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What is an ESS?

What is an ESS?. Jon Edney, Nokia. 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. The Distribution System (DS). Distribution System. AP. AP. AP.

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What is an ESS?

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  1. What is an ESS? Jon Edney, Nokia Jon Edney, Nokia

  2. 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

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

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

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

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

  7. 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. More (5.2.2.1) 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. Portal 3.39 portal: The logical point at which medium access control (MAC) service data units (MSDUs) from a non-IEEE 802.11 local area network (LAN) enter the distribution system (DS) of an extended service set (ESS). Jon Edney, Nokia

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

  11. SSID • 7.3.2.1 “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 • 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

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