1. 802.11 TGs Mesh Networking Proposal
March 2005
doc.: IEEE Mesh-networking-proposal-Nokia/0xxxr0
March 2005
TGs Mesh Networking Proposal
Authors:
Date:
Name
Address
Company
Phone
Stefano M. Faccin
6000 Connection Dr., Irving, TX USA
Nokia
Carl Wijting
Jarkko Kneckt
Ameya Damle
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Stefano Faccin et al., Nokia
Stefano Faccin et al., Nokia

2. March 2005
Stefano Faccin et al., Nokia

3. doc.: IEEE 802.11-Mesh-networking-proposal-Nokia/0xxxr0
March 2005
doc.: IEEE Mesh-networking-proposal-Nokia/0xxxr0
March 2005
Abstract
Contains an initial description of the proposal for mesh networking in TGs.
The proposal focuses on simplicity, flexibility and auto-
configuration
Stefano Faccin et al., Nokia
Stefano Faccin et al., Nokia

4. Content Document contains key points of proposed solution
March 2005
Content
Document contains key points of proposed solution
More details available at next meeting and through off-line discussion
Stefano Faccin et al., Nokia

5. Components of the proposal
March 2005
doc.: IEEE Mesh-networking-proposal-Nokia/0xxxr0
March 2005
Components of the proposal
Usage Scenarios
Topology and its discovery
Routing
Security
Mobility
QoS
Power efficiency
Performance Enhancements for IP Transport Protocols
Stefano Faccin et al., Nokia
Stefano Faccin et al., Nokia

6. Usage Scenarios Main focus on: Home Scenario Office environment
March 2005
Usage Scenarios
Main focus on:
Home Scenario
Office environment
Small Campus environment
WDS
WLAN3
WLAN2
WDS
WLAN1
WLAN3
WLAN2
WDS
WDS
WLAN1
Stefano Faccin et al., Nokia

7. Topology discovery and Maintenance
March 2005
Topology discovery and Maintenance
Topology discovery
Active, based on emitting probe messages (preferred)
Fast identification and set-up of the network
Passive, based on scanning the system (option for power-efficiency)
Could be applied in static or low mobility networks
Topology Maintenance
Passive, based on the reception of beacon messages
In case of mobility can be active by emitting probe message to new AP
Log off mechanism for APs
Stefano Faccin et al., Nokia

8. Topology: Wireless-ESS
March 2005
Topology: Wireless-ESS
– Gateway / routing
Mesh Point
– Mesh Point
Within one Wireless ESS the stations are:
Operating at the same frequency (channel)
Time synchronized, i.e. virtual carrier sensing, power-save etc can be used
Synchronization is achieved by using the one beaconing framework (algorithm) per Wireless ESS
In range Mesh Points can set-up direct links between each other
Out of range Mesh Points will use bridging (or routing) functionality to communicate
Stefano Faccin et al., Nokia

9. Topology: Full Meshed Networking
March 2005
Topology: Full Meshed Networking
Wireless ESS1
– Routing functionality R
– Gateway / routing
Mesh Point
– Mesh Point R R
Wireless ESS3
Wireless ESS2 R R
Larger networks can be formed using Gateways
A Gateway is connected to two wireless Mesh networks (Possibly operating on different channels, using different beaconing schedules etc)
Only one Gateway is allowed to interconnection two Wireless ESSs
Stefano Faccin et al., Nokia

10. Routing Mesh networks need Layer 2 Routing
March 2005
Routing
Mesh networks need Layer 2 Routing
Mesh Points access each other using MAC addresses and not IP addresses
 proposal uses layer 2 routing (based on MAC addresses)
Dynamic creation/maintenance of routing tables in Mesh Points
Self-starting and loop-free algorithm
On-demand route creation possible
Routing protocol tailored to usage scenario:
Proposal supports several routing solutions for different usage scenarios
Configurable algorithms (proactive vs. reactive), depending on topology to optimize efficiency
Information for creation/maintenance of routing tables can be carried as user data or action frames
Stefano Faccin et al., Nokia

11. March 2005
Routing (cont.d)
Need to know where STA1 is to route based on STA1 MAC address
“Dumb” Layer 2 Routing based on MAC addresses is heavy and cumbersome
STA mobility in mesh network causes updates to several routing tables
Result in large memory storage requirement and complex route maintenance on STA mobility
STA1
 Proposal addresses this by allowing optimized lightweight routing where only Mesh Point mobility impacts routing table updates
STA mobility does not trigger routing tables update
Addressing remains based on MAC addresses
Stefano Faccin et al., Nokia

12. March 2005
Routing (cont.d)
 Proposal defines a QoS, security, and power-efficiency aware layer 2 routing protocol
QoS, security and power efficiency are key factors
 Proposal integrates optimized routing with optimized support of L3 routing/mobility protocols
Optimized support of ARP, Mobile IP Router Advertisements, etc.
Stefano Faccin et al., Nokia

13. Security Aspects of proposal
March 2005
Security Aspects of proposal
AP/MP1
AP/MP2
STA DS
Authentication
STA authentication
MP authentication
 Proposal: the MP the STA is associating with is the authenticator
 Similarly, when MP joins a mesh network, authenticator is the AP/MP it is associating with
Aim is at minimizing changes to the “basic” STA functionality
“Basic” STA is an STA that does not act as an AP
Mesh Points capable of acting both as Authenticator and as Supplicant.
Aim at keeping the current key hierarchy
Key distribution is defined to achieve this
STA has the choice of selecting one of the AP’s if multiple access points can be reached
Security attributes maintained across multi hop connection
Stefano Faccin et al., Nokia

14. Security Aspects of proposal (cont.d)
March 2005
Security Aspects of proposal (cont.d)
Encryption
Various models are possible: per-hop encryption, end-to-end encryption, segmented encryption
 proposal is based on segmented encryption
Encryption is Source_STA-Source_AP/MP, Source_AP/MP-Dest_AP/MP, Dest_AMP/MP-Dest_STA
Intermediate nodes will verify integrity/data origination
Provides less complexity and computational burden on intermediate stations
No impact on QoS (marking of frames as per 11e is visible to intermediate nodes) and routing
Impact of frame aggregation on encryption is addressed
 Encryption based on shared keys (GTK) between meshed APs
Dynamic GTK update upon group changes (e.g. AP leaves)
Support for group key distribution in different mesh point movement scenarios
 Support of TGr ideas/mechanisms for STA and AP/MP mobility has been considered as a design target
Stefano Faccin et al., Nokia

15. March 2005
Mobility
Our proposal takes into consideration the following aspects of mobility
Low AP and Mesh point mobility
Medium / High Mesh point mobility coherent with the STA mobility
Example : Access Point and STA’s in a vehicle. Both move at the same time.
Medium / High Mesh point mobility not coherent with the STA mobility.
Fast Mobility
Our proposal supports solutions being defined in TGr
No difference from STA point of view
Stefano Faccin et al., Nokia

16. March 2005
Quality-of-Service
Enabling simultaneous operation of AP on backbone and access network
Introduction of time scheduling of inter AP traffic and in-cell traffic within Wireless ESS
Minimum guaranteed service level in backbone for inter AP traffic
Proposal: Use bandwidth request scheme for inter-AP traffic
Mapping of QoS levels between access and backbone
TSPEC signaling can be used for exchanging the QoS demands (data rate, delay bounds etc)
Stefano Faccin et al., Nokia

17. Quality-of-Service (cont.d)
March 2005
Quality-of-Service (cont.d)
Access Control for AP entering basic Wireless ESS
Maximum number of allowed APs is 32
Enabling guarantees for End-to-End Throughput, and Delay
Flow control over multi-hop paths
Focus on concentrated traffic near originating and destination Mesh Points
Both trunking and instantaneous forwarding for inter AP traffic depending on service type
Stefano Faccin et al., Nokia

18. March 2005
Power Efficiency
Introduce a metric to indicate for battery or wired operation
if battery driven, an additionally the remaining battery power / life-time can be indicated
Fair sharing of traffic through the network from a energy consumption point of view
Power-aware routing
RF parameter (like Tx power, sensitivity thresholds) exchange may be used for
Reducing power consumption
Efficient geographical reuse (interference)
Stefano Faccin et al., Nokia

19. Power Efficiency (cont.d)
March 2005
Power Efficiency (cont.d)
Overhead reduction preventing unnecessary transmissions
Mesh Points currently serving wireless stations or that are wire connected will not enter into possible sleep modes
Passive scanning as optional feature for power save
Stefano Faccin et al., Nokia

20. Performance Enhancements for IP Transport Protocols
March 2005
Performance Enhancements for IP Transport Protocols
Providing end –to- end reliability is main goal of any transport protocol
when wireless technology is used, the goal is affected by following factors
Link Layer unreliability
Limited Bandwidth (not a major concern with e)
Mobility: can have considerable impact on the performance of IP transport protocols
Mesh networks introduce new issues
 Proposal addresses optimized support of IP transport protocols
Stefano Faccin et al., Nokia

21. March 2005
Conclusion / Summary
A proposal for ESS mesh networking with the following
salient characteristics was presented :
Auto-configurable
Secure
Proposal for L2 routing
QoS mechanisms, including interaction between AP-to-AP traffic and intra-cell traffic
Power-aware
Stefano Faccin et al., Nokia

22. March 2005
Q & A
Stefano Faccin et al., Nokia