1. Packet forwarding for non-routable devices in Multi-hop Wireless Mesh
May 2006
doc.: IEEE /0661r0
May 2006
Packet forwarding for non-routable devices in Multi-hop Wireless Mesh
Date:
Authors:
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Hrishikesh Gossain, Motorola Inc.
Hrishikesh Gossain, Motorola Inc.

2. May 2006
doc.: IEEE /0661r0
May 2006
Abstract
Defines mechanism of multihop packet forwarding for non-routable devices (STAs) in Mesh.
Hrishikesh Gossain, Motorola Inc.
Hrishikesh Gossain, Motorola Inc.

3. Communication between two STAs
May 2006
doc.: IEEE /0661r0
May 2006
Motivation (1)
How to do multihop packet forwarding in Wireless Distribution System (WDS) using IEEE MAC, for non-routable device (STAs)?
802.11s requires AP (routable device) to forward packets for STA (non-routable device). RA TA DA SA
Hop by Hop Forwarding Address
Terminating Device or Terminating Device Proxy?
Originating Device or Originating Device Proxy?
Communication between two STAs
Hrishikesh Gossain, Motorola Inc.
Hrishikesh Gossain, Motorola Inc.

4. May 2006
Motivation (2)
Issues?
How do we set the DA during multihop forwarding, only one address (DA) available
Either put address of the MAP to which STA is proxied, or put address of the STA itself.
What extra information intermediate nodes need to maintain to facilitate packet forwarding for non-routable devices?
Mechanism of updating entries in intermediate node for non-routable device.
How is packet forwarding is done for non-routable devices.
Hrishikesh Gossain, Motorola Inc.

5. Problem Illustration (1)
May 2006
Problem Illustration (1)
Scenario I (with Portal):
Packet received from backbone (Portal has a route to the P1 currently proxied by MAP1).
At Portal, how to set DA?
Case I: DA = MAP1
Actual destination at the MAC is lost.
Case II: DA = P1
How to do forwarding for non-routable devices?
How to create proxy entries?
<Dest: P1, Src: B1>
<RA: MAP0, TA: Portal, DA: ?, SA: B1>
Portal
MAP0
MAP1 P1
STA
Hrishikesh Gossain, Motorola Inc.

6. Problem Illustration (2)
May 2006
doc.: IEEE /0661r0
May 2006
Problem Illustration (2)
Scenario II: Ad-Hoc Mode
Similar to Scenario I, intermediate nodes need to maintain proxy information <P2, MAP2> and <P1, MAP0>to forward packet.
How to do it in a on demand way?
MAP0
MAP1
MAP2 P1 P2
Hrishikesh Gossain, Motorola Inc.
Hrishikesh Gossain, Motorola Inc.

7. Proxy Forwarding (1) Routing Table and Proxy Table May 2006
For all known STA and their corresponding MAP.
Routing Table
Maintain route to meshed device.
Consult both Proxy and Routing Table to forward packet.
Hrishikesh Gossain, Motorola Inc.

8. Proxy Forwarding (2) RM-AODV: Proxy and Route Table Learning May 2006
Dest AP
Dest AP
Dest AP
Dest AP
Proxy
Table
Proxy
Table
Proxy
Table P1 A P1 A P1 A P2 D P2 D P2 D P2 D P1 A
Dest
Next
Hop
Dest
Next
Hop
Dest
Next
Hop
Route
Table
Route
Table
Route
Table
Dest
Next
Hop
Route
Table D B A A A B A C D C D D
RREQ
RREQ
RREQ A B C D
RREP
RREP
RREP
MAP
MAP
MAP
MAP P1 P2
STA
RREQ: Route Request
RREP: Route Reply
Hrishikesh Gossain, Motorola Inc.

9. Ad-hoc Mode Operation (1)
May 2006
Ad-hoc Mode Operation (1)
Changed Packet Format
RREQ
Routing Source includes Originating Device which is set to
Address of routable device in case the traffic was generated by itself.
Address of non-routable device in case the traffic was generated by a non-routable device currently proxied by itself.
Destination Only bit
RREQ Propagation
RREP
Routable Destination includes the Terminating Device which is set to.
Address of routable device in case the traffic was destined to itself.
Address of non-routable device in case the traffic was destined for a non-routable device currently proxied by itself.
RREP Propagation
Originating Device
Source
Terminating Device
CurrentHop
NextHop
Other Fields
Terminating Device
Destination
Source
CurrentHop
NextHop
Other Field
Hrishikesh Gossain, Motorola Inc.

10. Ad-hoc Mode Operation (2)
May 2006
Ad-hoc Mode Operation (2)
DATA
Packet is sent to a MAC address
Destination may be a non-routable device.
First look at the proxy table for the destination STA.
If (found) get the proxied AP address, use this address in routing table to get the next hop information.
Else (not found) directly look at the routing table.
If routing look up fails, generate a RERR for destination address.
CurrentHop
NextHop
Originating Device
Terminating Device
Mesh Header
--- Other Mesh Fields ---
Hrishikesh Gossain, Motorola Inc.

11. Ad-hoc Mode Operation (3)
May 2006
Ad-hoc Mode Operation (3)
Handoff
If a STA moves from one MAP to another MAP
Send two hop proxy update message in neighborhood
This invalidates the old proxy entry in the neighborhood.
Forces a new Route Discovery for the destination.
Hrishikesh Gossain, Motorola Inc.

12. Infrastructure Mode (1)
May 2006
Infrastructure Mode (1)
Built on top of ad hoc mode.
Binding Update
Addr
Owner
STA
MAP2
MAP3
MPP
MAP1
802.3
LAN
Proxy Table at Portal
Proxy Table At MAP1
Portal
Proxy Table At MAP3
Proxy Table At MAP2
STA2
STA1
Hrishikesh Gossain, Motorola Inc.

13. Proxy Forwarding: An Example
May 2006
Proxy Forwarding: An Example
RM-AODV Working Principle (Cont.)
Proxy
Table
Dest AP
Dest AP
Dest AP
Dest AP
Proxy
Table
Proxy
Table
Proxy
Table
P.1 D
P.1 D
P.1 D
P.1 D
Dest
Next
Hop
Precu-
rsors
Dest
Next
Hop
Precu-
rsors
Dest
Next
Hop
Precu-
rsors
Route
Table
Route
Table
Route
Table D B - D C A D D A A B C D
Node X B A
P.1 X C B
P.1 X D C
P.1 X
P.1 D X
MAP
MAP
Portal
MAP
P.1
STA
Packet forwarding from Backbone to STA “S” in WDS using Proxy Based Routing
Hrishikesh Gossain, Motorola Inc.

14. May 2006
Conclusion
Provides method to do multihop packet forwarding for non-routable devices using IEEE four address format as required by s.
Hrishikesh Gossain, Motorola Inc.

15. May 2006
References
Hrishikesh Gossain, Motorola Inc.

16. May 2006
Backup
Hrishikesh Gossain, Motorola Inc.

17. Proxy Forwarding (3) RM-AODV Operation in Ad-Hoc Mode
May 2006
Proxy Forwarding (3)
RM-AODV Operation in
Ad-Hoc Mode
Infrastructure Mode
Routing Domain
Source R1 R2 R3
P.1
P.2
Originating
Device
Terminating
Device
Hrishikesh Gossain, Motorola Inc.