1. Defining Usage Models for 802.11 ESS Mesh
W. Steven Conner
Intel Corp.
May 11, 2004

2. Outline Goals for Defining Usage Models Example Usage Models:
Home, Office, Hotzone
Requirements Based on Usage Models
Recommended Next Steps

3. Defining Usage Models for 802.11s
Exercise: Define and document expected use and behavior of ESS Mesh networks
Recent Example: TGn Usage Models (11-03/802)
Application: source or sink of wireless data
Environment: type of place where the WLAN deployed
Use Case: how an end-user uses a system that exercises the WLAN (application in a deployment environment)
Usage Model: Collection of one or more Use Cases that specifies a realistic scenario to evaluate
Additional Items Useful to Capture in ESS Mesh Usage Models:
Node mobility (mesh APs and clients)
Security misuse cases and threats
Connectivity to non networks
Network management activities

4. Why Define Usage Models?
Drive functional requirements
What are the functional components?
What are the requirements for each component?
Drive evaluation and comparison criteria
What are the performance evaluation metrics?
How to evaluate solutions against and security threats?

5. Home Network Usage Model Example
User Requirements:
Reliable high-bandwidth coverage throughout home
Internet access and high-bandwidth peer-to-peer A/V streams and data transfer (e.g., MPEG content between PVR and HDTV)
Self-managing and easy to install (non-technical consumers)
Network and data are “secure”
Deployment Characteristics:
Densely interconnected wireless topologies
Usually one broadband Internet connection out of home
Blurred lines between infrastructure and clients:
Many fixed or rarely moving devices such as Gateway/AP, PC, PVR (good candidates for Mesh APs)
Battery-powered clients may be mobile in the home (laptops, PDAs, cameras)
Office
Bedroom
Den
Mesh AP
Internet
Non-Mesh
Clients
Mesh AP
CE Devices
Mesh SoftAP PCs

6. Small/Medium Office Network Usage Model Example
User Requirements:
Reliable high-bandwidth network coverage anywhere in the office/campus
Applications primarily require access to Intranet services, with limited peer-to-peer (e.g. file/presentation sharing, printing)
Network administrator must be able to control and manage the ESS Mesh infrastructure
Network and data are “secure”
Deployment Characteristics:
Relatively dense infrastructure topology to support high client densities
Potentially multiple gateways to wired Intranet and other networks
Fixed Infrastructure may include Mesh APs and desktop Mesh SoftAP PCs
Fixed and mobile clients (PCs, laptops, PDAs, etc).
Non-mesh
clients
Mesh
SoftAP
Two Scenarios
AP mesh
SoftAP PC mesh

7. Hotzone Network Usage Model
User Requirements:
Reliable coverage anywhere in the hotzone), e.g., across airport or shopping center
Client applications primarily require Internet access
Network provider must be able to control and manage the ESS Mesh infrastructure
Network and data are “secure”
Deployment Characteristics:
Dedicated infrastructure of fixed-location Mesh APs (relatively sparse topology)
Potentially multiple gateways to Internet and other wired networks
Fixed and mobile clients (laptops, handhelds, etc.)
Wired Network

8. Summary of Deployment Characteristics
Home
Office
HotZone
Scale (Number of Mesh APs)
Small-
Medium
Medium-Large
Density of Mesh APs
High
Medium-
Low-
Frequency of Physical Mesh AP Topology Change
Low
Frequency of Mesh Link Quality Changes
Medium-High
Number of connections to other (e.g. wired) networks
Low (1-2)
Low-Medium

9. Possible Process for Driving Requirements and Evaluation Criteria with Usage Models
Functional
Components
Evaluation /
Comparison
Criteria
Evaluation /
Comparison
Criteria
Evaluation /
Comparison
Criteria
Evaluation /
Comparison
Criteria
Functional
Requirements
Evaluation /
Comparison
Criteria
Usage Models
Assumptions
Iteration

10. Proposed Next Steps Create common usage model description document
11n Usage Model document is a reasonable starting point, but need to extend and prioritize for ESS Mesh
Include security (mis)use-cases and threat analysis
Define major functional components and begin compiling requirements based on usage models

11. Thank You! Questions?

12. Backup

13. What Problems Motivate the Use of ESS Mesh?
Limited WLAN range/coverage
Reliability
Performance
Deployment cost/effort
Ease of use

14. Example Traffic Classes
Applications
Offered Load
Protocol
Maximum Packet Loss Rate
Maximum Delay
Internet File Transfer
( , web, chat)
1Mbps
TCP
Local File Transfer
(printing, backup, multimedia)
30Mbps
(bulk transfer)
Netmeeting application
500kbps
Internet Streaming Video/Audio
100kbps-4Mbps
UDP 1%
200ms
VoIP
20-150kbps 5%
30ms
SDTV
4-5Mbps
5x10-7
HDTV
Mbps
10-7
Source: TGn Usage Models 11-03/802r16