efficient algorithms for large-scale topology discovery benoit donnet joint work with philippe...
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Efficient Algorithms for Large-ScaleTopology Discovery
Benoit Donnetjoint work with Philippe Raoult, Timur Friedman
and Mark Crovella
Sigmetrics 2005 – Banff (Canada)
Context
● Network measurement● Internet topology discovery using distributed
traceroute monitors– IP interface level
● Existing tools:– Skitter (CAIDA)
– TTM (RIPE NCC)
– AMP (NLANR)
– DIMES (Tel Aviv U.)
Scaling Problem
● More monitors means more load on– network resources
– destinations
● Classical approaches either– stay small (skitter, TTM, AMP)
– trace slowly (DIMES)
● Can we trace more efficiently?
Contributions
● Quantification of scaling problems– Intra-monitor redundancy
– Inter-monitor redundancy
● Efficient cooperative topology discovery algorithm– Doubletree
Doubletree: Tree-like Structure of Routes
● Both redundancy (i.e. inter and intra) suggest two different probing schemes– They are based on the tree-like structure of routes
● Intra-monitor– monitor-rooted tree (first suggested by Govindan et al.)
● Inter-monitor– destination-rooted tree
Doubletree: Reconciliation
● Backward and forward probing are opposite schemes
● How can we reconciliate them?– Starts probing at some hop h
● First, performing forward probing from h● Second, performing backward probing from h-1
Doubletree: Stop Sets
● Not necessary to maintain the whole tree structure.
● Each monitor uses stop sets: {(interface, root)}– Local Stop Set B: {interface}
● Backward probing
– Global Stop Set F: {(interface, destination)}● Forward probing● Shared between monitors