This document discusses internetworking and the key concepts involved. It explains that an internetwork allows different networks to communicate by connecting them through intermediate systems like routers and bridges. There are two main architectural approaches for building an internetwork - connection-oriented which establishes virtual circuits, and connectionless which treats each packet independently. Connectionless is preferred and uses the Internet Protocol (IP). The document outlines the requirements, components, and operation of a connectionless internetwork. It also discusses important design issues like routing, datagram lifetime, fragmentation, error control, and flow control.
Packet switching approaches include datagram and virtual-circuit approaches. The virtual-circuit approach involves three phases: setup, data transfer, and teardown. During setup, routers create entries for a virtual circuit based on request and acknowledgment packets exchanged. This establishes a defined path for network-layer packets to follow, identified by a flow label. Once the virtual circuit is set up, packets can be forwarded independently based only on the flow label. Finally, teardown packets remove the entries from router tables once transfer is complete.
Packet transfer mechanism using routers and IP addresses myrajendra
The document discusses packet transfer mechanisms using routers and IP addresses. It explains that routers forward packets between interconnected networks using routing tables that contain the destination address and interface to route packets. Packets are forwarded either directly, if the source and destination are on the same network, or indirectly by moving from router to router. Forwarding techniques include next hop, network/host specific, default methods. Examples of routing protocols and an example routing table are also provided.
The network layer is responsible for host-to-host delivery of data packets. It provides packetizing, routing, and forwarding services. Packetizing involves encapsulating the transport layer payload with a network header at the source host and decapsulating it at the destination host. Routing determines the best path between source and destination hosts using routing protocols. Forwarding involves routers inspecting packet headers and sending packets to the next network along the path.
This document provides an overview of different types of switches and their structures used in computer networks. It discusses circuit switches, packet switches, and message switches. For structures, it covers space division switches like crossbar and multistage switches. It also discusses time division and time-space-time switches. Specific switch designs covered include Banyan switches, which route packets based on header bits, and Batcher-Banyan switches, which combine a Banyan network with a Batcher network to sort packets and reduce blocking.
This document discusses IP packet forwarding and routing tables. It explains that IP packets can be forwarded either based on the destination address using a connectionless protocol, or based on an attached label using a connection-oriented protocol. Forwarding requires looking up routing information in a forwarding table. The forwarding table structure for classless addressing requires the network mask, address, interface, and next hop router for each route. MPLS allows packets to be forwarded like routers, based on destination address, or like switches, based on an attached label.
The network layer is responsible for delivering packets from source to destination. It must know the topology of the subnet and choose appropriate paths. When sources and destinations are in different networks, the network layer must deal with these differences. The network layer uses logical addressing that is independent of the underlying physical network. Routing ensures packets are delivered through routers and switches from source to destination across interconnected networks.
Computer networking devices allow computers to communicate over a network. A network interface card (NIC) connects each computer to the network. Hubs connect multiple devices and broadcast all data to every port. Switches examine destination addresses and forward frames to the specific port, improving efficiency over hubs. Routers connect different networks and determine the best route to forward packets between networks.
Packet switching approaches include datagram and virtual-circuit approaches. The virtual-circuit approach involves three phases: setup, data transfer, and teardown. During setup, routers create entries for a virtual circuit based on request and acknowledgment packets exchanged. This establishes a defined path for network-layer packets to follow, identified by a flow label. Once the virtual circuit is set up, packets can be forwarded independently based only on the flow label. Finally, teardown packets remove the entries from router tables once transfer is complete.
Packet transfer mechanism using routers and IP addresses myrajendra
The document discusses packet transfer mechanisms using routers and IP addresses. It explains that routers forward packets between interconnected networks using routing tables that contain the destination address and interface to route packets. Packets are forwarded either directly, if the source and destination are on the same network, or indirectly by moving from router to router. Forwarding techniques include next hop, network/host specific, default methods. Examples of routing protocols and an example routing table are also provided.
The network layer is responsible for host-to-host delivery of data packets. It provides packetizing, routing, and forwarding services. Packetizing involves encapsulating the transport layer payload with a network header at the source host and decapsulating it at the destination host. Routing determines the best path between source and destination hosts using routing protocols. Forwarding involves routers inspecting packet headers and sending packets to the next network along the path.
This document provides an overview of different types of switches and their structures used in computer networks. It discusses circuit switches, packet switches, and message switches. For structures, it covers space division switches like crossbar and multistage switches. It also discusses time division and time-space-time switches. Specific switch designs covered include Banyan switches, which route packets based on header bits, and Batcher-Banyan switches, which combine a Banyan network with a Batcher network to sort packets and reduce blocking.
This document discusses IP packet forwarding and routing tables. It explains that IP packets can be forwarded either based on the destination address using a connectionless protocol, or based on an attached label using a connection-oriented protocol. Forwarding requires looking up routing information in a forwarding table. The forwarding table structure for classless addressing requires the network mask, address, interface, and next hop router for each route. MPLS allows packets to be forwarded like routers, based on destination address, or like switches, based on an attached label.
The network layer is responsible for delivering packets from source to destination. It must know the topology of the subnet and choose appropriate paths. When sources and destinations are in different networks, the network layer must deal with these differences. The network layer uses logical addressing that is independent of the underlying physical network. Routing ensures packets are delivered through routers and switches from source to destination across interconnected networks.
Computer networking devices allow computers to communicate over a network. A network interface card (NIC) connects each computer to the network. Hubs connect multiple devices and broadcast all data to every port. Switches examine destination addresses and forward frames to the specific port, improving efficiency over hubs. Routers connect different networks and determine the best route to forward packets between networks.
1) Computer networks allow computers to communicate and share resources by connecting them through communication channels. There are several types of networks including LANs, WANs, and MANs.
2) For communication between computers on a network, both sides must agree on protocols which are sets of rules that govern data transmission. The two main protocol stacks are OSI and TCP/IP.
3) The network layer is responsible for delivering packets from source to destination by choosing appropriate paths through routers. It provides connectionless and connection-oriented services to the transport layer above it.
1) In a connectionless datagram subnet, packets are routed independently without establishing a connection. Routers break messages into packets that are forwarded based on internal routing tables.
2) In a connection-oriented virtual circuit subnet, a connection path must be established before packets can be sent. Each packet carries an identifier of its virtual circuit. Routers replace circuit identifiers to avoid conflicts at downstream routers.
3) Both approaches were compared, noting that connectionless datagrams require no setup but have independent routing, while virtual circuits require setup but can forward all packets along the same pre-established path.
The Network Layer is concerned about getting packets from source to destination, no matter how many hops it may take. It’s all about routing.
5.1 Network Layer Design Issues
What do we need to think about in this layer?
5.2 Routing Algorithms
Strategies for getting from source to destination.
5.3 Congestion Control Algorithms
How do we keep from bottlenecking from too many packets?
5.4 Internetworking
Working with multiple networks and protocols in order to deliver packets.
5.5 The Network Layer in the Internet
Gluing together a collection of subnets.
Lab Seminar 2009 12 01 Message Drop Reduction And Movementtharindanv
The document describes a proposed cluster-based ad hoc network for a home environment using description-based addressing and routing. Key points:
- Nodes are clustered based on their physical locations in the home. Cluster heads route messages between clusters.
- Descriptions like "kitchen television" are used for addressing instead of IP addresses. Routing uses partial name matches to route in the general direction of the destination.
- A directional routing cache stores partial names of other clusters to route between clusters not directly connected. It is divided proportionally between outgoing links.
- Simulations show this approach achieves 100% delivery success rate with low message misdirection compared to a single non-directional cache. Introdu
The document summarizes routing tables and routing algorithms. It discusses how routing tables are structured with an array of buckets containing linked lists of route records. It describes the data fields within each route record and how routing lookups and maintenance are performed using procedures like netnum, netmatch, netmask, rthash, and rtget.
The Network Layer is concerned about getting packets from source to destination, no matter how many hops it may take. It’s all about routing.
5.1 Network Layer Design Issues
What do we need to think about in this layer?
5.2 Routing Algorithms
Strategies for getting from source to destination.
5.3 Congestion Control Algorithms
How do we keep from bottlenecking from too many packets?
5.4 Internetworking
Working with multiple networks and protocols in order to deliver packets.
5.5 The Network Layer in the Internet
Gluing together a collection of subnets.
Performance Observation of Proactive and Reactive Routing Protocols with Incr...Computer Science Journals
Mobile Ad-hoc network (MANET) is type of wireless network in which group of mobile nodes co-operate to forward the data packets to their neighbours without using centralized authority or any physical medium like cables or base station.
The document outlines Chapter 4 of a networking textbook. Chapter 4 covers the network layer, including network layer services, how routers work, routing algorithms, and implementations in the Internet. The key topics covered are virtual circuit versus datagram networks, the functions of routers including forwarding and routing, and routing algorithms like link state and distance vector.
1) Computer networks allow communication and sharing of resources between computer systems and devices through communication channels. There are several types of networks including LANs, WANs, and MANs.
2) For communication between systems, both must agree on a protocol which sets rules for data transmission. The two main protocol stacks are OSI and TCP/IP.
3) The network layer is responsible for delivering packets from source to destination. It uses services from the data link layer and provides services to the transport layer. Common network layer protocols are IP (Internet Protocol) for connectionless service and MPLS for connection-oriented service.
The document discusses the network layer in computer networking. It describes how the network layer is responsible for routing packets from their source to destination. It covers different routing algorithms like distance vector routing and link state routing. It also compares connectionless and connection-oriented services, as well as datagram and virtual circuit subnets. Key aspects of routing algorithms like optimality, stability, and fairness are defined.
Computer Communication Networks-Network LayerKrishna Nanda
The document discusses the network layer in computer networks. It describes that the network layer is responsible for packetizing data by encapsulating it and adding headers, routing packets from source to destination by determining the best path, and forwarding packets through routers along the path. It explains the two main approaches used at the network layer - connectionless datagram service where each packet is routed independently, and connection-oriented virtual circuit service where a connection is established and packets follow the same path.
The document discusses network layer performance and congestion control. It covers key network layer performance metrics like delay, throughput and packet loss. It then discusses various sources of delay like transmission, propagation, processing and queuing delays. It also discusses throughput and packet loss. The second half of the document focuses on congestion control techniques including open-loop methods like retransmission policies and closed-loop methods like backpressure and explicit signaling.
The document outlines the key concepts in the network layer chapter, including:
- The functions of the network layer including forwarding, routing, and connection setup in some architectures.
- The differences between virtual circuit and datagram networks and how routers and forwarding work differently in each.
- An overview of the main components and functions of a router, including routing processors, switching fabrics, input/output ports, and forwarding tables.
- Details on IP as the main network layer protocol used in the Internet, including its datagram format, addressing, and fragmentation.
The document compares layer 3 switches and routers. It discusses their differences in performance, cost, port density, flexibility and supported protocols. Layer 3 switches are faster than routers for routing within a LAN but routers can connect LANs, MANs and WANs. They both support static and dynamic routing protocols, though layer 3 switches have limitations. While routers have more capabilities, layer 3 switches are more cost effective for high-speed inter-VLAN routing within a LAN. Both devices are needed to build a fully functional network.
Routing is the process of moving information across an internetwork from a source to a destination. There are two types of routing: direct delivery where the source and destination are on the same network, and indirect delivery where packets travel through multiple routers to reach the destination on a different network. Distance vector routing protocols like RIP use hop count as the metric and periodically share routing tables with neighboring routers to allow all routers to learn the optimal paths. However, this can cause instability issues like two-node and three-node loops where routers incorrectly update their routing tables.
The document discusses key concepts about the network layer, including:
1) The network layer is responsible for transporting data segments from the sending host to the receiving host by encapsulating segments into datagrams. Network layer protocols exist in every host and router.
2) The main functions of the network layer are forwarding, which moves packets through routers from input to output, and routing, which determines the best path from source to destination using routing algorithms.
3) Network layers can provide either a connection-oriented service using virtual circuits, which require call setup, or a connectionless service using datagrams as in the Internet protocol.
This document discusses routing basics, including routing components, algorithms, and metrics. It provides an overview of the key concepts in routing, including:
- Routing involves determining optimal paths and packet switching along those paths. Path determination uses metrics and routing tables.
- Common routing algorithm types include static, dynamic, single-path, multipath, flat, and hierarchical. Link-state and distance vector algorithms differ in how routing information is shared.
- Routing metrics like path length, reliability, delay, bandwidth, and load are used to evaluate the best path between nodes.
The document discusses network layer design issues and protocols. It covers store-and-forward packet switching, the functions of the network layer including routing and congestion control. It then describes the implementation of connectionless and connection-oriented services, comparing virtual circuits and datagrams. Various routing algorithms are also summarized, such as shortest path, flooding, distance vector, and link state routing.
The document discusses creating and inserting nodes in HTML DOM using JavaScript. It describes how to create comment, element and text nodes using createComment(), createElement(), and createTextNode() respectively. It also explains how to create attributes using createAttribute(). Finally, it provides examples of inserting new elements into the document using insertBefore() and appendChild(), demonstrating how to insert a new paragraph before an existing <div> element.
The document discusses various CSS properties for controlling dimensions, positioning, and visibility of elements. It provides examples of using height, width, float, clear, and display properties to position images and text on a page. It also shows how to create a horizontal navigation menu using float and inline properties.
1) Computer networks allow computers to communicate and share resources by connecting them through communication channels. There are several types of networks including LANs, WANs, and MANs.
2) For communication between computers on a network, both sides must agree on protocols which are sets of rules that govern data transmission. The two main protocol stacks are OSI and TCP/IP.
3) The network layer is responsible for delivering packets from source to destination by choosing appropriate paths through routers. It provides connectionless and connection-oriented services to the transport layer above it.
1) In a connectionless datagram subnet, packets are routed independently without establishing a connection. Routers break messages into packets that are forwarded based on internal routing tables.
2) In a connection-oriented virtual circuit subnet, a connection path must be established before packets can be sent. Each packet carries an identifier of its virtual circuit. Routers replace circuit identifiers to avoid conflicts at downstream routers.
3) Both approaches were compared, noting that connectionless datagrams require no setup but have independent routing, while virtual circuits require setup but can forward all packets along the same pre-established path.
The Network Layer is concerned about getting packets from source to destination, no matter how many hops it may take. It’s all about routing.
5.1 Network Layer Design Issues
What do we need to think about in this layer?
5.2 Routing Algorithms
Strategies for getting from source to destination.
5.3 Congestion Control Algorithms
How do we keep from bottlenecking from too many packets?
5.4 Internetworking
Working with multiple networks and protocols in order to deliver packets.
5.5 The Network Layer in the Internet
Gluing together a collection of subnets.
Lab Seminar 2009 12 01 Message Drop Reduction And Movementtharindanv
The document describes a proposed cluster-based ad hoc network for a home environment using description-based addressing and routing. Key points:
- Nodes are clustered based on their physical locations in the home. Cluster heads route messages between clusters.
- Descriptions like "kitchen television" are used for addressing instead of IP addresses. Routing uses partial name matches to route in the general direction of the destination.
- A directional routing cache stores partial names of other clusters to route between clusters not directly connected. It is divided proportionally between outgoing links.
- Simulations show this approach achieves 100% delivery success rate with low message misdirection compared to a single non-directional cache. Introdu
The document summarizes routing tables and routing algorithms. It discusses how routing tables are structured with an array of buckets containing linked lists of route records. It describes the data fields within each route record and how routing lookups and maintenance are performed using procedures like netnum, netmatch, netmask, rthash, and rtget.
The Network Layer is concerned about getting packets from source to destination, no matter how many hops it may take. It’s all about routing.
5.1 Network Layer Design Issues
What do we need to think about in this layer?
5.2 Routing Algorithms
Strategies for getting from source to destination.
5.3 Congestion Control Algorithms
How do we keep from bottlenecking from too many packets?
5.4 Internetworking
Working with multiple networks and protocols in order to deliver packets.
5.5 The Network Layer in the Internet
Gluing together a collection of subnets.
Performance Observation of Proactive and Reactive Routing Protocols with Incr...Computer Science Journals
Mobile Ad-hoc network (MANET) is type of wireless network in which group of mobile nodes co-operate to forward the data packets to their neighbours without using centralized authority or any physical medium like cables or base station.
The document outlines Chapter 4 of a networking textbook. Chapter 4 covers the network layer, including network layer services, how routers work, routing algorithms, and implementations in the Internet. The key topics covered are virtual circuit versus datagram networks, the functions of routers including forwarding and routing, and routing algorithms like link state and distance vector.
1) Computer networks allow communication and sharing of resources between computer systems and devices through communication channels. There are several types of networks including LANs, WANs, and MANs.
2) For communication between systems, both must agree on a protocol which sets rules for data transmission. The two main protocol stacks are OSI and TCP/IP.
3) The network layer is responsible for delivering packets from source to destination. It uses services from the data link layer and provides services to the transport layer. Common network layer protocols are IP (Internet Protocol) for connectionless service and MPLS for connection-oriented service.
The document discusses the network layer in computer networking. It describes how the network layer is responsible for routing packets from their source to destination. It covers different routing algorithms like distance vector routing and link state routing. It also compares connectionless and connection-oriented services, as well as datagram and virtual circuit subnets. Key aspects of routing algorithms like optimality, stability, and fairness are defined.
Computer Communication Networks-Network LayerKrishna Nanda
The document discusses the network layer in computer networks. It describes that the network layer is responsible for packetizing data by encapsulating it and adding headers, routing packets from source to destination by determining the best path, and forwarding packets through routers along the path. It explains the two main approaches used at the network layer - connectionless datagram service where each packet is routed independently, and connection-oriented virtual circuit service where a connection is established and packets follow the same path.
The document discusses network layer performance and congestion control. It covers key network layer performance metrics like delay, throughput and packet loss. It then discusses various sources of delay like transmission, propagation, processing and queuing delays. It also discusses throughput and packet loss. The second half of the document focuses on congestion control techniques including open-loop methods like retransmission policies and closed-loop methods like backpressure and explicit signaling.
The document outlines the key concepts in the network layer chapter, including:
- The functions of the network layer including forwarding, routing, and connection setup in some architectures.
- The differences between virtual circuit and datagram networks and how routers and forwarding work differently in each.
- An overview of the main components and functions of a router, including routing processors, switching fabrics, input/output ports, and forwarding tables.
- Details on IP as the main network layer protocol used in the Internet, including its datagram format, addressing, and fragmentation.
The document compares layer 3 switches and routers. It discusses their differences in performance, cost, port density, flexibility and supported protocols. Layer 3 switches are faster than routers for routing within a LAN but routers can connect LANs, MANs and WANs. They both support static and dynamic routing protocols, though layer 3 switches have limitations. While routers have more capabilities, layer 3 switches are more cost effective for high-speed inter-VLAN routing within a LAN. Both devices are needed to build a fully functional network.
Routing is the process of moving information across an internetwork from a source to a destination. There are two types of routing: direct delivery where the source and destination are on the same network, and indirect delivery where packets travel through multiple routers to reach the destination on a different network. Distance vector routing protocols like RIP use hop count as the metric and periodically share routing tables with neighboring routers to allow all routers to learn the optimal paths. However, this can cause instability issues like two-node and three-node loops where routers incorrectly update their routing tables.
The document discusses key concepts about the network layer, including:
1) The network layer is responsible for transporting data segments from the sending host to the receiving host by encapsulating segments into datagrams. Network layer protocols exist in every host and router.
2) The main functions of the network layer are forwarding, which moves packets through routers from input to output, and routing, which determines the best path from source to destination using routing algorithms.
3) Network layers can provide either a connection-oriented service using virtual circuits, which require call setup, or a connectionless service using datagrams as in the Internet protocol.
This document discusses routing basics, including routing components, algorithms, and metrics. It provides an overview of the key concepts in routing, including:
- Routing involves determining optimal paths and packet switching along those paths. Path determination uses metrics and routing tables.
- Common routing algorithm types include static, dynamic, single-path, multipath, flat, and hierarchical. Link-state and distance vector algorithms differ in how routing information is shared.
- Routing metrics like path length, reliability, delay, bandwidth, and load are used to evaluate the best path between nodes.
The document discusses network layer design issues and protocols. It covers store-and-forward packet switching, the functions of the network layer including routing and congestion control. It then describes the implementation of connectionless and connection-oriented services, comparing virtual circuits and datagrams. Various routing algorithms are also summarized, such as shortest path, flooding, distance vector, and link state routing.
The document discusses creating and inserting nodes in HTML DOM using JavaScript. It describes how to create comment, element and text nodes using createComment(), createElement(), and createTextNode() respectively. It also explains how to create attributes using createAttribute(). Finally, it provides examples of inserting new elements into the document using insertBefore() and appendChild(), demonstrating how to insert a new paragraph before an existing <div> element.
The document discusses various CSS properties for controlling dimensions, positioning, and visibility of elements. It provides examples of using height, width, float, clear, and display properties to position images and text on a page. It also shows how to create a horizontal navigation menu using float and inline properties.
This document discusses the JavaScript Object Model. It describes how JavaScript can access and modify HTML element values. While each browser originally had its own document object model, newer standardized models add common properties and methods. These include properties to access elements, styles, and child nodes as well as methods to modify attributes, insert content, and more. The document provides examples of using the object model to retrieve forms, anchors, links and other page elements in order to manipulate them with JavaScript.
The document discusses Document Object Model (DOM) trees and nodes. It provides examples of HTML code and how it can be represented as a DOM tree with different node types. It then explains DOM node properties like nodeName, nodeType, parentNode etc. and provides examples of how to access and display these properties for various nodes in a DOM tree using JavaScript.
The document discusses layered network architecture and the ISO/OSI model. It begins by defining layered architecture as consisting of layers that divide communication functionality. Each layer provides services to the layer above it. There are then questions and answers about specific aspects of layers and the ISO/OSI model. Key points covered include that layers are required to divide complexity, peer-to-peer communication is between corresponding layers on different machines, and encapsulation is the process of adding headers at each layer. The ISO/OSI model contains 7 layers, with the application layer interacting with applications, and presentation layer responsible for translation, encryption, and data compression.
This document provides an overview of key concepts that will be covered in Lecture 2 of a Javascript course, including arrays, expressions and operators, functions, if/else and switch constructs, and loop constructs like for, while, and do-while loops. It also discusses data types in Javascript like integers, characters, strings, floats, and booleans. The summary defines arrays as collections of data of the same type with indexes starting at 0. It explains that functions are reusable blocks of code that can accept parameters and return values. Conditionals like if/else and switch-case are covered as constructs to control program flow based on conditions.
The document discusses transport layer protocols and services. It covers:
- The transport layer provides end-to-end data transport and shields users from network details. It has connection-oriented and connectionless services like TCP and UDP.
- Key functions of the transport layer with a reliable underlying network include addressing, multiplexing, flow control, and connection establishment/termination.
- Connection establishment allows negotiation of parameters and ensures both ends exist before data transfer. Flow control prevents buffer overflows using techniques like sliding windows or credit allocation.
This assignment requires students to design a web page that displays a different banner each time the page is refreshed by randomly selecting from a set of 6 banners, building on what was covered in class.
The network layer is responsible for end-to-end packet delivery across multiple hops between source and destination devices. It must choose appropriate paths through the network topology to avoid overloading some links while leaving others idle. The network layer deals with issues like routing, logical addressing, and internetworking between different network types. The main functions of the network layer are routing, logical addressing, internetworking, and fragmentation.
The document discusses various types of network hardware including bridges, hubs, switches, and routers. Bridges operate at the data link layer and forward packets based on physical addresses. Hubs simply repeat all signals received on one port to all other ports. Switches are smarter than hubs and only forward frames to the port associated with the destination address. Routers operate at the network layer and filter traffic based on logical IP addresses, allowing different network types to connect. Routing tables map destination networks to the next hop, whether a directly connected network or the address of the next downstream router.
Understanding Networking Devices – A Brief Introduction | TechLinu.comTechLinu.com
All but the most basic of networks require devices to provide connectivity and functionality. Understanding how these networking devices operate and identifying the tasks they perform are important skills for any network administrator and requirements for a Network+ candidate.
This brief guide introduces usually used networking devices that you may encounter in your career as Network Administrator. This guide is also useful for BCS students and for passionate network learners.
The document discusses the network layer and routing algorithms. It begins by defining the network layer and its responsibilities like routing packets across networks using logical addressing. It then discusses network layer design issues such as store-and-forward packet switching and services provided to the transport layer. Implementation of connectionless and connection-oriented services are explained along with a comparison of virtual-circuit and datagram networks. Finally, it covers routing algorithms like flooding and distance vector routing where routers maintain routing tables and exchange information with neighbors.
This document discusses different types of network devices used to connect computer networks, including gateways, bridges, and routers. Gateways connect different types of networks and perform protocol conversion. Bridges operate at the data link layer and forward packets between network segments based on MAC addresses. Routers use routing tables and protocols to determine the best path between networks and forward packets accordingly. Dynamic routing allows routers to automatically update their routing tables based on network changes.
E-Lins Technology provides an insight on routing. E-Lins Technology are the manufacturers and providers of the one of the best 3G/4G routers across the globe.
The network layer is responsible for routing packets from source to destination using a routing algorithm. The routing algorithm must deal with issues of correctness, stability, fairness, and optimality. The network layer also handles congestion when more packets enter an area than can be processed. When connecting different network technologies, the same problems are present but are worse as packets may travel through many different networks with different formats and technologies.
A hub is a networking device that connects multiple devices on a local area network (LAN). It receives data packets through one port and broadcasts them to all other ports so all connected devices can see the packets. Hubs operate in half duplex mode and have no bandwidth management or collision detection. Switches are more advanced devices that can connect more devices than hubs. Switches have buffers and port-to-MAC address tables that allow them to send frames to specific ports faster than hubs. Routers connect multiple networks like LANs and WANs. Routers use IP addresses to route packets between networks and can run routing protocols to dynamically learn routes.
Network devices like hubs, switches, and routers connect computers in a network and help manage traffic flow. Hubs broadcast all received data to all ports but have limited bandwidth. Switches can connect more devices than hubs and have features like VLANs. Routers connect different networks and use IP addresses to direct traffic. Other devices like firewalls, VPNs, and IDS/IPS provide network security functions.
This Presentation consists of various Network Devices
Hub, Router, Repeater, Bridge, Brouter, Gateway, NIC etc. It is very helpful for B.tech, BCA, MCA, M.Tech students and for those who is interested in networking.
The document discusses topics related to the network layer, including:
1. It describes virtual circuits and datagrams, which are two methods for transferring data across networks.
2. It covers IPv4 addressing concepts such as address space, notations, classful and classless addressing, subnetting, and network address translation.
3. It provides an overview of additional network layer topics like IPv6 addressing, routing algorithms, internet control protocols, and routing protocols.
This document summarizes key aspects of network routing protocols handling failures. It discusses how routing protocols use periodic advertisements and integration steps to propagate changes and converge on correct routes despite network changes. The HELLO protocol is used for neighbor discovery. Hop limits on packets prevent routing loops from causing dropped packets to circulate indefinitely. Link-state protocols will eventually converge provided packet delivery is sufficiently reliable and all nodes receive each other's advertisements.
For Introduction to Network1.What is computer networking means2.pdffippsximenaal85949
For Introduction to Network
1.What is computer networking means?
2.What is network topology list three and explain brifly?
3.What is router and how it works?
4.What is the different between Hub and Switch?
Solution
1. A computer network:
It is a telecommunications network which permits computers to swap data. In computer
networks, networked computing machines exchange data with every other using a data link. The
connections between nodes are instituted using either cable media or wireless media.
2. A topology is just put; a topology is explained of a network. There are actually three basic
kinds of topologies. They are Star, Bus, and Ring. All computers and devices be connected in
series to a solitary linear cable named a trunk or occasionally called a backbone.
Star: All computers and devices are attached to a centrally placed hub or switch. The hub or
switch collects and issues the flow of data within the network. It’s improved to employ a switch
than a hub as a switch transmits the data to the future recipient rather than to every host on a
network.
Bus: every computer and device is connected in series to a solitary linear cable named a trunk or
sometimes named a backbone. Both ends of the trunk must be ended to stop the signal from
bouncing back up the cable. As the bus topology does not have a central point it is hard to
troubleshoot problems. As well, a break at any point along the bus can reason the entire network
to go down.
Ring: In this topology, every computer and device is connected to cable that forms a closed loop.
Every computer on this sort of topology acts like a repeater and boosts the signal previous to
sending it to the after that computer. It broadcasts data by passing a token around the network.
Therefore this kind of network is commonly named a token ring network. Alike to the Bus
topology, if single computer fails, the whole network goes down.
3. Routing is the procedure of forwarding IP packets as of one network to another. A router is a
device that joins networks jointly and routes traffic among them. A router will contain at least
two network cards, one actually attached to one network and the further physically connected to
another network
4. Hubs, switches, and routers are all devices that let you attach one or more computers to further
computers, networked devices, or still other networks. all has two or more connectors named
ports into which you plug in the cables to create the connection..
This document discusses wide area network (WAN) technologies. It begins by defining WAN characteristics such as interconnecting computers over long distances using various media. It then describes different WAN technologies including circuit-switched networks, packet-switched networks, and virtual circuit networks. Specific routing protocols and concepts are explained like distance vector routing, link state routing, static versus dynamic routing. The document concludes by listing various WAN technology options for connecting sites like dial-up, leased lines, frame relay, ATM, microwave links and satellite.
Highlighted notes while studying Advanced Computer Networks:
Routing table
Source: Wikipedia
In computer networking a routing table, or routing information base (RIB), is a data table stored in a router or a network host that lists the routes to particular network destinations, and in some cases, metrics (distances) associated with those routes. The routing table contains information about the topology of the network immediately around it.
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Static routing tables require manual configuration and cannot automatically update when network changes occur. Dynamic routing tables use protocols like RIP, OSPF, or BGP to periodically update routing tables across routers when links or routers fail. Routing tables contain information like the network address, next hop address, interface, and flags to determine the best path for packet delivery.
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Ip protocol tedting
1. Lecture 14
Inter-network, we require inter-network, so that any two stations on any of the constituent
networks can communicate. However if each of the constituent network retains its
identity and communicated with the other constituent network by hopping across multiple
networks in between, this entire configuration is referred to as internet. Each constituent
network consists of systems referred to as End systems, and each constituent network is
referred as Autonomous system. Networks are connected by devices referred as
intermediate systems (ISs). Interconnection of these intermediate systems forms a
subnet.
Router is one such intermediate system which operates at layer 3 of the OSI architecture.
Also Bridge is a intermediate system which operates at layer 2 of the OSI architecture.
The overall requirements for an internetworking facility are as follows
1. Provide a link between networks.
2. Provide for the routing and delivering of data between processes on different
networks.
3. Provide an accounting service that keeps track of the use of the various networks
and routers and maintains status information.
4. Should be compatible with the existing network architecture.
- Different addressing scheme
- Different maximum packet size
- Different network addressing mechanism
- Different timeout
- Routing techniques
- Security and User Access Control
- Connection and Connectionless
1. Virtual Circuit
2. Datagram
Virtual Circuit is very much similar to circuit switching in data link layer. In Virtual
Circuit, a route is established between the source and destination, prior to any
transmission of packets. That defined route is given a unique virtual Circuit number,
and each router which falls along the route, makes an entry in its table, called as routing
table, about this virtual circuit number. When a packet sent through some source, it bears
a virtual circuit number, which when received by the router, the router looks in the table
for its virtual circuit number, and then generates or determines the outgoing line on to
which that packet need to be placed. All the packets from source to destination thus
follow the same path and reach in order. The over head with virtual circuit is maintaining
a routing table, and since router memory is small, so a large table cannot be maintained.
There is another technique called as datagram, where routers do have a routing table, but
this time routing table contains entry about which outgoing line to place the packet
2. depending upon the destination address contained in the packet. So determination of
route is still needed, but on the basis of destination address contained in the packet, in
circuit switching it was virtual circuit number, so packets routed using virtual circuit does
not contain the destination address, only they contain is virtual circuit number. Each
datagram must contain the full destination address, so that makes the packet very long, if
there are multiple routers in the way. Each packet may or may not follow the same route,
packet may or may not arrive in the same order.
There are two architectural approaches for building an Inter-network or internet
architecture, one is connection oriented and second one is connectionless.
In connection-oriented approach, each network provides a connection oriented form of
service. That is, a virtual circuit is established between the two entities, on different
Autonomous systems. After the virtual circuit is established, data packets are exchanged
on that established virtual circuit
A connectionless approach behaves very much similar to the packet switching network.
Each data packet of end system is treated as an independent unit and routed through
series of routers and networks. For each data unit transmitted by source, source makes the
decision as to which router next on the path should receive the data unit, and then hops
across the inter-network from one router to another until it reaches the destination or TTL
times out.
3. Connectionless approach is preferred over connection oriented approach, as various
different kind of networks may lie on the way, connection less or connection oriented, for
a connection oriented network to route the packet on a connection less network, puts an
extra overhead. Internet Protocol being a connection less protocol at the network layer is
widely used, and we will discuss it widely.
Advantages
Flexibility
Robust
No unnecessary overhead
Disadvantages
- Unreliable
- Not guaranteed delivery
- Not guaranteed order of delivery
- Reliability is responsibility of next layer up (e.g. TCP)
Operation of Connectionless Internetworking scheme
Diagram above shows the operation of connectionless Internetworking which uses IP
protocol. There is host A on one LAN and host B on another LAN. They are exchanging
data through the WAN between the two routers. The end systems and routers must share
a common internet protocol. Each end system must share the same protocol above IP.
The intermediate routers need to implement up through IP.
The IP at A receives blocks of data to be sent to B, from the upper layer. They from the
datagrams by prefixing the network header and pass these datagrams to the LLC, which
4. attaches the LLC header and then to the MAC, which attaches the MAC header and
finally to the physical layer for transmission.
Since the datagram contains the destination address of B, the IP module in A would like
to send the datagram to the next hop router. This is what physical layer does physically.
In this case router X (as shown in the diagram).
After reaching to router X, the router removes MAC and LLC header and analyzes the IP
addresses to determine the ultimate destination of data (This we will discuss in more
detail later, the processing of packets at the router). The router then makes a routing
decision. There are three possibilities
1. The destination station B is connected directly to one of the networks to which the
router is attached. If so the router sends the packet directly to the destination.
2. It may happen to reach the destination; packet may have to hop through one or
two additional routers even more than that. To which router, packet need to be
forwarded, this is decided by the router, and packet is placed on that
corresponding outgoing line.
3. The router doesn t know the destination address. Then there are two possibilities,
either router return the error message to the source, or he can forward the packet
on the default route.
In the above example, packet must pass through router Y (intermediate router) before
reaching the destination B. So router constructs a new packet by appending an X.25
header, and forwards it to router Y. When this packet arrives at router Y, it is stripped off,
and destination IP address is extracted. On comparing the destination IP address with the
contents of routing table, router Y determines that this destination address is on one of the
networks to which the router is attached, so router Y directly forwards the packet to end
system B.
Now this is how a packet travels through the inter network, but there are still very small
intricate details that need to be covered, in order to gain a proper insight of operation of
inter network.
Design issues of Inter-network
This topic discusses about the various issues that need to be implemented to
realize the above example, or one can say, the issues that creep in or were considered
during the implementation of above operation.
- Routing
- Datagram Lifetime
- Fragmentation and reassembly
- Error Control
- Flow Control
As discussed above, each router needs to do some processing with the packets it
receives. He has to actually process the packet. Now what does this processing means?
Processing here means that the router strip off the packet, extracts some information from
the packet, and takes some decision. Router extracts information like
5. - What is the destination address and which outgoing line the packet should
follow
- If there is any error in the received packet
- If TTL has expired or not.
- Is there any requirement to fragment, and If yes, can I fragment the packet.
All this information is contained in the packet, which network layer module tries to
derive and with this information and routing table, router makes the decision on which
outgoing line to forward the packet.
Routing
As briefly discussed, the decision on which outgoing line to forward the packet is
what we call as routing decision. Now how do the routers maintain this routing table?
There are various protocols, called as routing protocols, being used for maintaining
routing tables. There are actually three terms widely used in networking scenarios:
routing, routed protocols, and routing protocols.
There is story behind the difference between and routed and routing protocols.
The Story of Ted and Ting
Ted and Ting both work for the same company at a facility in Snellville, Georgia. They
work in the same department; their job is to make lots of widgets. (Widgets are imaginary
products; the term widget is used in the United States often to represent a product when
the actual product is not the topic of discussion.)
Ted worked quickly and was a hard worker. In fact, because he was a very intense
person, Ted tended to make more widgets than anyone else in Snellville, including Ting.
Ted also liked to have everything he needed instantly available when and where he
wanted it so that he could make the widgets more quickly.
Ting, on the other hand, also worked very hard but was much more of a planner. He
tended to think first and then act. Ting planned very well and had all supplies well
stocked, including all the instructions needed to make the different kinds of widgets. In
fact, all the information about how to build each type of widget was on a table by his
door. He had a problem with the table getting "reallocated" (that is, stolen), so he applied
a non-removable label with the words "Ting's Table" to the surface so that he could find
the table in case someone stole it.
It turns out that Ted's productivity was partly a result of sitting next to Ting. In fact, Ted
often was ready to make the next widget but needed something, such as the instruction
sheet for a particular unique widget. By swinging into Ting's office, Ted could be back at
it in just a few seconds. In fact, part of the reason Ting kept the instruction sheets on
Ting's Table by the door was that he was tired of Ted always interrupting him looking for
something.
6. Well, Ted got lots of bonuses for being the most productive worker, and Ting did not.
Being fair, though, Ted realized that he would not be as successful without Ting, so Ted
shared his bonuses with Ting. (Hey, it's an imaginary story!)
Then one day the president decided to franchise the company because it was the best
widget-making company in the world. The president, Dr. Rou (pronounced like the word
"ouch"), decided to create a manual to be used by all the franchisees to build their
business. So, Dr. Rou went to the most productive widget maker, Ted, and asked him
what he did every day. Along the way, Dr. Rou noticed that Ted went next door a lot. So,
being the bright guy that he was, Dr. Rou visited Ting next and asked him what he did.
The next day Dr. Rou emerged with the franchise manual. Being an ex computer
networking professional, he had called the manual "Protocols for Making Widgets."
One part of the protocol defined how Ted made widgets very quickly. Another part
described how Ting kept everything needed by Ted at arm's length, including all the
instructions that Ted needed.
It even mentioned Ting's Table as the place to store the instruction sheets. To give credit
where credit was due but not too much credit the names of these protocols were as
follows:
The "Rou-Ted Protocol" How to make widgets really quickly
The "Rou-Ting Protocol" How to plan and collect information so that the other guy
can make widgets fast
The "Rou-Ting Table" The place to store your widget-making instruction sheets
Similarly, with networking, the routed protocol is the one being routed, such as IP, IPX,
OSI, DECnet, and so forth. The routing protocol is the one preparing the information
needed to perform the routing process quickly, such as RIP, IGRP, OSPF, NLSP, and so
forth. The routing table is where the information needed to perform routing is held, as
built by the routing protocol and used by the routing process to forward the packets of the
routed protocol.
That's all just to distinguish among the terms routed protocol, routing protocol, and
routing table.
Datagram Lifetime
Since a packet travels from one router to another, and in case a destination doesn t
exist, it will keep on traveling, and thus a day may come in future, when there will be lots
of packets traveling in the inter-network locating for their unknown destination. These
wandering packets are of no use, infact they are utilizing the bandwidth of the network.
To make efficient utilization of bandwidth and providing release to these packets, there is
a field in the internet header, called as TTL field, which contains the number of hops a
packet should take to reach the destination. TTL is an acronym for Time To Live. Every
router who receives the packet, decrements the TTL value by 1, this value is initially set
by the source. If the value reaches 0, then the router discards the packet.
7. Fragmentation and Reassembly
Each underlying can handle only a maximum size of the packet, or can only
transmit some maximum size of the packet, called as MTU (Maximum Transferable
Unit). If the length of the received packet exceeds the MTU, it is fragmented and these
fragments may be reassembled at the converging Router or at the destination router? Can
anyone suggest why is not suitable to reassemble all the fragments at the converging
router?
We will discuss more about Segmentation and Reassembly during the discussion of IP
header.
Error Control
Since the IP protocol is not a connectionless service, it means it is unreliable also.
But routers that receive the datagram can check or determine if the packet is
contaminated or not. If they come to know, they use ICMP (Internet Control Message
Protocol) to send the error message back to the source.
Flow Control
Internet flow control allows the router and/or receiving stations to limit the rate at
which they receive data. The best approach is to send control packets (this time again
ICMP packets) to the intermediate nodes and source nodes to reduce their flow of data.
We will talk in detail about ICMP in future lectures.
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