Transcript Routing in Multiple Layers: Opportunities and Challenges

Routing in Multiple Layers:
Opportunities and Challenges
Mostafa Ammar, Srinivasan Seetharaman
Networking and Telecommunications Group
College of Computing
Georgia Institute of Technology
Overlays
P2P Nets
Service Overlays
Application Layer X (X= multicast, QoS, …)
Virtual Networks (a la PlanetLab, VINI,
GENI)
Overlays like to do routing!
Their raison d’etre
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Performance reasons
Fault recovery reasons
Resource management
To “battle” lower layer
Multi-Layer Routing
C
OVERLAY2
E
LAYER
B
C
A
C
OVERLAY1
F
G
D
B
A
E
E
F
H
LAYER
H
B
NATIVE IP
D
G
LAYER
Challenge 1: Objective Mismatch
Conflict in objective between the two layers
AS policy
violation
C
A
PROVIDER
C
OVERLAY1
F
G
D
B
A
E
E
F
H
LAYER
H
B
CUSTOMER
NATIVE IP
D
G
LAYER
Challenge 2: Functionality overlap
Each layer performs rerouting, with no knowledge of
which layer leads to optimal restoration
Overlay
rerouting
C
A
C
OVERLAY1
F
G
D
A
B
A
E
E
F
H
LAYER
H
X Failure
B
NATIVE IP
D
G
Native rerouting
LAYER
Challenge 3: Coexistence issues
In reality, coexistence is required between:
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overlay and legacy apps.
overlay and other overlay apps
C
A
C
OVERLAY1
F
G
D
B
A
E
E
F
H
LAYER
H
B
NATIVE IP
D
G
LAYER
Challenge 4: Unconstrained Design
Higher level of perceived freedom as you go up
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No knowledge of physical constraints & optimal placement
Essential nodes
C
A
F
C
OVERLAY1
G
D
B
A
E
E
F
H
LAYER
H
B
NATIVE IP
D
G
LAYER
Virtual network assignment (VNA)
Problem Statement
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Allowing virtual networks (VNs) to be assigned to the substrate network
efficiently and on-demand
Tasks
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Assign VNs to the substrate
Achieve low and balanced
load on both substrate
nodes and links
Importance
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Allows for accommodating
more VNs with limited
resources
Helps to handle dynamic
situation
Research Opportunities
Layer-aware design of protocols in all layers
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Sufficient incentive for inter-layer awareness
Level of awareness and cooperation needs to determined
Improves co-existence/resource sharing
Virtual network (resource) assignment
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Resource management
Intelligent placement
Efficient reconfiguration
Multi-layer testbed
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that allows control of multiple layers
That helps meter actual user experience