UPnP & DLNA

Report
IPv6-based wireless sensor
network
Speaker: Yi-Lei Chang
Advisor: Dr. Kai-Wei Ke
2012/05/15
1
Outline
•
•
•
•
•
•
Introduction
Challenges of IP over WSNs
Things we can do in link layer
Add an adaptation layer
Make network layer more suitable for WSNs
Conclusions
2
Introduction
• WSN
– Limited power
• Low TX power, unstable link…etc.
– Limited computing ability
– Low cost  lots of nodes
• IP over WSN
– Why need IP in WSNs
– IPv6 vs. IPv4
3
Challenges of IP over WSNs
• WSNs are...
– Limited node energy
• Less transmitting and computing power
– High packets loss rate
– Limited bandwidth
• 250 Kbps for IEEE 802.15.4
• So, when IP over WSNs…
– Large header overhead
• 40 bytes IPv6 header
– Global addressing scheme
• Need auto-configuration
– Other implementation challenges
• 127 bytes maximum physical layer packet size (IEEE 802.15.4) work with 1280 bytes
minimum MTU (IPv6)
• Transport protocol
• …
4
Things we can do in link layer
• Lower energy cost
– Duty-cycled link
• Sampled Listening
– Scheduling
– Listen-After-Send
• More quality link
– Streaming
– Redefined ACK Frame
5
Sampled Listening
6
Sampled Listening
Chirp Frame
7
Scheduling (Optimization)
8
Redefined ACK Frame
9
Listen-After-Send
10
Adaptation Layer ?
11
Node Software Architecture
12
Adaptation Layer
• Transmission of IPv6 Datagram over IEEE
802.15.4
– IPv6 header compression
• To reduce header overhead
– Datagram fragmentation
• Fragmentation header
• To support the IPv6 minimum MTU
– Support for layer-two forwarding
• Layer3 routing, layer2 forwarding
• Reduce processing power
13
14
IPv6 header compression
Header stack
15
IPv6 header compression
IPv6 header
16
Header compression
HC1 encoding (1byte)
Non-Compressed fields
source
address
destination
address
Traffic
Class
and
Flow
Label
Next
Header
HC2
encoding
2bit
2bit
1bit
2bit
1bit
Smaller !!
Find mostly used parameter, encode into less bit.
17
Header compression Cont.
• Source/destination address
–
–
–
–
00: PI, II
01: PI, IC
10: PC, II
11: PC, IC
–
–
–
–
PI: Prefix carried in-line
PC: Prefix compressed (link-local prefix assumed).
II: Interface identifier carried in-line
IC: Interface identifier elided (derivable from the
corresponding link-layer address)
18
Header compression Cont.
• Traffic Class and Flow Label
– 0: not compressed; full 8 bits for Traffic Class and
20 bits for Flow Label are sent
– 1: Traffic Class and Flow Label are zero
19
Header compression Cont.
• Next Header
– 00: not compressed; full 8 bits are sent
– 01: UDP
– 10: ICMP
– 11: TCP
20
Header compression Cont.
• HC2 encoding
• 0: No more header compression bits
• 1: HC1 encoding immediately followed by
more header compression bits per HC2
encoding format.
21
Make network layer more suitable
for WSNs
• Configuration and Management
– IPv6 address auto-configuration
– IPv6 neighbor discovery
• Forwarding
– Hop-by-Hop Recovery
– Quality of Service
• Routing
– DAG (Directed acyclic graph)
– distance-vector protocol
22
Configuration and Management
IPv6 address auto-configuration
• Statelessly by combining a 64-bits IEEE EUI64unique identifier with an IPv6 address prefix
(e.g., link-local or subnet ID) server
• Using DHCPv6 to assign an address
23
Configuration and Management
IPv6 neighbor discovery
• Neighbor Table
– Cache  Table
– Reduce address resolution exchange
• Address Resolution
– Link-local multicast query
 router advertisement
• Neighbor Unreachability Detection (NUD)
– Neighbor solicitation (NS)
– Neighbor advertisement (NA)
 link-layer acknowledgments
• Router Discovery
•
•
•
Router solicitation (RS)
Router advertisement (RA)
Dynamic RA interval
24
Forwarding
Hop-by-Hop Recovery
• The two most common reasons for delivery
failures
– Link transmission failures
– Queue congestion at the receiver
• Detected using hop-by-hop acknowledgments
• Using flag to tell the difference
• Forwarder can retransmit/reroute
25
Forwarding
Quality of Service
• Classes
– ND, routing protocols, and local communication
– Upward traffic towards edge routers for data
collection
– Downward traffic away from edge routers for
configuration or control traffic
• Queue reservations
26
Conclusions
• We can use link layer mechanism to lower power
consumption and improve link quality, make
WSNs more powerful to carry IP.
• For transmission of IPv6 Datagram (big packets)
over IEEE 802.15.4(more smaller packets), add an
adaptation layer
• We can modify some network layer mechanism
so they can be more suitable to WSNs
• And more…
27
Reference
[1]J.W. Hui and D.E. Culler, "IPv6 in Low-Power Wireless Networks,“ Proceedings of the
[1]IEEE, vol. 98, no. 11, pp. 1865-1878, November 2010.
[2]J.W. Hui, "An Extended Internet Architecture for Low-Power Wireless Networks
[1]Design and Implementation,” PhD thesis, University of California at Berkeley,
[1]Berkeley, CA, USA, 2008.
[3]Joel J. P. C. Rodrigues , Paulo A. C. S. Neves "A survey on IP-based wireless sensor
[1]network solutions", Int. J. Communication Systems, vol. 23, pp. 963–981, 2010.
[4]G. Montenegro, N. Kushalnagar, J. Hui, and D. Culler, “Transmission of IPv6 Packets
[1]Over IEEE 802.15.4 Networks,” RFC 4944 (Proposed Standard), September 2007.
[5] S. Deering and R. Hinden, “Internet Protocol, Version 6 (IPv6) Specification,” RFC
[1]2460 (Draft Standard), December 1998.
28
Thanks for Listening
Q&A
29

similar documents