Download Fast Failover for Control Traffic in Software-defined

Fast Failover
for
Control Traffic
in
Software-defined Networks
Globecom 2012
Neda B. & Ying Z.
Presented by: Szu-Ping Wang
Introduction
(1/2)
Controller
Control Plane
Control Traffic
Data Plane
Network Device
Traditional Switch
SDN
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Introduction
(2/2)
How to implement?
- Adding new links?
Cost increasing… Control
Plane
Control Traffic
- Choose one node in
original topology to be
controller?
Data
Plane
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Controller
Placement
(1/2)
• How to choose the best placement on
the original topology?
- Fast Failover
?
Backup Link
Protected Switch
Choose the best placement with
minimum number of unprotected switch.
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Controller
Placement
(2/2)
• Define the Protected Switch:
Unprotected!
1. Check the other nodes that is
not in the same sub-tree.
2. Does there exist a link between
target switch and the set of
green circle?
Protected!
Special case: controller’s immediate children check the all other
nodes except controller in step 1.
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Algorithm
overview
(1/1)
• Two algorithms for choosing the best
location for the network controller.
• One algorithm for improving the
resiliency of shortest path routing
tree.
• The ideas are all about protected
switches numbers.
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Algorithm 1
Opt. algo.
Unprotected!
(1/1)
Minimized the
descendants number of
unprotected switches.
Unprotected!
• Search through all switch and choose the one that minimized
the descendants number of unprotected switches.
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Algorithm 2
GREEDY algo.
(1/1)
• It’s non-practical if the size of the network is large!
• Heuristic Algorithm.
• Check only the neighbors of controller and choose the one
that maximized the number of protected switches.
• No need to find the routing tree first!
Protected!
Protected!
Special case: controller’s immediate
children check the all other nodes except
controller in step 1.
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Algorithm 3
routing. algo.
(1/1)
• Start from Shortest Path Tree.
• Try to modify the tree by replacing the edge to
the tree edge.
2
2
Switch
ID
Descendants number of
unprotected switches
Initial
2
a
0
b
2
c
0
0
a
b
c
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SIMULATION
(1/1)
• 10 real network topologies.
• Calculating the descendants number of unprotected
switches.
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Thanks !!
Presented by: Szu-Ping Wang
conclusion
(1/1)
• It’s practical for implement SDN on original
topology.
• The algorithm 1 and 3 are straightforward.
• There is no analysis for Algorithm 2.
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