OSPF uses cost as the metric value, which is calculated by dividing the reference bandwidth of 100 Mbps by the interface bandwidth. This means interfaces with higher bandwidth have lower costs by default. The default cost does not differentiate between interfaces faster than 100 Mbps. The OSPF router ID is a unique 32-bit identifier for each router and is usually the highest IP address of a loopback or active interface; it should not be changed without reloading the router.
The document provides an overview of the Border Gateway Protocol (BGP). It discusses BGP concepts such as autonomous systems, path attributes, and the BGP protocol operation. Key points include that BGP establishes peering sessions to exchange routing information, uses route attributes like AS path, next hop, and communities to determine the best path, and supports techniques like route reflection and confederation to improve scalability in large networks.
IP multicast is a method of sending Internet Protocol (IP) datagrams to a group of interested receivers in a single transmission. It is often employed for streaming media applications on the Internet and private networks.(wikipedia)
The document discusses the IS-IS (Intermediate System to Intermediate System) routing protocol. It was developed by DECnet as an interior gateway protocol to efficiently route data within networks. IS-IS determines the best routes between intermediate systems using a link-state algorithm. It exchanges routing information and builds a topology database to select optimal paths between nodes based on metrics like bandwidth and delay. The protocol supports different network types and uses levels, system IDs, and NSAP addresses in its operation.
OSPF uses cost as the metric value, which is calculated by dividing the reference bandwidth of 100 Mbps by the interface bandwidth. This means interfaces with higher bandwidth have lower costs by default. The default cost does not differentiate between interfaces faster than 100 Mbps. The OSPF router ID is a unique 32-bit identifier for each router and is usually the highest IP address of a loopback or active interface; it should not be changed without reloading the router.
The document provides an overview of the Border Gateway Protocol (BGP). It discusses BGP concepts such as autonomous systems, path attributes, and the BGP protocol operation. Key points include that BGP establishes peering sessions to exchange routing information, uses route attributes like AS path, next hop, and communities to determine the best path, and supports techniques like route reflection and confederation to improve scalability in large networks.
IP multicast is a method of sending Internet Protocol (IP) datagrams to a group of interested receivers in a single transmission. It is often employed for streaming media applications on the Internet and private networks.(wikipedia)
The document discusses the IS-IS (Intermediate System to Intermediate System) routing protocol. It was developed by DECnet as an interior gateway protocol to efficiently route data within networks. IS-IS determines the best routes between intermediate systems using a link-state algorithm. It exchanges routing information and builds a topology database to select optimal paths between nodes based on metrics like bandwidth and delay. The protocol supports different network types and uses levels, system IDs, and NSAP addresses in its operation.
- Open Shortest Path First (OSPF) is a link-state routing protocol that can be used for both small and large networks. It uses areas and hierarchical network design to reduce routing overhead and improve performance as the network scales.
- OSPF establishes neighbor relationships to exchange routing information. It elects a Designated Router and Backup Designated Router to optimize this exchange on multi-access networks. Link-state databases are synchronized between neighbors to calculate the shortest paths.
- Basic OSPF configuration involves enabling OSPF on interfaces and networks, setting authentication, and adjusting metrics and timers. Loopback interfaces ensure router IDs remain stable. Verification commands display neighbor relationships and routing tables.
1) OSPF is a link-state routing protocol where each router maintains an identical database describing the network topology by flooding link-state advertisements (LSAs) throughout the network.
2) The routers run the Dijkstra shortest path first algorithm on their link-state database to determine the optimal route to all reachable networks.
3) OSPF routers establish neighbor relationships by multicasting hello packets to discover one another, then exchange and synchronize their full link-state databases.
This document discusses configuring and troubleshooting single-area OSPF routing. It covers topics like:
- Configuring static and dynamic routing on distribution and core routers
- Configuring and verifying single-area OSPF
- Designated router election process for multiaccess networks
- Propagating default static routes in OSPF
- Securing OSPF with message digest 5 authentication
- Components of troubleshooting single-area OSPF like forming adjacencies and transitioning states
- The document discusses Linux network stack monitoring and configuration. It begins with definitions of key concepts like RSS, RPS, RFS, LRO, GRO, DCA, XDP and BPF.
- It then provides an overview of how the network stack works from the hardware interrupts and driver level up through routing, TCP/IP and to the socket level.
- Monitoring tools like ethtool, ftrace and /proc/interrupts are described for viewing hardware statistics, software stack traces and interrupt information.
- OSPF is a link-state routing protocol that is more scalable than RIP. It builds a complete "map" of the network to avoid routing loops.
- OSPF uses link-state advertisements and flooding to exchange routing information between routers. It elects a designated router and backup designated router to optimize this exchange.
- Routers using OSPF establish neighbor relationships, synchronize their link-state databases, and calculate the shortest path to all known destinations using an algorithm on the link-state database.
This document provides an overview of the Open Shortest Path First (OSPF) routing protocol. It describes OSPF's message encapsulation, packet types, neighbor discovery process using Hello packets, link state database and shortest path first algorithm, metric and cost calculation, and mechanisms for handling multi-access networks like designated router election. The objectives are to describe OSPF configuration and troubleshooting.
IS-IS and OSPF are both link-state interior gateway protocols that use the SPF algorithm and support VLSM. However, IS-IS operates above layer 2 and routers belong to one area, while OSPF operates at the IP layer and routers can belong to multiple areas. Additionally, IS-IS uses DIS while OSPF uses DR/BDR, and OSPF supports virtual links while IS-IS does not.
Interior Gateway Routing Protocol (IGRP) is a proprietary distance-vector routing protocol developed by Cisco that is used within an autonomous system to exchange routing information. The document describes IGRP configuration and operation, including setting the autonomous system number, configuring IGRP on routers, and verifying IGRP routes and neighbor adjacencies. Key aspects of IGRP covered are metrics, timers, and network diagrams demonstrating IGRP configuration between three routers to exchange routes.
IS-IS is an interior gateway protocol that uses link-state routing and SPF algorithms to calculate the shortest path. It supports both CLNP and IP and has three routing levels - level 1 for intra-area routing, level 2 for inter-area routing, and level 1/2 routers that connect levels 1 and 2. There are three types of IS-IS routers: level 1 that exchange intra-area topology, level 2 that exchange inter-area topology, and level 1/2 that act as border routers between levels 1 and 2.
Cisco Live! :: Introduction to IOS XR for Enterprises and Service ProvidersBruno Teixeira
The document provides an overview of an introductory session on IOS XR for enterprises and service providers. It outlines the agenda which includes discussing IOS XR architecture, modularity, scalability, stability, security, software packages, the command line interface, configuration management, monitoring tools, example configurations, and the route policy language. It also provides some logistical information about the session.
The document discusses the IS-IS routing protocol. It provides an overview of IS-IS, including that it is an interior gateway protocol used within an autonomous system. It also describes IS-IS levels, areas, and backbone routers. Finally, it discusses CLNS addressing, IS-IS PDUs like Hello packets, and other IS-IS concepts.
STP prevents loops by electing a single root bridge and blocking redundant links. It uses BPDUs containing bridge IDs and path costs to elect the root bridge with the lowest bridge ID. The switch with bridge ID 32768.0001.964E.7EBB is elected as the root bridge based on having the lowest bridge ID of the switches shown.
This document provides an overview of EtherChannel concepts and configuration. EtherChannel allows linking multiple physical Ethernet ports together to form a single logical trunk with increased bandwidth. It uses protocols like PAgP and LACP to dynamically establish and maintain EtherChannel bundles. EtherChannel load balances traffic across physical ports and treats the bundle as a single logical port for functions like spanning tree. The document outlines terminology, configuration, verification commands, and considerations for optimizing EtherChannel deployment.
This document discusses OSPF packet types used for communication between routers to discover network routes, add link state entries to maintain routing information using LSA sequence numbers which can be viewed using the show IP OSPF database command, and debugged in more detail using the debug ip OSPF packets command.
Open Shortest Path First (OSPF) is an interior gateway protocol that uses link state routing and the Dijkstra algorithm to calculate the shortest path to destinations within an autonomous system. It elects a Designated Router to generate network link advertisements and assist in database synchronization between routers. Routers run the Shortest Path First algorithm on their link state databases to determine the best routes and populate their routing tables.
La formation CCNP ENCOR 1 est le premier cours pour la préparation à la certification 350-401 ENCOR. Ce cours permet d’apprendre, d’appliquer et de mettre en pratique les connaissances et les compétences de CCNP Enterprise grâce aux concepts théoriques à une série d'expériences pratiques approfondies qui renforce l’apprentissage. Avec cette formation et la formation CCNP ENCOR, vous possédera les outils pour envisager une inscription à l’examen de certification 350-401.
- Open Shortest Path First (OSPF) is a link-state routing protocol that can be used for both small and large networks. It uses areas and hierarchical network design to reduce routing overhead and improve performance as the network scales.
- OSPF establishes neighbor relationships to exchange routing information. It elects a Designated Router and Backup Designated Router to optimize this exchange on multi-access networks. Link-state databases are synchronized between neighbors to calculate the shortest paths.
- Basic OSPF configuration involves enabling OSPF on interfaces and networks, setting authentication, and adjusting metrics and timers. Loopback interfaces ensure router IDs remain stable. Verification commands display neighbor relationships and routing tables.
1) OSPF is a link-state routing protocol where each router maintains an identical database describing the network topology by flooding link-state advertisements (LSAs) throughout the network.
2) The routers run the Dijkstra shortest path first algorithm on their link-state database to determine the optimal route to all reachable networks.
3) OSPF routers establish neighbor relationships by multicasting hello packets to discover one another, then exchange and synchronize their full link-state databases.
This document discusses configuring and troubleshooting single-area OSPF routing. It covers topics like:
- Configuring static and dynamic routing on distribution and core routers
- Configuring and verifying single-area OSPF
- Designated router election process for multiaccess networks
- Propagating default static routes in OSPF
- Securing OSPF with message digest 5 authentication
- Components of troubleshooting single-area OSPF like forming adjacencies and transitioning states
- The document discusses Linux network stack monitoring and configuration. It begins with definitions of key concepts like RSS, RPS, RFS, LRO, GRO, DCA, XDP and BPF.
- It then provides an overview of how the network stack works from the hardware interrupts and driver level up through routing, TCP/IP and to the socket level.
- Monitoring tools like ethtool, ftrace and /proc/interrupts are described for viewing hardware statistics, software stack traces and interrupt information.
- OSPF is a link-state routing protocol that is more scalable than RIP. It builds a complete "map" of the network to avoid routing loops.
- OSPF uses link-state advertisements and flooding to exchange routing information between routers. It elects a designated router and backup designated router to optimize this exchange.
- Routers using OSPF establish neighbor relationships, synchronize their link-state databases, and calculate the shortest path to all known destinations using an algorithm on the link-state database.
This document provides an overview of the Open Shortest Path First (OSPF) routing protocol. It describes OSPF's message encapsulation, packet types, neighbor discovery process using Hello packets, link state database and shortest path first algorithm, metric and cost calculation, and mechanisms for handling multi-access networks like designated router election. The objectives are to describe OSPF configuration and troubleshooting.
IS-IS and OSPF are both link-state interior gateway protocols that use the SPF algorithm and support VLSM. However, IS-IS operates above layer 2 and routers belong to one area, while OSPF operates at the IP layer and routers can belong to multiple areas. Additionally, IS-IS uses DIS while OSPF uses DR/BDR, and OSPF supports virtual links while IS-IS does not.
Interior Gateway Routing Protocol (IGRP) is a proprietary distance-vector routing protocol developed by Cisco that is used within an autonomous system to exchange routing information. The document describes IGRP configuration and operation, including setting the autonomous system number, configuring IGRP on routers, and verifying IGRP routes and neighbor adjacencies. Key aspects of IGRP covered are metrics, timers, and network diagrams demonstrating IGRP configuration between three routers to exchange routes.
IS-IS is an interior gateway protocol that uses link-state routing and SPF algorithms to calculate the shortest path. It supports both CLNP and IP and has three routing levels - level 1 for intra-area routing, level 2 for inter-area routing, and level 1/2 routers that connect levels 1 and 2. There are three types of IS-IS routers: level 1 that exchange intra-area topology, level 2 that exchange inter-area topology, and level 1/2 that act as border routers between levels 1 and 2.
Cisco Live! :: Introduction to IOS XR for Enterprises and Service ProvidersBruno Teixeira
The document provides an overview of an introductory session on IOS XR for enterprises and service providers. It outlines the agenda which includes discussing IOS XR architecture, modularity, scalability, stability, security, software packages, the command line interface, configuration management, monitoring tools, example configurations, and the route policy language. It also provides some logistical information about the session.
The document discusses the IS-IS routing protocol. It provides an overview of IS-IS, including that it is an interior gateway protocol used within an autonomous system. It also describes IS-IS levels, areas, and backbone routers. Finally, it discusses CLNS addressing, IS-IS PDUs like Hello packets, and other IS-IS concepts.
STP prevents loops by electing a single root bridge and blocking redundant links. It uses BPDUs containing bridge IDs and path costs to elect the root bridge with the lowest bridge ID. The switch with bridge ID 32768.0001.964E.7EBB is elected as the root bridge based on having the lowest bridge ID of the switches shown.
This document provides an overview of EtherChannel concepts and configuration. EtherChannel allows linking multiple physical Ethernet ports together to form a single logical trunk with increased bandwidth. It uses protocols like PAgP and LACP to dynamically establish and maintain EtherChannel bundles. EtherChannel load balances traffic across physical ports and treats the bundle as a single logical port for functions like spanning tree. The document outlines terminology, configuration, verification commands, and considerations for optimizing EtherChannel deployment.
This document discusses OSPF packet types used for communication between routers to discover network routes, add link state entries to maintain routing information using LSA sequence numbers which can be viewed using the show IP OSPF database command, and debugged in more detail using the debug ip OSPF packets command.
Open Shortest Path First (OSPF) is an interior gateway protocol that uses link state routing and the Dijkstra algorithm to calculate the shortest path to destinations within an autonomous system. It elects a Designated Router to generate network link advertisements and assist in database synchronization between routers. Routers run the Shortest Path First algorithm on their link state databases to determine the best routes and populate their routing tables.
La formation CCNP ENCOR 1 est le premier cours pour la préparation à la certification 350-401 ENCOR. Ce cours permet d’apprendre, d’appliquer et de mettre en pratique les connaissances et les compétences de CCNP Enterprise grâce aux concepts théoriques à une série d'expériences pratiques approfondies qui renforce l’apprentissage. Avec cette formation et la formation CCNP ENCOR, vous possédera les outils pour envisager une inscription à l’examen de certification 350-401.
2. Start With Why!
RIP souffre de certaines limitations qui ont poussé l'IETF à plancher sur un protocole plus robuste
supportant des réseaux de grande taille.
-Augmentation du trafic réseau
-Nombre de sauts maximum de 15, ce qui signifie que sur les grands réseaux, il est possible que d'autres
routeurs distants ne puissent pas être atteints.
-Le plus proche peut ne pas être plus court!!!
3. Start With Why!
OSPF:
-Amélioration du temps de Convergence
-Possibilite de gerer des domaines de diamètre >16
-segmentation possible des domaine en aires
-Métrique plus sophistiqué .
4. Les grands principes d'OSPF
-Il est ouvert : c'est le sens du terme Open de OSPF. Son fonctionnement est connu de tous
-Il utilise l'algorithme SPF pour Shortest Path First, plus connu sous le nom d'algorithme de
Dijkstra, afin d'élire la meilleure route vers une destination donnée
-Protocole à état de liens
-Notion de coûts
-Routage dynamique.
5. Le fonctionnement d'OSPF
1-établir la liste des routeurs voisins
2-élire le routeur désigné (et le routeur désigné de secours)
3-découvrir les routes ; élire les routes à utiliser
4-maintenir la base de donnée topologique.
12. Let’s Translate to
function Dijkstra(Graph, source):
dist[source] := 0 // Distance de la source est initialisé a 0
for each vertex v in Graph: // Initializations
if v ≠ source
dist[v] := infinity // distance inconnu = infinity
add v to Q // All nodes initialisé à Q
while Q is not empty:
v := vertex in Q with min dist[v]
remove v from Q
for each neighbor u of v:
alt := dist[v] + length(v, u)
if alt < dist[u]: // shorter path est trouvé
dist[u] := alt // Update la distance de u
return dist[]
end function
13. Différences dans OSPF V1 et V2:
Quelques modifications apportées à la procédure d'inondation Modification des préférences de chemin
externe
Une fois le calcul terminé, tous les chemins calculés contenant encore des sauts virtuels non résolus
doivent être ignorés
Résolution incomplète des prochains sauts virtuels L'une des fonctions du calcul consiste à déterminer le
ou les prochains sauts réels des destinations dont le prochain saut a été calculé comme un lien virtuel.
14. Différences dans OSPF V2et V3:
La sémantique d'adressage a été supprimée des paquets OSPF et des LSA (Link State Advertisements) de
base
La plupart des champs et des limitations de taille de paquet présents dans OSPF pour IPv4 ont été
assouplis. De plus, la gestion des options est devenue plus flexible
De nouveaux LSA (Link-state advertisement)ont été créés pour transporter les adresses IPv6 et les
préfixes.
15. Les différents types de routeur OSPF
Routeur interne : routeur dont toutes les interfaces se situent dans la même zone. Les
LSDB de tous les routeurs internes à une zone sont identiques.
Routeur fédérateur : routeur situé dans la zone fédératrice. Généralement, la zone
fédératrice est définie sur la zone 0
Routeur ABR (Area Border Router) : routeur possédant des interfaces dans différentes
zones
Routeur ASBR(Autonomous System Boundary Router ) : routeur possedant au moins
une interface associée a un interreseau externe (autre systéme autonome)
16. Les inconvénient D’OSPF
L'exécution de l'algorithme SPF nécessite un traitement supplémentaire du processeur.
Il est complexe à configurer et plus difficile à résoudre.
Il nécessite plus de mémoire pour contenir la contiguïté (liste des voisins OSPF), la topologie et les tables
de routage.
pas aussi facile à apprendre que d'autres protocoles.
Il Ya mêmes une faiblesse au niveau de algorithme