Internet Measurement Under Edge-Transit

Separation

Dept. of Electrical and Computer Eng. George Mason University

Fairfax, VA 22030-4444, USA

Kunpeng Liu

Feb 2011

Introduction (Transit-Edge Separation)

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• On BGP level, the Internet can be separated into two parts:– Edge: The set of ASes act as destination-only or appear at

most at the third last position of any AS path. Edge ASes count 97% of all the Ases

– Transit: The set of the rest Ases

Tools Introduction

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• Route Views are captured from an AS that peers with many big ISPs (bias)

• Clean scripts are used to clean some specific characters, like [ , { } ( ) ] as well as to add space to IP prefixes. (pay attention to AS4)

• Java tools are used to parse the routing tables.– MyLib is the libraries used in other java tools.– RouTabParse reads tables to create the link object– DrawGraph reads tables to create the graph– ReadResult reads the link object and graph to calculate

the statistics we need.

Tools Introduction (Link object)

• The link object

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SimpleAS a SimpleAS b SimpleAS c

LinkSimpleAS

– SimpleAS and LinkSimpleAS are defined in MyLib– SimpleAS is used to store the information of an AS,

including AS number, IP prefix, if use AS path prepending or not, in which position does the AS appear and so on

– LinkSimpleAS is the link of SimpleAS, implementing serialization operation.

Tools Introduction (Graph)

• Java Universal Network/Graph Framework (JUNG) http://jung.sourceforge.net/– ASLink is edges of the graph, used to record the AS

path prepending times, the usage frequency of a link and so on.

– ASNode is vertex of the graph.– ASLInk and ASNode are defined in MyLib

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An Example of Raw Routing Table

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Detail of Script

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Detail of Script (cont.)

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An Example of Clean Table

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Java Code-RouTabParse

public static void main(String[] args) throws IOException {System.out.println((new Date()));RouTabParse rtParse = new RouTabParse(args[0]);

try {rtParse.read();

} catch (Exception e) {e.printStackTrace();

}SimpleAS current = rtParse.totalASList.first;while(current!=null) {

current.findLevel();current = current.next;

}FileOutputStream f_out = new FileOutputStream(args[0]+".total");ObjectOutputStream obj_out = new ObjectOutputStream(f_out);rtParse.totalASList.writeExternal(obj_out);obj_out.flush();obj_out.close();f_out.close();

}

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Java Code-RouTabParse (Cont.)

void read() throws IOException {log("Reading from file.");int cout = 0;// Scanner scanner = new Scanner(new File(rTabName));try {

String text = br.readLine();while (text != null) {parseline(text.trim());text = br.readLine();cout++;

}} finally {

System.out.println("The total lines of routing table: "+cout);br.close();

}}

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Java Code-RouTabParse (Cont.)

void parseline(String text) {String[] list = text.split(" ");text = null;int length = list.length;SimpleAS simpleAS = null;int as=0; //use to eliminate AS path prependingint position=0;try {

as=Integer.parseInt(list[length - 1]);simpleAS = new SimpleAS(as);list[length - 1] = null;position++;simpleAS.addPosition(position);simpleAS.addAddr(list[0].trim());totalASList.insert(simpleAS);

} catch (Exception e) {System.out.println(list[length - 1]);

}

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int i=2;boolean isASprepended = false;while(i < length) {

int tmp=Integer.parseInt(list[length - i]);list[length - i] = null;if(as==tmp){

isASprepended = true;i++;continue;

}else{ as=tmp; i++;

simpleAS.setASPathPrepended(isASprepended); simpleAS = new SimpleAS(as); position++; simpleAS.addPosition(position); isASprepended = false; totalASList.insert(simpleAS); }

}

Java Code-DrawGraph

public static void main(String[] args) {System.out.println((new Date()));String filename = args[0];DrawGraph drawGraph = new DrawGraph(filename);drawGraph.init();try {

drawGraph.readSingleLine();FileOutputStream fos = new FileOutputStream(filename + ".graph");ObjectOutputStream out = new ObjectOutputStream(fos);out.writeObject(drawGraph.g);out.close();fos.close();System.out.println((new Date()));

} catch (Exception ex) {ex.printStackTrace();

}}

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Java Code-DrawGraph (Cont.)

void readSingleLine() throws IOException {System.out.print("Reading from file.");int cout = 0;try {

String text = br.readLine();while (text != null) {drawSingleLine(text.trim());text = br.readLine();cout++;

} finally {System.out.println("The total lines of routing table: " + cout);br.close();

}}

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Java Code-DrawGraph (Cont.)

void drawSingleLine(String rTabEntry) { String[] list = rTabEntry.split(" "); rTabEntry = null; int length = list.length; try { ASNode previousAS = null; ASNode currentAS = null; int previousASNo = 0; int currentASNo = 0; int weight = 1; for (int i = 1; i < length; i++) { currentASNo = Integer.parseInt(list[i]); if (previousASNo == currentASNo){ weight++; continue; } currentAS = findASNode(currentASNo); if (currentAS == null) { currentAS = new ASNode(currentASNo); g.addVertex(currentAS); }

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if (previousAS != null) {ASLink link = findASLink(previousAS, currentAS);if (link == null) {link = new ASLink(linkCount++);link.setWeight(weight);g.addEdge(link, previousAS, currentAS,EdgeType.UNDIRECTED);} else {int tmp = link.getWeight();if(weight>tmp)link.setWeight(weight);link.addReferCount();}weight = 1;}previousAS = currentAS;previousASNo = currentASNo;}} catch (Exception e) {e.printStackTrace();}

Internet Diameter

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Shortest paths

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CCDF of Ases’ Degree

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Model Parameters vs. Time

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Betweenness

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Routing Centrality

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T-E separation property

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AS Path Prepending Usage

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IP-Deaggregation

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IP-Deaggregation

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