The routing table contains direct, static, and dynamic routes. It examines level 1 routes first for the best match to the destination address before checking level 2 child routes. If no match is found, it will either drop the packet or search supernet routes depending on the routing behavior. The best match is the route with the most equivalent left-most bits to the destination address.
This document summarizes the routing table lookup process used by routers to determine the best route to forward IP packets. It begins by explaining the basic steps of the process, including finding a matching network route, determining if it is an ultimate or parent route, and checking for more specific subnet routes. It then provides examples to illustrate what constitutes a match between the destination IP address and routes in the routing table. The key points are that the subnet mask specifies the minimum number of bits that must match, and the route with the longest bit match is selected. The document uses a sample network configuration to demonstrate how the process works in practice when evaluating parent and child routes.
This document discusses internet routing and forwarding techniques. It explains how IP packets are routed from one sub-network to another using routers. It describes different forwarding techniques including next-hop, network-specific, host-specific, and default methods. It also discusses forwarding with classful and classless addressing as well as concepts like address aggregation, hierarchical routing, and geographical routing that help reduce routing table sizes.
This chapter discusses local area networks (LANs) and wide area networks (WANs). It covers the underlying technologies of wired and wireless Ethernet LANs as well as different types of point-to-point and switched WANs such as Frame Relay and ATM. The chapter also explains how devices like repeaters, bridges, and routers connect LANs and WANs to form internetworks.
The document discusses the Spanning Tree Algorithm used in bridges to prevent loops in an extended LAN network. It describes how each bridge runs the algorithm to elect a root bridge, determine the shortest path to the root on each of its ports, and elect a designated bridge for each LAN. Each bridge exchanges configuration messages containing root ID, distance to root, and sending bridge ID to build the spanning tree topology without loops.
The document summarizes key aspects of the data link layer:
- It is responsible for frame transmission and error detection/correction between directly connected hosts.
- It has two sublayers: logical link control for flow/error control and media access control for media access.
- Functions include framing, addressing, synchronization, error detection/correction, and flow control. Common error detection techniques are parity checks and cyclic redundancy checks.
The document discusses the OSI model, which defines 7 layers of network architecture: physical, data link, network, transport, session, presentation, and application. Each layer performs communication functions, with lower layers focusing on physical delivery and higher layers on software interoperability. The TCP/IP model is also examined, which has 5 layers that correspond to OSI but are organized differently. Network devices like hubs, switches, routers, and gateways are described along with their roles within the OSI layers. Examples are provided to illustrate addressing schemes and data flow between layers and devices.
This report describes experiments conducted with the RIP and OSPF routing protocols in a virtual network emulated using CORE. For RIP, the group configured a sample topology with multiple routers and networks, enabled RIP routing, and observed routing behavior under normal operation and when links were shut down. For OSPF, the group configured interface bandwidths, enabled OSPF routing between routers in a single area, and observed how route costs impacted path selection. The report analyzes routing tables and explains the routing behavior observed for both protocols.
This laboratory work report describes the configuration of multiple autonomous systems (ASes) interconnected through internal and external routing protocols. Key tasks included initializing ASes 65200, 65100 and 65000 according to constraints, with AS65200 and 65100 using RIP and OSPF internally and connecting to neighbors through BGP, and AS65000 using OSPF and connecting to two neighbors through BGP. Transit ASes 65300, 65400 and 65500 were also initialized. The ASes were globally connected while adhering to connectivity constraints between some AS pairs. Routing tables and connectivity tests confirmed all requirements were met.
This document summarizes the routing table lookup process used by routers to determine the best route to forward IP packets. It begins by explaining the basic steps of the process, including finding a matching network route, determining if it is an ultimate or parent route, and checking for more specific subnet routes. It then provides examples to illustrate what constitutes a match between the destination IP address and routes in the routing table. The key points are that the subnet mask specifies the minimum number of bits that must match, and the route with the longest bit match is selected. The document uses a sample network configuration to demonstrate how the process works in practice when evaluating parent and child routes.
This document discusses internet routing and forwarding techniques. It explains how IP packets are routed from one sub-network to another using routers. It describes different forwarding techniques including next-hop, network-specific, host-specific, and default methods. It also discusses forwarding with classful and classless addressing as well as concepts like address aggregation, hierarchical routing, and geographical routing that help reduce routing table sizes.
This chapter discusses local area networks (LANs) and wide area networks (WANs). It covers the underlying technologies of wired and wireless Ethernet LANs as well as different types of point-to-point and switched WANs such as Frame Relay and ATM. The chapter also explains how devices like repeaters, bridges, and routers connect LANs and WANs to form internetworks.
The document discusses the Spanning Tree Algorithm used in bridges to prevent loops in an extended LAN network. It describes how each bridge runs the algorithm to elect a root bridge, determine the shortest path to the root on each of its ports, and elect a designated bridge for each LAN. Each bridge exchanges configuration messages containing root ID, distance to root, and sending bridge ID to build the spanning tree topology without loops.
The document summarizes key aspects of the data link layer:
- It is responsible for frame transmission and error detection/correction between directly connected hosts.
- It has two sublayers: logical link control for flow/error control and media access control for media access.
- Functions include framing, addressing, synchronization, error detection/correction, and flow control. Common error detection techniques are parity checks and cyclic redundancy checks.
The document discusses the OSI model, which defines 7 layers of network architecture: physical, data link, network, transport, session, presentation, and application. Each layer performs communication functions, with lower layers focusing on physical delivery and higher layers on software interoperability. The TCP/IP model is also examined, which has 5 layers that correspond to OSI but are organized differently. Network devices like hubs, switches, routers, and gateways are described along with their roles within the OSI layers. Examples are provided to illustrate addressing schemes and data flow between layers and devices.
This report describes experiments conducted with the RIP and OSPF routing protocols in a virtual network emulated using CORE. For RIP, the group configured a sample topology with multiple routers and networks, enabled RIP routing, and observed routing behavior under normal operation and when links were shut down. For OSPF, the group configured interface bandwidths, enabled OSPF routing between routers in a single area, and observed how route costs impacted path selection. The report analyzes routing tables and explains the routing behavior observed for both protocols.
This laboratory work report describes the configuration of multiple autonomous systems (ASes) interconnected through internal and external routing protocols. Key tasks included initializing ASes 65200, 65100 and 65000 according to constraints, with AS65200 and 65100 using RIP and OSPF internally and connecting to neighbors through BGP, and AS65000 using OSPF and connecting to two neighbors through BGP. Transit ASes 65300, 65400 and 65500 were also initialized. The ASes were globally connected while adhering to connectivity constraints between some AS pairs. Routing tables and connectivity tests confirmed all requirements were met.
Computer Networks Unit 2 UNIT II DATA-LINK LAYER & MEDIA ACCESSDr. SELVAGANESAN S
The document discusses data link layer framing and protocols. It describes:
1) Two main approaches to framing - byte-oriented (using sentinel characters) and bit-oriented (using bit stuffing). Protocols discussed include BISYNC, DDCMP, and HDLC.
2) Features of PPP framing including negotiated field sizes and use of LCP control messages.
3) Functions of data link layer including framing, flow control, error control, and media access control. The relationship between the logical link control and media access control sublayers is also covered.
1. The document discusses the link layer in computer networks, including MAC addresses, ARP, Ethernet frames, and switches. MAC addresses are used locally to deliver frames between connected interfaces, while IP addresses are used for network layer forwarding.
2. ARP is used to map IP addresses to MAC addresses on the same local area network (LAN). Each node maintains an ARP cache that maps IP addresses to MAC addresses of other nodes on the LAN.
3. Switches learn the location of nodes by examining the source MAC addresses of received frames. They build forwarding tables that map MAC addresses to switch ports. This allows frames to be selectively forwarded to the correct destination port, improving scalability over hubs.
This document discusses the evolution of Ethernet standards over multiple generations, from the original Standard Ethernet to Fast Ethernet and Gigabit Ethernet. It describes the IEEE project that established networking standards and details key changes to Ethernet like increased speeds of 100 Mbps for Fast Ethernet and 1000 Mbps for Gigabit Ethernet. Diagrams and tables illustrate different implementations and topologies for the various Ethernet standards.
The document discusses the transport layer and key protocols TCP and UDP. It outlines the chapter which covers transport layer services like multiplexing and demultiplexing, connectionless transport with UDP, principles of reliable data transfer, connection-oriented transport with TCP including segment structure, reliable data transfer, flow control, and connection management, and principles of congestion control including TCP congestion control. It provides details on multiplexing and demultiplexing to direct segments to the appropriate socket, UDP using port numbers but providing unreliable delivery, and TCP using a 4-tuple to identify connections and providing reliable in-order byte stream delivery with congestion control and flow control.
This document provides an overview of computer networks and networking concepts. It begins with introducing data communications and defining networks. It then discusses the OSI model and TCP/IP protocol suite. The document outlines various networking topics such as bandwidth utilization, transmission media, switching techniques including circuit switching, datagram networks, and virtual circuit networks. It provides examples and illustrations to explain networking concepts and how different network components interact.
INTERNET PROTOCOL (IP)
, Datagram Format
, Fragmentation
, Options
, Security of IPv4 Datagrams
,ICMPv4
, MESSAGES
, Debugging Tools
, ICMP Checksum
, MOBILE IP
, Addressing
, Agents
, Three Phases
, Inefficiency in Mobile IP
This document discusses the use of BGP communities and route servers at CATNIX to facilitate interconnection and mitigate DDoS attacks. It provides a history of BGP and RFCs related to communities. CATNIX uses well-known and custom communities on its route servers to control route propagation and implement a blackholing service. The blackholing service allows members to redirect traffic for attacked prefixes to a blackhole server where it is dropped, providing DDoS mitigation. An example is given of how a member would configure route announcements to make use of the blackholing service during an attack.
Link state routing protocols work by having each node independently construct a map of the network connectivity and calculate the best path to every destination. Each node shares connectivity information with its neighbors by flooding link state advertisements. This allows each node to independently calculate the shortest path tree and routing table for the network. Key steps include determining neighbors, distributing link state information through flooding, running Dijkstra's algorithm to calculate the shortest path tree from each node to every other, and using this to populate each node's routing table.
SYBSC IT COMPUTER NETWORKS UNIT III Connecting LANs, Backbone Networks, and V...Arti Parab Academics
This document summarizes key networking devices:
- A repeater regenerates signals to extend transmission distances but does not amplify signals. It operates at the physical layer.
- A hub connects multiple ports but cannot filter data, sending all data to all connected devices, maintaining a single collision domain.
- A bridge can read MAC addresses to filter and forward data selectively between LANs on the same protocol, dividing collision domains but maintaining a single broadcast domain. It operates at the data link layer.
- A switch is like a multi-port bridge but can boost efficiency by forwarding only valid data to the correct port, dividing both collision and broadcast domains.
This document discusses different types of connecting devices used in computer networks, including passive hubs, active hubs, bridges, switches, routers and gateways. It also covers backbone networks that allow multiple LANs to be connected using bus or star topologies. Finally, it describes virtual LANs (VLANs) which use software rather than physical wiring to configure local area networks and control communication between switches.
The document discusses computer networks and media access control. It covers topics like Ethernet, wireless LANs, Bluetooth, Wi-Fi, switching, bridging, IP, and more. The key points are:
1. It provides an overview of the topics to be discussed, including media access control, Ethernet standards, wireless technologies, and internetworking basics.
2. It summarizes the evolution of Ethernet and discusses its physical properties, frame format, addressing, and transmitter algorithm using CSMA/CD.
3. It describes wireless LAN standards like Bluetooth and Wi-Fi, addressing problems in wireless networks, and discussing concepts like spread spectrum, CSMA/CA, and network architectures.
The document describes the Internet Protocol version 4 (IPv4). It discusses the IPv4 datagram format including the header fields, fragmentation, and options. It also covers how IPv4 provides an unreliable datagram delivery service and must be paired with TCP for reliability. The document discusses security issues with IPv4 like packet sniffing, modification, and spoofing, and how IPSec can provide protection against these attacks.
The document discusses various topics related to network layer in computer networks including network layer services, packet switching, IP addressing, forwarding of IP packets, routing algorithms, and IP protocols. Specifically, it covers logical addressing, services provided at different nodes, forwarding methods based on destination address and labels, IP version 4 addressing including classes and subnetting, and processing of packets at routers and destination computers.
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.
- The document proposes a new routing paradigm called Failure-Carrying Packets (FCP) that aims to eliminate routing convergence by having routers carry failure information in packet headers instead of propagating updates.
- Under FCP, when a router detects a failure, it reroutes packets locally around the failure and includes the failed link in packet headers. Other routers can then route packets avoiding the failed component using only the information in packet headers.
- This avoids routing convergence but introduces computational overhead as each router must recalculate routes. The paper proposes FCP with Source-Path Routing to reduce this overhead by having routers include the source route in packet headers instead of recomputing routes.
This document summarizes key topics from Chapter 5 of the textbook "Computer Networking: A Top Down Approach". It discusses:
- The link layer, which encapsulates datagrams into frames and transfers them between adjacent nodes. Different link layer protocols may be used on different links.
- Link layer services like framing, reliable delivery between nodes, error detection, flow control, and more. These services are implemented in network interface cards.
- Multiple access protocols that coordinate access to shared broadcast links, including TDMA, FDMA, ALOHA, and CSMA.
- Switches, which examine frame addresses and selectively forward frames to the correct outgoing link, avoiding collisions. Switches learn node
The document discusses distance vector routing protocols and their characteristics. It explains that distance vector protocols advertise routes as vectors containing the distance and direction to a destination. Periodic full table updates are sent to neighbors on a regular basis. Common distance vector protocols include RIP, IGRP and EIGRP. EIGRP differs in that it sends partial updates only when there are topological changes rather than full periodic updates.
This document discusses distance vector routing protocols. It provides an example of distance vector routing with 5 routers connected by 6 links. Initially, each router only knows about directly connected networks. Routers periodically exchange routing tables, allowing each to learn paths to all networks. After a few iterations, the routing tables converge with each router having an optimal path to every network. Distance vector protocols work by routers broadcasting their routing tables to neighbors and updating paths based on received distances.
This document provides notes on the fundamentals of switching for the CCNA 640-801 exam. It discusses key concepts such as LAN segmentation to reduce collisions, how switches build and use MAC address tables to forward frames, and spanning tree protocol which ensures a loop-free topology by blocking redundant paths. Spanning tree protocol exchanges BPDU messages and puts ports into different states like blocking, listening, and forwarding based on the topology.
Computer Networks Unit 2 UNIT II DATA-LINK LAYER & MEDIA ACCESSDr. SELVAGANESAN S
The document discusses data link layer framing and protocols. It describes:
1) Two main approaches to framing - byte-oriented (using sentinel characters) and bit-oriented (using bit stuffing). Protocols discussed include BISYNC, DDCMP, and HDLC.
2) Features of PPP framing including negotiated field sizes and use of LCP control messages.
3) Functions of data link layer including framing, flow control, error control, and media access control. The relationship between the logical link control and media access control sublayers is also covered.
1. The document discusses the link layer in computer networks, including MAC addresses, ARP, Ethernet frames, and switches. MAC addresses are used locally to deliver frames between connected interfaces, while IP addresses are used for network layer forwarding.
2. ARP is used to map IP addresses to MAC addresses on the same local area network (LAN). Each node maintains an ARP cache that maps IP addresses to MAC addresses of other nodes on the LAN.
3. Switches learn the location of nodes by examining the source MAC addresses of received frames. They build forwarding tables that map MAC addresses to switch ports. This allows frames to be selectively forwarded to the correct destination port, improving scalability over hubs.
This document discusses the evolution of Ethernet standards over multiple generations, from the original Standard Ethernet to Fast Ethernet and Gigabit Ethernet. It describes the IEEE project that established networking standards and details key changes to Ethernet like increased speeds of 100 Mbps for Fast Ethernet and 1000 Mbps for Gigabit Ethernet. Diagrams and tables illustrate different implementations and topologies for the various Ethernet standards.
The document discusses the transport layer and key protocols TCP and UDP. It outlines the chapter which covers transport layer services like multiplexing and demultiplexing, connectionless transport with UDP, principles of reliable data transfer, connection-oriented transport with TCP including segment structure, reliable data transfer, flow control, and connection management, and principles of congestion control including TCP congestion control. It provides details on multiplexing and demultiplexing to direct segments to the appropriate socket, UDP using port numbers but providing unreliable delivery, and TCP using a 4-tuple to identify connections and providing reliable in-order byte stream delivery with congestion control and flow control.
This document provides an overview of computer networks and networking concepts. It begins with introducing data communications and defining networks. It then discusses the OSI model and TCP/IP protocol suite. The document outlines various networking topics such as bandwidth utilization, transmission media, switching techniques including circuit switching, datagram networks, and virtual circuit networks. It provides examples and illustrations to explain networking concepts and how different network components interact.
INTERNET PROTOCOL (IP)
, Datagram Format
, Fragmentation
, Options
, Security of IPv4 Datagrams
,ICMPv4
, MESSAGES
, Debugging Tools
, ICMP Checksum
, MOBILE IP
, Addressing
, Agents
, Three Phases
, Inefficiency in Mobile IP
This document discusses the use of BGP communities and route servers at CATNIX to facilitate interconnection and mitigate DDoS attacks. It provides a history of BGP and RFCs related to communities. CATNIX uses well-known and custom communities on its route servers to control route propagation and implement a blackholing service. The blackholing service allows members to redirect traffic for attacked prefixes to a blackhole server where it is dropped, providing DDoS mitigation. An example is given of how a member would configure route announcements to make use of the blackholing service during an attack.
Link state routing protocols work by having each node independently construct a map of the network connectivity and calculate the best path to every destination. Each node shares connectivity information with its neighbors by flooding link state advertisements. This allows each node to independently calculate the shortest path tree and routing table for the network. Key steps include determining neighbors, distributing link state information through flooding, running Dijkstra's algorithm to calculate the shortest path tree from each node to every other, and using this to populate each node's routing table.
SYBSC IT COMPUTER NETWORKS UNIT III Connecting LANs, Backbone Networks, and V...Arti Parab Academics
This document summarizes key networking devices:
- A repeater regenerates signals to extend transmission distances but does not amplify signals. It operates at the physical layer.
- A hub connects multiple ports but cannot filter data, sending all data to all connected devices, maintaining a single collision domain.
- A bridge can read MAC addresses to filter and forward data selectively between LANs on the same protocol, dividing collision domains but maintaining a single broadcast domain. It operates at the data link layer.
- A switch is like a multi-port bridge but can boost efficiency by forwarding only valid data to the correct port, dividing both collision and broadcast domains.
This document discusses different types of connecting devices used in computer networks, including passive hubs, active hubs, bridges, switches, routers and gateways. It also covers backbone networks that allow multiple LANs to be connected using bus or star topologies. Finally, it describes virtual LANs (VLANs) which use software rather than physical wiring to configure local area networks and control communication between switches.
The document discusses computer networks and media access control. It covers topics like Ethernet, wireless LANs, Bluetooth, Wi-Fi, switching, bridging, IP, and more. The key points are:
1. It provides an overview of the topics to be discussed, including media access control, Ethernet standards, wireless technologies, and internetworking basics.
2. It summarizes the evolution of Ethernet and discusses its physical properties, frame format, addressing, and transmitter algorithm using CSMA/CD.
3. It describes wireless LAN standards like Bluetooth and Wi-Fi, addressing problems in wireless networks, and discussing concepts like spread spectrum, CSMA/CA, and network architectures.
The document describes the Internet Protocol version 4 (IPv4). It discusses the IPv4 datagram format including the header fields, fragmentation, and options. It also covers how IPv4 provides an unreliable datagram delivery service and must be paired with TCP for reliability. The document discusses security issues with IPv4 like packet sniffing, modification, and spoofing, and how IPSec can provide protection against these attacks.
The document discusses various topics related to network layer in computer networks including network layer services, packet switching, IP addressing, forwarding of IP packets, routing algorithms, and IP protocols. Specifically, it covers logical addressing, services provided at different nodes, forwarding methods based on destination address and labels, IP version 4 addressing including classes and subnetting, and processing of packets at routers and destination computers.
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.
- The document proposes a new routing paradigm called Failure-Carrying Packets (FCP) that aims to eliminate routing convergence by having routers carry failure information in packet headers instead of propagating updates.
- Under FCP, when a router detects a failure, it reroutes packets locally around the failure and includes the failed link in packet headers. Other routers can then route packets avoiding the failed component using only the information in packet headers.
- This avoids routing convergence but introduces computational overhead as each router must recalculate routes. The paper proposes FCP with Source-Path Routing to reduce this overhead by having routers include the source route in packet headers instead of recomputing routes.
This document summarizes key topics from Chapter 5 of the textbook "Computer Networking: A Top Down Approach". It discusses:
- The link layer, which encapsulates datagrams into frames and transfers them between adjacent nodes. Different link layer protocols may be used on different links.
- Link layer services like framing, reliable delivery between nodes, error detection, flow control, and more. These services are implemented in network interface cards.
- Multiple access protocols that coordinate access to shared broadcast links, including TDMA, FDMA, ALOHA, and CSMA.
- Switches, which examine frame addresses and selectively forward frames to the correct outgoing link, avoiding collisions. Switches learn node
The document discusses distance vector routing protocols and their characteristics. It explains that distance vector protocols advertise routes as vectors containing the distance and direction to a destination. Periodic full table updates are sent to neighbors on a regular basis. Common distance vector protocols include RIP, IGRP and EIGRP. EIGRP differs in that it sends partial updates only when there are topological changes rather than full periodic updates.
This document discusses distance vector routing protocols. It provides an example of distance vector routing with 5 routers connected by 6 links. Initially, each router only knows about directly connected networks. Routers periodically exchange routing tables, allowing each to learn paths to all networks. After a few iterations, the routing tables converge with each router having an optimal path to every network. Distance vector protocols work by routers broadcasting their routing tables to neighbors and updating paths based on received distances.
This document provides notes on the fundamentals of switching for the CCNA 640-801 exam. It discusses key concepts such as LAN segmentation to reduce collisions, how switches build and use MAC address tables to forward frames, and spanning tree protocol which ensures a loop-free topology by blocking redundant paths. Spanning tree protocol exchanges BPDU messages and puts ports into different states like blocking, listening, and forwarding based on the topology.
This document expresses beliefs that destiny is not an excuse for failure, that success is not limited by one's hometown but by how big one takes on the world, and that chances are like heartbeats and cannot afford to miss any. It also expresses that it is not just the runs that matter but how one runs the game, and that the world is yours to take on.
The routing table contains routes from various sources like directly connected networks, static routes, and dynamic routing protocols. It examines level 1 routes first for the best match to the destination IP address, then checks level 2 child routes if a parent route matches. If no match is found, it may use classful or classless routing behavior to continue searching supernet routes or the default route. The lookup process finds the longest matching prefix in the routing table to determine the best route for forwarding packets.
This document contains a list of 6 topics: mass media, dreams, sects, propaganda, hypnosis, and meditation. The list covers influences on human psychology from external sources like the media, as well as internal states like dreams and meditation.
Reservation is handled by the front office department. They are responsible for handling reservations made personally, through travel agents, or companies. They collect guest information like name, address, length of stay, payment method, and special requests. Reservations can be confirmed, tentative, double-booked, or on a waiting list. The front office prepares daily reports, files forms, answers calls, and handles reservations via multiple channels. They ensure reservations are complete, follow up on issues, upsell facilities, and establish good guest relations.
The document summarizes Swatch Group's brand management strategies. It discusses the company's portfolio of luxury watch brands including Omega, Longines and Tissot. It outlines Swatch's brand positioning as premium quality watches known for Swiss craftsmanship. Charts are included analyzing the brand's equity, customer decision making process, and Keller's brand pyramid showing how Swatch aims to create resonance through quality, style and premium imagery.
Here's the slides that helped me along at the December Brighton Social Media meet up where I spoke publicly for the first time :) If you came along - I hope you liked it! Connect with me on Twitter @digitaldabbler
This document discusses routing table structures and the routing lookup process. It describes how routing tables are hierarchical with level 1 and level 2 routes. Level 1 routes include directly connected networks, static routes, and routes learned from dynamic routing protocols. Level 2 routes are subnets of level 1 routes. The routing lookup process first checks for a match with level 1 routes, then checks level 2 child routes if there is a parent match. It will then determine if routing is classful or classless to know whether to drop the packet or check supernets/defaults if no child match is found.
This document is the first of two parts dealing with the routing table. Part I discusses the structure of the routing table, how routes are created. Part II discusses the routing table lookup process.
This document discusses routing tables, the routing table lookup process, and routing behaviors. It describes the hierarchical structure of routing tables, including level 1 routes and level 2 child routes. It also explains the routing table lookup process, which first examines level 1 routes, then checks for a match with child routes if the parent route matches. If no child route matches, the router will either drop the packet or search further depending on whether classful or classless routing behavior is configured.
The document contains information about websites that provide answers to Cisco CCNA exam questions. It lists the domains www.ccnafinal.net, www.ccnafinalexam.com, www.ccnaanswers.org, www.ccna4u.net, www.ccna4u.org, and www.ccna4u.info. It then provides 15 multiple choice questions and answers related to CCNA 2 exam content including routing protocols, classful vs classless routing, and route selection.
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.
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.
Wikipedia is a free online encyclopedia, created and edited by volunteers around the world and hosted by the Wikimedia Foundation.
Routers play a key role in TCP/IP networks by participating in routing protocols to determine the best path to send data packets between networks. There are two main types of routing - static routing, where administrators manually configure routes, and dynamic routing, where routers share information to determine optimal paths. Dynamic routing uses either distance vector protocols, where routers share hop counts to destinations, or link state protocols, where each router builds a map of the entire network topology. Common examples are RIP for distance vector and OSPF for link state routing.
The network layer is responsible for carrying packets between hosts and routing packets through routers and switches. It addresses each device with an IP address to allow global communication. Routing protocols like RIP, OSPF, and BGP are used for routing packets within and between autonomous systems. Multicast routing protocols deliver data from one source to multiple destinations, while flooding can be used for broadcast routing but wastes bandwidth. The network layer packetizes data, fragments packets if needed for transmission through different networks, and performs address resolution.
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.
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.
This chapter focuses on IP routing, which is the process of moving packets between networks using routers. It discusses the key components of a routing table that allow routers to determine the best path for packets. It also explains the step-by-step IP routing process that occurs when a host on one network attempts to communicate with a host on another network, including how the routing table is used to determine the appropriate interface to forward the packet out of. The chapter aims to provide readers with a firm understanding of the fundamentals of IP routing.
This chapter covers IP routing and routing basics. It discusses the components of a routing table and how a router makes forwarding decisions. It also explains static and dynamic routing configuration. The document then details the IP routing process, describing how a packet travels from one host to another on different networks, including the roles of ARP, switching, routing tables, and protocols like ICMP and IP. It uses diagrams and examples to illustrate routing concepts.
The document provides answers to questions from a CCNA 2 chapter exam. It addresses topics like administrative distance, metrics, classless routing protocols, load balancing, routing protocol characteristics, convergence, and static versus dynamic routing. Specifically, it discusses the differences between distance-vector and link-state routing protocols, and considerations for selecting a routing protocol for a growing medium-sized company network converting from static to dynamic routing.
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.
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.
Here are the steps to examine routes using PathPing and TraceRt:
1. Open a command prompt as Administrator.
2. To examine the route using PathPing, type:
pathping www.microsoft.com
3. Examine the output and note the routers used to reach the destination.
4. To get a quicker response, use TraceRt:
tracert www.microsoft.com
5. Note the routers displayed in the output. TraceRt and PathPing may display different results due to timing.
Examining routes will help understand the network path and identify any issues that could impact connectivity. You can then use this information for configuring static routes if needed.
This document provides an overview of routing concepts including:
- Routers use information in packets and routing tables to determine the best path and forward packets towards their destination.
- Basic router configuration is demonstrated including interface configuration, routing protocols, and verification commands.
- The routing table structure is explained, showing how directly connected networks, static routes, and dynamic routing protocols populate the table.
This document provides an overview of routing concepts including:
- Routers use information in packets and routing tables to determine the best path and forward packets towards their destination.
- Static and dynamic routing allow routers to build routing tables with routes to directly connected, remote, and default networks.
- Basic router configuration settings and verification commands are demonstrated on a sample topology.
IRJET- Comparative Study of Reactive Routing Protocols in MANET: A ReviewIRJET Journal
This document provides an overview and comparison of two reactive routing protocols for mobile ad hoc networks (MANETs): Dynamic Source Routing (DSR) and Ad Hoc On-Demand Distance Vector Routing (AODV). It describes the key characteristics of each protocol, including their approaches to route discovery and maintenance. DSR uses source routing, storing the complete hop-by-hop route in the packet header. AODV uses next-hop routing with destination sequencing to maintain routing tables. Both protocols operate reactively, searching for routes on demand, but AODV additionally requires periodic beacon messages for neighbor detection. The document compares the performance and overhead of each protocol.
Philippine Edukasyong Pantahanan at Pangkabuhayan (EPP) CurriculumMJDuyan
(𝐓𝐋𝐄 𝟏𝟎𝟎) (𝐋𝐞𝐬𝐬𝐨𝐧 𝟏)-𝐏𝐫𝐞𝐥𝐢𝐦𝐬
𝐃𝐢𝐬𝐜𝐮𝐬𝐬 𝐭𝐡𝐞 𝐄𝐏𝐏 𝐂𝐮𝐫𝐫𝐢𝐜𝐮𝐥𝐮𝐦 𝐢𝐧 𝐭𝐡𝐞 𝐏𝐡𝐢𝐥𝐢𝐩𝐩𝐢𝐧𝐞𝐬:
- Understand the goals and objectives of the Edukasyong Pantahanan at Pangkabuhayan (EPP) curriculum, recognizing its importance in fostering practical life skills and values among students. Students will also be able to identify the key components and subjects covered, such as agriculture, home economics, industrial arts, and information and communication technology.
𝐄𝐱𝐩𝐥𝐚𝐢𝐧 𝐭𝐡𝐞 𝐍𝐚𝐭𝐮𝐫𝐞 𝐚𝐧𝐝 𝐒𝐜𝐨𝐩𝐞 𝐨𝐟 𝐚𝐧 𝐄𝐧𝐭𝐫𝐞𝐩𝐫𝐞𝐧𝐞𝐮𝐫:
-Define entrepreneurship, distinguishing it from general business activities by emphasizing its focus on innovation, risk-taking, and value creation. Students will describe the characteristics and traits of successful entrepreneurs, including their roles and responsibilities, and discuss the broader economic and social impacts of entrepreneurial activities on both local and global scales.
THE SACRIFICE HOW PRO-PALESTINE PROTESTS STUDENTS ARE SACRIFICING TO CHANGE T...indexPub
The recent surge in pro-Palestine student activism has prompted significant responses from universities, ranging from negotiations and divestment commitments to increased transparency about investments in companies supporting the war on Gaza. This activism has led to the cessation of student encampments but also highlighted the substantial sacrifices made by students, including academic disruptions and personal risks. The primary drivers of these protests are poor university administration, lack of transparency, and inadequate communication between officials and students. This study examines the profound emotional, psychological, and professional impacts on students engaged in pro-Palestine protests, focusing on Generation Z's (Gen-Z) activism dynamics. This paper explores the significant sacrifices made by these students and even the professors supporting the pro-Palestine movement, with a focus on recent global movements. Through an in-depth analysis of printed and electronic media, the study examines the impacts of these sacrifices on the academic and personal lives of those involved. The paper highlights examples from various universities, demonstrating student activism's long-term and short-term effects, including disciplinary actions, social backlash, and career implications. The researchers also explore the broader implications of student sacrifices. The findings reveal that these sacrifices are driven by a profound commitment to justice and human rights, and are influenced by the increasing availability of information, peer interactions, and personal convictions. The study also discusses the broader implications of this activism, comparing it to historical precedents and assessing its potential to influence policy and public opinion. The emotional and psychological toll on student activists is significant, but their sense of purpose and community support mitigates some of these challenges. However, the researchers call for acknowledging the broader Impact of these sacrifices on the future global movement of FreePalestine.
Andreas Schleicher presents PISA 2022 Volume III - Creative Thinking - 18 Jun...EduSkills OECD
Andreas Schleicher, Director of Education and Skills at the OECD presents at the launch of PISA 2022 Volume III - Creative Minds, Creative Schools on 18 June 2024.
1. Chapter 8
THE ROUTING TABLE:
A CLOSER LOOK
Reporters:
Norly A. Estopa
Namerto C. Medura
Andy D. Ando
Junrey F. Layao
2. THE ROUTING TABLE:
A CLOSER LOOK
Objectives:
- Describe the various route types found in the routing table
- Describe the routing table look-up process
- Describe the routing behavior in routed networks
- Determine the parent route and child route
3. This chapter analyzes the lookup process of the routing
table. Discuss classful routing behavior, as well as classless routing
behavior, which uses the no ip classless and ip classless commands.
Also, will take a closer look at the routing table. This chapter
focuses on the structure of Cisco's IP routing table. Examine the
format of the routing table and learn about level 1 and level 2 routes.
4. Routing Table Entries
The sample routing table in the
figure consists of route entries from
the following sources:
Directly connected networks
Static routes
Dynamic routing protocols
The source of the route does not
affect the structure of the routing
table. The figure shows a sample
routing table with directly
connected, static, and dynamic
routes. Notice that the Note: The routing table hierarchy in Cisco IOS was
172.16.0.0/24 subnets have a originally implemented with the classful routing
combination of all three types of scheme. Although the routing table incorporates both
routing sources. classful and classless addressing, the overall structure
is still built around this classful scheme.
5. Level 1 Routes
Routers R1 and R3 already have their interfaces configured with the appropriate
IP addresses and subnet masks. We will now configure the interfaces for R2 and use debug
ip routing to view the routing table process that is used to add these entries.
The figure shows what happens as the Serial 0/0/1 interface for R2 is configured
with the 192.168.1.1/24 address. As soon as no shutdown is entered, the output from
debug ip routing shows that this route has been added to the routing table.
6. Level 1 Routes
A level 1 route can function as a:
Default route - A default route is a
static route with the address
0.0.0.0/0.
Supernet route - A supernet route is a
network address with a mask
less than the classful mask.
Network route - A network route is a
route that has a subnet mask
equal to that of the classful
mask. A network route can
also be a parent route. Parent C 192.168.1.0/24 is directly connected,
routes will be discussed in the Serial0/0/1
next section.
7. Ultimate Route
The level 1 route
192.168.1.0/24 can be further
defined as an ultimate route.
An ultimate route is a route
that includes:
- either a next-hop IP address
(another path)
- and/or an exit interface
The directly connected
network 192.168.1.0/24 is a
level 1 network route because
it has a subnet mask that is the C 192.168.1.0/24 is directly connected,
same as its classful mask. This Serial0/0/1
same route is also an ultimate
route because it contains the We will see in the next topic that level 2
exit interface Serial 0/0/1. routes are also ultimate routes.
8. Parent and Child Routes : Classful Networks
When the 172.16.3.0 subnet was added to the routing table, another route,
172.16.0.0, was also added. The first entry, 172.16.0.0/24, does not contain any next-
hop IP address or exit interface information. This route is known as a level 1 parent
route.
9. A level 1 parent route is a
network route that does not
contain a next-hop IP address
or exit interface for any
network.
172.16.0.0/24 is subnetted, 1 subnets
A level 2 route is a route that is a
subnet of a classful network
address
C 172.16.3.0 is directly connected,
FastEthernet0/0
10. Level 1 Parent Route
This parent route contains the following
information:
172.16.0.0 - The classful network address for
our subnet. Remember, the Cisco IP routing
table is structured in a classful manner.
/24 - The subnet mask for all of the child
routes. If the child routes have variable length
subnet masks (VLSM), the subnet mask will be
excluded from the parent route and included
with the individual child routes. This will be
shown in a later section.
is subnetted, 1 subnet - This part of the route
specifies that this is a parent route and in this
case has one child route, that is, 1 subnet.
11. Level 2 Child Route
The second entry, 172.16.3.0, is the actual
route for our directly connected network. This
is a level 2 route, also known as a child route,
and contains the following information:
C - The route code for directly connected
network.
172.16.3.0 - The specific route entry.
is directly connected - Along with the route
code of C, this specifies that this is a directly
connected network with an administrative
distance of 0.
FastEthernet0/0 - The exit interface for
forwarding packets that match this specific
route entry.
12. The level 2 child route is the specific route
entry for the 172,16.3.0/24 subnet. Notice
that the subnet mask is not included with
the subnet, the level 2 child route. The
subnet mask for this child route (subnet) is
the /24 mask included in its parent route,
172.16.0.0.
Level 2 child routes contain the route
source and the network address of the
route.
Level 2 child routes are also considered
ultimate routes because they will contain
the next-hop IP address and/or exit
interface.
13. Parent and Child Routes : Classful
Networks
The parent route contains the
following information:
172.16.0.0 - The parent route, the
classful network address associated
with all child routes.
/16 - The classful subnet mask of
the parent route.
variably subnetted - States that the 3 subnets, 2 masks - Indicates the number of
child routes are variably subnetted subnets and the number of different subnet
and that there are multiple masks masks for the child routes under this parent
for this classful network. route.
14. Parent and Child Routes : Classful
Networks
Using one of the child routes as an
example, we can see the following
information:
C - The route code for a directly
connected network.
172.16.1.4 - The specific route entry.
/30 - The subnet mask for this specific
route.
is directly connected - Along with the Serial0/0/0 - The exit interface for forwarding
route code of C, specifies that this is a packets that match this specific route entry.
directly connected network with an
administrative distance of 0.
15. Steps in the Route Look up process
The Route Lookup Process
Follow these steps in the figure to
see the route lookup process.
Don't worry about fully
understanding the steps right
now. You will better understand
this process when we examine a
few examples in the following
sections.
16. Steps in the Route Look up process
Step 1.
The router examines level 1 routes, including network routes and supernet
routes, for the best match with the destination address of the IP packet.
17. Steps in the Route Look up process
Step 1a.
If the best match is a level 1 ultimate route - a classful network, supernet,
or default route - this route is used to forward the packet.
18. Steps in the Route Look up process
Step 1b.
If the best match is a level 1 parent route, proceed to Step 2.
19. Steps in the Route Look up process
Step 2.
The router examines child routes (the subnet routes) of the
parent route for a best match.
20. Steps in the Route Look up process
Step 2a.
If there is a match with a level 2 child route, that subnet will be used to
forward the packet.
21. Steps in the Route Look up process
Step 2b.
If there is not a match with any of the level 2 child routes, proceed to
Step 3.
22. Steps in the Route Look up process
Step 3.
Is the router implementing classful or classless routing behavior?
23. Steps in the Route Look up process
Step 3a.
Classful routing behavior: If classful routing behavior is in effect,
terminate the lookup process and drop the packet.
24. Steps in the Route Look up process
Step 3b.
Classless routing behavior: If classless routing behavior is in effect,
continue searching level 1 supernet routes in the routing table for a
match, including the default route, if there is one.
25. Steps in the Route Look up process
Step 4.
If there is now a lesser match with a level 1 supernet or default routes,
the router uses that route to forward the packet.
26. Steps in the Route Look up process
Step 5.
If there is not a match with any route in the routing table, the router
drops the packet.
27. Steps in the Route Look up process
Note:
A route referencing only a next-hop IP address and not an
exit interface must be resolved to a route with an exit interface. A
recursive lookup is performed on the next-hop IP address until the
route is resolved to an exit interface.
28. Longest Match :
Level 1 Network
Routes
The best match or
longest match is the
route in the routing
table that has the
most number of left-
most matching bits
with the destination
IP address of the The route with the most number of equivalent left-most
packet. bits, or the longest match, is always the preferred route.
29. Step 1-there is a match between the
destination IP address 192.168.1.2 and
the level 1 ultimate route of
192.168.1.0/24.
Step 1a - R 192.168.1.0/24 [120/1] via
172.16.2.2, 00:00:25, Serial0/0/0
30. Level 1 Ultimate Route
The subnet mask that is used to
determine the longest match is not
always obvious. Let's examine this
concept in more detail, using several
examples.
31. The 172.16.0.0/24 is a parent route of three subnets or child routes.
Before a child route is examined for a match, there must be at least a
match between the destination IP address of the packet and the classful
address of the parent route, or 172.16.0.0/16.
32. Note:
Remember that the route lookup process will need to do a
recursive lookup on any route that references only a next-hop IP
address and not an exit interface. For a review of recursive lookups,
refer to Chapter 2, "Static Routing."
33. Routing Table Lookup Process
As shown in the figure, a parent route does not include a next-hop address or an exit interface but is only a "header" for its level 2
child routes, the subnets.
The subnet mask for the child routes - /24 in the figure - is displayed in the parent route, 172.16.0.0, for subnets that use the same
subnet mask.
Before any level 2 child routes are examined for a match, there must first be a match between the classful address of the level 1
parent route and the destination IP address of the packet.
34. Routing Table Lookup Process
Example: Level 1 Parent
Route and Level 2 Child
Routes
• In the example in the
figure, PC1 sends a ping to
PC2 at 172.16.3.10. R1
receives the packet and
begins to search the routing
table for a route.
35. Routing Table Lookup Process
The first match that occurs is with
the level 1 parent route, 172.16.0.0.
Remember, with non-VLSM subnets
the classful mask of the parent is
now displayed. Before any child
routes (subnets) are examined for a
match, there must first be a match
with the classful address of the
parent route.
Because the first route entry is a
level 1 parent route that matches
the destination address (Step 1b of
the route lookup process), the route
lookup process moves to Step 2.
36. Routing Table Lookup Process
Because there is a match with the
parent route, the level 2 child routes
will be examined for a match.
However, this time the actual subnet
mask of /24 is used for the minimum
number of left-most bits that must
match.
37. Routing Table Lookup Process
The route lookup process searches
the child routes for a match. In this
case, there must be a minimum of 24
bits that match.
38. Routing Table Lookup Process
• After the match with parent route has been made Level 2 child routes
will be examined for a match
-Route lookup process searches for child
routes with a match with destination IP
39. Routing Table Lookup Process
First, the router examines the
parent route for a match. In
this example, the first 16 bits
of the IP address must match
that of the parent route. The
left-most 16 bits must match
because that is the classful
mask of the parent route, /16.
If there is a match with the
parent route, then the router
checks the 172.16.1.0 route.
Child routes are only
examined when there is a
match with the classful mask
of the parent.
40. Routing Table Lookup Process
Checking the first subnet,
172.16.1.0, the 23rd bit does
not match; therefore, this
route is rejected because the
first 24 bits do not match.
41. Routing Table Lookup Process
Next, the router checks the
172.16.2.0/24 route. Because
the 24th bit does not match,
this route is also rejected. All
24 bits must match.
42. Routing Table Lookup Process
The router checks the last child route for 172.16.3.0/24 and finds a match. The first 24 bits do
match. The routing table process will use this route, 172.16.3.0/24, to forward the packet with
the destination IP address of 172.16.3.10 out the exit interface of Serial 0/0/0.
R 172.16.3.0 [120/1] via 172.16.2.2, 00:00:25, Serial0/0/0
What happens if the router does not have a route? Then it discards the packet.
43. Routing Table Lookup Process
• How a router finds a match with one of the level 2 child routes
-First router examines parent routes for a match
-If a match exists then:
Child routes are examined
Child route chosen is the one with the
longest match
44. Routing Table Lookup Process
Example: Route Lookup Process with VLSM
• What about our RouterX topology, which is using a VLSM
addressing scheme? How does this change the lookup
process?
• Using VSLM does not change the lookup process. With VLSM,
the /16 classful mask is displayed with the level 1 parent
route (172.16.0.0/16 in the figure).
• As with non-VLSM networks, if there is a match between the
packet's destination IP address and the classful mask of the
level 1 parent route, the level 2 child routes will be searched.
• The only difference with VLSM is that child routes display
their own specific subnet masks. These subnet masks are
used to determine the number of left-most bits that must
match the packet's destination IP address. For example, for
there to be a match with the 172.16.1.4 child route, a
minimum of 30 left-most bits must match because the subnet
mask is /30.
45. Routing Table Lookup Process
• Example: Route
Lookup Process with
VLSM
-The use of VLSM does not
change the lookup process
-If there is a match between
destination IP address and the
level 1 parent route then
-Level 2 child routes will be
searched