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Wen Xu and Jennifer Rexford
Department of Computer Science
Princeton University
Chuck Short
CS622
Dr. C. Edward Chow
5/25/2017
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Autonomous System (AS)
Border Gateway Protocol (BGP)
Internet Service Provider (ISP)
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Single route advertisement is not flexible
enough
BGP is sufficient for most traffic
Control over path properties rather than
complete path is desirable
Intermediate router may be willing direct
traffic along another path
Current methods for influencing path choices
are limited
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BGP
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Source Routing
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Single best path selection
End to end path selection
Overlay Networks
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Virtual network topology
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Extension of BGP
AS-Level path selection
Negotiation for alternate routes
Policy driven export of alternate routes
Tunnels to direct traffic on alternate routes
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Intra-AS Architecture
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Data Plane Packet Encapsulation
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AS may consist of many internal routers and paths
IP over IP encapsulation
Control Plane Tunnel Management
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Creation and destruction of tunnels based upon
negotiation
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Simulated operating environment
Infer AS relationships
Assume each AS selects and exports routes based
on business relationships
Each AS treated as one node
GAO Algorithm
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L. Gao, “On inferring Autonomous System relationships
in the Internet,” IEEE/ACM Trans. Networking, vol. 9, no. 6,
pp. 733–745, 2001.
Data (October 2000, 2003, 2005)
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www.routeviews.org
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Strict Policy
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Respect Export Policy
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Responding AS announces routes with same local
preference as the original default route
Responding AS announces alternate routes using an
export policy
Most Flexible Policy
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Responding AS announces all possible routes
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1)
1-hop set
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2)
Path set
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AS negotiates with each immediate neighbor
AS negotiates with any AS along BGP path
300 million (source,destination) pairs evaluated
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Avoid for security or performance reasons
Calculate triple for every
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(Source, Destination, AS to avoid)
Don’t avoid immediate neighbors
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Assumptions
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Each source generates equal traffic
 Total traffic estimated by number of sources using link
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All traffic sent through an intermediate AS always
transits through that AS
 Total traffic a single AS can move if switched to a
different route
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Power node concept
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Node lies on destination path for many sources
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10,383 multi-homed AS studied
Around 90% can move 10% of traffic
50% can move
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40% of traffic under flexible policy
25% of traffic under strict policy
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90% of Power Nodes had 200+ neighbors
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Most likely Tier 1 AS
Immediate neighbors only constitute 9% of
Power Nodes
68% of Power Nodes are 2 hops away
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Need negotiation rules
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Establish and manages negotiation process
Need route selection rules
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Filter and rank available alternatives
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Potential for oscillation
Solution:
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If upstream AS does not advertise the tunnel MIRO
is guaranteed to converge whenever BGP converges
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MIRO is backward compatible with BGP
MIRO can provide the flexibility to negotiate
alternate routes as needed
MIRO can provide transit AS more control over
traffic across their network
MIRO is comparable to Source Routing at
avoiding an intermediate AS
Most alternate route possibilities are provided
by the most connected nodes (ISP’s)
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Build prototype
Explore security via AS trust relationships
Devise centralized load balancing scheme to
prevent oscillation
Explore the incorporation of price, performance
and load information into the route selection
process
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Border Gateway Protocol (BGP)
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http://www.rfc-editor.org/rfc/rfc4271.txt
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