[PPT] - NETWORK LAYER INTERNET TOPOLOGY CONSTRUCTION M. Engin Tozal & PowerPoint Presentation

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NETWORK LAYER INTERNET TOPOLOGY CONSTRUCTION

M. Engin Tozal & Kamil Sarac

The University of Texas at Dallas

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AGENDA

 Internet Topology and its Representation  Existing Topology Representations  Subnet Level Topologies  Subnet Inference with XNET  Current Research

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Internet Topology

 Internet Topology Maps

 Represented as a graph G(V,E) such that V is the set of

bjects and E is the set of links between objects in V.

 Vertices:

 Autonomous Systems (ASes)  Routers  Router Triangles  Interfaces  Subnetworks (Subnets)

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Internet Topology

 Inter-Connections

 Policy-based connections  Subnets  Routers

 Do we really have a distinction between components in

the Internet and their inter-connections?

 Or is it a matter of representation and interest?

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AGENDA

 Internet Topology and its Representation  Existing Topology Representations  Subnet Level Topologies  Subnet Inference with XNET  Current Research

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Existing Internet Topologies

 AS Level  Interface Level  Router Level

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Existing Internet Topologies AS Level

AS1 AS2 AS3 AS4 A Sample Section of the Internet Topology at the Network Layer

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Existing Internet Topologies AS Level

AS2 AS1 AS3 AS4 AS Level Representation

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Existing Internet Topologies Interface Level

AS1 AS2 AS3 AS4

X Z Y

A Sample Section of the Internet Topology at the Network Layer

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Existing Internet Topologies Interface Level

Interface Level Representation

X Z Y

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Existing Internet Topologies Router Level

A Sample Section of the Internet Topology at the Network Layer

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R1 R3 R2 S5 S4 S3 S2 S1 R4 R6 R5 R7 R8

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Existing Internet Topologies Router Level

Router Level Representation

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R1 R3 R2 R4 R6 R5 R7 R8

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AGENDA

 Internet Topology and its Representation  Existing Topology Representations  Subnet Level Topologies  Subnet Inference with XNET  Current Research

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Subnet Level Topologies

A Sample Section of the Internet Topology at the Network Layer

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R1 R3 R2 S5 S4 S3 S2 S1 R4 R6 R5 R7 R8

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Subnet Level Topologies

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S5 S4 S3 S2 S1

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Subnet Level Topologies

Subnet Level Representation

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S5 S4 S3 S2 S1 /30 /29 /31 /29 /31

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Subnet Level Topologies

 Subnet Level Internet Topologies

 A subnet S is defined by the set of interfaces that it

accommodates

 A vertex in the graph is a subnet  A link between two subnets represents the router that

directly connects two subnets to each other

 TraceNET is a tool for building subnet level Internet

topologies

 XNET is another tool for inferring individual subnets

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Utility of Subnet Level Topologies

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 Building node-and-link disjoint end-to-end paths for

verlay network design

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Utility of Subnet Level Topologies

 Studying Subnet Level Topology Characteristics

 Degree Distribution  IP address space Utilization  Betweenness  Assortativity  Clustering Coefficient  and so on…

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AGENDA

 Internet Topology and its Representation  Existing Topology Representations  Subnet Level Topologies  Subnet Inference with XNET  Current Research

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Subnet Inference with XNET

 ExploreNET (XNET)

 Given an IP address t, XNET builds the subnet S hosting

t

 Collects all alive IP addresses accommodated by S  Labels S by its observed subnet mask  TraceNET

 Given a destination address d

 Returns a list of subnets appearing between the source and

the destination address d

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Subnet Inference with XNET

 XNET vs TraceNET

 Both are based on the same principles  TraceNET has more data to draw inference (subnets

and IP addresses appearing in previous hops)

 XNET can be utilized in uniform random subnet

sampling

 TraceNET sampling possesses source dependency bias

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Subnet Inference with XNET

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A S

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Subnet Inference with XNET

 Scope Delimitation Test  Far Fringe Interface Detection Test  Ingress Fringe Interface Detection Test  Close Fringe Interface Detection Test

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Subnet Inference with XNET

Fringe Interface Detection

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A

Far-fringe interfaces Close-fringe interfaces Ingress-fringe interfaces

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AGENDA

 Internet Topology and its Representation  Existing Topology Representations  Subnet Level Topologies  Subnet Inference with XNET  Current Research

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Current Research

 Network Level Internet Topology Maps  A mathematical framework for sampling subnets

using XNET

 Developing a network generation model based on

subnets

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Internet Topology Representations

Example Internet Topology

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Internet Topology Representations

Router Level Representation

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Internet Topology Representations

Subnet Level Representation

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Internet Topology Representations

Network Level Representation

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Discussion

 Questions & Comments

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Evaluations

 Characteristics of subnets in six geographically

disperse Tier-2 ISP networks

 PCCW Global (ISP-1)  nLayer (ISP-2)  France Telecom (ISP-3)  Telecom Italia Sparkle (ISP-4)  Interroute (ISP-5)  MZIMA (ISP-6)

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Evaluations

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Evaluations

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Evaluations

 Power Law in Prefix Length Distribution

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Evaluations

 Power Law in Prefix Length Distribution

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Subnet Inference with XNET

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