AODV%20update

1
AODV update

• Charles E. Perkins
• Elizabeth M. Royer
• Samir R. Das

2
MobiHOC

• http//users.ece.gatech.edu/cktoh/workshop.html

3
Forgetting sequence numbers
C
A
B
D

• Suppose A?D via B, C?D via B
• Suppose B reboots and forgets everything
• Suppose A does not know this yet
• If B sends RREQ to C a routing loop results

4
DELETE PERIOD

• Long enough for Bs neighbors to find out that
  links to B have broken
• After neighbors find out, they maintain last
  sequence number for at least DELETE_PERIOD
• After reboot, B sends RERRs in response to
  receiving any data packets
• Lifetime of route assumes dual role

5
Multicast after reboot

• A node loses all of its multicast tree info
• Broadcast a MACT with R bit set
• Upstream neighbors delete the node from any
  relevant lists of next hops
• Downstream neighbors try to rebuild their tree
  branch

6
IP Address Autoconfiguration

• Some nodes may not have IP addresses
• Following zeroconf idea, try 169.254/16
• Pick an address from upper 62k range
• Perform duplicate address detection by sending
  RREQ for that address
• For source address of RREQ, pretend to be a node
  in lower 2k range
• Sequence numbers to be zero

7
Other details

• Assigned type numbers for extensions
• Changes appendix added
• Typos, improvements
• Corrected sequence number handling in RERR message

8
Other issues

• IPv6 versions for messages by next IETF
• Should RREQ/RREP contain source routes?
• if so, how long should route information persist?
• Rethink service discovery extensions?