The document provides an overview of network layer concepts including:
1) The network layer is responsible for path determination, switching, and call setup between sending and receiving hosts.
2) The network layer uses either a virtual circuit or datagram model - virtual circuits maintain connection state while datagrams do not.
3) In the datagram model used by the Internet, routers make local routing decisions based on packet destination without maintaining per-connection state.
This document provides an overview of MPLS (Multi-Protocol Label Switching). It discusses the basic idea behind MPLS, the history and components. MPLS assigns labels to IP flows to create label switched paths between ingress and egress routers. Routers forward packets based on lookups of these labels rather than long IP addresses. MPLS supports traffic engineering and quality of service across networks while integrating technologies like IP, ATM, and Frame Relay.
The document summarizes packet switch architectures. It discusses how packet switches perform packet lookup and classification to determine the next hop for packets. It also describes different switching fabrics that transport packets through the switch. Example packet switches include IP routers, Ethernet switches, ATM switches, and MPLS switches. The document outlines techniques for performing packet lookups, such as direct lookup, hashing, and longest prefix matching.
This document provides an overview of MPLS (Multi-Protocol Label Switching) including its motivation, basics, components, operation, and advantages/disadvantages. MPLS was created to combine the fast packet forwarding of ATM with the flexibility of IP by using labels to direct network traffic. Key components include label edge routers that apply/remove labels, label switching routers that forward based on labels, label distribution protocols to disseminate label mappings, and label switched paths that represent forwarding equivalency classes. MPLS allows for traffic engineering, quality of service, and network scalability.
MPLS is a forwarding mechanism that uses labels instead of IP addresses to forward packets. It allows routers to forward based on simple label lookups rather than complex routing lookups. MPLS has benefits like supporting multiple applications and decreasing forwarding overhead on core routers. It has a control plane that exchanges routing information and labels, and a data plane that forwards packets based on labels. Label Switch Routers implement MPLS forwarding by exchanging labels and forwarding packets based on those labels.
The document discusses cabling Cisco devices. It covers identifying and connecting necessary components to enable connectivity between routers and switches, as well as WAN connectivity over serial or ISDN connections. It also discusses setting up console connections. The document provides information on Ethernet and WAN cabling standards, requirements for different media types, and how to determine straight-through vs. crossover cables.
The document discusses traffic engineering in networks using MPLS. It begins by defining traffic engineering and explaining how shortest path routing can lead to link congestion and underutilized paths. It then describes MPLS, constraint-based routing, and enhanced interior gateway protocols. Constraint-based routing computes paths subject to constraints like bandwidth and policies. MPLS extends routing to control packet forwarding and paths. The document outlines the basic components and functioning of an MPLS system for traffic engineering, including setting up label switched paths (LSPs) with attributes like bandwidth, priority, affinity and establishing multiple LSPs between endpoints to distribute load.
Tutorial about MPLS Implementation with Cisco Router, this first of two chapter discuss about What is MPLS, Network Design, P, PE, and CE Router Description, Case Study of IP MPLS Implementation, IP and OSPF Routing Configuration
This document provides an overview of MPLS (Multi-Protocol Label Switching). It discusses the basic idea behind MPLS, the history and components. MPLS assigns labels to IP flows to create label switched paths between ingress and egress routers. Routers forward packets based on lookups of these labels rather than long IP addresses. MPLS supports traffic engineering and quality of service across networks while integrating technologies like IP, ATM, and Frame Relay.
The document summarizes packet switch architectures. It discusses how packet switches perform packet lookup and classification to determine the next hop for packets. It also describes different switching fabrics that transport packets through the switch. Example packet switches include IP routers, Ethernet switches, ATM switches, and MPLS switches. The document outlines techniques for performing packet lookups, such as direct lookup, hashing, and longest prefix matching.
This document provides an overview of MPLS (Multi-Protocol Label Switching) including its motivation, basics, components, operation, and advantages/disadvantages. MPLS was created to combine the fast packet forwarding of ATM with the flexibility of IP by using labels to direct network traffic. Key components include label edge routers that apply/remove labels, label switching routers that forward based on labels, label distribution protocols to disseminate label mappings, and label switched paths that represent forwarding equivalency classes. MPLS allows for traffic engineering, quality of service, and network scalability.
MPLS is a forwarding mechanism that uses labels instead of IP addresses to forward packets. It allows routers to forward based on simple label lookups rather than complex routing lookups. MPLS has benefits like supporting multiple applications and decreasing forwarding overhead on core routers. It has a control plane that exchanges routing information and labels, and a data plane that forwards packets based on labels. Label Switch Routers implement MPLS forwarding by exchanging labels and forwarding packets based on those labels.
The document discusses cabling Cisco devices. It covers identifying and connecting necessary components to enable connectivity between routers and switches, as well as WAN connectivity over serial or ISDN connections. It also discusses setting up console connections. The document provides information on Ethernet and WAN cabling standards, requirements for different media types, and how to determine straight-through vs. crossover cables.
The document discusses traffic engineering in networks using MPLS. It begins by defining traffic engineering and explaining how shortest path routing can lead to link congestion and underutilized paths. It then describes MPLS, constraint-based routing, and enhanced interior gateway protocols. Constraint-based routing computes paths subject to constraints like bandwidth and policies. MPLS extends routing to control packet forwarding and paths. The document outlines the basic components and functioning of an MPLS system for traffic engineering, including setting up label switched paths (LSPs) with attributes like bandwidth, priority, affinity and establishing multiple LSPs between endpoints to distribute load.
Tutorial about MPLS Implementation with Cisco Router, this first of two chapter discuss about What is MPLS, Network Design, P, PE, and CE Router Description, Case Study of IP MPLS Implementation, IP and OSPF Routing Configuration
The document discusses performance measurements of MPLS traffic engineering and QoS. It provides background on traditional IP routing and its disadvantages, and explains the need for MPLS to address issues like traffic engineering, QoS, and scalability. Key MPLS concepts covered include FEC, LER, LSR, LSP, labels, label switching, label stacking, LIB tables, and the forwarding process. Traditional IP routing is compared to MPLS forwarding.
This document provides an overview of Multi-Protocol Label Switching (MPLS) technology. It discusses MPLS fundamentals, components, operations, applications for traffic engineering, virtual private networks, and any transport over MPLS. It also outlines topics like MPLS label distribution, virtual private network models, and future developments in MPLS. The document is intended to guide readers on key concepts in MPLS and provide background for further study.
MPLS is a forwarding scheme designed to speed up IP packet forwarding by using fixed length labels in packet headers to determine forwarding instead of long IP addresses. MPLS provides fast failure restoration through approaches like local protection which uses label stacking to allow a single bypass tunnel to protect multiple primary label switched paths (LSPs). Frame Relay is a public WAN technology based on packet switching that establishes virtual circuits between user ports to transport variable length data frames. It offers advantages over leased lines like more efficient use of bandwidth and topology flexibility but does not guarantee frame delivery. Asynchronous Transfer Mode (ATM) is a cell switching standard using small fixed size packets to efficiently multiplex different types of digital traffic like voice, data and images.
Overview of the MPLS backbone transmission technology.
MPLS (MultiProtocol Layer Switching) is a layer 2.5 technology that combines the virtues of IP routing and fast layer 2 packet switching.
IP packet forwarding is not suited for high-speed forwarding due to the need to evaluate multiple routes for each IP packet in order to find the optimal route, i.e. the route with the longest prefix match.
However, Internet Protocol routing provides global reachability through the IP address and through IP routing protocols like BGP or OSPF.
Layer 2 packet switching has complementary characteristics in that it does not provide global reachability through globally unique addresses but allows fast packet forwarding in hardware through the use of small and direct layer 2 lookup addresses.
MPLS combines IP routing and layer 2 switching by establishing layer 2 forwarding paths based on routes received through IP routing protocols like BGP or OSPF.
Thus the control plane of an MPLS capable device establishes layer 2 forwarding paths while the data plane then performs packet forwarding, often in hardware.
MPLS is not a layer 2 technology itself, i.e. it does not define a layer 2 protocol but rather makes use of existing layer 2 technologies like Ethernet, ATM or Frame Relay.
MPLS Traffic Engineering provides mechanisms to optimize network traffic flow and efficiently utilize bandwidth. It determines paths based on additional parameters like available resources and constraints. This allows load balancing across unequal paths and routing around failed links or nodes. MPLS TE uses extensions to IGPs to distribute link attributes and tunnel information. Constrained Shortest Path First (CSPF) is used for path computation to find paths meeting constraints like bandwidth and affinities. Tunnels are set up using RSVP-TE and traffic can be forwarded down tunnels using methods like static routes, auto-routing, or policy routing. Fast Re-Route provides local repair of TE tunnels if a link or node fails to minimize traffic loss.
- Multi-Protocol Label Switching (MPLS) improves forwarding speed and enables new capabilities like traffic engineering and virtual private networks. It uses short fixed-length labels to represent IP packets and make forwarding decisions.
- MPLS was originally conceived as being independent of Layer 2 but has found success deploying IP networks across ATM backbones. Standards are being developed and it is seen as an important network development.
- MPLS encapsulates IP packets with labels which are then used instead of the IP header for forwarding decisions, allowing separation of the forwarding and control planes.
MPLS (Multi-Protocol Label Switching) simplifies packet forwarding by assigning labels to packets and using these labels for forwarding instead of long network addresses. It allows for traffic engineering and quality of service by establishing Label Switched Paths (LSPs) to direct different types of traffic over specific paths. MPLS supports various Layer 2 and Layer 3 protocols and improves network performance and scalability compared to traditional IP routing. It is widely used to implement virtual private networks (VPNs) across shared infrastructures.
The document discusses underlying technologies for computer networks including transmission media, local area networks (LANs) like Ethernet and Token Ring, switching methods like circuit switching and packet switching, wide area networks (WANs) like PPP, X.25 and Frame Relay, interconnecting devices, and differences between shared media and switched LAN architectures. It provides details on CSMA/CD and IEEE 802 standards for Ethernet, features and problems of Ethernet, Token Ring features, circuit switching vs. packet switching, PPP, X.25, Frame Relay, ATM, internetworking terms, transparent bridges, and differences between shared media and switched LAN architectures.
This document provides an overview and introduction to MPLS (Multi-Protocol Label Switching). It defines key MPLS concepts such as label switching, forwarding equivalence classes, label switched paths, and label distribution protocols. It also describes how MPLS works, the benefits it provides including traffic engineering and virtual private networks, and examples of MPLS encapsulation over different link layer technologies like ATM, Frame Relay, and PPP/LAN networks.
This document provides an overview of MPLS basics:
- MPLS integrates Layer 2 switching and Layer 3 routing to satisfy networking requirements for various applications. It groups packets into forwarding equivalence classes (FECs) and assigns each FEC a label.
- Label switching routers (LSRs) establish label switched paths (LSPs) to forward labeled packets hop-by-hop through the MPLS network. The ingress LER labels incoming packets and the egress LER removes labels before forwarding.
- MPLS supports technologies like VPNs and traffic engineering to provide benefits like address multiplexing, QoS, and traffic control capabilities.
1. MPLS simplifies forwarding by introducing label switching which uses a forwarding table and label carried in each packet rather than conventional IP routing based on IP addresses.
2. MPLS establishes label switched paths between routers where each router along the path transmits the packet to the next router by means of a label. Edge routers analyze packets and assign an initial label.
3. The main benefits of MPLS include improved performance, scalability, and traffic engineering capabilities compared to conventional IP routing.
The document provides information about a training event on Deploy MPLS Traffic Engineering taking place from 20 February to 2 March 2017 in Ho Chi Minh City, Vietnam. It includes details about two presenters - Nurul Islam Roman, Manager of Training & Technical Assistance at APNIC, and Jessica Wei, Training Officer at APNIC. It also acknowledges Cisco Systems and provides an agenda with topics on why MPLS Traffic Engineering is used and how it works.
This document provides an overview and student guide for the "Implementing Cisco MPLS (MPLS) Version 2.2" course. It introduces basic MPLS concepts including the MPLS architecture, labels, label stacks, and applications such as MPLS VPNs and traffic engineering. It also covers frame-mode MPLS implementation on Cisco IOS platforms, including configuration, monitoring, and troubleshooting tasks. Finally, it discusses MPLS VPN technology in depth, including the MPLS VPN architecture, routing model, and packet forwarding mechanisms.
MPLS is a forwarding scheme that uses fixed-length labels to simplify packet forwarding. It allows explicit routing and fast restoration from failures. MPLS headers carry labels that are used by routers to forward packets based on forwarding equivalence classes. This enables traffic management and quality of service routing. Local protection techniques like bypass tunnels and label stacking allow MPLS to provide fast restoration by pre-establishing backup label switched paths.
MPLS is a technology that allows traffic to be forwarded through networks based on short fixed length labels rather than long network addresses, enabling traffic engineering and quality of service. It works by classifying packets into forwarding equivalency classes, assigning labels when packets enter the MPLS domain, and using label switching to forward packets along label switched paths. MPLS provides advantages like simplified packet forwarding, efficient traffic engineering capabilities, and virtual private networks.
The document provides information about computer networks and routing & switching certification (CCNA). It discusses TCIL-IT, a company that provides computer networking education and training. It then covers topics such as network design, types of networks, network topologies, networking devices, cables, IP addresses, and basic router configuration commands. The document is intended to provide an overview of concepts relevant to the CCNA certification program for computer networking.
MPLS is a forwarding technique that uses fixed-length labels to make forwarding decisions instead of long variable-length IP addresses. MPLS inserts a label between the link layer and network layer headers. Routers along the path are known as label switching routers that use label values for forwarding instead of lookups in routing tables. MPLS supports quality of service and fast restoration upon failures by pre-establishing backup label switched paths.
This document discusses MPLS VPN and its three main types: point-to-point VPNs using pseudowires to encapsulate traffic between two sites; layer 2 VPNs called VPLS that provide switched VLAN services across sites; and layer 3 VPNs known as VPRN that utilize VRF tables to segment routing for each customer using BGP. It describes how MPLS VPN works using CE, PE, and P routers to forward labeled packets through the provider network and pop the label at the destination PE to deliver the packet. Finally, it provides additional resources for learning more about MPLS VPN technologies.
Dokumen tersebut membahas tentang metode akuntansi persediaan barang dagangan perusahaan, yaitu metode periodik dan metode perpetual. Metode periodik mencatat persediaan hanya pada awal dan akhir periode untuk menentukan harga pokok penjualan, sedangkan metode perpetual mencatat persediaan secara detail pada saat dibeli dan dijual.
Dokumen tersebut membahas tentang akuntansi persediaan pemerintah daerah berbasis akrual. Ia menjelaskan definisi persediaan, klasifikasi persediaan, pengakuan persediaan dan beban persediaan, sistem pencatatan persediaan, serta pengukuran nilai persediaan.
The document discusses performance measurements of MPLS traffic engineering and QoS. It provides background on traditional IP routing and its disadvantages, and explains the need for MPLS to address issues like traffic engineering, QoS, and scalability. Key MPLS concepts covered include FEC, LER, LSR, LSP, labels, label switching, label stacking, LIB tables, and the forwarding process. Traditional IP routing is compared to MPLS forwarding.
This document provides an overview of Multi-Protocol Label Switching (MPLS) technology. It discusses MPLS fundamentals, components, operations, applications for traffic engineering, virtual private networks, and any transport over MPLS. It also outlines topics like MPLS label distribution, virtual private network models, and future developments in MPLS. The document is intended to guide readers on key concepts in MPLS and provide background for further study.
MPLS is a forwarding scheme designed to speed up IP packet forwarding by using fixed length labels in packet headers to determine forwarding instead of long IP addresses. MPLS provides fast failure restoration through approaches like local protection which uses label stacking to allow a single bypass tunnel to protect multiple primary label switched paths (LSPs). Frame Relay is a public WAN technology based on packet switching that establishes virtual circuits between user ports to transport variable length data frames. It offers advantages over leased lines like more efficient use of bandwidth and topology flexibility but does not guarantee frame delivery. Asynchronous Transfer Mode (ATM) is a cell switching standard using small fixed size packets to efficiently multiplex different types of digital traffic like voice, data and images.
Overview of the MPLS backbone transmission technology.
MPLS (MultiProtocol Layer Switching) is a layer 2.5 technology that combines the virtues of IP routing and fast layer 2 packet switching.
IP packet forwarding is not suited for high-speed forwarding due to the need to evaluate multiple routes for each IP packet in order to find the optimal route, i.e. the route with the longest prefix match.
However, Internet Protocol routing provides global reachability through the IP address and through IP routing protocols like BGP or OSPF.
Layer 2 packet switching has complementary characteristics in that it does not provide global reachability through globally unique addresses but allows fast packet forwarding in hardware through the use of small and direct layer 2 lookup addresses.
MPLS combines IP routing and layer 2 switching by establishing layer 2 forwarding paths based on routes received through IP routing protocols like BGP or OSPF.
Thus the control plane of an MPLS capable device establishes layer 2 forwarding paths while the data plane then performs packet forwarding, often in hardware.
MPLS is not a layer 2 technology itself, i.e. it does not define a layer 2 protocol but rather makes use of existing layer 2 technologies like Ethernet, ATM or Frame Relay.
MPLS Traffic Engineering provides mechanisms to optimize network traffic flow and efficiently utilize bandwidth. It determines paths based on additional parameters like available resources and constraints. This allows load balancing across unequal paths and routing around failed links or nodes. MPLS TE uses extensions to IGPs to distribute link attributes and tunnel information. Constrained Shortest Path First (CSPF) is used for path computation to find paths meeting constraints like bandwidth and affinities. Tunnels are set up using RSVP-TE and traffic can be forwarded down tunnels using methods like static routes, auto-routing, or policy routing. Fast Re-Route provides local repair of TE tunnels if a link or node fails to minimize traffic loss.
- Multi-Protocol Label Switching (MPLS) improves forwarding speed and enables new capabilities like traffic engineering and virtual private networks. It uses short fixed-length labels to represent IP packets and make forwarding decisions.
- MPLS was originally conceived as being independent of Layer 2 but has found success deploying IP networks across ATM backbones. Standards are being developed and it is seen as an important network development.
- MPLS encapsulates IP packets with labels which are then used instead of the IP header for forwarding decisions, allowing separation of the forwarding and control planes.
MPLS (Multi-Protocol Label Switching) simplifies packet forwarding by assigning labels to packets and using these labels for forwarding instead of long network addresses. It allows for traffic engineering and quality of service by establishing Label Switched Paths (LSPs) to direct different types of traffic over specific paths. MPLS supports various Layer 2 and Layer 3 protocols and improves network performance and scalability compared to traditional IP routing. It is widely used to implement virtual private networks (VPNs) across shared infrastructures.
The document discusses underlying technologies for computer networks including transmission media, local area networks (LANs) like Ethernet and Token Ring, switching methods like circuit switching and packet switching, wide area networks (WANs) like PPP, X.25 and Frame Relay, interconnecting devices, and differences between shared media and switched LAN architectures. It provides details on CSMA/CD and IEEE 802 standards for Ethernet, features and problems of Ethernet, Token Ring features, circuit switching vs. packet switching, PPP, X.25, Frame Relay, ATM, internetworking terms, transparent bridges, and differences between shared media and switched LAN architectures.
This document provides an overview and introduction to MPLS (Multi-Protocol Label Switching). It defines key MPLS concepts such as label switching, forwarding equivalence classes, label switched paths, and label distribution protocols. It also describes how MPLS works, the benefits it provides including traffic engineering and virtual private networks, and examples of MPLS encapsulation over different link layer technologies like ATM, Frame Relay, and PPP/LAN networks.
This document provides an overview of MPLS basics:
- MPLS integrates Layer 2 switching and Layer 3 routing to satisfy networking requirements for various applications. It groups packets into forwarding equivalence classes (FECs) and assigns each FEC a label.
- Label switching routers (LSRs) establish label switched paths (LSPs) to forward labeled packets hop-by-hop through the MPLS network. The ingress LER labels incoming packets and the egress LER removes labels before forwarding.
- MPLS supports technologies like VPNs and traffic engineering to provide benefits like address multiplexing, QoS, and traffic control capabilities.
1. MPLS simplifies forwarding by introducing label switching which uses a forwarding table and label carried in each packet rather than conventional IP routing based on IP addresses.
2. MPLS establishes label switched paths between routers where each router along the path transmits the packet to the next router by means of a label. Edge routers analyze packets and assign an initial label.
3. The main benefits of MPLS include improved performance, scalability, and traffic engineering capabilities compared to conventional IP routing.
The document provides information about a training event on Deploy MPLS Traffic Engineering taking place from 20 February to 2 March 2017 in Ho Chi Minh City, Vietnam. It includes details about two presenters - Nurul Islam Roman, Manager of Training & Technical Assistance at APNIC, and Jessica Wei, Training Officer at APNIC. It also acknowledges Cisco Systems and provides an agenda with topics on why MPLS Traffic Engineering is used and how it works.
This document provides an overview and student guide for the "Implementing Cisco MPLS (MPLS) Version 2.2" course. It introduces basic MPLS concepts including the MPLS architecture, labels, label stacks, and applications such as MPLS VPNs and traffic engineering. It also covers frame-mode MPLS implementation on Cisco IOS platforms, including configuration, monitoring, and troubleshooting tasks. Finally, it discusses MPLS VPN technology in depth, including the MPLS VPN architecture, routing model, and packet forwarding mechanisms.
MPLS is a forwarding scheme that uses fixed-length labels to simplify packet forwarding. It allows explicit routing and fast restoration from failures. MPLS headers carry labels that are used by routers to forward packets based on forwarding equivalence classes. This enables traffic management and quality of service routing. Local protection techniques like bypass tunnels and label stacking allow MPLS to provide fast restoration by pre-establishing backup label switched paths.
MPLS is a technology that allows traffic to be forwarded through networks based on short fixed length labels rather than long network addresses, enabling traffic engineering and quality of service. It works by classifying packets into forwarding equivalency classes, assigning labels when packets enter the MPLS domain, and using label switching to forward packets along label switched paths. MPLS provides advantages like simplified packet forwarding, efficient traffic engineering capabilities, and virtual private networks.
The document provides information about computer networks and routing & switching certification (CCNA). It discusses TCIL-IT, a company that provides computer networking education and training. It then covers topics such as network design, types of networks, network topologies, networking devices, cables, IP addresses, and basic router configuration commands. The document is intended to provide an overview of concepts relevant to the CCNA certification program for computer networking.
MPLS is a forwarding technique that uses fixed-length labels to make forwarding decisions instead of long variable-length IP addresses. MPLS inserts a label between the link layer and network layer headers. Routers along the path are known as label switching routers that use label values for forwarding instead of lookups in routing tables. MPLS supports quality of service and fast restoration upon failures by pre-establishing backup label switched paths.
This document discusses MPLS VPN and its three main types: point-to-point VPNs using pseudowires to encapsulate traffic between two sites; layer 2 VPNs called VPLS that provide switched VLAN services across sites; and layer 3 VPNs known as VPRN that utilize VRF tables to segment routing for each customer using BGP. It describes how MPLS VPN works using CE, PE, and P routers to forward labeled packets through the provider network and pop the label at the destination PE to deliver the packet. Finally, it provides additional resources for learning more about MPLS VPN technologies.
Dokumen tersebut membahas tentang metode akuntansi persediaan barang dagangan perusahaan, yaitu metode periodik dan metode perpetual. Metode periodik mencatat persediaan hanya pada awal dan akhir periode untuk menentukan harga pokok penjualan, sedangkan metode perpetual mencatat persediaan secara detail pada saat dibeli dan dijual.
Dokumen tersebut membahas tentang akuntansi persediaan pemerintah daerah berbasis akrual. Ia menjelaskan definisi persediaan, klasifikasi persediaan, pengakuan persediaan dan beban persediaan, sistem pencatatan persediaan, serta pengukuran nilai persediaan.
Makalah ini membahas tentang syarat sahnya suatu perjanjian dan dasar hukumnya. Ada empat syarat sah perjanjian menurut KUHPer yaitu sepakat, cakap, mengenai hal tertentu, dan sebab yang halal. Makalah ini juga menjelaskan pengertian masing-masing syarat tersebut serta jenis dan macam perjanjian.
[Ringkasan]
1. Bab ini membahas penilaian persediaan dengan pendekatan biaya pokok. Ada beberapa metode penilaian persediaan yang dibahas seperti FIFO, rata-rata tertimbang, identifikasi khusus, dan LIFO.
2. Perusahaan harus memilih asumsi arus biaya yang tepat untuk mengalokasikan biaya barang tersedia untuk dijual antara barang yang dijual dan barang persediaan.
3. Kesalahan pencatatan persediaan dapat
The document discusses characterizing an existing internetwork before designing enhancements. It provides details on mapping the logical and physical structure, addressing, wiring, constraints, and health of the network. Key aspects include characterizing protocols, bandwidth utilization, response times, and checking router/switch/firewall status to understand where the network is and where it can be improved. Understanding the existing infrastructure helps ensure new design goals are realistic and identifies where new equipment should be placed.
This document discusses network architectures and protocols. It describes the OSI 7-layer model and the TCP/IP model. The key layers of each model are presented, including their functions and example protocols. Encapsulation is defined as the process of adding header and trailer data to messages at each layer. This allows protocols to communicate indirectly through lower level protocols in the protocol graph.
TCP/IP is the standard communication protocol on the internet. It is comprised of several layers including application, transport, internet, and link layers. The transport layer includes TCP and UDP which provide connection-oriented and connectionless data transmission respectively. TCP ensures reliable data delivery through features like connections, acknowledgments, and flow control. IPv6 is the latest version of the Internet Protocol which addresses the shortcomings of IPv4 like limited address space. IPv6 features include a larger 128-bit address space, simplified header format, built-in security, and autoconfiguration capabilities.
This document provides an overview of the IoT protocol stack, with a focus on IEEE 802.15.4 and RPL. It describes the 7-layer IoT World Forum reference model and the layers' functions. It then discusses the IEEE 802.15.4 standard for low-rate wireless personal area networks, including its physical layer specifications, MAC layer features, and supported network topologies. Finally, it explains the RPL routing protocol for low-power and lossy networks, covering its directed acyclic graph structure, control messages, objective functions, and self-healing capabilities.
This document discusses the logical design and building blocks of IoT systems. It describes the key functional blocks that provide identification, sensing, actuation, communication, and management capabilities. These include hardware components, IoT networking using various wireless standards, communication protocols like MQTT for messaging, and higher layer protocols. Challenges in IoT like interoperability, security, scalability, and data issues are also summarized. Finally, examples of IoT applications like connected cars, health, farms and smart grids are provided.
This document provides an overview of IP RAN network design for 2G and 3G networks. It discusses key aspects of IP RAN including transport connectivity, network synchronization, quality of service, and security. The document also presents case studies of 2G and 3G network topologies designed using IP RAN principles.
1. Routing is the process of forwarding packets between source and destination networks through routing devices. Routing protocols are used for topology and path discovery.
2. Routers maintain routing tables containing paths to known destinations and routing information like metrics, next hops, and ages. Administrative distances define route preferences.
3. The Internet uses interior gateway protocols (IGPs) within autonomous systems (ASes) and exterior gateway protocols (EGPs) between ASes. Common IGPs include RIP, OSPF, IS-IS. BGP is a prominent EGP.
RouteFlow & IXPs
This talk will discuss the architecture of RouteFlow which is a leading OpenFlow based virtual router. It will focus on the new projects based upon RouteFlow which are finding traction in Internet eXchange Points (IXPs) - Cardigan being one of the most popular one. Some common aspects of IXPS will be shown. The talk will conclude with a list of future projects and vision of SDN routing.
About Raphael Vincent Rosa
Raphael is a Communications Network Engineer. He finished his MS in Computer Science working with intra datacenter routing, contributing to open source SDN projects such as Ryu network controller and RouteFlow platform. Currently he is pursuing PhD research under the guidance of Dr. Christian Esteve Rothenburg with main interests in SDN and Distributed-NFV topics.
Implementation of intelligent wide area network(wan)Jatin Singh
This project implements an intelligent wide area network (WAN) using several routing protocols and technologies. It uses Border Gateway Protocol (BGP) for routing between autonomous systems, Enhanced Interior Gateway Routing Protocol (EIGRP) for interior routing, and Multi-Protocol Label Switching (MPLS) to improve routing performance. It also implements Dynamic Multipoint VPN (DMVPN) to provide secure remote connectivity between sites using a hub-and-spoke topology in a scalable and economical way. The combination of these protocols and technologies enhances routing capabilities, improves traffic engineering, and enables secure virtual private networking across the intelligent WAN.
Chapter 4 internetworking [compatibility mode]Sĩ Anh Nguyễn
The document provides an overview of network layer concepts including internetworking, IP addressing, routing protocols, and routing algorithms. Some key points include:
- Internetworking allows different networks to connect through protocols like virtual circuits and tunneling.
- IP addresses identify systems on a network and consist of a network portion and host portion. Private IP addresses are used internally.
- Routing protocols like RIP, OSPF, and BGP allow routers to share route information and determine the best path between networks.
- Subnetting divides network classes into smaller subnets to better manage IP addresses and network design.
The document provides an overview of protocols and the TCP/IP protocol suite. It discusses what protocols are, the need for mutually agreed upon conventions and rules for communication. It then covers protocol architecture principles like layered structures and peer-to-peer protocols. The document explains concepts like the network access layer, transport layer, application layer, and addressing requirements. It also summarizes standard protocol architectures like OSI and TCP/IP and their layered models.
The document provides an overview of key topics in computer networks that will be discussed in Part 2, including topology, network stack, modulation, collision, error checking and correction codes, MAC, routing, DNS, URL structure, basic networking tools, protocols, HTTP, email, HTTPS, and some common network applications. It also provides brief definitions and explanations of several of these topics, such as defining topology as the manner of connecting computers in a network, describing network stack implementation of networking protocol suites, and explaining modulation as the conversion of carrier signals.
This document provides an overview of connectivity and data protocols used in Internet of Things (IoT) communication. It discusses 6LoWPAN and RPL as connectivity protocols that allow low-power wireless devices to connect to IP networks. It also examines common IoT data protocols including MQTT, CoAP, and AMQP, describing their messaging architectures and how they enable communication between IoT devices and applications.
This deck introduces the Panduit Signature Core Fiber Optic Cabling System, a complete end-to-end solution for high speed applications that enables users to implement 40G in virtually any data center using multimode optics.
Mobile Ad Hoc Network of Simulation Framework Based on OPNETateeq ateeq
This document discusses mobile ad hoc networks (MANETs) and their simulation in OPNET. It defines MANETs as wireless networks without centralized administration composed of nodes that can freely and dynamically self-organize. The key characteristics of MANETs are that nodes are equal, there is no central control, and topology is dynamic. Common routing protocols for MANETs include DSDV, AODV, DSR. The document outlines modeling MANETs in OPNET including the network model with nodes, node model with routing/wireless modules, and analyzing performance metrics like delay from simulation results.
The document discusses the evolution of data centers towards virtualization and cloud computing. It highlights how technologies like the x86 platform and VMWare have enabled this change, and how networking, computing and storage systems need to evolve as well to support increased virtualization. This includes improvements in areas like virtual network integration, higher bandwidth connectivity, storage unification, faster provisioning times, and virtual desktop solutions. The network is positioned as the platform enabling these changes in virtualized data centers.
The document discusses various Internet of Things (IoT) communication technologies and protocols. It describes IEEE 802.15.4, which defines the physical and media access control layers for low-rate wireless personal area networks. It also covers ZigBee, which is built on top of IEEE 802.15.4 and adds network and security layers to enable mesh networking. Finally, it discusses 6LoWPAN, which allows IPv6 packets to be transmitted over IEEE 802.15.4 networks and interfaces them with the Internet using header compression and addressing translation techniques.
This document provides instructions for installing and configuring the Ulteo Open Virtual Desktop system, which includes installing and configuring:
1. A Session Manager, which is the main server and requires a LAMP stack.
2. An Application Server, where desktops and applications will run. This requires installing the ulteo-ovd-application-server package.
3. Configuring the Application Server in the Session Manager interface by registering the server and switching it to production mode. Redirection names can also be set.
Quality circles are voluntary groups of employees who meet regularly to discuss and solve work-related problems. They aim to improve quality and productivity through employee participation in decision-making. Quality circles were developed in Japan in the 1960s and introduced to the US in the 1950s and 1970s. They can be an effective tool if properly implemented, though some organizations struggled with issues like inadequate training, unclear purpose, and lack of management support.
The document discusses several key functions and design goals of the network layer in internet architecture. It covers routing algorithms like distance vector and link state routing, as well as routing protocols like RIP. It also provides an overview of the TCP/IP protocol stack and some of its core components like IP, ICMP, TCP and UDP.
The network layer is responsible for transporting data between hosts on different networks. It handles tasks like addressing, routing, fragmentation, and quality of service. The main network layer protocol is IP, which uses addresses and routing to deliver packets in an unreliable, connectionless manner. IPv6 was created to replace IPv4 due to its limited address space and remove unnecessary features to simplify processing. During the transition, IPv6 can be tunneled inside IPv4 packets to allow communication between IPv6 and IPv4 networks.
How to Fix the Import Error in the Odoo 17Celine George
An import error occurs when a program fails to import a module or library, disrupting its execution. In languages like Python, this issue arises when the specified module cannot be found or accessed, hindering the program's functionality. Resolving import errors is crucial for maintaining smooth software operation and uninterrupted development processes.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
Assessment and Planning in Educational technology.pptxKavitha Krishnan
In an education system, it is understood that assessment is only for the students, but on the other hand, the Assessment of teachers is also an important aspect of the education system that ensures teachers are providing high-quality instruction to students. The assessment process can be used to provide feedback and support for professional development, to inform decisions about teacher retention or promotion, or to evaluate teacher effectiveness for accountability purposes.
This presentation includes basic of PCOS their pathology and treatment and also Ayurveda correlation of PCOS and Ayurvedic line of treatment mentioned in classics.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
2. 4/4/2011
Virtual circuits Virtual circuits: signaling protocols
• The source‐to‐destination path tries to behave like a physical • used to setup, maintain, and teardown VC
circuit • used in ATM (Asynchronous Transfer Mode), frame‐
relay, X.25
• The network layer maintains the illusion of a circuit:
• not used in today’s Internet
– call setup for each call before data can flow (teardown
after)
– each packet carries VC identifier (instead of the destination application
host ID) 5. Data flow begins 6. Receive data application
transport
4. Call connected transport
– every router on source‐destination path maintains “state” network 3. Accept call
1. Initiate call network
data link 2. incoming call
for each passing connection physical
data link
– link, router resources (bandwidth, buffers) may be physical
allocated to VC
7 8
Datagram networks: The Internet
Routing in a datagram model
model
• no call setup at network layer
• routers: no state about end‐to‐end connections • Moving packets to their destination is done as a series of
• packets typically routed using destination host ID local routing decisions at each switch
– packets between same source‐dest pair may take different • Each switch maintains a forwarding or routing table that says
paths!
which way packets have to go to reach a particular
destination
• The information in the routing table is gathered using a
application routing protocol
application
transport
transport
network Dest Port
data link 1. Send data 2. Receive data network 1
data link A 2
physical
physical 2
B 3 3
C 1
9 10
Network layer service models Datagram vs. VC network
Guarantees ?
Network Service Congestion Internet (IP) ATM
Architecture Model Bandwidth Loss Order Timing feedback
• data exchange among computers • evolved from telephony
Internet best effort none no no no no (inferred – “elastic” service, no strict timing • human conversation
via loss) req. – strict timing, reliability
ATM CBR constant yes yes yes no • “smart” end systems (computers) requirements
rate congestion – can adapt, perform control, – need for guaranteed service
ATM VBR guaranteed yes yes yes no error recovery • “dumb” end systems
rate congestion – telephones
– simple inside network,
ATM ABR guaranteed no yes no yes – complexity inside network
complexity at “edge”
minimum • Today not really used and being
ATM UBR none no yes no no • many link types
phased out
– different characteristics
Recommended reading:
CBR = Constant Bit Rate VBR = Variable Bit Rate ABR = Average Bit Rate – uniform service difficult http://en.wikipedia.org/wiki/Asynchronous_Transfer_Mode
UBR = Unspecified Bit Rate
Recommended reading => http://en.wikipedia.org/wiki/Traffic_contract
11 12
2
3. 4/4/2011
Internetworking (IP)
Internet Protocol (IP)
Source:http://en.wikipedia.org/wiki/Internet_Protocol
13 14
Internetworking (IP) Packet format
0 4 8 16 19 31
Type of
• The Internet Protocol Version Hdr length service Length
– Datagram based Identifier Flags Offset
• Best effort, unreliable Upper Layer
Time To Live Header Checksum
Protocol
• Simple routers Source Address
• Packet fragmentation and reassembly
Destination Address
Options (optional)
– Addressing schema
• IP Addresses
DATA
– Routing protocols
15 16 http://en.wikipedia.org/wiki/IPv4#Packet_structure
Fragmentation and reassembly IP Fragmentation and Reassembly
length ID fragflag offset
• IP needs to work over many different physical networks =4000 =x =0 =0
– Networks have different maximum packet sizes
One large datagram becomes
– IP needs to fragment and reassemble packets to make several smaller datagrams
them fit in the frames of the next layer
• Every network has a Maximum Transmission Unit: the largest length ID fragflag offset
=1500 =x =1 =0
IP datagram it can carry in the payload of a frame
length ID
• Fragment when needed, reassemble only at destination fragflag offset
=1500 =x =1 =1480
• The fields “identifier”, “flag”, and “offset” are used to mark
the fragments and reassemble them as needed. length ID fragflag offset
=1040 =x =0 =2960
17 18
3
4. 4/4/2011
IP addressing
• The Internet Protocol is meant as a protocol to communicate
across networks: Internetworking
– There is not a single network but a hierarchy of networks
– Routing happens within networks and across networks
IP Addresses – Addresses are designed to reflect the hierarchical
organization of the networks comprising the Internet
19 20
IP Addresses Initial Internet design
Up to 126 class A (wide area) networks
“class‐full” addressing: 3 types of networks plus some
reserved addresses (http://en.wikipedia.org/wiki/IP_address)
Class A Class A Class A
class
1.0.0.0 to
A 0 network host 127.255.255.255
class B (campus area) networks (64x256)
B network 128.0.0.0 to
10 host
191.255.255.255
Class B Class B Class B Class B Class B Class B
192.0.0.0 to
C 110 network host
223.255.255.255
224.0.0.0 to
D 1110 multicast address
239.255.255.255 class C (local area) networks (32x256x256)
32 bits
Class C Class C Class C Class C Class C Class C Class C
8 bits
21 http://en.wikipedia.org/wiki/IP_address 22
IP Addressing IP Addressing
223.1.1.1
223.1.1.1
223.1.2.1
• IP address: 32‐bit identifier for • IP address 223.1.1.2
223.1.2.1
host or router interface 223.1.1.2 – network part (high order 223.1.1.4 223.1.2.9
223.1.1.4 223.1.2.9 bits)
• Interface: connection to a 223.1.2.2
physical link 223.1.2.2 – host part (low order bits) 223.1.1.3 223.1.3.27
223.1.1.3 223.1.3.27
– routers typically have • What’s a (local) network? (from
LAN
multiple interfaces IP address perspective)
– host may have multiple – device interfaces with same 223.1.3.1 223.1.3.2
interfaces 223.1.3.1 223.1.3.2 network part of IP address
– IP addresses associated with – can physically reach each
interface, not host or router other without intervening
network consisting of 3 IP networks
router (for IP addresses starting with 223,
223.1.1.1 = 11011111 00000001 00000001 00000001 the first 24 bits are network address)
223 1 1 1
23 24
4
5. 4/4/2011
IP addressing: CIDR IP addresses: how to get one?
• class‐full addressing:
– inefficient use of address space, address space exhaustion How do hosts get one? (host portion)
– e.g., class B net allocated enough addresses for 65K hosts, even if • Either hard‐coded by system admin in a file
only 2K hosts in that network
• CIDR: Classless InterDomain Routing – Wintel: control‐panelnetworkconfiguration
– An improvement over basic IP addressing for more efficient use of tcp/ipproperties
addresses – UNIX: /etc/rc.config
– network portion of address of arbitrary length • Or DHCP: Dynamic Host Configuration Protocol
– address format: a.b.c.d/x, where x is number of bits defining the – dynamically get address: “plug‐and‐play”
network portion of address
– host broadcasts “DHCP discover” message
network host – DHCP server responds with “DHCP offer” message
part part – host requests IP address: “DHCP request” message
11001000 00010111 00010000 00000000 – DHCP server sends address: “DHCP ack” message
200.23.16.0/23
25 http://en.wikipedia.org/wiki/Classless_Inter‐Domain_Routing 26
Hierarchical addressing: route
IP addresses: how to get one? aggregation
Network (network portion) Hierarchical addressing allows efficient advertisement of
• get allocated portion of ISP’s address space routing information:
Organization 0
ISP's block 11001000 00010111 00010000 00000000 200.23.16.0/20 200.23.16.0/23
Organization 1
“Send me anything
Organization 0 11001000 00010111 00010000 00000000 200.23.16.0/23 200.23.18.0/23 with addresses
Organization 2 beginning
Organization 1 11001000 00010111 00010010 00000000 200.23.18.0/23 200.23.20.0/23 . Fly‐By‐Night‐ISP 200.23.16.0/20”
.
. . Internet
.
Organization 2 11001000 00010111 00010100 00000000 200.23.20.0/23
Organization 7 .
200.23.30.0/23
... ….. …. ….
“Send me anything
ISPs‐R‐Us
with addresses
Organization 7 11001000 00010111 00011110 00000000 200.23.30.0/23 beginning
199.31.0.0/16”
27 28
Hierarchical addressing: more
IP addressing: the last word...
specific routes
What if Organization 1 wants to change the provider?
ISPs‐R‐Us has a more specific route to Organization 1 • How does an ISP get a block of addresses?
Organization 0
– from another (bigger) ISP or
200.23.16.0/23
– with ICANN: Internet Corporation for Assigned
“Send me anything Names and Numbers
with addresses
Organization 2 beginning • allocates addresses
200.23.20.0/23 . Fly‐By‐Night‐ISP 200.23.16.0/20”
• manages DNS
.
. . Internet
. • assigns domain names, resolves disputes
Organization 7 .
200.23.30.0/23
ISPs‐R‐Us
“Send me anything • Will there be enough IP addresses, ever?
with addresses
Organization 1 beginning 199.31.0.0/16 – No, there are some hacks around the corner (later)
or 200.23.18.0/23”
200.23.18.0/23
29 30
5
6. 4/4/2011
Getting a datagram from source to
destination Getting a datagram from source to destination
routing table in A
Dest. Net. next router #hops
misc Dest. Net. next router #hops
data
Known as “forwarding” 223.1.1 1 fields 223.1.1.1 223.1.1.3
223.1.1 1
223.1.2 223.1.1.4 2
Starting at A, given IP datagram 223.1.2 223.1.1.4 2
223.1.3 223.1.1.4 2
misc source dest addressed to B: 223.1.3 223.1.1.4 2
IP datagram: data
fields IP addr IP addr
A look up net. address of B
datagram remains unchanged, as
223.1.1.1 A 223.1.1.1
find B is on same net. as A
it travels from source to 223.1.2.1
destination 223.1.1.2 link layer will send datagram directly to 223.1.2.1
223.1.1.2
223.1.1.4 223.1.2.9 B inside link‐layer frame
addr fields of interest here B A and B are directly connected
223.1.1.4 223.1.2.9
223.1.2.2 B
223.1.1.3 223.1.3.27 E 223.1.2.2
E
223.1.1.3 223.1.3.27
223.1.3.1 223.1.3.2
223.1.3.1 223.1.3.2
31 32
Getting a datagram from source to destination Getting a datagram from source to destination
Dest. next
misc Dest. Net. next router #hops misc network router #hops interface
data
fields 223.1.1.1 223.1.2.2
data fields 223.1.1.1 223.1.2.2
223.1.1 1 223.1.1 ‐ 1 223.1.1.4
Starting at A with destination E 223.1.2 223.1.1.4 2 Arriving at 223.1.1.4, destined for 223.1.2 ‐ 1 223.1.2.9
223.1.3 223.1.1.4 2 223.1.2.2 223.1.3 ‐ 1 223.1.3.27
look up network address of E
look up network address of E
E on different network A
A 223.1.1.1 E on same network as router’s 223.1.1.1
A, E not directly attached
interface 223.1.2.9 223.1.2.1
routing table: next hop router to E is 223.1.2.1
223.1.1.2 router, E directly attached 223.1.1.2
223.1.1.4 223.1.2.9 223.1.1.4 223.1.2.9
223.1.1.4
link layer sends datagram to 223.1.2.2
link layer sends datagram to router B B
inside link‐layer frame via interface 223.1.2.2
223.1.1.4 inside link‐layer frame
223.1.1.3 223.1.3.27
223.1.2.2
E 223.1.2.9 223.1.1.3 223.1.3.27 E
datagram arrives at 223.1.1.4
datagram arrives at 223.1.2.2 223.1.3.1 223.1.3.2
223.1.3.2
… 223.1.3.1
33 34
ICMP: Internet Control Message
Protocol
• used by hosts, routers, gateways Some typical types/codes
to communication network‐level Type Code description
information 0 0 echo reply (ping)
– error reporting: unreachable 3 0 dest. network unreachable
3 1 dest host unreachable
Additional protocols dealing with host, network, port, protocol
– echo request/reply (used by
3 2 dest protocol unreachable
3 3 dest port unreachable
Network Layer information ping)
• network‐layer “above” IP:
3 6 dest network unknown
3 7 dest host unknown
– ICMP msgs carried in IP 4 0 source quench (congestion
datagrams control ‐ not used)
• ICMP message: type, code plus 8 0 echo request (ping)
first 8 bytes of IP datagram 9 0 route advertisement
causing error 10 0 router discovery
11 0 TTL expired
35 36 12 0 bad IP header
6
7. 4/4/2011
DHCP: Dynamic Host
DHCP client‐server scenario
Configuration Protocol
Goals
• allow host to dynamically obtain its IP address from network server A 223.1.1.1 DHCP 223.1.2.1
when it joins network server
• Can renew its lease on address in use 223.1.1.2
• Allows reuse of addresses 223.1.1.4 223.1.2.9
(only hold address while connected and “on”) B
223.1.2.2 arriving DHCP
• Support for mobile users who want to join network (more shortly) 223.1.1.3 223.1.3.27 E client needs
DHCP review address in this
223.1.3.1 223.1.3.2
network
• host broadcasts “DHCP discover” message
• DHCP server responds with “DHCP offer” message
• host requests IP address: “DHCP request” message
• DHCP server sends address: “DHCP ack” message
37 38
DHCP client‐server scenario
DHCP server: 223.1.2.5 arriving
NAT: Network Address Translation
DHCP discover
client
src : 0.0.0.0, 68
dest.: 255.255.255.255,67 rest of local network
yiaddr: 0.0.0.0 Internet (e.g., home network)
transaction ID: 654 10.0.0.1
10.0.0/24
DHCP offer
src: 223.1.2.5, 67 10.0.0.4
dest: 255.255.255.255, 68 10.0.0.2
yiaddr: 223.1.2.4
transaction ID: 654 138.76.29.7
Lifetime: 3600 secs
DHCP request
src: 0.0.0.0, 68
10.0.0.3
dest:: 255.255.255.255, 67
yiaddr: 223.1.2.4
transaction ID: 655 All datagrams leaving local Datagrams with source or
Lifetime: 3600 secs
time
network have same single source NAT IP destination in this network
DHCP ACK address: 138.76.29.7, have 10.0.0/24 address for
src: 223.1.2.5, 67 different source port numbers source, destination (as usual)
dest: 255.255.255.255, 68
yiaddr: 223.1.2.4
transaction ID: 655
Lifetime: 3600 secs
39 40
NAT: Network Address Translation NAT: Network Address Translation
Implementation: NAT router must
• Motivation
– local network uses just one IP address as far as outside • outgoing datagrams: replace (source IP address, port #) of every outgoing
world is concerned datagram to (NAT IP address, new port #)
– remote clients/servers will respond using
– no need to be allocated range of addresses from ISP (NAT IP address, new port #) as destination addr.
– just one IP address is used for all devices
– can change addresses of devices in local network without • remember (in NAT translation table) every (source IP address, port #) to (NAT
IP address, new port #) translation pair
notifying outside world
– can change ISP without changing addresses of devices in local • incoming datagrams: replace (NAT IP address, new port #) in dest fields of
network every incoming datagram with corresponding (source IP address, port #)
stored in NAT table
– devices inside local net not explicitly addressable, visible by
outside world (a security plus).
– BUT: machines cannot be servers!
41 42
7
8. 4/4/2011
NAT: Network Address Translation NAT: Network Address Translation
NAT translation table
2: NAT router 1: host 10.0.0.1
WAN side addr LAN side addr
changes datagram sends datagram to
source addr from
138.76.29.7, 5001 10.0.0.1, 3345 128.119.40, 80 • 16‐bit port‐number field
…… ……
10.0.0.1, 3345 to – 60,000 simultaneous connections with a single LAN‐side address!
138.76.29.7, 5001, S: 10.0.0.1, 3345
updates table D: 128.119.40.186, 80
10.0.0.1 • NAT is controversial
1
S: 138.76.29.7, 5001 – routers should only process up to layer 3
2 D: 128.119.40.186, 80 10.0.0.4
10.0.0.2 – violates end‐to‐end argument
138.76.29.7 S: 128.119.40.186, 80 • NAT possibility must be taken into account
4
S: 128.119.40.186, 80
D: 10.0.0.1, 3345 by app designers, e.g., P2P applications
3 10.0.0.3
D: 138.76.29.7, 5001
4: NAT router – address shortage should instead be solved by IPv6
3: Reply arrives changes datagram
dest. address: • delays deployment of IPv6
dest addr from
138.76.29.7, 5001 138.76.29.7, 5001 to 10.0.0.1, 3345
43 44
Routing
5
Routing protocol
B 3 C
Goal: determine “good” path 2 5
(sequence of routers) through A 2 1 F
network from source to dest. 3
1 2
D E
1
Routing
Graph abstraction for routing
“good” path:
• graph nodes are routers
• graph edges are physical links typically means
minimum cost path
– link cost: delay, $ cost, or
congestion level other definitions
possible
45 46
Routing protocol classes Important properties of routing protocols
• Distance vector protocols • Information needed
– Nodes know only distance (cost) to neighbors – Messages involved
– Exchange distance to all nodes with neighbors – Storage necessary to keep the information
– Update local information based on received information • Convergence
– How fast until it stabilizes
• Link state protocols – How fast it reacts to changes
– All nodes know network topology and cost of each link
(propagated through the network by flooding)
– Run protocol to find shortest path to each destination
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Distance Vector Routing: Intuition
Geneva Zurich
a b c
Distance Vector Protocols
RIP (Routing Information Protocol) Routing Table of b
Destination Dir
Geneva a
Zurich c
49
50
Distance Vector Routing Distance Vector Routing Algorithm
Algorithm is iterative
Distance Zurich: 7 Zurich? Distance Zurich: 3
• continues until no nodes Routing Table with distance info
exchange info • each node has one
a b c • self‐terminating: no “signal” • a node x has for each neighbor z an entry
to stop for each destination y (as in example
asynchronous before); Dx(y,z) = distance from x to y
• nodes need not to iterate in through z
Distance Zurich: 4 lock‐step • the best route for a given destination is
distributed marked
• each node communicates
Destination Dir Dst only with direct neighbors
Distance Zurich: 5!
Geneva a 10
Zurich c 4
52
51
Distance Vector Algorithm Distance table gives routing table
cost to destination via
E Outgoing link
D () A B D to use, cost
Y
2 1 A 1 14 5 A A, 1
X Z
7 1
B 7 8 5 B D, 5 B C
7
A 8 2
C 6 9 4 C D, 4 1
E D
2
D 4 11 2 D D, 2
Distance table Routing table
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Count to Infinity Problem when
Distance Vector Routing
links break
Each node executes a loop: c: 2 c: 1
Local iteration caused by
• local link cost change wait for (change in local link a b c
• Neighbor sends a message saying cost or msg from neighbor)
that (at least) one of its least cost
paths changed
Algorithm is distributed
c: 3
recompute distance table
• each node notifies neighbors only c: 4
when its least cost path to any c: 5
destination changes
if least cost path to any dest has c: 6
– neighbors then notify their
neighbors if necessary, etc. changed, notify all neighbors c: 7
c: 8
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Distance Vector: link cost changes Distance Vector: link cost changes
Link cost changes
1 • What if the cost of a link grows? 60
node detects local link cost change
Y • Compare with the count to infinity problem Y
updates distance table 4 1 4 1
if cost change in least cost path, notify X Z (More on this later) X Z
50 50
neighbors
algorithm
algorithm
terminates
“good continues
on!
news
travel
fast”
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RIP (Routing Information Protocol) RIP (Routing Information Protocol)
z
• Distance vector algorithm
• Included in BSD‐UNIX Distribution in 1982 w x y …
• Distance metric: number of hops (max = 15 hops) A D B
• Distance vectors: exchanged every 30 sec via
Response Message (also called “advertisement”) C
• Each advertisement: route to up to 25 destination networks Routing table in D
Destination Network Next Router Num. of hops to dest.
w A 2
y B 2
z B 7
x ‐‐ 1
…. …. ....
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RIP: Link Failure and Recovery Distance Vector: poisoned reverse
If no advertisement heard after 180 sec then neighbor/link declared dead If Z routes through Y to get to X :
60
– routes via neighbor invalidated Z tells Y its (Z’s) distance to X is infinite (so Y Y
won’t route to X via Z) 4 1
– new advertisements sent to neighbors
X Z
– neighbors in turn send out new advertisements (if tables changed) Avoids the loop between 2 nodes 50
– link failure info quickly propagates to entire net algorithm
terminates
– poison reverse (next slide) used to prevent ping‐pong loops
(infinite distance = 16 hops)
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[E]IGRP: [Enhanced] Interior
RIP Table processing
Gateway Routing Protocol
• RIP routing tables managed by application‐level process called route‐d
(daemon) • CISCO proprietary; successor of RIP (mid 80s)
• advertisements sent in UDP packets, periodically repeated • Distance Vector, like RIP
• several cost metrics (delay, bandwidth, reliability, load etc)
• uses TCP to exchange routing updates
• Loop‐free routing via Distributed Updating Algorithm (DUAL)
based on diffused computation
63 64
Link state routing (intuition)
• Every node knows the topology and cost of every link
– Achieved through flooding
• Nodes send the information on their links and neighbors to all
neighbors
Link state routing protocols • Nodes forward information about other nodes to their neighbors
• ACKs used to prevent message loss
OSPF (Open Shortest Path First) • Sequence numbers used to compare versions
• With the information on topology and cost
– Calculate the shortest path to every possible destination
• Dijkstra’s algorithm
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Link state routing algorithm:
Algorithm idea
Dijkstra
• There are 3 groups of nodes in the network
– To the green nodes we know the shortest path Notation
– The blue nodes are directly reachable from the green nodes Dijkstra’s algorithm • c(i,j): link cost from node i to j.
– All other nodes are black Can be infinite if not direct
• net topology, link costs known to
neighbors, costs define
all nodes adjacency matrix.
• Basic algorithm: v
– accomplished via “link state
w • v.distance: current value of cost
– Start with broadcast”
source s as the of path from source s to
only green node u – all nodes have same info destination v.
x • v.visited: boolean variable that
– Color the • computes single‐source shortest
best* blue path tree determines if optimal path to v
s was found.
node green,
– gives routing table for source
one after another, • v.pred: the predecessor node of
until all nodes are green v in the routing tree.
(*best = minimum distance from source s of all blue nodes) • B: the set of blue nodes.
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Dijkstra’s Algorithm (for source s
Dijkstra’s algorithm: example
and edge costs c)
Step visited Set of blue nodes B (with distance)
s.visited := true; s.distance := 0; s.pred := s; // init source s 0 A D (1), B (2), C (5)
for all nodes v in V except s do // init all other nodes 1 A, D (1) E (2), B (2), C (4)
v.visited := false; v.distance := 1; v.pred := undefined;
2 AD, E (2) B (2), C (3), F(4)
B := {} // B is the set of blue nodes, initially all neighbors of s 3 ADE, B (2) C (3), F(4)
for all nodes v in V that are direct neighbors of s 4 ADEB, C (3) F(4)
B := B + {v}; v.distance := c(s,v); v.pred := s; 5 ADEBC, F (4) ‐
while B not empty do // always choose the best blue node v
v := node in B with minimum v.distance; 5
B := B – {v}; 3
v.visited := true; // turns the node green B C 5
for all neighbors w of v with w.visited = false; // update neighbors of v
2
if w not in B then A 2 1 F
3
B := B + {w}; w.distance := v.distance+c(v,w); w.pred := v; 1 2
if w in B then D E
if (v.distance+c(v,w) < w.distance) then 1
w.distance := v.distance+c(v,w); w.pred := v;
69 endwhile 70
Dijkstra’s algorithm, correctness OSPF (Open Shortest Path First)
• “open”: publicly available
Oscillations possible
• Uses Link State algorithm
• For example if link costs depend on the amount of carried traffic.
– LS packet dissemination
Example: three flows to node A, with traffic 1, 1, and e (<1)
– Topology map at each node
A – Route computation using Dijkstra’s algorithm
1 1+e 2+e
A A A
0 0 2+e 2+e 0
D 0 0 B D B D B D B
1+e 1 0 0 1+e 1 • OSPF advertisement carries one entry per neighbor router
0 e 0 0 1 1+e 0 e
1
C C C C • Advertisements disseminated via flooding
1
e
B and C have D, C, B have etc.
initially
better routes better routes
• Dijkstra’s algorithm is optimal for constant (and positive!) link costs
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OSPF “advanced” features
Hierarchical OSPF
(not in RIP)
• Security
– all OSPF messages authenticated
– therefore no malicious intrusion
– TCP connections used
• Multiple same‐cost paths allowed (only one path in RIP)
• For each link, multiple cost metrics for different TOS (Type of Service)
– e.g., satellite link cost set “low” for best effort; high for real time
• Integrated uni‐ and multicast support:
– Multicast OSPF (MOSPF) uses same topology data base as OSPF
• Hierarchical OSPF in large domains
73 74
Hierarchical OSPF
• Two‐level hierarchy: local area or backbone
– Link‐state advertisements only in area
– each node has detailed area topology but only knows direction
(shortest path) to networks in other areas.
• Area border routers
– “summarize” distances to networks in own area Comparing routing algorithms
– advertise to other area border routers.
• Backbone routers
– run OSPF routing limited to backbone.
• Boundary routers
– connect to other autonomous systems.
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Link‐State vs. Distance‐Vector
Distance vector vs link state
Routing
• Distance vector: Message complexity Robustness
• LS: with n nodes, m links, • what happens if router
Each node talks only to its directly connected neighbors but network flooded with O(nm) malfunctions?
tells them all it has learned (distance to all nodes) messages LS:
• DV: exchange between neighbors – node can advertise incorrect
only link cost
– convergence time varies – each node computes only its
• Link state own table
Speed of Convergence
Each node talks to all other nodes but tells them only about DV:
• LS: O(m + n log n)
the state of its directly connected links – DV node can advertise
– may have oscillations
incorrect path cost
• DV: convergence time varies
– each node’s table used by
– count‐to‐infinity problem
others: errors propagate
through the network
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