BGP Routing inside an AS

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "BGP Routing inside an AS"

Transcription

1 Hot Potatoes Heat Up BGP Routing Renata Teixeira (UC San Diego) with Aman Shaikh (AT&T), Tim Griffin(Intel), and Jennifer Rexford(AT&T) 30 th NANOG Miami, Florida BGP Routing inside an AS Most people think BGP = inter-domain routing Routing inside an AS = OSPF/IS-IS But in large transit ASes Most traffic is routed using BGP IGP changes affect BGP decisions 30 th NANOG 2 1

2 Hot-Potato Routing San Francisco ISP network 9 New York Hot-potato routing = route to closest exit point when there is more than one route to destination 30 th NANOG 3 Hot-Potato Routing San Francisco failure planned maintenance traffic engineering 11 Consequences: Transient forwarding instability Traffic shift Inter-domain routing changes ISP network 9 New York Routes to thousands of destinations switch exit point!!! 30 th NANOG 4 2

3 BGP Decision Process equally good Ignore if exit point unreachable Highest local preference Lowest AS path length Lowest origin type Lowest MED (with same next hop AS) Lowest IGP cost to next hop Lowest router ID of BGP speaker 30 th NANOG 5 Why Care about Hot Potatoes? Large number of routes potentially affected All routes from peers and multi-homed customers Understanding of impact in real networks How often hot-potato changes happen in a real network and how many prefixes do they affect? What are the convergence delays? Avoiding routing instability Operators: avoid hot-potato changes Vendors: reduce impact of hot-potato changes 30 th NANOG 6 3

4 Measuring Hot-Potato Routing Collect measurement of both protocols BGP monitor and OSPF monitor M AT&T backbone AS 7018 Pre-process each stream Clustering related messages Correlate the two streams of data Match BGP updates with OSPF events OSPF LSAs 30 th NANOG 7 M BGP updates from every PoP Heuristic for Matching Stream of OSPF messages Transform stream of OSPF messages into routing changes refresh link failure chg cost del weight change chg cost Match BGP updates with OSPF events that happen close in time time Classify BGP updates by possible OSPF causes Stream of BGP updates 30 th NANOG 8 4

5 Impact of OSPF/BGP Interaction (June 2003) High variability according to location and day Impact on external BGP measurements and customers location rich peering no peering % updates min max 0% 5.3% 0% 46.5% days > % of hot-potato changes 0 5 One LSA can have a big impact location LSAs with no impact rich peering 95.1% no peering 94.8% prefixes impacted by an LSA less than 1% 59% 30 th NANOG 9 Delay for BGP Routing Change Router rerunning BGP decision process Implementation specific Timer driven (tunable parameter) Event driven Internal BGP route propagation delay Internal BGP hierarchy (route reflectors) Wait for another router to change best route Transmitting many BGP messages Latency for transferring the data Delays very sensitive to router implementation decisions and network design! 30 th NANOG 5

6 Delay for First BGP Update Uniform distribution: 60 sec timer to revisit BGP decision Two runs of timer? Fraction of Hot-Potato Changes 60-second timer Routers in backbone (June) Routers in backbone (September) Router in lab time BGP update time LSA (seconds) 30 th NANOG 11 Transferring Multiple Prefixes Cumulative Number of Hot-Potato Changes Worst case scenario: 120 sec to revisit BGP decision 80 sec to send multiple updates Last prefix may take 3 minutes to converge! 81 seconds delay time BGP update time LSA (seconds) 30 th NANOG 12 6

7 Implications on Packet Forwarding Forwarding plane convergence FIB update only when both IGP and BGP converge Measuring the performance impact Do we need new measurement techniques? 30 th NANOG 13 Forwarding Plane Convergence R 1 R 2 0 X Scan process runs in R R 2 starts using R 1 to reach 3 - R 1 s scan process can take up to 60 seconds to run Packets to may be caught in a loop for 60 seconds! R 1 R th NANOG 14 7

8 Detecting Loops is Hard Active probing of forwarding path Probing machines just have one exit point customer traffic in loop R 1 R 2 W W 2 Operator probes 30 th NANOG 15 Avoiding Unnecessary Hot-Potato Changes Router connectivity to exit points Likelihood of hot-potato routing changes Cost in/out of links during maintenance 30 th NANOG 16 8

9 SF Comparison of Network Designs NY Small changes will make switch exit points to SF SF NY 1 00 NY More robust to intra-domain routing changes 30 th NANOG 17 Careful Cost in/out Links SF NY Traffic is more predictable Faster convergence Less impact on neighbors 30 th NANOG 18 9

10 Conclusions Hot potatoes can affect a lot of prefixes and have high convergence delays Vendors: Event-driven implementations Understand network-wide effect Operators: Tuning timer Network design Maintenance practices 30 th NANOG 19 Future Work Impact of the IGP-triggered BGP updates Sudden shifts in the flow of traffic Forwarding loops during convergence Externally visible BGP routing changes 30 th NANOG 20

Dynamics of Hot-Potato Routing in IP Networks

Dynamics of Hot-Potato Routing in IP Networks Dynamics of Hot-Potato Routing in IP Networks Jennifer Rexford AT&T Labs Research http://www.research.att.com/~jrex Joint work with Renata Teixeira (UCSD), Aman Shaikh (AT&T), and Timothy Griffin (Intel)

More information

Hot Potatoes Heat Up BGP Routing

Hot Potatoes Heat Up BGP Routing Hot Potatoes Heat Up BGP Routing Renata Teixeira Laboratoire d Informatique de Paris 6 Université Pierre et Marie Curie Amsterdam Internet Routing Architecture Verio AT&T AOL Web Server UCSD Sprint User

More information

Impact of Hot-Potato Routing Changes in IP Networks

Impact of Hot-Potato Routing Changes in IP Networks Impact of Hot-Potato Routing Changes in IP Networks Renata Teixeira Aman Shaikh Tim Griffin Jennifer Rexford CNRS and Univ. Pierre et Marie Curie AT&T Labs Research University of Cambridge Princeton University

More information

Outline Computer Networking. Inter and Intra-Domain Routing. Internet s Area Hierarchy Routing hierarchy. Internet structure

Outline Computer Networking. Inter and Intra-Domain Routing. Internet s Area Hierarchy Routing hierarchy. Internet structure Outline 15-441 15-441 Computer Networking 15-641 Lecture 10: Inter-Domain outing Border Gateway Protocol -BGP Peter Steenkiste Fall 2016 www.cs.cmu.edu/~prs/15-441-f16 outing hierarchy Internet structure

More information

CS 640: Introduction to Computer Networks. Intra-domain routing. Inter-domain Routing: Hierarchy. Aditya Akella

CS 640: Introduction to Computer Networks. Intra-domain routing. Inter-domain Routing: Hierarchy. Aditya Akella CS 640: Introduction to Computer Networks Aditya Akella Lecture 11 - Inter-Domain Routing - BGP (Border Gateway Protocol) Intra-domain routing The Story So Far Routing protocols generate the forwarding

More information

Lecture 4: Intradomain Routing. CS 598: Advanced Internetworking Matthew Caesar February 1, 2011

Lecture 4: Intradomain Routing. CS 598: Advanced Internetworking Matthew Caesar February 1, 2011 Lecture 4: Intradomain Routing CS 598: Advanced Internetworking Matthew Caesar February 1, 011 1 Robert. How can routers find paths? Robert s local DNS server 10.1.8.7 A 10.1.0.0/16 10.1.0.1 Routing Table

More information

Finding a Needle in a Haystack: Pinpointing Significant BGP Routing Changes in an IP Network

Finding a Needle in a Haystack: Pinpointing Significant BGP Routing Changes in an IP Network Finding a Needle in a Haystack: Pinpointing Significant BGP Routing Changes in an IP Network Jian Wu (University of Michigan) Z. Morley Mao (University of Michigan) Jennifer Rexford (Princeton University)

More information

CS 43: Computer Networks Internet Routing. Kevin Webb Swarthmore College November 16, 2017

CS 43: Computer Networks Internet Routing. Kevin Webb Swarthmore College November 16, 2017 CS 43: Computer Networks Internet Routing Kevin Webb Swarthmore College November 16, 2017 1 Hierarchical routing Our routing study thus far - idealization all routers identical network flat not true in

More information

Inter-Autonomous-System Routing: Border Gateway Protocol

Inter-Autonomous-System Routing: Border Gateway Protocol Inter-Autonomous-System Routing: Border Gateway Protocol Antonio Carzaniga Faculty of Informatics University of Lugano June 14, 2005 Outline Hierarchical routing BGP Routing Routing Goal: each router u

More information

Inter-Domain Routing: BGP

Inter-Domain Routing: BGP Inter-Domain Routing: BGP Richard T. B. Ma School of Computing National University of Singapore CS 3103: Compute Networks and Protocols Inter-Domain Routing Internet is a network of networks Hierarchy

More information

BGP. Autonomous system (AS) BGP version 4. Definition (AS Autonomous System)

BGP. Autonomous system (AS) BGP version 4. Definition (AS Autonomous System) BGP Border Gateway Protocol (an introduction) Karst Koymans Informatics Institute University of Amsterdam (version 310, 2014/03/11 10:50:06) Monday, March 10, 2014 General ideas behind BGP Background Providers,

More information

BGP. Autonomous system (AS) BGP version 4

BGP. Autonomous system (AS) BGP version 4 BGP Border Gateway Protocol (an introduction) dr. C. P. J. Koymans Informatics Institute University of Amsterdam March 11, 2008 General ideas behind BGP Background Providers, Customers and Peers External

More information

Interdomain Routing Reading: Sections P&D 4.3.{3,4}

Interdomain Routing Reading: Sections P&D 4.3.{3,4} Interdomain Routing Reading: Sections P&D 4.3.{3,4} EE122: Intro to Communication Networks Fall 2006 (MW 4:00-5:30 in Donner 155) Vern Paxson TAs: Dilip Antony Joseph and Sukun Kim http://inst.eecs.berkeley.edu/~ee122/

More information

CS519: Computer Networks. Lecture 4, Part 5: Mar 1, 2004 Internet Routing:

CS519: Computer Networks. Lecture 4, Part 5: Mar 1, 2004 Internet Routing: : Computer Networks Lecture 4, Part 5: Mar 1, 2004 Internet Routing: AS s, igp, and BGP As we said earlier, the Internet is composed of Autonomous Systems (ASs) Where each AS is a set of routers, links,

More information

Backbone Networks. Networking Case Studies. Backbone Networks. Backbone Topology. Mike Freedman COS 461: Computer Networks.

Backbone Networks. Networking Case Studies. Backbone Networks. Backbone Topology. Mike Freedman COS 461: Computer Networks. Networking Case Studies Datacenter Backbone Networks Enterprise Backbone Mike Freedman COS 6: Computer Networks Cellular h>p://www.cs.princeton.edu/courses/archive/spr/cos6/ Wireless Backbone Networks

More information

Inter-Domain Routing: BGP II

Inter-Domain Routing: BGP II Inter-Domain Routing: BGP II Mark Handley UCL Computer Science CS 3035/GZ01 BGP Protocol (cont d) BGP doesn t chiefly aim to compute shortest paths (or minimize other metric, as do DV, LS) Chief purpose

More information

Routing in the Internet

Routing in the Internet Routing in the Internet Daniel Zappala CS 460 Computer Networking Brigham Young University Scaling Routing for the Internet 2/29 scale 200 million destinations - can t store all destinations or all prefixes

More information

Inter-Autonomous-System Routing: Border Gateway Protocol

Inter-Autonomous-System Routing: Border Gateway Protocol Inter-Autonomous-System Routing: Border Gateway Protocol Antonio Carzaniga Faculty of Informatics University of Lugano December 10, 2014 Outline Hierarchical routing BGP Routing 2005 2007 Antonio Carzaniga

More information

Lecture 17: Border Gateway Protocol

Lecture 17: Border Gateway Protocol Lecture 17: Border Gateway Protocol CSE 123: Computer Networks Alex C. Snoeren Some figures courtesy Mike Freedman Lecture 18 Overview Border Gateway Protocol (BGP) The canonical path vector protocol How

More information

Routing(2) Inter-domain Routing

Routing(2) Inter-domain Routing Routing(2) Inter-domain Routing Information Network I Youki Kadobayashi 1 Outline! Distance vector routing! Link state routing! IGP and EGP Intra-domain routing protocol, inter-domain routing protocol!

More information

Internet inter-as routing: BGP

Internet inter-as routing: BGP Internet inter-as routing: BGP BGP (Border Gateway Protocol): the de facto standard BGP provides each AS a means to: 1. Obtain subnet reachability information from neighboring ASs. 2. Propagate the reachability

More information

Inter-AS routing and BGP. Network Layer 4-1

Inter-AS routing and BGP. Network Layer 4-1 Inter-AS routing and BGP Network Layer 4-1 Review: intra-as routing v Also known as interior gateway protocols (IGP) v Most common intra-as routing protocols: RIP: Routing Information Protocol, distance

More information

CSc 450/550 Computer Networks Internet Routing

CSc 450/550 Computer Networks Internet Routing CSc 450/550 Computer Networks Internet Routing Jianping Pan Summer 2007 7/12/07 CSc 450/550 1 Review Internet Protocol (IP) IP header addressing class-based, classless, hierarchical, NAT routing algorithms

More information

Last time. Transitioning to IPv6. Routing. Tunneling. Gateways. Graph abstraction. Link-state routing. Distance-vector routing. Dijkstra's Algorithm

Last 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 information

An overview of how packets are routed in the Internet

An overview of how packets are routed in the Internet An overview of how packets are routed in the Internet 1 Dijkstra s shortest path first algorithm (example of a Link State Algorithm ) 1. Exchange link state: A router floods to every other router the state

More information

Interplay Between Routing, Forwarding

Interplay Between Routing, Forwarding Internet Routing 1 Interplay Between Routing, Forwarding routing algorithm local forwarding table header value output link 0100 0101 0111 1001 3 1 value in arriving packet s header 0111 3 1 Graph Abstraction

More information

Case Studies in Intra-Domain Routing Instability

Case Studies in Intra-Domain Routing Instability Case Studies in Intra-Domain Routing Instability Zhang Shu National Institute of Information and Communications Technology, Japan NANOG31 San Francisco, 2004/5/25 Overview Intra-domain routing instability

More information

Fast IP Convergence. Section 4. Period from when a topology change occurs, to the moment when all the routers have a consistent view of the network.

Fast IP Convergence. Section 4. Period from when a topology change occurs, to the moment when all the routers have a consistent view of the network. Fast IP Convergence Section 4 2899_05_2001_c1 2001, Cisco Systems, Inc. All rights reserved. 1 IP Convergence Convergence Time Period from when a topology change occurs, to the moment when all the routers

More information

BGP Additional Paths. Finding Feature Information. Information About BGP Additional Paths. Problem That Additional Paths Can Solve

BGP Additional Paths. Finding Feature Information. Information About BGP Additional Paths. Problem That Additional Paths Can Solve The feature allows the advertisement of multiple paths through the same peering session for the same prefix without the new paths implicitly replacing any previous paths. This behavior promotes path diversity

More information

COMP/ELEC 429 Introduction to Computer Networks

COMP/ELEC 429 Introduction to Computer Networks COMP/ELEC 429 Introduction to Computer Networks Lecture 11: Inter-domain routing Slides used with permissions from Edward W. Knightly, T. S. Eugene Ng, Ion Stoica, Hui Zhang T. S. Eugene Ng eugeneng at

More information

Routing Concepts. IPv4 Routing Forwarding Some definitions Policy options Routing Protocols

Routing Concepts. IPv4 Routing Forwarding Some definitions Policy options Routing Protocols Routing Basics 1 Routing Concepts IPv4 Routing Forwarding Some definitions Policy options Routing Protocols 2 IPv4 Internet uses IPv4 Addresses are 32 bits long Range from 1.0.0.0 to 223.255.255.255 0.0.0.0

More information

Configuring BGP on Cisco Routers Volume 1

Configuring BGP on Cisco Routers Volume 1 Volume 1 I. Course Introduction A. Overview/Learner Skills and Knowledge B. Course Flow C. Additional References 1. Cisco Glossary of Terms D. Your Training Curriculum II. BGP Overview III. Introducing

More information

Network-Wide Prediction of BGP Routes

Network-Wide Prediction of BGP Routes Network-Wide Prediction of BGP Routes Nick Feamster Jennifer Rexford Georgia Tech Princeton University feamster@cc.gatech.edu jrex@cs.princeton.edu Abstract This paper presents provably correct algorithms

More information

Introduction to routing

Introduction to routing DD2490 p4 2010 Introduction to routing Olof Hagsand KTH/CSC Network example: KTH Intranet Levels of abstraction The Internet is huge Necessary to divide the routing problem into sub-problems. There are

More information

Antonio Cianfrani. Routing Protocols

Antonio Cianfrani. Routing Protocols Antonio Cianfrani Routing Protocols Routing protocols A routing protocol provides a communication channel among routers to exchange reachability information about networks Routing tables are properly configured

More information

Routing on the Internet. Routing on the Internet. Hierarchical Routing. Computer Networks. Lecture 17: Inter-domain Routing and BGP

Routing on the Internet. Routing on the Internet. Hierarchical Routing. Computer Networks. Lecture 17: Inter-domain Routing and BGP Routing on the Internet Computer Networks Lecture 17: Inter-domain Routing and BGP In the beginning there was the ARPANET: route using GGP (Gateway-to-Gateway Protocol), a distance vector routing protocol

More information

Chapter 5: Maintaining and Troubleshooting Routing Solutions

Chapter 5: Maintaining and Troubleshooting Routing Solutions Chapter 5: Maintaining and Troubleshooting Routing Solutions CCNP TSHOOT: Maintaining and Troubleshooting IP Networks Course v6 1 Troubleshooting Network Layer Connectivity 2 Routing and Routing Data Structures

More information

ISP Border Definition. Alexander Azimov

ISP Border Definition. Alexander Azimov ISP Border Definition Alexander Azimov ISP goal (one ASN) BGP Decision Process Step Attribute Transit 1 Highest Local Preference value Non-transit 2 Lowest AS Path length Transit 3 Lowest

More information

CSCI-1680 Network Layer: Inter-domain Routing Rodrigo Fonseca

CSCI-1680 Network Layer: Inter-domain Routing Rodrigo Fonseca CSCI-1680 Network Layer: Inter-domain Routing Rodrigo Fonseca Based partly on lecture notes by Rob Sherwood, David Mazières, Phil Levis, John Janno? Today Last time: Intra-Domain Routing (IGP) RIP distance

More information

Routing on the Internet! Hierarchical Routing! The NSFNet 1989! Aggregate routers into regions of autonomous systems (AS)!

Routing on the Internet! Hierarchical Routing! The NSFNet 1989! Aggregate routers into regions of autonomous systems (AS)! Routing on the Internet! Hierarchical Routing! Aggregate routers into regions of autonomous systems (AS)! In the beginning there was the ARPANET:! route using GGP (Gateway-to-Gateway Protocol)," a distance

More information

Top-Down Network Design, Ch. 7: Selecting Switching and Routing Protocols. Top-Down Network Design. Selecting Switching and Routing Protocols

Top-Down Network Design, Ch. 7: Selecting Switching and Routing Protocols. Top-Down Network Design. Selecting Switching and Routing Protocols Top-Down Network Design Chapter Seven Selecting Switching and Routing Protocols Copyright 2010 Cisco Press & Priscilla Oppenheimer 1 Switching 2 Page 1 Objectives MAC address table Describe the features

More information

BGP Route Propagation between Neighboring Domains

BGP Route Propagation between Neighboring Domains BGP Route Propagation between Neighboring Domains Renata Teixeira 1, Steve Uhlig 2, and Christophe Diot 3 1 Univ. Pierre et Marie Curie, LIP6-CNRS, renata.teixeira@lip6.fr 2 Delft University of Technology

More information

CS Networks and Distributed Systems. Lecture 8: Inter Domain Routing

CS Networks and Distributed Systems. Lecture 8: Inter Domain Routing CS 3700 Networks and Distributed Systems Lecture 8: Inter Domain Routing Revised 2/4/2014 Network Layer, Control Plane 2 Data Plane Application Presentation Session Transport Network Data Link Physical

More information

Multi Topology Routing Truman Boyes

Multi Topology Routing Truman Boyes Multi Topology Routing Truman Boyes truman@juniper.net Copyright 2008 Juniper Networks, Inc. 1 Traffic Engineering Choices Today: IGP Metric Costing RSVP TE end to end Policy based routing EROs, Offline

More information

Introduction to BGP. ISP Workshops. Last updated 30 October 2013

Introduction to BGP. ISP Workshops. Last updated 30 October 2013 Introduction to BGP ISP Workshops Last updated 30 October 2013 1 Border Gateway Protocol p A Routing Protocol used to exchange routing information between different networks n Exterior gateway protocol

More information

Implementing BGP. BGP Functional Overview. Border Gateway Protocol (BGP) is an Exterior Gateway Protocol (EGP) that allows you to create loop-free

Implementing BGP. BGP Functional Overview. Border Gateway Protocol (BGP) is an Exterior Gateway Protocol (EGP) that allows you to create loop-free Border Gateway Protocol (BGP) is an Exterior Gateway Protocol (EGP) that allows you to create loop-free interdomain routing between autonomous systems. An autonomous system is a set of routers under a

More information

Module 6 Implementing BGP

Module 6 Implementing BGP Module 6 Implementing BGP Lesson 1 Explaining BGP Concepts and Terminology BGP Border Gateway Protocol Using BGP to Connect to the Internet If only one ISP, do not need BGP. If multiple ISPs, use BGP,

More information

Routing Protocols of IGP. Koji OKAMURA Kyushu University, Japan

Routing Protocols of IGP. Koji OKAMURA Kyushu University, Japan Routing Protocols of IGP Koji OKAMURA Kyushu University, Japan Routing Protocol AS (Autonomous System) Is operated autonomous in the organization. 6bit IGP (Interior Gateway Protocol) Routing Control inside

More information

BGP Diverse Path Using a Diverse-Path Route Reflector

BGP Diverse Path Using a Diverse-Path Route Reflector BGP Diverse Path Using a Diverse-Path Route Reflector The feature allows Border Gateway Protocol (BGP) to distribute an alternative path other than the best path between BGP speakers when route reflectors

More information

Master Course Computer Networks IN2097

Master Course Computer Networks IN2097 Chair for Network Architectures and Services Prof. Carle Department of Computer Science TU München Master Course Computer Networks IN2097 Prof. Dr.-Ing. Georg Carle Chair for Network Architectures and

More information

Chapter 4: Network Layer

Chapter 4: Network Layer Chapter 4: Network Layer 4. 1 Introduction 4.2 Virtual circuit and datagram networks 4.3 What s inside a router 4.4 IP: Internet Protocol Datagram format IPv4 addressing ICMP IPv6 4.5 Routing algorithms

More information

HP Load Balancing Module

HP Load Balancing Module HP Load Balancing Module Appendix Protocol Reference Part number: 5998-4222 Software version: Feature 3221 Document version: 6PW100-20130326 Legal and notice information Copyright 2013 Hewlett-Packard

More information

Computer Networking Introduction

Computer Networking Introduction Computer Networking Introduction Halgurd S. Maghdid Software Engineering Department Koya University-Koya, Kurdistan-Iraq Lecture No.15 Chapter 4: outline 4.1 introduction 4.2 virtual circuit and datagram

More information

Company Overview. Network Overview

Company Overview. Network Overview Company Overview InfiniComm is an imaginary Internet Service Provider (ISP) in the United States that owns its fiber transmission facilities as well as a Layer 2 switching infrastructure (ATM) across the

More information

Border Gateway Protocol

Border Gateway Protocol 39 CHAPTER Chapter Goals Understand the purpose of the. Explain BGP attributes and their use in route selection. Examine the BGP route selection process. Introduction The (BGP) is an interautonomous system

More information

COMP211 Chapter 5 Network Layer: The Control Plane

COMP211 Chapter 5 Network Layer: The Control Plane COMP211 Chapter 5 Network Layer: The Control Plane All material copyright 1996-2016 J.F Kurose and K.W. Ross, All Rights Reserved Computer Networking: A Top Down Approach 7 th edition Jim Kurose, Keith

More information

Computer 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) 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 information

Lecture 13: Traffic Engineering

Lecture 13: Traffic Engineering Lecture 13: Traffic Engineering CSE 222A: Computer Communication Networks Alex C. Snoeren Thanks: Mike Freedman, Nick Feamster Lecture 13 Overview Evolution of routing in the ARPAnet Today s TE: Adjusting

More information

MPLS Core Networks Николай Милованов/Nikolay Milovanov

MPLS Core Networks Николай Милованов/Nikolay Milovanov Tuning Core Routing Protocols Николай Милованов/Nikolay Milovanov Contents ISIS overview ISIS tuning http://niau.org 2 ISIS overview 3 IP routing design requirements Requirements towards the IGP protocols:

More information

Programmatic Interface to Routing

Programmatic Interface to Routing Programmatic Interface to Routing NANOG 61 Draft version, slides will be updated before presentation Applications and Networks Routing system players: the Application and the Network. Different interdependent

More information

Overview. Problem: Find lowest cost path between two nodes Factors static: topology dynamic: load

Overview. 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 information

Architectures and Protocols for Integrated Networks. Intra-domain and Inter-domain Routing Protocols

Architectures and Protocols for Integrated Networks. Intra-domain and Inter-domain Routing Protocols Architectures and Protocols for Integrated Networks Intra-domain and Inter-domain Routing Protocols How is the routing table built? Path finding Paths from a device to any other device. Aggregated according

More information

Stable Internet Route Selection

Stable Internet Route Selection Stable Internet Route Selection Brighten Godfrey Matthew Caesar Ian Haken Scott Shenker Ion Stoica UC Berkeley pbg@cs.berkeley.edu NANOG 40 June 6, 2007 BGP instability: trouble control plane data plane

More information

Routing. Outline. Algorithms Scalability

Routing. Outline. Algorithms Scalability Routing Outline Algorithms Scalability 1 Internetworking What is internetwork An arbitrary collection of networks interconnected to provide some sort of host-host to packet delivery service A simple internetwork

More information

BGP can also be used for carrying routing information for IPv6 prefix over IPv6 networks.

BGP can also be used for carrying routing information for IPv6 prefix over IPv6 networks. This chapter describes how to configure the Cisco ASA to route data, perform authentication, and redistribute routing information using the Border Gateway Protocol (). About, page 1 Guidelines for, page

More information

Internet Routing Protocols Lecture 01 & 02

Internet Routing Protocols Lecture 01 & 02 Internet Routing Protocols Lecture 01 & 02 Advanced Systems Topics Lent Term, 2010 Timothy G. Griffin Computer Lab Cambridge UK Internet Routing Outline Lecture 1 : Inter-domain routing architecture, the

More information

Announcements. CS 5565 Network Architecture and Protocols. Project 2B. Project 2B. Project 2B: Under the hood. Routing Algorithms

Announcements. CS 5565 Network Architecture and Protocols. Project 2B. Project 2B. Project 2B: Under the hood. Routing Algorithms Announcements CS 5565 Network Architecture and Protocols Lecture 20 Godmar Back Project 2B due in 2 parts: Apr 29 and May 6 Extra Credit Opportunities: Expand simulator (and your implementation) to introduce

More information

CS 268: Computer Networking. Next Lecture: Interdomain Routing

CS 268: Computer Networking. Next Lecture: Interdomain Routing CS 268: Computer Networking L-3 BGP Next Lecture: Interdomain Routing BGP Assigned Reading MIT BGP Class Notes [Gao00] On Inferring Autonomous System Relationships in the Internet 2 Outline Need for hierarchical

More information

E : Internet Routing

E : Internet Routing E6998-02: Internet Routing Lecture 16 Border Gateway Protocol, Part V John Ioannidis AT&T Labs Research ji+ir@cs.columbia.edu Copyright 2002 by John Ioannidis. All Rights Reserved. Announcements Lectures

More information

BGP made easy. John van Oppen Spectrum Networks / AS11404

BGP made easy. John van Oppen Spectrum Networks / AS11404 1 BGP made easy John van Oppen Spectrum Networks / AS11404 2 What is BGP? Snarky answer: RFC-4271 BGP is an Exterior gateway protocol, the only one used on the public Internet and is used for inter-autonomous

More information

Configuring Advanced BGP

Configuring Advanced BGP CHAPTER 6 This chapter describes how to configure advanced features of the Border Gateway Protocol (BGP) on the Cisco NX-OS switch. This chapter includes the following sections: Information About Advanced

More information

CSCE 463/612 Networks and Distributed Processing Spring 2018

CSCE 463/612 Networks and Distributed Processing Spring 2018 CSCE 463/612 Networks and Distributed Processing Spring 2018 Network Layer IV Dmitri Loguinov Texas A&M University April 12, 2018 Original slides copyright 1996-2004 J.F Kurose and K.W. Ross 1 Chapter

More information

Next Lecture: Interdomain Routing : Computer Networking. Outline. Routing Hierarchies BGP

Next Lecture: Interdomain Routing : Computer Networking. Outline. Routing Hierarchies BGP Next Lecture: Interdomain Routing BGP 15-744: Computer Networking L-3 BGP Assigned Reading MIT BGP Class Notes [Gao00] On Inferring Autonomous System Relationships in the Internet Ooops 2 Outline Need

More information

Lecture 16: Border Gateway Protocol

Lecture 16: Border Gateway Protocol Lecture 16: Border Gateway Protocol CSE 123: Computer Networks Alex C. Snoeren Some figures courtesy Mike Freedman Lecture 16 Overview Border Gateway Protocol (BGP) The canonical path vector protocol How

More information

Inter-AS routing. Computer Networking: A Top Down Approach 6 th edition Jim Kurose, Keith Ross Addison-Wesley

Inter-AS routing. Computer Networking: A Top Down Approach 6 th edition Jim Kurose, Keith Ross Addison-Wesley Inter-AS routing Computer Networking: A Top Down Approach 6 th edition Jim Kurose, Keith Ross Addison-Wesley Some materials copyright 1996-2012 J.F Kurose and K.W. Ross, All Rights Reserved Chapter 4:

More information

Deriving Traffic Demands for Operational IP Networks: Methodology and Experience

Deriving Traffic Demands for Operational IP Networks: Methodology and Experience Deriving Traffic Demands for Operational IP Networks: Methodology and Experience Anja Feldmann University of Saarbrücken Albert Greenberg, Carsten Lund, Nick Reingold, Jennifer Rexford, and Fred True Internet

More information

Hierarchical Routing. Our routing study thus far - idealization all routers identical network flat not true in practice

Hierarchical Routing. Our routing study thus far - idealization all routers identical network flat not true in practice Hierarchical Routing Our routing study thus far - idealization all routers identical network flat not true in practice scale: with 200 million destinations: can t store all destinations in routing tables!

More information

Hierarchical Routing. Our routing study thus far - idealization all routers identical network flat not true in practice

Hierarchical Routing. Our routing study thus far - idealization all routers identical network flat not true in practice Hierarchical Routing Our routing study thus far - idealization all routers identical network flat not true in practice scale: with 200 million destinations: can t store all destinations in routing tables!

More information

Modelling Inter-Domain Routing

Modelling Inter-Domain Routing Modelling Inter-Domain Routing Olaf Maennel University of Adelaide Wolfgang MühlbauerM Technical University Munich Anja Feldmann Technical University Munich Steve Uhlig Université catholique de Louvain

More information

5.1 introduction 5.5 The SDN control 5.2 routing protocols plane. Control Message 5.3 intra-as routing in Protocol the Internet

5.1 introduction 5.5 The SDN control 5.2 routing protocols plane. Control Message 5.3 intra-as routing in Protocol the Internet Chapter 5: outline 5.1 introduction 5.5 The SDN control 5.2 routing protocols plane link state 5.6 ICMP: The Internet distance vector Control Message 5.3 intra-as routing in Protocol the Internet t 5.7

More information

CSC 4900 Computer Networks: Routing Protocols

CSC 4900 Computer Networks: Routing Protocols CSC 4900 Computer Networks: Routing Protocols Professor Henry Carter Fall 2017 Last Time Link State (LS) versus Distance Vector (DV) algorithms: What are some of the differences? What is an AS? Why do

More information

Chapter 20 IPv6 BGP Unicast Address Family Commands

Chapter 20 IPv6 BGP Unicast Address Family Commands Chapter 20 IPv6 BGP Unicast Address Family Commands NOTE: The IPv6 BGP unicast address family configuration level is present only on HP devices that support IPv6 and the ProCurve 9408sl Routing Switch

More information

IBGP internals. BGP Advanced Topics. Agenda. BGP Continuity 1. L49 - BGP Advanced Topics. L49 - BGP Advanced Topics

IBGP internals. BGP Advanced Topics. Agenda. BGP Continuity 1. L49 - BGP Advanced Topics. L49 - BGP Advanced Topics IBGP internals BGP Advanced Topics main IBGP aspects inside an AS continuity all packets entering the AS that were not blocked by some policies should reach the proper exit BGP router all transit routers

More information

BGP Attributes and Policy Control

BGP Attributes and Policy Control BGP Attributes and Policy Control ISP/IXP Workshops 1 Agenda BGP Attributes BGP Path Selection Applying Policy 2 BGP Attributes The tools available for the job 3 What Is an Attribute?... Next Hop......

More information

CS 268: Computer Networking

CS 268: Computer Networking CS 268: Computer Networking L-3 BGP Outline BGP ASes, Policies BGP Attributes BGP Path Selection ibgp 2 1 Autonomous Systems (ASes) Autonomous Routing Domain Glued together by a common administration,

More information

Building the Routing Table. Introducing the Routing Table Directly Connected Networks Static Routing Dynamic Routing Routing Table Principles

Building the Routing Table. Introducing the Routing Table Directly Connected Networks Static Routing Dynamic Routing Routing Table Principles Building the Routing Table Introducing the Routing Table Directly Connected Networks Static Routing Dynamic Routing Routing Table Principles Introducing the Routing Table R1# show ip route Codes: C - connected,

More information

MPLS VPN Carrier Supporting Carrier Using LDP and an IGP

MPLS VPN Carrier Supporting Carrier Using LDP and an IGP MPLS VPN Carrier Supporting Carrier Using LDP and an IGP Last Updated: December 14, 2011 Multiprotocol Label Switching (MPLS) Virtual Private Network (VPN) Carrier Supporting Carrier (CSC) enables one

More information

BGP. Border Gateway Protocol (an introduction) Karst Koymans. Informatics Institute University of Amsterdam. (version 17.3, 2017/12/04 13:20:08)

BGP. Border Gateway Protocol (an introduction) Karst Koymans. Informatics Institute University of Amsterdam. (version 17.3, 2017/12/04 13:20:08) BGP Border Gateway Protocol (an introduction) Karst Koymans Informatics Institute University of Amsterdam (version 17.3, 2017/12/04 13:20:08) Tuesday, December 5, 2017 Karst Koymans (UvA) BGP Tuesday,

More information

TIE Breaking: Tunable Interdomain Egress Selection

TIE Breaking: Tunable Interdomain Egress Selection TIE Breaking: Tunable Interdomain Egress Selection Renata Teixeira Timothy G. Griffin Mauricio G. C. Resende Jennifer Rexford UC San Diego University of Cambridge AT&T Labs Research Princeton University

More information

BGP Support for Next-Hop Address Tracking

BGP Support for Next-Hop Address Tracking The feature is enabled by default when a supporting Cisco software image is installed. BGP next-hop address tracking is event driven. BGP prefixes are automatically tracked as peering sessions are established.

More information

Interdomain routing with BGP4 Part 4/5

Interdomain routing with BGP4 Part 4/5 Interdomain routing with BGP4 Part 4/5 Olivier Bonaventure Department of Computing Science and Engineering Université catholique de Louvain (UCL) Place Sainte-Barbe, 2, B-1348, Louvain-la-Neuve (Belgium)

More information

CS 204: BGP. Jiasi Chen Lectures: MWF 12:10-1pm Humanities and Social Sciences

CS 204: BGP. Jiasi Chen Lectures: MWF 12:10-1pm Humanities and Social Sciences CS 204: BGP Jiasi Chen Lectures: MWF 12:10-1pm Humanities and Social Sciences 1403 http://www.cs.ucr.edu/~jiasi/teaching/cs204_spring17/ 1 Overview AS relationships Inter-AS routing BGP Example Paper discussion

More information

MPLS VPN Carrier Supporting Carrier Using LDP and an IGP

MPLS VPN Carrier Supporting Carrier Using LDP and an IGP MPLS VPN Carrier Supporting Carrier Using LDP and an IGP Multiprotocol Label Switching (MPLS) Virtual Private Network (VPN) Carrier Supporting Carrier (CSC) enables one MPLS VPN-based service provider

More information

DATA COMMUNICATOIN NETWORKING

DATA COMMUNICATOIN NETWORKING DATA COMMUNICATOIN NETWORKING Instructor: Ouldooz Baghban Karimi Course Book & Slides: Computer Networking, A Top-Down Approach By: Kurose, Ross Introduction Course Overview Basics of Computer Networks

More information

A Measurement Study on the Impact of Routing Events on End-to-End Internet Path Performance

A Measurement Study on the Impact of Routing Events on End-to-End Internet Path Performance A Measurement Study on the Impact of Routing Events on End-to-End Internet Path Performance Feng Wang University of Mass., Amherst fewang@ecs.umass.edu Zhuoqing Morley Mao University of Michigan zmao@eecs.umich.edu

More information

Traffic Engineering with Estimated Traffic Matrices

Traffic Engineering with Estimated Traffic Matrices Traffic Engineering with Estimated Traffic Matrices Matthew Roughan Mikkel Thorup Yin Zhang www.research.att.com/~roughan www.research.att.com/~mthorup www.research.att.com/~yzhang Shannon Lab AT&T Research

More information

TDC 363 Introduction to LANs

TDC 363 Introduction to LANs TDC 363 Introduction to LANs Routing Protocols and RIP Greg Brewster DePaul University TDC 363 1 Dynamic Routing Routing Protocols Distance Vector vs. Link State Protocols RIPv1 & RIPv2 RIP Problems Slow

More information

Routing part 2. Electrical and Information Technology

Routing part 2. Electrical and Information Technology Routing part 2 Jens A Andersson Electrical and Information Technology Routing Introduction Inside the Router Unicast Routing Intra Domain Routing Inter Domain Routing MANET and AdHoc routing Multicast

More information

Achieving Fast BGP Reroute with Traffic Engineering Using Multiple Routing Planes

Achieving Fast BGP Reroute with Traffic Engineering Using Multiple Routing Planes Achieving Fast BGP Reroute with Traffic Engineering Using Multiple Routing Planes Yu Guo, Ning Wang, Kin-Hon Ho, Michael Howarth, and George Pavlou 2 Centre for Communication Systems Research, University

More information

Routing. Routing. Overview. Overview. Routing vs. Forwarding. Why Routing

Routing. 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 information