Routing. 4. Mar INF-3190: Switching and Routing
|
|
- Hector Paul
- 6 years ago
- Views:
Transcription
1 Routing 4. Mar INF-3190: Switching and Routing
2 Routing: Foundations! Task! To define the route of packets through the network! From the source! To the destination system! Routing algorithm! Defines on which outgoing line an incoming packet will be transmitted! Route determination! Datagram! Routing algorithm makes individual decision for each packet! Virtual circuit! Routing algorithm runs only during connect (session routing) 4. Mar. 004 INF-3190: Switching and Routing
3 Routing: Routing and Forwarding! Distinction can be made! Routing: makes decision which route to use! Forwarding: what happens when a packet arrives Topology, link utilization, etc. information Router Routing Process Fills & Updates destination link A 0 B 3 Routing table C 1 Uses & Looks up D 4 Data packets Incoming lines Forwarding Process Outgoing lines 4. Mar INF-3190: Switching and Routing
4 Good Properties for Routing Algorithms! Correctness! Simplicity! Minimize load of routers! Robustness! Compensation for IS and link failures! Handling of topology and traffic changes! Stability! Consistent results! No volatile adaptations to new conditions! Fairness! Among different sources compared to each other! Optimality 4. Mar INF-3190: Switching and Routing
5 Routing Algorithms: Conflicting Properties! Often conflicting: fairness and optimization! Some different optimization criteria! Average packet delay! Total throughput! Individual delay! Conflict! Example: A B C X X A B C! Communication among A A, B B, C C uses full capacity of horizontal line! Optimized throughput, but! No fairness for X and X! Tradeoff between fairness and optimization! Therefore often! Hop minimization per packet! It tends to reduce delays and decreases required bandwidth! Also tends to increase throughput 4. Mar INF-3190: Switching and Routing
6 Classes of Routing Algorithms! Class Non-adaptive Algorithms! Current network state not taken into consideration! Assume average values! All routes are defined off-line before the network is put into operation! No change during operation (static routing)! With knowledge of the overall topology! Spanning tree! Flow-based routing! Without knowledge of the overall topology! Flooding! Class Adaptive Algorithms! Decisions are based on current network state! Measurements / estimates of the topology and the traffic volume! Further sub-classification into! Centralized algorithms! Isolated algorithms! Distributed algorithms 4. Mar INF-3190: Switching and Routing
7 Optimality Principle and Sink Tree! General statement about optimal routes! If router J is on optimal path from router I to router K! Then the optimal path from router J to router K uses the same route! Example:! r1: route from I to J! r: route from J to K! If better route r from J to K would exist! Then! Concatenation of r1 and r would improve route from I to K! Set of optimal routes! From all sources! To a given destination form a tree rooted at the destination: Sink Tree r1 r1 I J K r 4. Mar INF-3190: Switching and Routing
8 Sink Tree Subnet! Comments! Tree: no loops F A K G L D B M H E! Each optimal route is finite with bounded number of hops! Not necessarily unique! Other trees with same path lengths may exist! Goal of all routing algorithms! Discover and use the sink trees for all routers! Not realistic to use Sink Trees as real-life routing algorithm! Need complete information about topology! Sink Tree is only a benchmark for routing algorithms 4. Mar INF-3190: Switching and Routing I C J N O Sink Tree for Destination B
9 Methodology & Metrics! Networks represented as graphs:! Node represents a router! Edge represents a communication line (link)! Compute the shortest path between a given pair of routers! Different metrics for path lengths can be used! Can lead to different results! Sometime even combined (but this leads to computational problems)! Metrics for the "ideal" route, e.g., a "short" route! Number of hops! Geographical distance! Bandwidth! Average data volume! Cost of communication! Delay in queues! Mar INF-3190: Switching and Routing
10 Non- Adaptive Routing Shortest Path Routing 4. Mar INF-3190: Switching and Routing
11 Non-Adaptive Shortest Path Routing! Static Procedure! Network operator generates tables! Tables! Are loaded when IS operation is initiated and! Will not be changed any more! Characteristics! Simple! Good results with relatively consistent topology and traffic! But! Poor performance if traffic volume or topologies change over time 4. Mar INF-3190: Switching and Routing
12 Non-Adaptive Shortest Path Routing! Spanning Tree and Optimized Route! Information about the entire network has to be available! i. e. application actually as a benchmark comparison! Example! Link is labeled with distance / weight! Node is labeled with distance from source node along best known path (in parentheses)! Find the shortest path from A to D A 6 B (,-) 1 G (,-) 7 E (,-) 4 3 F (,-) C (,-) 3 H (,-) D (,-) 4. Mar INF-3190: Switching and Routing
13 Non-Adaptive Shortest Path Routing! Procedure: e. g. according to Dijkstra! Find the shortest path from A to D! Labels may be permanent or tentative! Initially, no paths are known! All nodes are labeled with infinity (tentative)! Discover the labels that represent shortest possible path from source to any node! Make those labels permanent 1. Node A labeled as permanent (filled-in circle). Relabel all directly adjacent nodes with the distance to A (path length, nodes adjacent to source) 3. Examine all tentatively labeled nodes, make the node with the smallest label permanent 4. This node will be the new working node for the iterative procedure (i.e., continue with step.) 4. Mar INF-3190: Switching and Routing
14 Non-Adaptive Shortest Path Routing B (,A) (,-) 7 C (,-) A 6 1 G (,-) (6,A) E (,-) 4 3 F (,-) 3 H (,-) D (,-)! Procedure: e. g. according to Dijkstra! Find the shortest path from A to D: 1. A flagged as permanent (filled-in circle). Relabel all directly adjacent nodes with the distance to A! (path length, IS adjacent to the source): 4. Mar INF-3190: Switching and Routing
15 Non-Adaptive Shortest Path Routing B (,A) 7 C (,-) A 6 1 G (6,A) E (,-) 4 3 F (,-) 3 H (,-) D (,-)! Procedure: e. g. according Dijkstra! Find the shortest path from A to D:! Compare all recent, not firmly flagged IS;! flag the one with the lowest number as fixed 4. This IS is the origin of the iterative procedure! (i. e. continue with item.) 4. Mar INF-3190: Switching and Routing
16 Non-Adaptive Shortest Path Routing B (,A) 7 C (,-) (9,B) A 6 1 G (6,A) E (,-) (4,B) 4 3 F (,-) 3 H (,-) D (,-)! Procedure: e.g., according to Dijkstra! Find the shortest path from A to D: 1. Node B has been labeled as permanent (filled-in circle). relabel all directly adjacent nodes with the distance to B (path length, nodes adjacent to source):! A (does not apply, because it is the origin), 4. Mar INF-3190: Switching and Routing
17 Non-Adaptive Shortest Path Routing A 6 B (,A) 1 G (5,E) (6,A) 7 E (4,B) 4 3 F (,-) (6,E) C (9,B) 3 H (,-) (8,F) (9,G) D (,-) (10,H)! Procedure: e.g., according to Dijkstra! find the shortest path from A to D: examine all tentatively labeled nodes;! make the node with the smallest label permanent 4. this node will be the new working node for the iterative procedure Mar INF-3190: Switching and Routing
18 Non- Adaptive Routing Flooding 4. Mar INF-3190: Switching and Routing
19 Flooding! Principle! IS transmits the received packet to all adjacent IS! But generates "an infinite amount" of packets! Flood limitations! Hop counter in the packet header! Initialize to destination s distance, or subnet diameter is unknown! Decrement per hop, discard packet at 0! Keeping history of transferred packets in ISs, delete copies! Source router inserts sequence number into each packet! ISs keeps per-router history of sequence numbers! Old packets are dropped 4. Mar INF-3190: Switching and Routing
20 Selective Flooding! Approach! Do not send out on every line! IS transmits received packet to adjacent stations, located in the Direction of the Destination! With regular topologies this makes sense and is an optimization! But some topologies do not fit well to this approach! Comment! Geographically-oriented routing got recent interest for mobile scenarios 4. Mar INF-3190: Switching and Routing
21 Flooding! Evaluation and use! In most scenarios impractical because of overhead! Extremely robust! Reaches all ISs! Does not need topology information, no bootstrap! Always finds the shortest path 4. Mar INF-3190: Switching and Routing
22 Adaptive Routing 4. Mar. 004 INF-3190: Switching and Routing
23 Adaptive Routing! Class Adaptive Algorithms! Decisions are based on current network state! Measurements / estimates of the topology and the traffic volume! Further sub-classification into! Centralized algorithms! Isolated algorithms! Distributed algorithms 4. Mar INF-3190: Switching and Routing
24 Adaptive Routing Centralized Routing 4. Mar INF-3190: Switching and Routing
25 Adaptive Centralized Routing! Principle! One routing control center (RCC) exists in the network! Each IS sends periodically status updates to the RCC! Available neighbors! Current queue length! Line utilization!! RCC! Collects information! Computes the optimal path each IS pair! Forms routing tables! Distributes tables to ISs 4. Mar INF-3190: Switching and Routing
26 Adaptive Centralized Routing! Characteristics! RCC has complete information! IS is free of routing calculations! But! Re-calculations quite often necessary (approx. once/min or more often)! Low robustness! No correct decisions if network is partitioned! ISs receive tables at different times! Traffic concentration in RCC proximity RCC 4. Mar INF-3190: Switching and Routing
27 Adaptive Routing Isolated Routing 4. Mar INF-3190: Switching and Routing
28 Adaptive Isolated Routing through Backward Learning! Isolated routing! Every IS makes decision based on locally gathered information only! No exchange of routing information among nodes! Only limited adaptation possibility to changed traffic or topology! IS learns from received packets! Source IS! Distance estimate by hop count 4. Mar INF-3190: Switching and Routing
29 Adaptive Isolated Routing through Backward Learning! Packet! From source S! received on line L! after C hops S is reachable on L within C hops! Routing table in IS! L - table (destination - IS, outgoing line, C min )! Update of the routing table! IS receives packet (..., S, C,... ) on L if not (S in L-Table) then Add(S,L,C) else if C < C min then Update(S,L,C) 4. Mar INF-3190: Switching and Routing
30 Adaptive Isolated Routing through Backward Learning! Example: D learns about A! packet (..., source - IS, section counter,...)! P1 (..., A, 4,... ) Add ( A, l1, 4 )! P (..., A, 3,... ) Update ( A, l, 3 )?? I 1 A?? I D 4. Mar INF-3190: Switching and Routing
31 Adaptive Isolated Routing through Backward Learning! Problem! Packets use a different route, e. g. because of failures, high load! Algorithm retains only the old value (because it was "better"),! i. e. algorithm does not react to deteriorations! Solution! Periodic deletion of routing tables (new learning period)! Table deletion! Too often: mainly during the learning phase! Not often enough: reaction to deteriorations too slow 4. Mar INF-3190: Switching and Routing
32 Adaptive Routing Distributed Routing Distance Vector 4. Mar INF-3190: Switching and Routing
33 Distance Vector Routing! Distance-Vector Routing! Group of Distance Vector Routing Algorithms! Also known as! Distributed Bellman-Ford algorithm, Ford-Fulkerson algorithm! Use! Was the original ARPANET routing algorithm! Has been used in the Internet as RIP (Routing Information Protocol)! Basic principle! IS maintains table (i.e., vector) stating! Best known distance to destinations! And line to be used! ISs update tables! By exchanging routing information with their neighbors 4. Mar INF-3190: Switching and Routing
34 Distance Vector Routing! Each IS! maintains routing table with one entry per router in the subnet! is assumed to know the distances to each neighbor! IS sends list with estimated distances to each destination periodically to its neighbors! X receives list E(Z) from neighbor Y! Distance X to Y: e! Distance Y to Z: E(Z)! Distance X to Z via Y: E(Z)+e! IS computes new routing table from the received lists containing! Destination IS! Preferred outgoing path! Distance 4. Mar INF-3190: Switching and Routing
35 Distance Vector Routing A B C D G E H F I J K L A A 0 B 1 C 5 D 40 E 14 F 3 G 18 H 17 I 1 J 9 K 4 L 9 I H K line 8 A 0 A 8 IH 0 17 I 30 I 18 H 1 H 10 I 0-6 K 15 K delay JA 8 JI 10 JH 1 JK 6! Previous routing table will not be taken into account! Reaction to deteriorations 4. Mar INF-3190: Switching and Routing
36 Distance Vector Routing! Fast route improvement! Fast distribution of information about new short paths (with few hops)! Example! initially A unknown! later: A connected with distance 1 to B, this will be announced! Distribution proportional to topological spread! Synchronous (stepwise) update is a simplification A B C D E Mar INF-3190: Switching and Routing
37 Distance Vector Routing! Slow distribution of information about new long paths (with many hops)! Count to Infinity problem of DVR! Example: deterioration! Here: connection destroyed! A previously known, but now detached! The values are derived from (incorrect) connections of distant IS! Comment! Limit "infinite" to a finite value, depending on the metrics, e.g.! infinite = maximum path length+1 A B C D E Mar INF-3190: Switching and Routing
38 Distance Vector Routing! Variant: Split Horizon Algorithm! Objective: improve the "count to infinity" problem! Principle! In general, to publicize the "distance" to each neighbour! If neighbor Y exists on the reported route, X reports the response "false" to Y! distance X (via Y) according to arbitrary i:! Example: deterioration (connection destroyed)! B to C: A = (real), C to B: A = (because A is on path),...! But: still poor, depending on topology, example! Connection CD is removed! A receives "false information" via B! B receives "false information" via A! Slow distribution (just as before) A B C D E Mar INF-3190: Switching and Routing A B C D
39 Adaptive Routing Distributed Routing Link State Routing 4. Mar INF-3190: Switching and Routing
40 Link State Routing! Basic principle! IS measures the "distance" to the directly adjacent IS! Distributes information! Calculates the ideal route! Procedure 1. Determine the address of adjacent IS. Measure the "distance" (delay,...) to neighbouring IS 3. Organize the local link state information in a packet 4. Distribute the information to all IS 5. Calculate the route based on the information of all IS! Use! Introduced into the ARPANET in 1979, nowadays most prevalent! IS-IS (Intermediate System-Intermediate System)! developed by DECNET! also used as ISO CLNP in NSFNET! Novell Netware developed its own variation from this (NLSP)! OSPF (Open Shortest Path First)! since 1990 Internet RFC Mar INF-3190: Switching and Routing
41 Link State Routing 1. Phase: gather information about the adjacent intermediate systems B D E G H I B D E G H I A C F A C LAN F 4. Mar INF-3190: Switching and Routing
42 Link State Routing 1. Phase: gather information about the adjacent intermediate systems B D E G H I B D E G H I A C F A C F LAN Initialization procedure! New IS! Sends a HELLO message over each L channel! Adjacent IS! Responds with its own address, unique within the network N 4. Mar INF-3190: Switching and Routing
43 Link State Routing. Phase: measure the "distance"! Definition of distance needed! Usually delay! Where to measure? Topology, link utilization, etc. information Router Routing Process Fills & Updates destination link A 0 B 3 Routing table When to start timer? C 1 Uses & Looks up D 4 Data packets ECHO Incoming lines Forwarding Process Queues HELLO Outgoing lines 4. Mar INF-3190: Switching and Routing
44 Link State Routing. Phase: measure the "distance! Queuing delay! Measuring without does not take load into account! Measuring with does usually better West East G B C F A H D E I J! But! Possibility for oscillations (route flapping)! Once per routing table update 4. Mar INF-3190: Switching and Routing
45 Link State Routing 3. Phase: organizing the information as link state packet! Including own address, sequence number, age, "distance"! Timing problems: validity and time of sending! Periodically! In case of major changes A B C E 8 F D Link State Packets: A Seq. Age B 4 E 5 B C D E F Seq. Seq. Seq. Seq. Seq. Age Age Age Age Age A 4 B C3 A 5 B 6 C D 3 F 7 C 1 D 7 F 6 E 1 F 8 E 8 4. Mar INF-3190: Switching and Routing
46 Link State Routing 4. Distributing the local information to all IS! By applying the flooding procedure (very robust)! Therefore sequence number in packets! Problem: inconsistency! Varying states simultaneously available in the network! Indicate and limit the age of packet, i. e. IS removes packets that are too old 5. Computing new routes! Each IS for itself! Possibly larger amount of data available 4. Mar INF-3190: Switching and Routing
Routing Algorithms. CS158a Chris Pollett Apr 4, 2007.
Routing Algorithms CS158a Chris Pollett Apr 4, 2007. Outline Routing Algorithms Adaptive/non-adaptive algorithms The Optimality Principle Shortest Path Routing Flooding Distance Vector Routing Routing
More informationLayer 3: Network Layer. 9. Mar INF-3190: Switching and Routing
Layer 3: Network Layer 9. Mar. 2005 1 INF-3190: Switching and Routing Network Layer Goal Enable data transfer from end system to end system End systems Several hops, (heterogeneous) subnetworks Compensate
More informationChapter 22 Network Layer: Delivery, Forwarding, and Routing 22.1
Chapter 22 Network Layer: Delivery, Forwarding, and Routing 22.1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 22-3 UNICAST ROUTING PROTOCOLS 22.2 A routing
More informationRouting. Advanced Computer Networks: Routing 1
Routing Advanced Computer Networks: Routing 1 Gateway To internet or wide area network Metropolitan Area Network (MAN) s s Organization Servers Backbone R S R R Departmental Server s R S R s S R s s s
More information5.2 Routing Algorithms
CEN445 Network Protocols and Algorithms Chapter 5 Network Layer 5. Routing Algorithms Dr. Mostafa Hassan Dahshan Department of Computer Engineering College of Computer and Information Sciences King Saud
More informationRouting in packet-switching networks
Routing in packet-switching networks Circuit switching vs. Packet switching Most of WANs based on circuit or packet switching Circuit switching designed for voice Resources dedicated to a particular call
More informationETSF05/ETSF10 Internet Protocols Routing on the Internet
ETSF05/ETSF10 Internet Protocols Routing on the Internet 2014, (ETSF05 Part 2), Lecture 1.1 Jens Andersson Circuit switched routing 2014 11 05 ETSF05/ETSF10 Internet Protocols 2 Packet switched Routing
More informationECE 333: Introduction to Communication Networks Fall 2001
ECE : Introduction to Communication Networks Fall 00 Lecture : Routing and Addressing I Introduction to Routing/Addressing Lectures 9- described the main components of point-to-point networks, i.e. multiplexed
More informationChapter 12. Routing and Routing Protocols 12-1
Chapter 12 Routing and Routing Protocols 12-1 Routing in Circuit Switched Network Many connections will need paths through more than one switch Need to find a route Efficiency Resilience Public telephone
More informationLecture on Computer Networks
Lecture on Computer Networks Historical Development Copyright (c) 28 Dr. Thomas Haenselmann (Saarland University, Germany). Permission is granted to copy, distribute and/or modify this document under the
More informationICMP, ARP, RARP, IGMP
Internet Layer Lehrstuhl für Informatik 4 Raw division into three tasks: Data transfer over a global network Route decision at the sub-nodes Control of the network or transmission status Routing Protocols
More informationFairness Example: high priority for nearby stations Optimality Efficiency overhead
Routing Requirements: Correctness Simplicity Robustness Under localized failures and overloads Stability React too slow or too fast Fairness Example: high priority for nearby stations Optimality Efficiency
More informationETSF05/ETSF10 Internet Protocols. Routing on the Internet
ETSF05/ETSF10 Internet Protocols Routing on the Internet Circuit switched routing ETSF05/ETSF10 - Internet Protocols 2 Routing in Packet Switching Networks Key design issue for (packet) switched networks
More informationRouting, Routing Algorithms & Protocols
Routing, Routing Algorithms & Protocols Computer Networks Lecture 6 http://goo.gl/pze5o8 Circuit-Switched and Packet-Switched WANs 2 Circuit-Switched Networks Older (evolved from telephone networks), a
More informationRouting in Switched Data Networks
in Switched Data Networks ITS323: Introduction to Data Communications Sirindhorn International Institute of Technology Thammasat University Prepared by Steven Gordon on 23 May 2012 ITS323Y12S1L10, Steve/Courses/2012/s1/its323/lectures/routing.tex,
More informationWilliam Stallings Data and Computer Communications 7 th Edition. Chapter 12 Routing
William Stallings Data and Computer Communications 7 th Edition Chapter 12 Routing Routing in Circuit Switched Network Many connections will need paths through more than one switch Need to find a route
More informationLecture 4 Wide Area Networks - Routing
DATA AND COMPUTER COMMUNICATIONS Lecture 4 Wide Area Networks - Routing Mei Yang Based on Lecture slides by William Stallings 1 ROUTING IN PACKET SWITCHED NETWORK key design issue for (packet) switched
More informationData and Computer Communications. Chapter 12 Routing in Switched Networks
Data and Computer Communications Chapter 1 Routing in Switched Networks Routing in Packet Switched Network Select route between end nodes Characteristics required: Correctness Simplicity Robustness Stability
More informationBLM6196 COMPUTER NETWORKS AND COMMUNICATION PROTOCOLS
BLM696 COMPUTER NETWORKS AND COMMUNICATION PROTOCOLS Prof. Dr. Hasan Hüseyin BALIK (7 th Week) 7. Routing 7.Outline Routing in Packet-Switching Networks Examples: Routing in ARPANET Internet Routing Protocols
More informationTelecommunication Protocols Laboratory Course. Lecture 3
Telecommunication Protocols Laboratory Course Lecture 3 Course map Last time: we discussed protocols of the Medium Access Control (MAC) sub-layer Deal with broadcast channels and their (multi-party) protocols
More informationWilliam Stallings Data and Computer Communications. Chapter 10 Packet Switching
William Stallings Data and Computer Communications Chapter 10 Packet Switching Principles Circuit switching designed for voice Resources dedicated to a particular call Much of the time a data connection
More informationAlternate Routing Diagram
68 0 Computer Networks Chapter Routing Routing in Circuit Switched Network Many connections will need paths through more than one switch Need to find a route Efficiency Resilience Public telephone switches
More informationComputer Networks. Routing Algorithms
Computer Networks Routing Algorithms Topics Routing Algorithms Shortest Path (Dijkstra Algorithm) Distance Vector Routing Count to infinity problem Solutions for count to infinity problem Link State Routing
More informationRouting. Information Networks p.1/35
Routing Routing is done by the network layer protocol to guide packets through the communication subnet to their destinations The time when routing decisions are made depends on whether we are using virtual
More informationChapter 5 (Week 9) The Network Layer ANDREW S. TANENBAUM COMPUTER NETWORKS FOURTH EDITION PP BLM431 Computer Networks Dr.
Chapter 5 (Week 9) The Network Layer ANDREW S. TANENBAUM COMPUTER NETWORKS FOURTH EDITION PP. 343-396 1 5.1. NETWORK LAYER DESIGN ISSUES 5.2. ROUTING ALGORITHMS 5.3. CONGESTION CONTROL ALGORITHMS 5.4.
More informationECE 435 Network Engineering Lecture 11
ECE 435 Network Engineering Lecture 11 Vince Weaver http://web.eece.maine.edu/~vweaver vincent.weaver@maine.edu 5 October 2017 Announcements Back from Memsys. Related things: fast memories for network
More informationComputer Networks 1 (Mạng Máy Tính 1) Lectured by: Dr. Phạm Trần Vũ
Computer Networks 1 (Mạng Máy Tính 1) Lectured by: Dr. Phạm Trần Vũ Lecture 5: Network Layer Reference: Chapter 5 - Computer Networks, Andrew S. Tanenbaum, 4th Edition, Prentice Hall, 2003. Contents The
More informationYouki Kadobayashi NAIST
Information Network 1 Routing (1) Image: Part of the entire Internet topology based on CAIDA dataset, using NAIST Internet viewer Youki Kadobayashi NAIST 1 The Routing Problem! How do I get from source
More informationC13b: Routing Problem and Algorithms
CISC 7332X T6 C13b: Routing Problem and Algorithms Hui Chen Department of Computer & Information Science CUNY Brooklyn College 11/20/2018 CUNY Brooklyn College 1 Acknowledgements Some pictures used in
More informationCHAPTER 9: PACKET SWITCHING N/W & CONGESTION CONTROL
CHAPTER 9: PACKET SWITCHING N/W & CONGESTION CONTROL Dr. Bhargavi Goswami, Associate Professor head, Department of Computer Science, Garden City College Bangalore. PACKET SWITCHED NETWORKS Transfer blocks
More informationUNIT 2 ROUTING ALGORITHMS
UNIT ROUTING ALGORITHMS Routing Algorithms Structure Page Nos..0 Introduction 3. Objectives 3. Flooding 3.3 Shortest Path Routing Algorithm 5.4 Distance Vector Routing 6.4. Comparison.4. The Count-to-Infinity
More information06/02/ Local & Metropolitan Area Networks. Overview. Routing algorithm ACOE322. Lecture 6 Routing
Local & Metropolitan rea Networks OE3 Lecture 6 Routing r. L. hristofi Overview The main function of the network layer is routing packets from the source to the destination machine. The only exception
More informationECE 435 Network Engineering Lecture 11
ECE 435 Network Engineering Lecture 11 Vince Weaver http://web.eece.maine.edu/~vweaver vincent.weaver@maine.edu 11 October 2018 Midterm on Tues Announcements 1 HW#4 Review maine.edu created? What is a
More informationCEN445 Network Protocols and Algorithms. Chapter 2. Routing Algorithms. Dr. Ridha Ouni
3/4/04 EN44 Network Protocols and lgorithms hapter Routing lgorithms Dr. Ridha Ouni Department of omputer Engineering ollege of omputer and Information Sciences King Saud University References Some slides
More informationLecture (08, 09) Routing in Switched Networks
Agenda Lecture (08, 09) Routing in Switched Networks Dr. Ahmed ElShafee Routing protocols Fixed Flooding Random Adaptive ARPANET Routing Strategies ١ Dr. Ahmed ElShafee, ACU Fall 2011, Networks I ٢ Dr.
More informationThis Lecture. BUS Computer Facilities Network Management. Switching Network. Simple Switching Network
This Lecture BUS0 - Computer Facilities Network Management Switching networks Circuit switching Packet switching gram approach Virtual circuit approach Routing in switching networks Faculty of Information
More informationYouki Kadobayashi NAIST
Information Network 1 Routing (1) Image: Part of the entire Internet topology based on CAIDA dataset, using NAIST Internet viewer Youki Kadobayashi NAIST 1 The Routing Problem How do I get from source
More informationYouki Kadobayashi NAIST
Information Network 1 Routing (1) Youki Kadobayashi NAIST 1 The Routing Problem! How do I get from source to destination?! Which path is best? In terms of:! Number of hops! Delay! Bandwidth! Policy constraints!
More informationRouting Strategies. Fixed Routing. Fixed Flooding Random Adaptive
Routing Strategies Fixed Flooding Random Adaptive Fixed Routing Single permanent route for each source to destination pair Determine routes using a least cost algorithm Route fixed, at least until a change
More informationComputer Networking. Intra-Domain Routing. RIP (Routing Information Protocol) & OSPF (Open Shortest Path First)
Computer Networking Intra-Domain Routing RIP (Routing Information Protocol) & OSPF (Open Shortest Path First) IP Forwarding The Story So Far IP addresses are structured to reflect Internet structure IP
More informationModule 8. Routing. Version 2 ECE, IIT Kharagpur
Module 8 Routing Lesson 27 Routing II Objective To explain the concept of same popular routing protocols. 8.2.1 Routing Information Protocol (RIP) This protocol is used inside our autonomous system and
More informationII. Principles of Computer Communications Network and Transport Layer
II. Principles of Computer Communications Network and Transport Layer A. Internet Protocol (IP) IPv4 Header An IP datagram consists of a header part and a text part. The header has a 20-byte fixed part
More informationRouting in a network
Routing in a network Focus is small to medium size networks, not yet the Internet Overview Then Distance vector algorithm (RIP) Link state algorithm (OSPF) Talk about routing more generally E.g., cost
More informationNetwork Layer: Routing
Network Layer: Routing The Problem A B R 1 R 2 R 4 R 3 Goal: for each destination, compute next hop 1 Lecture 9 2 Basic Assumptions Trivial solution: Flooding Dynamic environment: links and routers unreliable:
More informationUnit 3: Dynamic Routing
Unit 3: Dynamic Routing Basic Routing The term routing refers to taking a packet from one device and sending it through the network to another device on a different network. Routers don t really care about
More informationRedes de Computadores. Shortest Paths in Networks
Redes de Computadores Shortest Paths in Networks Manuel P. Ricardo Faculdade de Engenharia da Universidade do Porto » What is a graph?» What is a spanning tree?» What is a shortest path tree?» How are
More informationOutline. Routing. Introduction to Wide Area Routing. Classification of Routing Algorithms. Introduction. Broadcasting and Multicasting
Outline Routing Fundamentals of Computer Networks Guevara Noubir Introduction Broadcasting and Multicasting Shortest Path Unicast Routing Link Weights and Stability F2003, CSG150 Fundamentals of Computer
More informationCMPE 150: Introduction to Computer Networks
CMPE 50: Introduction to Computer Networks Dr. Chane L. Fullmer chane@cse.ucsc.edu Spring 003 UCSC cmpe50 Homework Assignments Homework assignment #3 Chapter Four Due by May Spring 003 UCSC cmpe50 CMPE
More informationEITF25 Internet Routing. Jens A Andersson
EITF25 Internet Routing Jens A Andersson Study Guide Kihl & Andersson: Ch 8, 9.3 9.4 Stallings: Ch 19.1 & 19.2 Forouzan 5th ed Ch 20.1 20.3, 21.1 21.2 Routing The Routing Concept Unicast Routing Multicast
More informationCSE 461 Routing. Routing. Focus: Distance-vector and link-state Shortest path routing Key properties of schemes
CSE 46 Routing Routing Focus: How to find and set up paths through a network Distance-vector and link-state Shortest path routing Key properties of schemes Application Transport Network Link Physical Forwarding
More informationLecture 12. Introduction to IP Routing. Why introduction? Routing
Lecture. Introduction to IP Routing Why introduction? Routing: very complex issue need in-depth study entire books on routing our scope: give a flavour of basic routing structure and messaging give an
More informationNetwork Protocols. Routing. TDC375 Autumn 03/04 John Kristoff - DePaul University 1
Network Protocols Routing TDC375 Autumn 03/04 John Kristoff - DePaul University 1 IPv4 unicast routing All Internet hosts perform basic routing for local net destinations, forward to local host for non-local
More informationComputer Networks. Wenzhong Li. Nanjing University
Computer Networks Wenzhong Li Nanjing University 1 Chapter 3. Packet Switching Networks Switching and Forwarding Virtual Circuit and Datagram Networks ATM and Cell Switching X.25 and Frame Relay Routing
More informationHelsinki University of Technology Telecommunications Laboratory. OSPF Routing Protocol Licenciate course seminar paper
Helsinki University of Technology Telecommunications Laboratory OSPF Routing Protocol Licenciate course seminar paper Shkumbin I. Hamiti, 08.10.1996 Communications Laboratory, TKK-HUT email: bini#tiltu.hut.fi
More informationCourse Routing Classification Properties Routing Protocols 1/39
Course 8 3. Routing Classification Properties Routing Protocols 1/39 Routing Algorithms Types Static versus dynamic Single-path versus multipath Flat versus hierarchical Host-intelligent versus router-intelligent
More informationYouki Kadobayashi NAIST
Information Network 1 Routing (1) Image: Part of the entire Internet topology based on CAIDA dataset, using NAIST Internet viewer Youki Kadobayashi NAIST 1 The Routing Problem How do I get from source
More informationWe will discuss about three different static routing algorithms 1. Shortest Path Routing 2. Flooding 3. Flow Based Routing
In this lecture we will discuss about Routing algorithms Congestion algorithms Lecture 19 The routing algorithm is that part of the network layer software, which is responsible for deciding which output
More informationCommunication Systems Network Layer
Communication Systems Network Layer Prof. Dr.-Ing. Lars Wolf TU Braunschweig Institut für Betriebssysteme und Rechnerverbund Mühlenpfordtstraße 23, 38106 Braunschweig, Germany Email: wolf@ibr.cs.tu-bs.de
More informationComputer Networks. Routing
Computer Networks Routing Topics Link State Routing (Continued) Hierarchical Routing Broadcast Routing Sending distinct packets Flooding Multi-destination routing Using spanning tree Reverse path forwarding
More informationOperation Manual IPv4 Routing H3C S3610&S5510 Series Ethernet Switches. Table of Contents
Table of Contents Table of Contents Chapter 1 Static Routing Configuration... 1-1 1.1 Introduction... 1-1 1.1.1 Static Route... 1-1 1.1.2 Default Route... 1-1 1.1.3 Application Environment of Static Routing...
More informationTopology. Youki Kadobayashi NAIST. Outline. Routing system: its function. Gateway Model Revisited. Routing system: its structure
Information Network 1 Routing (1) Topology Topology 1: 2a (1): a branch of mathematics concerned with those properties of geometric configurations (as point sets) which are unaltered by elastic deformations
More informationInternet Routing Protocols Tuba Saltürk
Internet Routing Protocols 15505068 Tuba Saltürk Outline Internet Routers Routing Protocol Interior Gateway Protocol (IGP) Distance- Vector Routing Protocol Routing Information Protocol (RIP) Interior
More informationThe Internet Protocol
The Internet Protocol Stefan D. Bruda Winter 2018 THE INTERNET PROTOCOL A (connectionless) network layer protocol Designed for use in interconnected systems of packet-switched computer communication networks
More informationIP Routing. Bharat S. Chaudhari International Institute of Information Technology Pune, India
IP Routing Bharat S. Chaudhari International Institute of Information Technology Pune, India June 21, 2005 Network Devices: Ø The networking and internetworking devices are divided in the following categories:
More informationTo contain/reduce broadcast traffic, we need to reduce the size of the network (i.e., LAN).
2.3.3 Routers 2.3.3.1 Motivation Bridges do not stop broadcast traffic. This can lead to broadcast storms (e.g., more than 100 nonunicast frames/sec) which can be catastrophic. This can bring the network
More informationICS 351: Today's plan. distance-vector routing game link-state routing OSPF
ICS 351: Today's plan distance-vector routing game link-state routing OSPF distance-vector routing game 1. prepare a list of all neighbors and the links to them, and the metric for each link 2. create
More informationThe Network Layer. Network Layer Design Objectives
1 next CITS3002 help3002 CITS3002 schedule The Network Layer The Data Link Layer had the responsibility of reliably transmitting frames across along a single wire (or wireless,...) link. The Network Layer's
More informationHow Routing Algorithms Work
How Routing Algorithms Work A router is used to manage network traffic and find the best route for sending packets. But have you ever thought about how routers do this? Routers need to have some information
More informationCSEP 561 Routing. David Wetherall
CSEP 561 Routing David Wetherall djw@cs.washington.edu Routing Focus: How to find and set up paths through a network Distance-vector and link-state Application Shortest path routing Transport Key properties
More informationITEC310 Computer Networks II
ITEC310 Computer Networks II Chapter 22 Network Layer:, and Routing Department of Information Technology Eastern Mediterranean University Objectives 2/131 After completing this chapter you should be able
More informationRouting Outline. EECS 122, Lecture 15
Fall & Walrand Lecture 5 Outline EECS, Lecture 5 Kevin Fall kfall@cs.berkeley.edu Jean Walrand wlr@eecs.berkeley.edu Definition/Key Questions Distance Vector Link State Comparison Variations EECS - Fall
More informationICS 351: Today's plan. OSPF BGP Routing in general
ICS 351: Today's plan OSPF BGP Routing in general link-state routing in distance-vector (Bellman-Ford, Ford-Fulkerson, RIP-style) routing, each router distributes its routing table to its neighbors an
More informationIP Protocols. ALTTC/Oct
IP Protocols Internet or IP technology over the years has emerged as the most prominent data communication technology. TCP/IP protocol has become de-facto data comm standard throughout the world. It can
More informationTHE INTERNET PROTOCOL INTERFACES
THE INTERNET PROTOCOL The Internet Protocol Stefan D. Bruda Winter 2018 A (connectionless) network protocol Designed for use in interconnected systems of packet-switched computer communication networks
More informationCompSci 356: Computer Network Architectures. Lecture 12: Dynamic routing protocols: Link State Chapter Xiaowei Yang
CompSci 356: Computer Network Architectures Lecture 12: Dynamic routing protocols: Link State Chapter 3.3.3 Xiaowei Yang xwy@cs.duke.edu Today Routing Information Protocol Link-state routing Algorithm
More informationRouting Basics. What is Routing? Routing Components. Path Determination CHAPTER
CHAPTER 5 Routing Basics This chapter introduces the underlying concepts widely used in routing protocols Topics summarized here include routing protocol components and algorithms In addition, the role
More informationTop-Down Network Design
Top-Down Network Design Chapter Seven Selecting Switching and Routing Protocols Original slides by Cisco Press & Priscilla Oppenheimer Selection Criteria for Switching and Routing Protocols Network traffic
More informationRouting Protocols. The routers in an internet are responsible for receiving and. forwarding IP datagrams through the interconnected set of
Routing Protocols MITA DUTTA The routers in an internet are responsible for receiving and forwarding IP datagrams through the interconnected set of sub-networks from source to destination. Routing protocols
More informationNetwork Protocols. Routing. TDC375 Winter 2002 John Kristoff - DePaul University 1
Network Protocols Routing TDC375 Winter 2002 John Kristoff - DePaul University 1 IP routing Performed by routers Table (information base) driven Forwarding decision on a hop-by-hop basis Route determined
More informationLast time. Transitioning to IPv6. Routing. Tunneling. Gateways. Graph abstraction. Link-state routing. Distance-vector routing. Dijkstra's Algorithm
Last time Transitioning to IPv6 Tunneling Gateways Routing Graph abstraction Link-state routing Dijkstra's Algorithm Distance-vector routing Bellman-Ford Equation 10-1 This time Distance vector link cost
More informationOverview. Problem: Find lowest cost path between two nodes Factors static: topology dynamic: load
Dynamic Routing Overview Forwarding vs Routing forwarding: to select an output port based on destination address and routing table routing: process by which routing table is built Network as a Graph C
More informationRouting. Routing. Overview. Overview. Routing vs. Forwarding. Why Routing
Routing Dr. Arjan Durresi Department of Computer Science Louisiana State University Overview Routing vs. Forwarding Routing Algorithms, Distance Vector, Link State Dijkstra s Algorithm ARPAnet Routing
More informationFrom Routing to Traffic Engineering
1 From Routing to Traffic Engineering Robert Soulé Advanced Networking Fall 2016 2 In the beginning B Goal: pair-wise connectivity (get packets from A to B) Approach: configure static rules in routers
More informationCourse 6. Internetworking Routing 1/33
Course 6 Internetworking Routing 1/33 Routing The main function of the network layer is routing packets from the source machine to the destination machine. Along the way, at least one intermediate node
More informationTable of Contents 1 Static Routing Configuration RIP Configuration 2-1
Table of Contents 1 Static Routing Configuration 1-1 Introduction 1-1 Static Route 1-1 Default Route 1-1 Application Environment of Static Routing 1-1 Configuring a Static Route 1-2 Configuration Prerequisites
More informationLecture 12: Link-state Routing. Lecture 12 Overview. Router Tasks. CSE 123: Computer Networks Chris Kanich. Routing overview
Lecture : Link-state Routing CSE 3: Computer Networks Chris Kanich Lecture Overview Routing overview Intra vs. Inter-domain routing Link-state routing protocols CSE 3 Lecture : Link-state Routing Router
More informationTHE INTERNET PROTOCOL/1
THE INTERNET PROTOCOL a (connectionless) network layer protocol designed for use in interconnected systems of packet-switched computer communication networks (store-and-forward paradigm) provides for transmitting
More informationJaringan Komputer. Network Layer. Network Layer. Network Layer. Network Layer Design Issues. Store-and-Forward Packet Switching
Network Layer Jaringan Komputer Network Layer Concerned with getting packets from the source all the way to the destination May require making many hops at intermediate routers along the way Contrasts
More informationCS 5114 Network Programming Languages Control Plane. Nate Foster Cornell University Spring 2013
CS 5 Network Programming Languages Control Plane http://www.flickr.com/photos/rofi/0979/ Nate Foster Cornell University Spring 0 Based on lecture notes by Jennifer Rexford and Michael Freedman Announcements
More informationDistributed Routing. EECS 228 Abhay Parekh
Distributed Routing EECS 228 Abhay Parekh parekh@eecs.berkeley.edu he Network is a Distributed System Nodes are local processors Messages are exchanged over various kinds of links Nodes contain sensors
More informationReview for Chapter 4 R1,R2,R3,R7,R10,R11,R16,R17,R19,R22,R24, R26,R30 P1,P2,P4,P7,P10,P11,P12,P14,P15,P16,P17,P22,P24,P29,P30
Review for Chapter 4 R1,R2,R3,R7,R10,R11,R16,R17,R19,R22,R24, R26,R30 P1,P2,P4,P7,P10,P11,P12,P14,P15,P16,P17,P22,P24,P29,P30 R1. Let s review some of the terminology used in this textbook. Recall that
More informationRouting, Routers, Switching Fabrics
Routing, Routers, Switching Fabrics Outline Link state routing Link weights Router Design / Switching Fabrics CS 640 1 Link State Routing Summary One of the oldest algorithm for routing Finds SP by developing
More informationDistance vector and RIP
DD2490 p4 2008 Distance vector and RIP Olof Hagsand KTHNOC/NADA Literature RIP lab RFC 245: RIPv2. Sections 1 2 contains some introduction that can be useful to understand the context in which RIP is specified..1.4
More informationOverview 4.2: Routing
Overview 4.2: Routing Forwarding vs Routing forwarding: to select an output port based on destination address and routing table routing: process by which routing table is built Network as a Graph A 6 1
More informationComputer Networks II IPv4 routing
Dipartimento di Informatica e Sistemistica Computer Networks II IPv4 routing Luca Becchetti Luca.Becchetti@dis.uniroma1.it A.A. 2009/2010 NEXT WEEK... 2 exercise classes on topics covered so far Please
More information2008 NDP Lectures 7 th Semester
2008 NDP Lectures 7 th Semester Neeli R. Prasad, Associate Professor Head of Wireless Security and Sensor Networks Group Networking and Security Aalborg University Niels Jernes Vej 12, 9220 Aalborg East,
More informationThe most simple way to accelerate a Router is at 9.8 m/sec/sec.
Routing Introduction Direct vs. Indirect Delivery Static vs. Dynamic Routing Distance Vector vs. Link State (C) Herbert Haas 2005/03/11 The most simple way to accelerate a Router is at 9.8 m/sec/sec. Seen
More informationLink-State Routing OSPF
CE Computer Networks Link-State Routing OSPF Behnam Momeni Computer Engineering Department Sharif University of Technology Acknowledgments: Lecture slides are from Computer networks course thought by Jennifer
More informationEECS 122, Lecture 16. Link Costs and Metrics. Traffic-Sensitive Metrics. Traffic-Sensitive Metrics. Static Cost Metrics.
EECS 122, Lecture 16 Kevin Fall kfall@cs.berkeley.edu edu Link Costs and Metrics Routing protocols compute shortest/cheapest paths using some optimization criteria Choice of criteria has strong effect
More informationNetworking: Network layer
control Networking: Network layer Comp Sci 3600 Security Outline control 1 2 control 3 4 5 Network layer control Outline control 1 2 control 3 4 5 Network layer purpose: control Role of the network layer
More information