OSPF%20extension%20for%20MANET%20based%20on%20MPR

1
67th IETF OSPF WG in San Diego, Nov. 7th 2006

• OSPF extension for MANET based on MPR
• draft-baccelli-ospf-mpr-ext-02.txt
• Emmanuel Baccelli

2
Agenda

1. Overview of the extension for MANETs
2. Recent Developments
3. GTNetS simulation
4. Next steps

3
OSPF MANET interface type

• Addresses mobile ad hoc specificities
• Wireless link issues
• Highly dynamic topology
• MANET interface type properties
• Overhead reduction (flooding, adjacency,
  topology)
• Convergence time
• OSPF legacy preserved over MANET
• MPR approach allows
• flooding optimization
• adjacency reduction
• topology reduction

4
MPR Multi-Point Relays

• What are they?
• - subset of links covering the network

MPR

• MPR Properties
• 2-hop neighborhood coverage
• shortest paths coverage

MPR
MPR

• ... allows for
• - Flooding Optimization
• - Adjacency Reduction
• - Topology Reduction

Works very well in sparse, dense, slow, fast
mobility (Mathematical models, real world
deployments)
5
Recent Developments

• As discussed in Design Team
• Modified structure to match better RFC 2740 and
  2328
• Heuristic for MPR selection taking into account
  link costs
• Carried out GTNetS simulations
• Inside common framework provided by Boeing
• Code base derived from OR code

6
Flooding efficiency with the MPR extension
full LSA full synchronization
Packet Rates 100 x less
Overhead in Kbits per sec.
1000x1000 square network
7
Flooding Efficiency with the MPR extension
full LSA full synchronization
Packet Rates 100x less
Overhead in Kbits per sec.
500x500 square network
8
Topology Reduction with the MPR extension
reduced LSA full synchronization
Packet Rates
similar
Overhead in Kbits per sec.
30 gain
1000x1000 square network
9
Topology Reduction with the MPR extension
reduced LSA full synchronization
Packet Rates
more packets but
Overhead in Kbits per sec.
50 gain in Kbps
500x500 square network
10
Comparison full LSA versus reduced LSA
in packets/s
in Kbps
75 Gain in advertized links/s
500x500 square network
11
Confirming with Independent simulations (Maple)
Random walk mobility model full LSA versus
reduced LSA
packets/s
links/s
500x500 square network
12
Confirming with Independent simulations (Maple)
Random walk mobility model full LSA versus
reduced LSA
packets/s
links/s
1000x1000 square network
13
Analytic Model Why LSA flooding overhead is
larger than synchronization overhead

• Random walk model, full synchro, full LSA
• average link lifetime
• links creation frequency (N network size, M
  average neighbor size)
• nodes ID exchanged in synchro
• links advertized in flooding
• number of retransmissions per
  neighborhood
• frequency of link creation and
  dying

14
Next Steps

• Simulations are necessary step, but
• No satisfying wireless model known to date
• Scenarii are too restrictive
• Not sufficient to evaluate real deployment
  problems
• Experimental status
• To leverage the work of the design team so far
• To gather real world experience