1. doc.: IEEE 802.11-00/xxx Jon Edney, Nokia
Month 2000
doc.: IEEE /xxx
May 2004
What is an ESS?
Jon Edney, Nokia
Jon Edney, Nokia
John Doe, His Company

2. Anecdotal Definitions for ESS (I have heard people use)
Month 2000
doc.: IEEE /xxx
May 2004
Anecdotal Definitions for ESS (I have heard people use)
Any group of APs having:
the same SSID and connected via a Layer 2 network
the same SSID and connected by any network
the same SSID
Jon Edney, Nokia
John Doe, His Company

3. The Distribution System (DS)
May 2004
The Distribution System (DS)
Distribution System AP AP AP
Jon Edney, Nokia

4. May 2004
The BSS DS AP
STA
STA
Jon Edney, Nokia

5. May 2004
ESS
Distribution System AP AP AP
STA
STA
Jon Edney, Nokia

6. NO NON 802.11 terminations allowed
May 2004
ESS
Distribution System AP AP AP
MSDU
MSDU
STA
STA
THIS IS ALL
NO NON terminations allowed
Jon Edney, Nokia

7. What does the standard say?
May 2004
What does the standard say?
3.25 extended service set (ESS):
A set of one or more interconnected basic service sets (BSSs) and integrated local area networks (LANs) that appears as a single BSS to the logical link control layer at any station associated with one of those BSSs.
Jon Edney, Nokia

8. May 2004
More ( )
The key concept is that the ESS network appears the same to an LLC layer as an IBSS network. Stations within an ESS may communicate and mobile stations may move from one BSS to another (within the same ESS) transparently to LLC.
Jon Edney, Nokia

9. May 2004
Portal
3.39 portal: The logical point at which medium access control (MAC) service data units (MSDUs) from a non-IEEE local area network (LAN) enter the distribution system (DS) of an extended service set (ESS).
Jon Edney, Nokia

10. Portal Distribution System May 2004 HOST Router 802.3 network AP AP AP
STA
Jon Edney, Nokia

11. May 2004
SSID
“The SSID element indicates the identity of an ESS or IBSS”
There is no such thing as “ESSID”
Jon Edney, Nokia

12. Summary SSID does not define ESS
May 2004
Summary
SSID does not define ESS
Any network technology can be used for DS but…
The only terminations allowed are APs or portals
DS must provide a tunnel for MSDUs – effectively this means layer 2 delivery
Connections through portal do not change when you roam within ESS
If STA is required to change IP address when it roams then it cannot be intra-ESS roaming.
Jon Edney, Nokia