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Backbone Support for Host Mobility:
A Joint ORBIT/VINI Experiment
Jennifer Rexford
Princeton University
Joint work with the ORBIT team (Rutgers)
and Andy Bavier and Changhoon Kim (Princeton)
Mobility Challenges
• Seamless transmission to a mobile host
A
B
2
No Backbone Changes: Mobile IP
• Mobile node has home address & care-of address
• Care-of address changes as mobile node moves
• Packets relayed through the home agent to node
B
home agent
12.34.45.7
73.26.101.3
3
Injecting Address of Mobile Node
• Mobile node has a single, persistent address
• Address injected into routing protocol (e.g., OSPF)
• But, flat addressing causes scalability challenges
A
12.34.45.0/24
B
12.34.45.7/32
Similar to approach used in the Boeing Connexion service…
4
Scalable Flat Addressing: SEIZE
• Storing location information at a small set of nodes
• Fetching based on hash of address, then caching
• Cut-through to send traffic directly to mobile node
h(12.34.45.7)
Query location
Publish
location
A
B
12.34.45.7
http://www.cs.princeton.edu/~chkim/publications/conext06-chkim.pdf
5
VINI: Virtual Network Infrastructure
• VINI design
– Multiple virtual networks on a shared substrate
– Each virtual network may have its own topology
– Connects to the Internet and carries real traffic
– Experimenter can inject network events (e.g., failures)
• VINI deployment
– Abilene Internet2 backbone (11 sites)
– National Lambda Rail (7 sites)
• Example experiments
– Intradomain routing protocol convergence
– New routing and forwarding architectures
6
Intradomain Routing and Forwarding
s
856
2095
700
260
1295
c
639
366
233
548
587
846
902
1893
1176
Abilene topology and intradomain routing configuration
7
Joint ORBIT and VINI Experiment
• ORBIT: wireless edge
– Two wireless access points
– Each tunneled to a different VINI node
– Mobile device that moves back and forth
• VINI: wired backbone
– Virtual network topology (e.g., Abilene backbone)
– Option #1: OSPF with /32 route injection
– Option #2: scalable flat addressing with SEIZE
• Experiment
– Download a video stream as the wireless node moves
– Measure and observe quality of the video stream
– Measure state and flooding overhead in the backbone
8
Conclusion
• Wired networks should support mobility
– Route injection of mobile node addresses
– Scalable support for flat addressing
• Evaluation requires joint capabilities
– Wireless devices, access points, and mobility
– Wired networks with programmable protocols
• Initial experiments spanning ORBIT and VINI
– Work in progress…
9