Measurement in the Internet. Outline Internet topology Bandwidth estimation Tomography Workload characterization Routing dynamics.

Slides:



Advertisements
Similar presentations
Multihoming and Multi-path Routing
Advertisements

University of Nevada, Reno Router-level Internet Topology Mapping CS790 Presentation Modified from Dr. Gunes slides by Talha OZ.
IPv6 Victor T. Norman.
COS 461 Fall 1997 Routing COS 461 Fall 1997 Typical Structure.
CSCI 4550/8556 Computer Networks Comer, Chapter 23: An Error Reporting Mechanism (ICMP)
Traffic Management - OpenFlow Switch on the NetFPGA platform Chun-Jen Chung( ) SriramGopinath( )
Chapter 10 Introduction to Wide Area Networks Data Communications and Computer Networks: A Business User’s Approach.
Routing and Routing Protocols Introduction to Static Routing.
Heuristics for Internet Map Discovery R. Govindan, H. Tangmunarunkit Presented by Zach Schneirov.
ICMP: Ping and Trace CCNA 1 version 3.0 Rick Graziani Spring 2005.
Network Measurement Bandwidth Analysis. Why measure bandwidth? Network congestion has increased tremendously. Network congestion has increased tremendously.
ROUTING PROTOCOLS Rizwan Rehman. Static routing  each router manually configured with a list of destinations and the next hop to reach those destinations.
1 ICMP – Using Ping and Trace CCNA Semester
Jennifer Rexford Fall 2010 (TTh 1:30-2:50 in COS 302) COS 561: Advanced Computer Networks Stub.
INTERNET TOPOLOGY MAPPING INTERNET MAPPING PROBING OVERHEAD MINIMIZATION  Intra- and inter-monitor redundancy reduction IBRAHIM ETHEM COSKUN University.
Information-Centric Networks07b-1 Week 7 / Paper 2 NIRA: A New Inter-Domain Routing Architecture –Xiaowei Yang, David Clark, Arthur W. Berger –IEEE/ACM.
CCNA Introduction to Networking 5.0 Rick Graziani Cabrillo College
Guide to TCP/IP, Third Edition
How the Internet Works Acknowledgment and Disclaimer: This presentation is supported in part by the National Science Foundation under Grant Any.
Network Redundancy Multiple paths may exist between systems. Redundancy is not a requirement of a packet switching network. Redundancy was part of the.
Introduction to Routing and Routing Protocols By Ashar Anwar.
Chapter 4. After completion of this chapter, you should be able to: Explain “what is the Internet? And how we connect to the Internet using an ISP. Explain.
CCNA – Cisco Certified Network Associates Routing and Static Routes By Roshan Chaudhary Lecturer Islington College.
Exploring the Packet Delivery Process Chapter
1 Version 3.1 modified by Brierley Module 8 TCP/IP Suite Error and Control Messages.
Distance Vector Routing Protocols W.lilakiatsakun.
Distance Vector Routing Brad Karp UCL Computer Science CS 6007/GC15/GA07 5 th, 6 th March, 2008.
1 © 2003, Cisco Systems, Inc. All rights reserved. CCNA 2 Module 6 Routing and Routing Protocols.
Switched network.
© 2002, Cisco Systems, Inc. All rights reserved..
Objectives: Chapter 5: Network/Internet Layer  How Networks are connected Network/Internet Layer Routed Protocols Routing Protocols Autonomous Systems.
Technical Refresher Session 3. Overview Difference between communication between devices on a single logical network and communication between different.
POSTECH DP&NM Lab. Internet Traffic Monitoring and Analysis: Methods and Applications (1) 4. Active Monitoring Techniques.
10/8/2015CST Computer Networks1 IP Routing CST 415.
1 © 2003, Cisco Systems, Inc. All rights reserved. CCNA 2 Module 9 Basic Router Troubleshooting.
Advanced Networking Lab. Given two IP addresses, the estimation algorithm for the path and latency between them is as follows: Step 1: Map IP addresses.
PC1 LAN GW SP RTR1 SP RTR2 DST 4 * 25 ms 21 ms dst [ ] 4. A third packet is sent with TTL=3, which decrements at each hop, and expires after RTR2,
Network Layer4-1 Chapter 4: Network Layer r 4. 1 Introduction r 4.2 Virtual circuit and datagram networks r 4.3 What’s inside a router r 4.4 IP: Internet.
Chapter 4 Network Layer Computer Networking: A Top Down Approach 6 th edition Jim Kurose, Keith Ross Addison-Wesley March 2012 A note on the use of these.
A Routing Underlay for Overlay Networks Akihiro Nakao Larry Peterson Andy Bavier SIGCOMM’03 Reviewer: Jing lu.
1 Internet Control Message Protocol (ICMP) Used to send error and control messages. It is a necessary part of the TCP/IP suite. It is above the IP module.
1 Network Layer Lecture 13 Imran Ahmed University of Management & Technology.
Page 110/27/2015 A router ‘knows’ only of networks attached to it directly – unless you configure a static route or use routing protocols Routing protocols.
1 Countering DoS Through Filtering Omar Bashir Communications Enabling Technologies
OSI Model. Switches point to point bridges two types store & forward = entire frame received the decision made, and can handle frames with errors cut-through.
© 2008 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 Chapter 6: Static Routing Routing and Switching Essentials.
April 4th, 2002George Wai Wong1 Deriving IP Traffic Demands for an ISP Backbone Network Prepared for EECE565 – Data Communications.
1 A Framework for Measuring and Predicting the Impact of Routing Changes Ying Zhang Z. Morley Mao Jia Wang.
Internet Protocols. ICMP ICMP – Internet Control Message Protocol Each ICMP message is encapsulated in an IP packet – Treated like any other datagram,
1 Version 3.1 Module 6 Routed & Routing Protocols.
© 2008 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 Chapter 6: Static Routing Routing and Switching Essentials.
Routing in the Inernet Outcomes: –What are routing protocols used for Intra-ASs Routing in the Internet? –The Working Principle of RIP and OSPF –What is.
Univ. of TehranComputer Network1 Advanced topics in Computer Networks University of Tehran Dept. of EE and Computer Engineering By: Dr. Nasser Yazdani.
TCP Traffic Characteristics—Deep buffer Switch
Internet Traffic Engineering Motivation: –The Fish problem, congested links. –Two properties of IP routing Destination based Local optimization TE: optimizing.
Day 13 Intro to MANs and WANs. MANs Cover a larger distance than LANs –Typically multiple buildings, office park Usually in the shape of a ring –Typically.
Static Routing CCNA Routing and Switching Semester 2 Chapter 6
1 © 2004, Cisco Systems, Inc. All rights reserved. CCNA 2 v3.1 Module 8 TCP/IP Suite Error and Control Messages.
Fall, 2001CS 6401 Switching and Routing Outline Routing overview Store-and-Forward switches Virtual circuits vs. Datagram switching.
ROUTING.
Network Tools and Utilities
Introduction to Networking
Introduction to Networking
Ping Hackathon 2018.
COS 561: Advanced Computer Networks
COS 561: Advanced Computer Networks
Switching Techniques.
BGP Interactions Jennifer Rexford
Lecture 26: Internet Topology CS 765: Complex Networks.
An Empirical Evaluation of Wide-Area Internet Bottlenecks
Presentation transcript:

Measurement in the Internet

Outline Internet topology Bandwidth estimation Tomography Workload characterization Routing dynamics

Why study Internet topology? General understanding of growth of Internet Fragility/robustness to failures and attacks Are there feasible design principles to: –improve robustness –reduce deployment/growth costs –make maintenance/support easier –improve performance for users/customers Realistic input to simulators

"topology" - misleading word Unlabelled graph links do not capture the problem. BGP routing behavior is determined by policies, not just connectivity. –Peers, customers and providers are very different. Bandwidth, latency, and congestion at the router level matters. –A small ISP peering link is not the same as a large ISP backbone link.

Scales/Hierarchies of topology Routing/BGP connectivity of ASes or ARDs –What are the connectivity patterns between organizations? Are there cluster patterns? Geographic/logical clusters within large organizations (particularly ISPs) Router-level Switches, hubs, firewalls, hosts

traceroute Tracing route to cider.caida.org [ ] over a maximum of 30 hops: 1 <10 ms <10 ms 10 ms <10 ms <10 ms <10 ms ntc-1-rsmx.rswitch.umn.edu [ ] 3 40 ms 30 ms 90 ms ntc-1-rsmx.rswitch.umn.edu [ ] 4 <10 ms <10 ms 10 ms tc3x.router.umn.edu [ ] 5 <10 ms <10 ms 10 ms telecomb-52-g-0-2.router.umn.edu [ ] 6 <10 ms <10 ms 10 ms telecomb-53-g-0-2.router.umn.edu [ ] 7 <10 ms <10 ms 10 ms tc1-g-2-0.router.umn.edu [ ] 8 <10 ms <10 ms 10 ms i2r-a northernlights.gigapop.net [ ] 9 30 ms 30 ms 30 ms abilene-mn.northernlights.gigapop.net [ ] ms 30 ms 40 ms kscyng-iplsng.abilene.ucaid.edu [ ] ms 40 ms 40 ms dnvrng-kscyng.abilene.ucaid.edu [ ] ms 70 ms 70 ms snvang-dnvrng.abilene.ucaid.edu [ ] ms 80 ms 80 ms losang-snvang.abilene.ucaid.edu [ ] ms 80 ms 80 ms hpr-lax-gsr1--abilene-LA-10ge.cenic.net [ ] ms 81 ms 80 ms sdg-hpr1--lax-hpr1-10ge.-l3.cenic.net [ ] ms 80 ms 80 ms hpr-sdsc-sdsc2--sdg-hpr-ge.cenic.net [ ] ms 80 ms 80 ms pinot.sdsc.edu [ ] 18 * * * Request timed out.

How traceroute works All IP packets have a Time-To-Live (TTL) field specifying the number of router hops the packet is allowed to be in the network. When an IP device (router or host) receives a packet: –if the packet is for the device, the device processes the packet –otherwise, decrement the TTL if TTL > 0, forward packet towards destination if TTL = 0, drop this data packet and send error packet back to source

How traceroute works traceroute tries to measure the forward-path (one direction only) from source to destination each router hop on the path is found one at a time source sends a packet with TTL 1 and waits for an error from the router 1 hop away, use the source IP address of error as the identity of this hop source repeats with larger TTLs until it reaches the destination (or gives up)

However, there are multiple potential choices for the IP address in the message from an intermediary hop. Every interface on a router has a different IP address. AI- input interface to A from source AO- output interface towards destination from A AR- return path interface towards source from A How traceroute works Router A AOAI AR

traceroute to topology Apply traceroute methodology from multiple sources to multiple destinations to discover links. Number of sources and destinations necessary not clearly known. –There are diminishing returns of discovering new links, but not always clear if they are important or not. –We know that it is bad in some cases, but how bad is it?

traceroute and routers traceroute only finds interface IP addresses, so we need a way to collapse those on the same router load-balancing and non-atomicity can lead to false links

Big questions for topology We know we can't see all backup and peering links. –How much might we really be off? –What set of possible "actual networks" could lead to what has been measured, and can we assign probabilities? –How much does it matter for different problems? Are there ways of targetting measurement to improve coverage? How do we understand the network with partial link characteristic or traffic information?

Why bandwidth estimation? Not all link bandwidths and utilizations are the same. Realistic inputs to simulators and models. End hosts and routers may want to make intelligent decisions based on more knowledge about the network.

Bandwidth estimation Capacity vs. available bandwidth Network does not directly expose this information. May be variable over short-time scales. Cross-traffic can cause confusion. Convolution of forward-path and return-paths in some techniques.

Bandwidth estimation Link techniques try to find bandwidth for each link (hop) along a path. Path techniques try to find to the bandwidth along the entire path. Typically large numbers of probes needed, due to variability in measurements.

Tomography Two forms of this problem –given edge measurements infer something about the inside state of the network (link speeds, bandwidth, congestion) –given internal state of the network infer something about the traffic entering/exiting the network What measurements yield the most information? How much might results be off?

Why study workload characterization? Capacity planning Understanding trends in network usage to predict deployment needs Interactions between applications and protocols Input for new protocol design Predicting effects from network changes Detecting anomalous behavior

Why study routing dynamics? Is global reachability goal of Internet met? How fragile is the routing system to failures or attacks? How much does policy effect performance?