6lowpan ND Optimization draft Update

1
6lowpan ND Optimization draft Update

• Samita Chakrabarti
• samita.chakrabarti_at_azairenet.com
• Erik Nordmark
• erik.nordmark_at_sun.com
• IETF 69, 2007
• draft-chakrabarti-6lowpan-ipv6-nd-03.txt

2
Document History

• The draft has been around since 2006
• Several modifications based on wg comments
• Several presentations were made at the IETF
  working group meetings.
• Version 03 is the latest

3
6Lowpan IPv6 ND Background

• The solution handles prefix assignment and
  assumes one IPv6 router per 6lowpan network
• Main Goals for optimization
• Reduce or avoid DAD in 6lowpan network
• Minimize multicast messages in RA, RS, NS and
  reduce un-needed unicast messages (NUD)?
• Captures basic 6lowpan network topologies and
  components based on interim wg comments
• Many optimizations in this solution are
  applicable to non-multicast or non-broadcast
  network in general

4
Simple Star Topology

• Assume IP link (subnet) has one PAN coordinator
• Assume one 6lowpan is one PAN ID
• Assume the coordinator's unicast address is known
  from joining the PAN

5
L2 Mesh Topology Support

• Assume one PAN coordinator per 6lowpan link
• Assume each coordinator has a parent coordinator
• Allows a unicast-only path to PAN coordinator
• Can send packets to all-routers MC using this

6
Recent Changes

• Added text on Security section
• The threat level of a 6lowpan IPv6 router is a
  bit higher because the end-nodes are battery
  powered.
• A need for authenticated RA and NA IPv6 router
  is the central point for address resolution.
• Due to reduced processing power of the end-nodes,
  it is assumed that SEND protocol may not be
  directly applicable in 6lowpan ND. For example,
  RSA keys are too large for such small devices.
  Perhaps ECC instead of RSA algorithm.
• Senders of neighbor solicitations should use SEND
  nonce option to match the response.
• Limited 6lowpan ND security along with applied
  802.15.4 level security may be sufficient in most
  situations

7
Bootstrapping Information in this draft?

• Bootstrapping requirements
• Assignment of IPv6 prefix
• Finding out IPv6 router, co-ordinators L2
  addresses
• Finding out 6lowpan service information?
• Any mechanism for access key and subsequent key
  derivation for secure ND and data transfer
• Anything else?

8
Next Revision

• To Do
• Handle short addresses ?
• Handling bootstrapping information?
• More investigation on secure 6lowpan ND ?

9
Next Step

• Should this draft be published as a working
  group item ?
• Should this draft be written as a generic ND
  solution for non-broadcast and non-multicast
  network with an addendum for 6lowpan networks?