acn note1.pdf.pdf

Ur Engineering Friend Advance Computer Network About Subject ACN ( elective ) -: In Maharashtra State Board of Technical Education (MSBTE) diploma programs, an elective subject is a course that students can choose from a set of options, in addition to the core curriculu...

Ur Engineering Friend Advance Computer Network About Subject ACN ( elective ) -: In Maharashtra State Board of Technical Education (MSBTE) diploma programs, an elective subject is a course that students can choose from a set of options, in addition to the core curriculum. Elective subjects allow students to tailor their education to their interests and career goals by selecting topics that are not mandatory but are available as part of the broader curriculum. These subjects often provide specialized knowledge and skills that can enhance a student's expertise in a particular area of their field. The "Advanced Computer Network" subject in a diploma or engineering program typically covers in- depth topics related to computer networking. The curriculum aims to provide students with a comprehensive understanding of advanced networking concepts, protocols, and technologies. Chapters / Syllabus 1. Network Layers & Protocols 2. Next Generation IP 3. Unicast & Multicast Routing Protocols 4. Transport Layer Protocols 5. Application Layer Protocols Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend Chapter 1 -: Network Layers & Protocols ( Part 1 ) Explain Network Layer -: The network layer, also known as Layer 3 in the OSI (Open Systems Interconnection) model, is responsible for the delivery of packets across different networks. Its primary functions include logical addressing, routing, and packet forwarding, ensuring that data can travel from the source to the destination across multiple interconnected networks. Here's a short note detailing its key aspects: Functions of the Network Layer: 1. Logical Addressing: The network layer assigns unique addresses to devices on a network, using IP addresses (IPv4 or IPv6). This ensures that each device can be uniquely identified and located within the network. Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend 2. Routing: Routing is the process of determining the optimal path for data packets to travel from the source to the destination. Routers, which operate at the network layer, use routing algorithms and protocols (e.g., OSPF, BGP) to find and maintain the best paths. 3. Packet Forwarding: Once the route is determined, the network layer forwards packets to the next hop on the path toward their final destination. This involves making decisions based on the destination IP address and routing tables. 4. Fragmentation and Reassembly: The network layer can break down large packets into smaller fragments to accommodate the maximum transmission unit (MTU) of the underlying data link layer. These fragments are then reassembled at the destination. 5. Error Handling and Diagnostics: The network layer uses protocols like ICMP (Internet Control Message Protocol) to provide error messages and operational information. For instance, ICMP is used in the ping and trace route utilities to diagnose network connectivity issues. 1.1 Explain IP Addressing IP addressing is a fundamental concept in networking, crucial for identifying devices and facilitating communication across networks. It involves assigning unique addresses to devices to ensure they can be located and interact with each other. There are two main versions of IP addresses in use: IPv4 and IPv6. IPv4 Address: A 32-bit numerical address divided into four octets, each ranging from 0 to 255. It is typically represented in decimal format separated by periods, such as 192.168.1.1. Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend IPv6 Address: A 128-bit address, represented as eight groups of four hexadecimal digits, separated by colons (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334). Working of an IP Address ? The working of IP addresses is similar to other languages. It can also use some set of rules to send information. Using these protocols we can easily send, and receive data or files to the connected devices. There are several steps behind the scenes. Let us look at them Your device directly requests your Internet Service Provider which then grants your device access to the web. And an IP Address is assigned to your device from the given range available. Your internet activity goes through your service provider, and they route it back to you, using your IP address. Your IP address can change. For example, turning your router on or off can change your IP Address. When you are out from your home location your home IP address doesn’t accompany you. It changes as you change the network of your device. 1.2 Explain Address Space An address space is the total number of addresses used by the protocol. If a protocol uses N bits to define an address , the address space is 2^N because each bit can have two different values and N bits can have 2^N values. Types of IP IPv4 IPv6 Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend Ipv4 : Internet Protocol version 4. It consists of 4 numbers separated by the dots. Each number can be from 0-255 in decimal numbers. But computers do not understand decimal numbers, they instead change them to binary numbers which are only 0 and 1. Therefore, in binary, this (0-255) range can be written as (00000000 – 11111111). Since each number N can be represented by a group of 8-digit binary digits. So, a whole IPv4 binary address can be represented by 32-bits of binary digits. In IPv4, a unique sequence of bits is assigned to a computer, so a total of (2^32) devices approximately = 4,294,967,296 can be assigned with IPv4. IPv4 can be written as: 189.123.123.90 Ipv6 : But, there is a problem with the IPv4 address. With IPv4, we can connect only the above number of 4 billion devices uniquely, and apparently, there are much more devices in the world to be connected to the internet. So, gradually we are making our way to IPv6 Address Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend which is a 128-bit IP address. In human-friendly form, IPv6 is written as a group of 8 hexadecimal numbers separated with colons(:). But in the computer-friendly form, it can be written as 128 bits of 0s and 1s. Since, a unique sequence of binary digits is given to computers, smartphones, and other devices to be connected to the internet. So, via IPv6 a total of (2^128) devices can be assigned with unique addresses which are actually more than enough for upcoming future generations. IPv6 can be written as: 2011:0bd9:75c5:0000:0000:6b3e:0170:8394 1.3 Explain Notations IP addresses can be represented in various notations to suit different purposes, such as ease of reading, understanding network structure, or performing binary operations. The three common notations are binary notation, hexadecimal notation, and dotted decimal notation. IPv4 Binary Notation Format: A 32-bit binary number. Structure: Divided into four octets (8 bits each), separated by periods. Example: For the IP address 192.168.1.1: o Convert each decimal octet to binary: ▪ 192 -> 11000000 ▪ 168 -> 10101000 ▪ 1 -> 00000001 ▪ 1 -> 00000001 o Binary Notation: 11000000.10101000.00000001.00000001 IPv4 Hexadecimal Notation Format: Four groups of two hexadecimal digits separated by periods. Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend Structure: Each group represents an 8-bit segment of the address. Example: For the IP address 192.168.1.1: o Convert each decimal octet to hexadecimal: ▪ 192 -> C0 ▪ 168 -> A8 ▪ 1 -> 01 ▪ 1 -> 01 o Hexadecimal Notation: C0.A8.01.01 IPv4 Dotted Decimal Notation Format: Four decimal numbers separated by periods. Structure: Each decimal number represents an 8-bit octet. Example: For the IP address 192.168.1.1: o Dotted Decimal Notation: 192.168.1.1 1.4 Explain Classful addressing Classful IP addressing was the original method used to allocate IP addresses in IPv4 networks, dividing the address space into five classes (A, B, C, D, and E) based on the leading bits of the address. This system was used before the introduction of CIDR (Classless Inter-Domain Routing) and is now largely obsolete, but it remains important for understanding the evolution of IP addressing. Structure of IPv4 Addresses IPv4 addresses are 32-bit numbers, typically represented in dotted decimal notation (e.g., 192.168.1.1). In classful addressing, the address space is divided into fixed-length blocks, each assigned to a specific class. Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend Classes of IP Addresses Class A Leading Bits: 0 Address Range: 1.0.0.0 to 126.0.0.0 Default Subnet Mask: 255.0.0.0 (or /8 in CIDR notation) Number of Networks: 128 (2^7, with 0 and 127 reserved) Hosts per Network: 16,777,214 (2^24 - 2, excluding the network and broadcast addresses. Usage: Designed for very large networks with a high number of hosts per network. Example: IP Address: 10.0.0.1 Network Address: 10.0.0.0 Host Range: 10.0.0.1 to 10.255.255.254 Broadcast Address: 10.255.255.255 Class B Leading Bits: 10 Address Range: 128.0.0.0 to 191.255.0.0 Default Subnet Mask: 255.255.0.0 (or /16 in CIDR notation) Number of Networks: 16,384 (2^14) Hosts per Network: 65,534 (2^16 - 2, excluding the network and broadcast addresses) Usage: Designed for medium-sized networks with a moderate number of hosts per network. Example: IP Address: 172.16.0.1 Network Address: 172.16.0.0 Host Range: 172.16.0.1 to 172.16.255.254 Broadcast Address: 172.16.255.255 Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend Class C Leading Bits: 110 Address Range: 192.0.0.0 to 223.255.255.0 Default Subnet Mask: 255.255.255.0 (or /24 in CIDR notation) Number of Networks: 2,097,152 (2^21) Hosts per Network: 254 (2^8 - 2, excluding the network and broadcast addresses) Usage: Designed for small networks with a small number of hosts per network. Example: IP Address: 192.168.1.1 Network Address: 192.168.1.0 Host Range: 192.168.1.1 to 192.168.1.254 Broadcast Address: 192.168.1.255 Class D Leading Bits: 1110 Address Range: 224.0.0.0 to 239.255.255.255 Usage: Reserved for multicast groups. It is not used for traditional unicast communication. Subnet Mask: Not applicable. Example: Multicast Group Address: 224.0.0.1 Class E Leading Bits: 1111 Address Range: 240.0.0.0 to 255.255.255.255 Usage: Reserved for experimental purposes. Not used in public networks. Subnet Mask: Not applicable. Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend Advantages and Disadvantages of Classful Addressing Advantages Simplicity: Easy to understand and implement due to fixed classes. Historical Significance: Laid the foundation for IP addressing and routing. Disadvantage Inefficient Use of Address Space: Large networks might waste addresses, and small networks might not have enough addresses. Lack of Flexibility: Fixed class boundaries do not accommodate varying network sizes. Address Exhaustion: Contributed to the rapid depletion of available IPv4 addresses. 1.5 Explain Classless addressing Classless Inter-Domain Routing (CIDR) is another name for classless addressing. This addressing type aids in the more efficient allocation of IP addresses. This technique assigns a block of IP addresses based on specified conditions when the user demands a specific amount of IP addresses. This block is known as a "CIDR block", and it contains the necessary number of IP addresses. When allocating a block, classless addressing is concerned with the following three rules. Rule 1 − The CIDR block's IP addresses must all be contiguous. Rule 2 − The block size must be a power of two to be attractive. Furthermore, the block's size is equal to the number of IP addresses in the block. Rule 3 − The block's first IP address must be divisible by the block size. Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend 1.6 Explain Subnetting Subnetting in computer networking refers to the practice of dividing a larger IP address space into smaller, more manageable subnetworks or subnets. This is done to improve network efficiency, manage IP address allocation, and enhance security and organization within a network. Subnetting allows a single IP address range to be used across different physical or logical segments of a network, helping to control the flow of traffic and manage network resources effectively. In subnetting, an IP address is divided into two parts: the network portion and the host portion. The network portion identifies the specific subnet to which a device belongs, while the host portion identifies the individual device within that subnet. This is accomplished by using a subnet mask, which is a 32-bit value that consists of consecutive "1" bits in the network portion and "0" bits in the host portion. Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend Advantages of Subnetting are : 1. Efficient IP Address Utilization : Subnetting allows organizations to efficiently allocate IP addresses within their network, preventing the wastage of IP addresses. 2. Improved Network Performance : By segmenting the network into smaller subnets, broadcast traffic is contained within each subnet, reducing the overall volume of broadcast traffic on the network and improving performance. 3. Enhanced Security : Subnetting helps to isolate different parts of a network, making it more challenging for unauthorized users or malicious software to move freely within the network. 4. Flexibility and Scalability : Subnetting provides the flexibility to add new devices or subnets without changing the entire IP addressing scheme, making network expansion easier to manage. 5. Simplified Network Management : Smaller subnets are easier to manage and troubleshoot, as network administrators can focus on specific segments of the network at a time. 1.7 Explain Supernetting Supernetting, also known as route aggregation or route summarization, is a technique used in computer networking to reduce the size of routing tables and improve routing efficiency. Unlike subnetting, which involves dividing a larger IP address range into smaller subnets, supernetting involves grouping multiple smaller IP address ranges (subnets) into a larger, summarized address range. This can help reduce the number of entries in routing tables and simplify the routing process within a network. Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend The primary goal of supernetting is to minimize the amount of routing table space required in routers and to make routing decisions more quickly. By aggregating multiple individual routes into a single summarized route, routers can process routing information more efficiently. This is particularly important in large- scale networks where the number of routes can become overwhelming, leading to increased memory and processing requirements for routers. Here's a simplified example to illustrate supernetting: Let's say you have the following three subnets: 1. 192.168.1.0/24 2. 192.168.2.0/24 3. 192.168.3.0/24 Instead of advertising these three separate subnets individually, you can use supernetting to aggregate them into a single route: 192.168.0.0/22 Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend In this example, the /22 subnet mask indicates that the first 22 bits represent the network portion, covering all three original subnets. By advertising the summarized route, routers in the network only need to store one entry in their routing tables for the aggregated subnet, rather than three separate entries. Key benefits of supernetting include: 1. Reduced Routing Table Size : Supernetting reduces the number of entries in routing tables, which helps conserve memory and processing resources in routers. 2. Faster Routing Decisions : With fewer entries to evaluate, routers can make routing decisions more quickly, leading to improved network performance. 3. Simplified Configuration : Managing and configuring routing protocols becomes easier due to the reduced number of routes that need to be exchanged and maintained. 1.8 Explain Masking In advanced computer networks, masking is a technique primarily used in subnetting and IP addressing to separate the network portion of an IP address from the host portion. IP Address: An IP (Internet Protocol) address is a unique identifier assigned to each device connected to a network. It consists of two parts: the network part and the host part. Subnetting: Subnetting is the process of dividing a larger network into smaller, more manageable subnetworks. This helps in improving network performance and security. Subnet Mask: A subnet mask is used to determine which portion of an IP address represents the network and which part represents the host. - The subnet mask has the same format as an IP address (e.g., 255.255.255.0 for IPv4) and works by performing a bitwise AND operation between the IP address and the subnet mask. Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend How Masking Works: Each bit in the subnet mask corresponds to a bit in the IP address. If a bit in the subnet mask is set to 1, the corresponding bit in the IP address is part of the network address. If a bit in the subnet mask is set to 0, the corresponding bit in the IP address is part of the host address. For example, consider the IP address `192.168.1.10` and the subnet mask `255.255.255.0`: In binary form: IP address: `11000000.10101000.00000001.00001010` Subnet mask: `11111111.11111111.11111111.00000000` The network part is extracted by ANDing the IP address with the subnet mask: Network address: `11000000.10101000.00000001.00000000` (192.168.1.0) Advantages of Masking: Efficient IP Address Utilization: Allows for the efficient use of IP addresses by dividing a large network into smaller subnets, reducing wastage. Improved Security: By segmenting networks, it isolates subnetworks, thereby enhancing security. Better Network Management: Simplifies network management by organizing IP addresses into logical groups. Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend 1.9 Explain NAT ( Network Address Translation ) Network Address Translation (NAT) is a technique used in computer networks to modify network address information in IP packet headers while they are in transit across a traffic routing device. This process allows multiple devices on a local network to be mapped to a single public IP address, facilitating internet connectivity and improving security and address conservation. Important Features of NAT 1. Multiple Devices, One IP: NAT allows multiple devices in a home or office to share one public IP address when accessing the internet. 2. Privacy: NAT helps hide the IP addresses of devices in your private network, adding a layer of privacy. 3. Security: By masking internal IP addresses, NAT makes it harder for hackers to directly attack individual devices on your network. 4. Address Conservation: NAT conserves the number of public IP addresses needed, which is important because there are only a limited number of them available. 5. Translation Table: NAT devices (like routers) keep a table to track which private IP addresses correspond to which public IP addresses and ports. 6. Port Forwarding: NAT can be configured to allow external devices to access specific services (like a web server) on your private network through port forwarding. 7. Compatibility: Some older internet applications may not work well with NAT because they expect direct IP-to-IP communication. 8. Dynamic Assignment: With Dynamic NAT, the public IP address assigned to a private IP can change each time a device accesses the internet. 9. Static Assignment: With Static NAT, a specific private IP address always maps to the same public IP address. Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend 10. Common in Routers: Most home and office routers use NAT to manage traffic between the local network and the internet. 11. Essential for IPv4: NAT is especially important for IPv4 networks, where the number of available addresses is limited. How NAT Works 1. Outgoing Traffic (Local to Global): When a device in a private network sends data to the internet, the router or NAT device modifies the source IP address in the IP packet header from the private IP address to the public IP address. The NAT device also modifies the source port number to ensure the return traffic is routed correctly. This is especially true in the case of PAT. The NAT device maintains a translation table that keeps track of which internal private IP addresses and port numbers correspond to which external public IP addresses and port numbers. 2. Incoming Traffic (Global to Local): When a response from the internet reaches the NAT device, it uses the translation table to determine the correct private IP address and port number to forward the packet to. The NAT device then modifies the destination IP address and port number in the packet header to the appropriate private IP address and port number before forwarding the packet to the destination device on the private network. Advantages of NAT 1. IP Address Conservation: By allowing multiple devices on a local network to share a single public IP address, NAT helps to conserve the limited number of available IPv4 addresses. Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel  Ur Engineering Friend 2. Improved Security: NAT hides the internal network structure and IP addresses from the external network, making it harder for external attackers to directly target internal devices. 3. Flexible IP Addressing: NAT allows for the use of private IP addresses internally, which can be easily changed without affecting external communication. Disadvantages of NAT 1. Complexity in Certain Applications: Some applications, especially those requiring peer- to-peer connectivity, VoIP, and online gaming, may face challenges due to the modifications in IP addresses and ports. 2. Performance Overhead: NAT introduces an additional processing overhead on the router or NAT device due to the need to maintain and consult the translation table for every packet. 3. Limited Transparency: NAT can obscure end-to-end connectivity and transparency, making network troubleshooting and monitoring more complex. Join Maharashtra’s No. 1 Online Class – Course Details Youtube Channel