topology discovery - correlating different network topology layers
TRANSCRIPT
Topology DiscoveryCorrelating different network topology layers in
heterogeneous environments
Diederik Vandevenne Dennis Pellikaan
February 8, 2013
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Introduction
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Research question
What are the challenges with the correlation of physical topologyinformation based on LLDP and logical topology information?
Working hypotheses
LLDP is mature enough and widely implemented, which makes it auseful protocol for topology discovery in heterogeneous networkenvironments
All information needed to correlate the different network topologylayers is available in the Management Information Base
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Link Layer Discovery Protocol
LLDP Data Unit
Chassis ID
Port ID
Time to Live
Optional fields
End of LLDPDU
Operation modes
Send onlyReceive onlySend and receive
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Topology based on LLDP
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Ethernet with STP
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VLANs
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IP
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Complete Topology
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Implementation
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Findings
Maturity of LLDP at SURFsara
124 devices83% supports LLDP9% does not support LLDP8% unknown
NOT all relevant information for topology discovery can be retrievedfrom standardized management information base objects
Not all standardized MIB objects are supported by all vendorsSome information can only be retrieved from proprietary MIB objects
Device IDs (ChassisID, IP address) must be unique
Layer two path finding might be needed to create a correct IP layertopology
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Conclussions
Challenges of topology discovery
LLDP is mature enough and widely implemented,which makes it a useful protocol for topology dis-covery purposes in heterogeneous network environ-ments
All information needed to correlate the differentnetwork topology layers is available in the man-agement information base
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Questions?
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