CS 145A Contextual investigation: Streamlined BGP Limited State Machine.


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CS 145A Contextual investigation: Disentangled BGP Limited State Machine Netlab.caltech.edu/course Today Short Presentation of steering conventions A case of Limited State Machine Lab 3 What does the Web resemble? Sample: (/sbin/traceroute) C:\>tracert cwis.usc.edu
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Slide 1

CS 145A Case Study: Simplified BGP Finite State Machine Netlab.caltech.edu/course

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Today Brief Introduction of steering conventions An illustration of Finite State Machine Lab 3

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What does the Internet resemble? Sample: (/sbin/traceroute) C:\>tracert cwis.usc.edu Tracing course to cwis.usc.edu [128.125.253.146] 1 <1 ms Jorgensen-RSM-44.caltech.edu [131.215.44.253] 2 <1 ms Booth-border.ilan.caltech.edu [131.215.254.254] 3 <1 ms CalREN-Caltech.caltech.edu [192.41.208.49] 4 <1 ms JPL- - CIT.POS.calren2.net [198.32.248.5] 5 1 ms UCLA- - JPL.POS.calren2.net [198.32.248.1] 6 1 ms ISI- - UCLA.POS.calren2.net [198.32.248.29] 7 2 ms USC- - ISI.POS.calren2.net [198.32.248.25] 8 3 ms rtr43-c2-gw.usc.edu [128.125.251.66] 9 2 ms rtr-gw-1.usc.edu [128.125.254.1] 10 2 ms cwis.usc.edu [128.125.253.146]

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Topology of the Network

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The Journey of a bundle (1) 131.215.44.214->131.215.44.253

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The Journey of a parcel (2) 131.215.44.253

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The Journey of a parcel (2) 131.215.44.253

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The Journey of a bundle (2) 131.215.44.253

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Necessary Information (1) Where should I pass the bundle, for a given destination IP address? – Routing Table Exmaple: [weixl@orchestra:~]> course

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How can the switches know the steering data?

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How? Physically include/erase directing sections Automatically trade steering data between switches.

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Routing Protocol A: hey, would you say you are there? B: yes. A: Can I let you know a bit of news? B: Sure. An: I have an approach to get to www.usc.edu. B: alright. I will send all of you the parcels that are going to www.usc.edu. … B: Hi, Can I let you know a few news, as well? A: Yes! B: I can unite with every one of the machines in “ cs.caltech.edu ” An: alright. I will send all of you the parcels that are going to “ cs.caltech.edu ” . ……

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Routing Protocol A to C: hello, would you say you are there? ... A to C: greetings, would you say you are there? … A to B: I think C is down. Furthermore, starting now and into the foreseeable future, I can\'t contact USC. B: OK. I will attempt different ways when I get bundles for USC. …

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Routing Protocol Good: Efficiently telecast up and coming directing data Bad: Rumor may be show productively, as well. Contention: If the larger part is great … The calculation ought to be right in dispersed situations.

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Routing Protocols Autonomous System

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Routing Protocols Inside Autonomous System: Embrace the Freedom! Tear (Routing Information Protocol) OSPF (Open Shortest Path First) Between Autonomous System (Exterior Gateway Protocol): More thought … BGP (Border Gateway Protocol)

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Border Gateway Protocol-4 Inter-Autonomous System Communication Propagate Path Information Support Policy Incremental Updates Assume solid transmission (TCP) http://www.ietf.org/rfc/rfc1771.txt

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Simplified BGP State Machine

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BGP Packets Format: 0 - 15 th Byte: FF (hexadecimal) 16-17 th Byte: Unsigned number, Length of the Packet (>=19) 18 th Byte: Packet Type: 1 OPEN 2 UPDATE 3 NOTIFICATION 4 KEEPALIVE 19 th Byte to the Packet\'s end: Routing Data

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Detailed Specification http://www.ietf.org/rfc/rfc1771.txt Appendix I (page 47)

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Lab 3

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Lab 3 - Task Implement a (rearranged) improved BGP Finite State Machine: Ignore the clocks Ignore the points of interest of Routing Data

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Lab3 - Finite State Machine

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Lab 3 - Requirements The usage depends on TCP. The usage has the capacity effectively join with different machines and it has the capacity acknowledge demands from numerous machines. The usage permits at most one association from one machine (recognized by IP/hostname). For every association, the execution actualizes the Lab3 Finite State Machine.

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Lab 3 - Details A project “ server ” Read from a document called “ server.conf ” . Organization of “ server.conf ” : (1 st line:) Listen_Port Connection_Num(N) (2 nd line:) IP_1 Port_1 ( … ) (N+1 st line:) IP_N Port_N The server ought to peruse from “ server.conf ” , listen to Listen_Port for new association, in the meantime, effectively interface the predetermined machines (IP_1:Port_1, IP_2:Port_2, … IP_N:Port_N)

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Lab 3 - Possible Problems Implementation of Finite State Machine Check the slips (counting operation lapses and Packet mistakes) Multiple associations from the same machine

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Lab 3 - Tips Re-Use the codes in Lab 1 How to execute the Finite State Machine? “ if … then …” “ State move table ” How to test? Incremental Development DON ’ T START AT THE LAST MOMENT!

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Lab 3 Due: Dec 1 st (Sunday) 23:59:59 Email: weixl@caltech.edu Grading TA h

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