as both clients and - **Hyperlinks**: Hyperlinks are clickable elements within web pages that allow users - Users typically authen cate themselves using a username and password to access files
servers to share resources directly with each other. to navigate between different pages or resources on the web. on the FTP server. Some servers may allow anonymous FTP access, where users log in with
- **Principle**: Peers collaborate by sharing files, distribu ng processing tasks, or 2. **Hypertext Transfer Protocol (HTTP)**: - **Defini on**: HTTP is the protocol used for a generic username like "anonymous" or " p" and provide their email address as a
collec vely contribu ng to a network’s func onality. P2P networks are decentralized and transmi ng web pages and other resources over the Internet. It defines how messages are password.
can dynamically adapt to changes in network condi ons or peer availability. forma ed and transmi ed between clients (web browsers) and servers (web servers). 3. **Features and Commands**:- **File Opera ons**: FTP supports basic file opera ons
3. **Service Models**: - **Connec on-oriented**: Applica ons that require a reliable and - **Principle**: HTTP operates on a request-response model, where: such as uploading, downloading, renaming, and dele ng files and directories on the server.
ordered data delivery mechanism use connec on-oriented service models. Examples - **Client**: Sends HTTP requests to the server, specifying the type of request (e.g., GET - **Directory Naviga on**: Users can navigate through directories on the server to locate
include file transfer protocols (e.g., FTP) and email transmission (e.g., SMTP). for retrieving resources, POST for submi ng data). specific files for transfer.
- **Connec onless**: Applica ons that priori ze speed and do not require a dedicated - **Server**: Receives and processes the HTTP request, then sends back an HTTP - **Transfer Modes**: FTP supports two transfer modes:
connec on use connec onless service models. Examples include DNS (Domain Name response containing the requested resource (e.g., HTML document, image, video). - **ASCII mode**: Used for transferring text files, where line terminators are converted
System) for domain name resolu on and UDP-based applica ons for real- me - **Key Features**: as necessary between the client and server.
communica on (e.g., VoIP). - **Stateless**: HTTP is stateless, meaning each request-response cycle is independent - **Binary mode**: Used for transferring non-text files, preserving the exact file
4. **Protocols and APIs**: - **Protocols**: Network applica ons rely on protocols (e.g., and does not retain informa on about previous interac ons. This simplifies contents without modifica on.
HTTP, FTP, SMTP) that define rules and formats for communica on between devices. These implementa on but requires addi onal mechanisms (e.g., cookies, sessions) for - **Passive and Ac ve Mode**: FTP supports both passive and ac ve data transfer
protocols ensure compa bility and standardiza on across different systems and networks. maintaining state between requests. modes:
- **APIs (Applica on Programming Interfaces)**: APIs provide a set of func ons and - **Methods**: HTTP defines several methods (GET, POST, PUT, DELETE, etc.) that - **Ac ve mode**: The server ini ates a data connec on to the client.
procedures that allow developers to create network-aware applica ons. They abstract the specify the ac on to be performed on a resource. For example, GET retrieves data, while - **Passive mode**: The client ini ates a data connec on to the server. Passive mode is
complexi es of network communica on, providing a standardized interface for accessing POST submits data to be processed. more commonly used due to firewall and NAT (Network Address Transla on)
network services and resources. 3. **Web Architecture** - **Client**: Web browsers (e.g., Chrome, Firefox) render HTML considera ons.
5. **Security and Reliability**:- **Security**: Network applica ons must ensure data pages received from servers and handle user interac ons such as clicking links and 4. **Security**:- Tradi onal FTP transmits user creden als and file contents in plain text,
integrity, confiden ality, and availability. Secure protocols (e.g., HTTPS, SSH) and submi ng forms. making it vulnerable to intercep on (eavesdropping). FTPS (FTP Secure) and SFTP (SSH File
encryp on mechanisms (e.g., TLS/SSL) protect sensi ve data from unauthorized access and - **Server**: Web servers (e.g., Apache, Nginx) store and serve web content in response Transfer Protocol) are secure alterna ves that encrypt data using SSL/TLS or SSH
a acks. - **Reliability**: Reliable delivery mechanisms (e.g., TCP) and error handling to client requests. They may dynamically generate web pages using server-side respec vely, ensuring confiden ality and integrity during transmission.
protocols (e.g., TCP’s acknowledgment and retransmission mechanism) ensure that data is technologies like PHP, Python, or Node.js. 5. **Use Cases**: - FTP is widely used for transferring large files or collec ons of files over
transmi ed accurately and completely across networks. - **Protocols**: Besides HTTP, secure variants like HTTPS (HTTP over SSL/TLS) encrypt networks, par cularly in scenarios where real- me collabora on or remote access to files
data for secure transmission, ensuring confiden ality and integrity of web is required. - It is commonly employed in web development for uploading website content
1. Understanding these principles helps in designing, developing, and deploying communica ons. to web servers, in backup opera ons for transferring backup files to remote storage, and in
network applica ons that effec vely u lize network resources while maintaining Understanding the web and HTTP is crucial for developers, network administrators, and publishing environments for distribu ng files to content distribu on networks (CDNs).
security and reliability. Each principle plays a crucial role in shaping the behavior and users alike, as it forms the basis of how informa on is accessed and transmi ed across the Understanding FTP is essen al for network administrators and developers working with file
performance of applica ons in diverse network environments. Internet. These technologies enable the rich mul media experience and global transfer opera ons across computer networks, providing a straigh orward and versa le
connec vity that characterize modern web browsing and online services. method for managing files remotely.
7. DNS Unit III 9. Explain in detail about connec onless and connec on oriented protocol
DNS (Domain Name System) is a crucial component of computer networks that 8. Mul plexing and demul plexing in detail In computer networks, communica on protocols can be broadly categorized into
translates domain names into IP addresses, allowing devices to locate resources on Mul plexing and demul plexing are essen al concepts in computer networks that connec onless and connec on-oriented protocols, each offering dis nct methods for
the Internet. Here’s an explana on of DNS in computer networks: involve combining mul ple data streams into a single transmission channel transmi ng data. Here's an explana on of each:
1. **Defini on**: - DNS is a hierarchical distributed naming system for computers, (mul plexing) and separa ng them back into individual streams at the receiving end 1. **Connec onless Protocol**: A connec onless protocol does not establish a
services, or any resource connected to the Internet or a private network. It associates (demul plexing). Here’s an explana on of mul plexing and demul plexing in detail: dedicated connec on before transmi ng data. Instead, each packet is treated
various informa on with domain names assigned to each of the par cipa ng en e 1. **Mul plexing**: independently and may take different paths to reach its des na on. • The sender
• - DNS enables users to type domain names (e.g., www.example.com) into web - **Defini on**: Mul plexing is the process of combining mul ple data streams simply sends packets into the network without prior nego a on or establishment of
browsers instead of IP addresses (e.g., 192.0.2.1), making it easier to remember and into a single stream for transmission over a shared medium or channel. a session. Each packet includes the des na on address, allowing routers to
access resources. - **Purpose**: Mul plexing allows efficient u liza on of network resources by independently forward packets based on the current network condi ons. • User
2. **Working Principle**:- **Domain Name Resolu on**: When a user enters a enabling mul ple signals or data streams to share the same communica on channel Datagram Protocol (UDP)** is a prominent connec onless protocol used in network
domain name in a web browser or applica on, the DNS resolver (usually provided by simultaneously. applica ons where speed and efficiency are priori zed over reliability. Examples
the ISP or configured locally) ini ates a query to find the corresponding IP address. - **Techniques**: • - **Frequency Division Mul plexing (FDM)**: In FDM, mul ple include real- me applica ons like video streaming, VoIP (Voice over IP), online
- **Hierarchy**: DNS operates in a hierarchical manner, with mul ple levels of DNS signals are combined for transmission by alloca ng each signal a unique frequency gaming, and DNS (Domain Name System) queries.
servers organized into a global hierarchy • - **Root DNS Servers**: These servers band within the channel. This is commonly used in analog communica on systems - **Characteris cs**: • **No Connec on Establishment**: No ini al handshake or
are at the top of the hierarchy and maintain informa on about the authorita ve DNS like radio broadcas ng. •**Time Division Mul plexing (TDM)**: In TDM, mul ple session setup is required between sender and receiver. • - **Unreliable Delivery**:
servers for top-level domains (TLDs) like .com, .org, .net, etc. • **TLD DNS Servers**: signals are interleaved in the me domain. Each signal is assigned a me slot within a Packets may arrive out of order, duplicated, or lost due to network conges on or
These servers store informa on specific to their domain extensions (e.g., .com, .org). fixed me frame, and data is transmi ed sequen ally in these slots. TDM is widely errors.
- **Authorita ve DNS Servers**: These servers store specific DNS records (e.g., A used in digital communica on systems like telephone networks. • - **Sta s cal - **Low Overhead**: Minimal overhead in terms of packet headers and
records for IPv4 addresses, AAAA records for IPv6 addresses, MX records for mail Mul plexing**: Sta s cal mul plexing dynamically allocates bandwidth based on processing, making it suitable for applica ons that can tolerate occasional data loss.
servers) for individual domains. •- **Caching**: DNS resolvers cache DNS records to demand and traffic pa erns, op mizing resource u liza on. Techniques like packet 2. **Connec on-Oriented Protocol**:• A connec on-oriented protocol establishes a
improve efficiency and reduce the load on DNS servers. Cached records have a switching in networks such as Ethernet and the Internet u lize sta s cal dedicated connec on between the sender and receiver before any data transfer
specified me-to-live (TTL) a er which they expire and must be refreshed. mul plexing. occurs. This connec on remains ac ve for the dura on of the communica on
3. **Components and Records**: - **DNS Records**: DNS stores different types of 2. **Demul plexing**: - **Defini on**: Demul plexing is the process of separa ng session. • The protocol follows a three-way handshake process to establish and
records that map domain names to various types of informa on: • - **A Record**: combined data streams back into their individual components upon recep on at the confirm the connec on parameters, ensuring reliable data delivery and
Maps a domain name to an IPv4 address. • - **AAAA Record**: Maps a domain des na on. • - **Purpose**: Demul plexing ensures that each intended recipient acknowledgment between endpoints. •**Transmission Control Protocol (TCP)** is
name to an IPv6 address. • **MX Record**: Specifies the mail servers responsible receives their respec ve data stream accurately and in its original form a er the most widely used connec on-oriented protocol in computer networks. It
for receiving email on behalf of a domain. • **CNAME Record**: Maps an alias transmission over a shared channel. guarantees reliable and ordered delivery of data by using acknowledgments,
(canonical name) to the true domain name. • - **DNS Resolver**: The DNS resolver - **Techniques** • - **Based on Mul plexing Technique**: Demul plexing retransmissions, and flow control mechanisms.
is responsible for ini a ng DNS queries on behalf of clients and caching DNS records. techniques correspond to the mul plexing techniques used: • - In FDM, - **Characteris cs**: • Connec on Establishment**: Before data transfer begins, a
4. **Use Cases**: - **Web Browsing**: DNS resolves domain names to IP demul plexing involves separa ng different frequency bands to extract individual handshake process verifies communica on parameters (e.g., window size, ini al
addresses, allowing users to access websites by typing domain names into web signals. • - In TDM, demul plexing involves iden fying and extrac ng data from sequence numbers). • **Reliable Delivery**: TCP ensures that data arrives at the
browsers • - **Email**: DNS is used to locate mail servers (via MX records) for assigned me slots within the transmi ed frames. • - In sta s cal mul plexing, des na on in the correct order and without errors through acknowledgment of
sending and receiving email messages. • - **Network Services**: DNS is essen al for demul plexing involves iden fying and direc ng packets or data streams based on received packets and retransmission of lost or corrupted packets.
various network services such as VoIP (Voice over IP), FTP (File Transfer Protocol), des na on addresses or iden fiers. 3. **Comparison**: •**Reliability**: Connec on-oriented protocols like TCP offer
and VPN (Virtual Private Network), where domain names are used to access services. 3. **Applica ons**: • **Telecommunica on Networks**: Mul plexing and reliable delivery by guaranteeing that data arrives intact and in order. Connec onless
5. **Security and DNSSEC**: - **Security**: DNS is vulnerable to various a acks demul plexing are fundamental in telecommunica on networks for efficient protocols like UDP do not guarantee reliable delivery and are more suitable for
such as DNS spoofing (DNS cache poisoning) and DNS amplifica on a acks. Measures transmission of voice, data, and video signals. •- **Data Transmission**: In computer applica ons where occasional packet loss is acceptable. • Connec on-oriented
like DNS Security Extensions (DNSSEC) provide authen ca on and data integrity for networks, mul plexing allows mul ple users or applica ons to share network protocols are typically used for applica ons such as web browsing, file transfer, and
DNS responses, preven ng DNS spoofing and ensuring that DNS data has not been resources such as Ethernet cables or wireless channels. • - **Broadcas ng**: In email, where data integrity and sequencing are cri cal. Connec onless protocols are
tampered with. broadcas ng systems (e.g., satellite TV), mul plexing enables mul ple TV channels to preferred for real- me applica ons where speed and efficiency are priori zed over
be transmi ed simultaneously over a single satellite transponder. reliability, such as mul media streaming and online gaming.

10. Explain the concept of TCP conges on control Unit IV

TCP (Transmission Control Protocol) conges on control is a crucial mechanism in 11. Explain in detail about Internet protocol 12. Rou ng algorithm
computer networks that manages the rate at which data is transmi ed between A rou ng algorithm in computer networks refers to the method or set of rules
hosts to avoid network conges on and ensure efficient u liza on of network Sure, here's a detailed explana on of the Internet Protocol (IP) in computer used by routers to determine the op mal path for forwarding data packets from
resources. Here’s an explana on of TCP conges on control in detail: networks: a source to a des na on across a network. Here’s a detailed explana on
1. **Defini on**: •TCP conges on control refers to the set of algorithms and **Internet Protocol (IP):** suitable for 5 marks:
techniques used by TCP to regulate the flow of data between sender and Internet Protocol (IP) is a fundamental protocol used in computer networks **Rou ng Algorithm in Computer Networks:** :Rou ng algorithms are essen al
receiver based on network condi ons. • Its primary goal is to prevent network to facilitate communica on and the rou ng of data packets between in computer networks to efficiently manage and direct the flow of data packets
conges on by adjus ng the transmission rate dynamically in response to devices. It is a part of the TCP/IP protocol suite, which is the standard set of between devices across interconnected networks. The main objec ves of
changes in network conges on levels, packet loss, and available bandwidth. protocols used for communica on on the internet and many private rou ng algorithms include minimizing latency, maximizing throughput, avoiding
2. **Mechanisms**: • - **AIMD (Addi ve Increase, Mul plica ve Decrease)**: networks. network conges on, and ensuring reliable delivery of packets.
- **Addi ve Increase**: When TCP detects that the network is not congested **Key Features of IP:** **Key Characteris cs of Rou ng Algorithms:**
(through ACKs received), it increases its sending rate by a small amount, 1. **Path Determina on:** Rou ng algorithms determine the best path for data
1. **Addressing:** IP provides a unique iden fica on for each device
typically by one segment per RTT (Round-Trip Time) • - **Mul plica ve packets based on various metrics such as hop count (number of intermediate
connected to a network, known as an IP address. These addresses are
Decrease**: If TCP detects packet loss, which indicates conges on, it reduces its devices), delay ( me taken for packet transmission), bandwidth availability, and
either IPv4 (32-bit) or IPv6 (128-bit) format. IPv4 addresses are the most reliability of links.
sending rate significantly, typically by halving the current conges on window
widely used today, but IPv6 is gradually being adopted to address the 2. **Rou ng Metrics:** Different algorithms may priori ze different metrics
size (conges on avoidance phase)• - TCP uses a conges on window (cwnd) to
control the amount of data that can be transmi ed before receiving
exhaus on of IPv4 addresses. depending on network condi ons and requirements. For example,algorithms
acknowledgment from the receiver.• - The size of the conges on window 2. **Rou ng:** IP enables routers (network devices that forward data focus on minimizing hop count for shorter paths, while others priori ze
determines how many packets can be sent before wai ng for acknowledgment, packets between networks) to determine the best path for data packets to available bandwidthleast congested routes.
thereby regula ng the rate of data transmission. travel from the source to the des na on across mul ple networks. This 3. **Types of Rou ng Algorithms:** • - **Distance Vector Rou ng:** Also
3. **Detec on and Reac on to Conges on**: **: TCP interprets packet loss as a process is based on the des na on IP address in each packet. known as Bellman-Ford algorithm, this approach involves routers exchanging
sign of conges on and reduces its transmission rate by performing mul plica ve 3. **Packe za on:** Data transmi ed over IP networks is divided into rou ng tables periodically with their neighbors, upda ng and calcula ng the
decrease.- **Explicit Conges on No fica on (ECN)**: In modern TCP small units called packets. Each packet contains a header with control shortest path based on cumula ve hop counts. • - **Link State Rou ng:**
implementa ons, routers can no fy TCP of impending conges on using ECN informa on, including the source and des na on IP addresses, enabling Used in protocols like OSPF (Open Shortest Path First), routers exchange link-
markings in IP headers, allowing TCP to react before actual packet loss occurs. routers to properly route packets to their intended des na on. state packets to build a detailed network map, calculate shortest paths using
4. **Benefits**:-Efficient Network U liza on: TCP conges on control ensures 4. **Connec onless Protocol: IP is a connec onless protocol, meaning it Dijkstra's algorithm, and maintain consistent rou ng informa on. • - **Path
that network resources are u lized efficiently without overwhelming the does not establish a dedicated connec on between sender and receiver Vector Rou ng:** Similar to distance vector but includes informa on about the
network with too much traffic, which could lead to packet loss and degraded before data transmission. Each packet is treated independently, which en re path to a des na on, enabling be er handling of policy-based rou ng
performance. • Fairness: By adjus ng transmission rates based on network allows for flexibility but does not guarantee reliable delivery or packet and loop preven on.
condi ons (e.g., available bandwidth, round-trip me, packet loss), TCP 4. **Dynamic vs. Sta c Rou ng:** Dynamic rou ng algorithms automa cally
sequencing (these are handled by higher-level protocols like TCP).
conges on control promotes fairness among compe ng flows sharing the same adjust to changes in network topology and traffic condi ons by upda ng rou ng
5. **Version Support:** IP has gone through several versions, with IPv4
network link. tables based on real- me informa on. In contrast, sta c rou ng uses manually
being the predominant version used for several decades. IPv6 was configured paths that do not change unless modified by network administrators.
5. **Implementa ons**: Various TCP conges on control algorithms have been
developed to address the limita ons of IPv4, par cularly the limited 5. **Rou ng Protocol Examples:** Common rou ng protocols that implement
developed over me, such as TCP Reno, TCP New Reno, TCP Vegas, and TCP
number of available addresses, and to accommodate the growing number these algorithms include RIP (Rou ng Informa on Protocol), OSPF, BGP (Border
Cubic, each op mizing different aspects of conges on control like response to
packet loss, fairness, and scalability in high-speed networks.Understanding TCP of devices connec ng to the internet. Gateway Protocol), and EIGRP (Enhanced Interior Gateway Rou ng Protocol),
conges on control is essen al for network administrators and developers to **Conclusion:** In summary, Internet Protocol (IP) is a crucial protocol in each suited for different types of networks and scalability requirements.
op mize network performance, improve throughput, and ensure reliable data computer networks that provides addressing, rou ng, packe za on, and
connec vity services for transmi ng data packets across networks.
 15. Explain in about error detec on and correc on techniques
13. Rou ng Unit V Certainly! Here's an explana on of error detec on and correc on techniques in computer
Rou ng in computer networks is a fundamental process that involves 14. Define mul ple access links & protocols networks.
determining the op mal path for data packets to travel from a source to a Certainly! Here's an explana on of mul ple access links and protocols in **Error Detec on and Correc on Techniques in Computer Networks:**
computer networks Error detec on and correc on techniques are essen al mechanisms used in computer
des na on across a network. Here's a detailed explana on suitable for 5 marks:
**Mul ple Access Links & Protocols in Computer Networks:** : Mul ple access networks to ensure the integrity and reliability of data transmi ed between devices. These
**Rou ng in Computer Networks:** Rou ng refers to the mechanism by which techniques help detect errors that may occur during transmission and, in some cases,
data packets are forwarded from one network device (such as a router) to links refer to communica on channels or links that allow mul ple devices to
correct them to ensure accurate data delivery.
another based on the most efficient path determined by rou ng algorithms. It access and transmit data simultaneously. In computer networks, these links are **Key Techniques:**
ensures that data is delivered reliably and efficiently across interconnected crucial for enabling efficient sharing of network resources among mul ple 1. **Error Detec on:**
networks. devices. Various protocols govern how devices access and share these links to - **Checksums:**
**Key Components of Rou ng:** avoid collisions and ensure orderly transmission of data. - **Defini on:** Checksums are values calculated from the data transmi ed along with
**Key Concepts:** the data itself. Receivers compute checksums based on received data and compare them
1. **Rou ng Table:** Each router maintains a rou ng table that lists available
1. **Mul ple Access Links:** **Defini on:** Mul ple access links are physical with the transmi ed checksum to detect errors.
paths to different network des na ons along with associated metrics (like cost - **Example:** Internet Protocol (IP) uses a checksum field in the header to detect
or distance). These tables are updated dynamically based on changes in network or virtual communica on paths in a network that enable mul ple devices to
errors in IP packets.
topology and rou ng protocol updates. transmit and receive data concurrently • - **Types:** Common types include - **Cyclic Redundancy Check (CRC):**
2. **Rou ng Protocols:** Rou ng protocols are a set of rules and procedures Ethernet (shared medium access), wireless LANs (Wi-Fi), satellite links, and - **Defini on:** CRC is a more robust error detec on technique that generates a fixed-
used by routers to exchange rou ng informa on and maintain updated rou ng broadband cable networks. **Characteris cs:** They support simultaneous size checksum based on the transmi ed data. The receiver recalculates the CRC and
tables. Examples include RIP (Rou ng Informa on Protocol), OSPF (Open access by mul ple devices, which is essen al for achieving efficient u liza on of compares it with the received CRC to detect errors.
Shortest Path First), BGP (Border Gateway Protocol), and EIGRP (Enhanced network resources and accommoda ng diverse communica on needs. - **Example:** Used extensively in Ethernet networks to detect errors in frames
2. **Protocols for Mul ple Access:** - **Carrier Sense Mul ple Access transmi ed over the network.
Interior Gateway Rou ng Protocol). • 3. **Rou ng Algorithms:** These
(CSMA):** - **CSMA/CD (Collision Detec on):** Used in Ethernet networks, 2. **Error Correc on:**
algorithms determine the best path for forwarding packets based on various - **Forward Error Correc on (FEC):**
metrics such as shortest path (e.g., Dijkstra's algorithm), hop count (number of devices listen to the network before transmi ng to avoid collisions. If a collision
- **Defini on:** FEC is a technique where addi onal bits (redundant informa on) are
routers between source and des na on), link state informa on, available is detected, devices wait for a random period before retransmi ng. added to the transmi ed data to allow the receiver to detect and correct errors without
bandwidth, and network conges on. • 5. **Rou ng Decision Process:** When a - **CSMA/CA (Collision Avoidance):** Used in wireless networks (e.g., Wi-Fi), needing retransmission.
router receives a packet, it examines the des na on IP address, searches its devices use a reserva on mechanism to avoid collisions by wai ng for a clear - **Example:** Used in satellite communica on systems and some wireless
rou ng table for a matching entry, and forwards the packet accordingly. If no channel before transmi n** - **Defini on:** Divides a communica on communica on standards like LTE to improve reliability.
channel into me slots, allowing mul ple devices to transmit in assigned me - **Automa c Repeat reQuest (ARQ):**
exact match is found, the router uses its rou ng algorithm to determine the
intervals without overlapping. - **Example:** Used in GSM (Global System for - **Defini on:** ARQ is a protocol that detects errors by acknowledging received data
next best hop towards the des na on. and reques ng retransmission of corrupted or lost packets.
**Importance and Benefits:** : Effec ve rou ng is crucial for network efficiency, Mobile communica ons) networks to allocate specific me slots to each user for
- **Example:** TCP (Transmission Control Protocol) uses ARQ to ensure reliable data
scalability, and reliability. It op mizes resource usage, reduces latency, and transmi ng voice or data. delivery by acknowledging data segments and retransmi ng them if necessary.
ensures that data packets reach their des na ons in a mely manner. Rou ng **Importance and Applica ons:** : Mul ple access links and protocols are **Importance and Applica ons:**
protocols and algorithms play a key role in managing complex networks, cri cal for efficient and scalable communica on in modern computer networks. Error detec on and correc on techniques are crucial for maintaining data integrity and
accommoda ng diverse network topologies, and suppor ng various services They enable mul ple devices to share network resources effec vely, support ensuring reliable communica on in computer networks. They help minimize the impact of
and applica ons. various network architectures (wired and wireless), and facilitate the seamless transmission errors, improve network efficiency, and support the delivery of error-free
opera on of applica ons and services across diverse environments. data across diverse network environments.
**Conclusion: In conclusion, rou ng in computer networks is a dynamic process
**Conclusion:** In conclusion, mul ple access links and protocols are **Conclusion:**
that involves selec ng the best paths for data packets to travel across In conclusion, error detec on and correc on techniques play a vital role in computer
interconnected networks. It relies on rou ng tables, algorithms to ensure founda onal elements of computer networks, enabling concurrent data
networks by detec ng transmission errors and either correc ng them or reques ng
efficient and reliable communica on between devices and networks, transmission by mul ple devices while ensuring efficient resource u liza on retransmission. These techniques are essen al for ensuring data integrity, reliability, and
contribu ng to overall network performance and func onality. and minimizing collisions. Understanding these concepts is essen al for the seamless opera on of communica on protocols and applica ons in modern network
designing and managing robust and high-performance network infrastructures. infrastructures.

16. Discuss Switched Local Area Networks 17. Explain in detail about retrospec ve
Switched Local Area Networks (LANs) are a fundamental component of modern computer In the context of computer networks, "retrospec ve" typically refers to a method or
networks, offering efficient and high-performance connec vity within a limited geographic approach used for troubleshoo ng or analyzing network issues a er they have occurred.
area such as an office building, campus, or data center. Here's a detailed explana on Here's a detailed explana on.
suitable **Retrospec ve in Computer Networks:** Retrospec ve analysis in computer
**Switched Local Area Networks (LANs):** networks involves examining past events, logs, or data to diagnose and
Switched LANs u lize network switches to connect mul ple devices within a local understand network problems, performance issues, or security incidents that
area, enabling direct and simultaneous communica on between devices. Unlike have already occurred. This approach is crucial for maintaining network
tradi onal Ethernet LANs that use hubs, switched LANs provide dedicated bandwidth reliability, op mizing performance, and enhancing overall network
for each device connected to the switch.
management. **Key Aspects:* 1. **Log Analysis:** - Retrospec ve analysis
**Key Features and Components:**
o en involves reviewing logs generated by network devices, servers,
1. **Network Switches:* - **Defini on:** Network switches are devices that
applica ons, and security systems. These logs contain valuable informa on such
operate at the data link layer of the OSI model, forwarding data packets based on
MAC addresses.**Func on:** Switches create dynamic forwarding tables (MAC as events, errors, traffic pa erns, and system states during specific me periods.
address tables) by learning the MAC addresses of connected devices through • Tools and so ware are used to parse, filter, and analyze log data to iden fy
incoming data frames. This enables efficient and direct data transmission between anomalies, errors, or pa erns indica ve of network issues.
devices within the LAN. 2. **Incident Response:** - In the event of a network incident or security
2. **Collision Domain vs. Broadcast Domain:** **Collision Domain:** In tradi onal breach, retrospec ve analysis helps in reconstruc ng the sequence of events
Ethernet hubs, all devices share the same collision domain, which can lead to leading up to and following the incident. This includes iden fying the ini al
collisions and reduced network performance as the number of devices and traffic cause, understanding how the incident propagated, and assessing the impact on
increases.**Broadcast Domain:** Switches break up broadcast domains, meaning network opera ons. - Incident response teams use retrospec ve analysis to
broadcast packets are only forwarded to ports where devices are connected that learn from past incidents, improve response procedures, and strengthen
need to receive them, reducing unnecessary network traffic. network defenses against future threats.
3. **Advantages of Switched LANs:* - **Increased Performance:** Each device on a 3. **Performance Op miza on:** - Retrospec ve analysis is also valuable for
switched LAN has dedicated bandwidth, avoiding the conges on and performance op mizing network performance. By reviewing historical data on network
issues associated with shared media (like in hub-based networks). u liza on, bandwidth consump on, latency metrics, and applica on
- **Enhanced Security:** Switches filter traffic based on MAC addresses, isola ng
performance, network administrators can iden fy bo lenecks, inefficiencies, or
traffic between devices connected to different switch ports and enhancing network
resource constraints.• - Based on this analysis, nfrastructure upgrades to
security. **Scalability:** Switched LANs can easily scale by adding more switches and
improve overall performance and user experience.
connec ng them via backbone links to accommodate growing numbers of devices
and increasing network traffic. 4. **Con nuous Improvement:**- Beyond troubleshoo ng and incident
4. **Applica ons:** Switched LANs are widely used in various environments, response, retrospec ve analysis supports con nuous improvement ini a ves in
including offices, schools, data centers, and enterprise networks. network management. By evalua ng past network changes, upgrades, or
- They support a wide range of applica ons such as file sharing, video conferencing, maintenance ac vi es, organiza ons can assess their effec veness and impact
real- me communica ons, and access to centralized resources like servers and on network performance.
printers. **Conclusion:** In conclusion, retrospec ve analysis plays a cri cal role in
**Conclusion:** In conclusion, Switched Local Area Networks (LANs) provide efficient computer networks by enabling organiza ons to analyze past events,
and reliable connec vity by using network switches to create dedicated troubleshoot network issues, enhance security posture, op mize performance,
communica on paths between devices within a local area. They offer improved and drive con nuous improvement in network management prac ces. By
performance, security, and scalability compared to tradi onal hub-based LANs, leveraging historical dataand maintain a robust and reliable network
making them essen al for modern network infrastructures suppor ng diverse infrastructure.
applica ons and services.