IETF 6LoWPAN WG 66th, Montreal, CA
6LoWPAN Ad Hoc On-Demand
Distance Vector Routing (LOAD)
Ki-Hyung Kim, S. Daniel Park, G. Montenegro,
S. Yoo, and N. Kushalnagar
draft-daniel-6lowpan-load-adhoc-routing-02.txt
Mesh Routing underneath to IPv6 Layer
Application
Application
Application
Transport
Transport
Transport
IPv6
IPv6
IPv6
Adaptation
Adaptation
Adaptation
802.15.4 MAC
802.15.4 MAC
802.15.4 MAC
PHY
PHY
PHY
12 July 2006
IETF 6LoWPAN WG 66th, Montreal
2
LoWPAN Optimizations
 Sub-IP Routing
 Allows efficient header compression, smaller route tables
 Use EUI-64 or 16 bit addresses
 Use prot_type field to indicate AODV control messages
instead of UDP ports
 Utilization of 6lowpan characteristics
 Use the route cost by utilizing the LQI of the 6LoWPAN
PHY
 Allow multiple schemes such as hop counts, aggregated LQI
values, and minimum LQI value along a route
 Hello messages are not used, instead use 802.15.4 link
layer mechanisms such as ACKs, beacon responses,
overhearing packets, etc
 Use broadcast in the route discovery
12 July 2006
IETF 6LoWPAN WG 66th, Montreal
3
LoWPAN Optimizations II
 Minimize power consumption and complexity
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Do not use the destination sequence number
Only destination Replies to RREQ by RREP
Do not use the local repair
Report back to the originator by RERR upon a link break
Do not maintain the precursorlist
Send RERR only to the originator of the data which
caused the link break
 Utilize Efficient RERR reporting
 Reuse existing specs, such as AODV and DYMO,
as much as possible
12 July 2006
IETF 6LoWPAN WG 66th, Montreal
4
Change Log
 Define the route cost by LQI and weak links
 Hop counts while avoiding weak links
 Several comments
 Default value of weak LQI  Is there a systematic way to determine
it
 The necessity of the sequence number
 To prevent a routing loop  Only destination replies to RREQ
 Sequence numbers could also be used as an indicator of the freshness
of routes  Sequence number could be beneficial for routing ability
 Interaction between QoS metric and distance vector routing
(Introduction of weak links in addition to the hop count)
 Lifetime definition
 Link monitoring (route timeout by timers?)  should consider the
expiration policy of routing entries based on energy consumption
 Weak link indicator by LQI
 Unidirectional links?
 RERR for low battery and “route cost not supported” should be
avoided
th
12 July 2006
IETF 6LoWPAN WG 66 , Montreal
5
LOAD/DYMO-low Implementations in Progress
 By Pere Salvatella, Wireless Networks Group,
Technical University of Catalonia (UPC)

12 July 2006
+---------------------------------------------+
| Aplication Layer (WebServer, TelnetServer) |
+---------------------------------------------+
|
IP Layer (uIP IPv4 Stack TCP/UDP) |
+---------------------------------------------+
|
Routing Layer (DYMO-low, LOAD)
|
+---------------------------------------------+
| 6lowpan header (simplified version) |
+---------------------------------------------+
| Physical Layer (IEEE 802.15.4 radio) |
+---------------------------------------------+
IETF 6LoWPAN WG 66th, Montreal
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Prototype Implementation
 http://www.6lowpan.org
 Test bed Implementation
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Segmentation and Reassembly
Header compression (Format document)
Gateway between 6lowpan and IPv6 networks
LOAD/DYMO-low
Hi-Low
12 July 2006
IETF 6LoWPAN WG 66th, Montreal
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Overall Architecture of the 6lowpan Testbed
12 July 2006
IETF 6LoWPAN WG 66th, Montreal
8
Protocol stack of 6lowpan router
12 July 2006
IETF 6LoWPAN WG 66th, Montreal
9
Performance Results of
LOAD/DYMO-low
Topology for Testing
12 July 2006
IETF 6LoWPAN WG 66th, Montreal
11
Identifying Weak Links
1
Delivery Rate
0.8
0.6
0.4
0.2
Avoid Weak Links
0
0
4
8
12
16
20
24
28
32
LQI threshold value
12 July 2006
IETF 6LoWPAN WG 66th, Montreal
12
Delivery Ratio
Comparison of Delivery Rate
100%
90%
80%
Delivery Rate .
70%
60%
50%
40%
30%
20%
WL-Delivery Rate(%)
MHC-Delivery Rate(%)
10%
0%
0
10
20
30
40
50
60
70
80
Samples
12 July 2006
IETF 6LoWPAN WG 66th, Montreal
13
Transmission Delay
Comparison of Transmission Delay
45
40
Transmission Delay .
35
30
25
20
15
10
MHC-End-to-End Delay(ms)
WL-End-to-End Delay(ms)
5
0
0
10
20
30
40
50
60
70
80
Samples
12 July 2006
IETF 6LoWPAN WG 66th, Montreal
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Summary
 Feedback is welcome
 Accept it as a WG item ?
12 July 2006
IETF 6LoWPAN WG 66th, Montreal
15