1. Is Spanning Tree Protocol Right for ESS Mesh?
May 2004
Is Spanning Tree Protocol Right for ESS Mesh?
Tyan-Shu Jou, Ted Kuo, and Ming Sheu
Janusys Networks, Inc.
Date: May 11, 2004
Tyan-Shu Jou, et al., Janusys Networks

2. Forwarding Topologies to Prevent Traffic Looping on an ESS Mesh
Month 2002
doc.: IEEE /xxxr0
May 2004
Forwarding Topologies to Prevent Traffic Looping on an ESS Mesh
One global spanning tree (802.1d/802.1w)
Shortest Path based routing algorithms
(Spanning tree algorithms are essentially Distance Vector routing protocol running at Layer 2 that computes the lowest cost paths to the designated Root node)
Tyan-Shu Jou, et al., Janusys Networks
John Doe, His Company

3. Advantages of Using Spanning Tree on ESS Mesh
Month 2002
doc.: IEEE /xxxr0
May 2004
Advantages of Using Spanning Tree on ESS Mesh
Proven & standard algorithm
Rapid Spanning Tree (802.1w) can converge within a short time
(Although on wireless networks, link up/down detection are timer dependent)
Low processing overhead
Tyan-Shu Jou, et al., Janusys Networks
John Doe, His Company

4. Disadvantages of using Spanning Tree on ESS Mesh
May 2004
Disadvantages of using Spanning Tree on ESS Mesh
Not optimal connections between wireless peers
Not intended for dynamic topology – the global tree has to be reconstructed for any link change
Load sharing is difficult—eg., in case multiple border nodes to wired network exist
Difficult to reflect dynamic metrics such as receiving signal strength
Tyan-Shu Jou, et al., Janusys Networks

5. Examples of Shortest-path forwarding Algorithms
May 2004
Examples of Shortest-path forwarding Algorithms
OSPFv3 extension for wireless ad-hoc network
IETF MANET: 4 IP routing protocols for wireless ad-hoc network
Many others (NRL Dynamic backbone, Zigbee, …)
Tyan-Shu Jou, et al., Janusys Networks

6. May 2004
Questions for the SG
Should we decide which layer (or, what address) the forwarding algorithm should be based?
Should we decide one forwarding algorithm?
Can we define only the communication message format but not the algorithm?
Can we only define the MAC interface so the same hardware module can be shared?
How much interoperability among vendors is required?
Tyan-Shu Jou, et al., Janusys Networks