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Backward Compatibility Case Studies. Eldad Perahia (Cisco Systems) Adrian Stephens (Intel) Sean Coffey (TI). Enterprise Scenario. Initial State 3 Channels of 802.11g 19 Channels of 802.11a/h Example New State 3 Channels of 802.11g 19-N Channels of 802.11a/h N Channels of 802.11n/h
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Backward CompatibilityCase Studies Eldad Perahia (Cisco Systems) Adrian Stephens (Intel) Sean Coffey (TI) Eldad Perahia, Cisco Systems
Enterprise Scenario • Initial State • 3 Channels of 802.11g • 19 Channels of 802.11a/h • Example New State • 3 Channels of 802.11g • 19-N Channels of 802.11a/h • N Channels of 802.11n/h • The IT manager would use a RRM tool to reallocate the channels. Eldad Perahia, Cisco Systems
Enterprise Scenario (Access Points) • 802.11n/h Access Points • Be able to detect legacy clients and access points operating in their channels and report that information to the RRM tool. • Communicate with legacy clients and move them to channels served by legacy access points. • 802.11a/h Access Points • Continue to operate as they had before the installation of the new 802.11n systems. Eldad Perahia, Cisco Systems
Enterprise Scenario (Clients) • 802.11n/h Clients 1. Search for 802.11n access points. If they fail to find them, search for legacy access points and operate in a fallback mode. • 802.11a/h Clients • Continue to operate as they had before the installation of the new 802.11n systems. Eldad Perahia, Cisco Systems
Hot Spot Scenario (Airport) • Initial State • Many different types of legacy systems • 3 Channels of 802.11g • 1-19 Channels of 802.11a/h • Many different networks • Service providers, security, baggage handling, vendors, passengers in ad-hoc mode. • New State • Service provider adds 802.11n/h access points. Eldad Perahia, Cisco Systems
Hot Spot Scenario (Access Points) • 802.11n/h Access Points • Scan all channels to find the cleanest one(s). • Present scan results to the service provider along with suggested channels. • Three potential situations in which channel(s) are used and the modes are operated in: • 11n only operation • Fallback mode (802.11g or 802.11a/h) • Dual – mode operation (802.11a/h or 802.11n/h) • If it detects legacy clients on its channel, try to move those clients to another channel. • If it detects legacy access points on its channel, update the “cleanest channel” information. Eldad Perahia, Cisco Systems
Hot Spot Scenario (Clients) • 802.11n/h Clients 1. Search for 802.11n access points. If they fail to find them, search for legacy access points and operate in a fallback mode. • 802.11a/h Clients 1. Continue to operate as they had before the installation of the new 802.11n systems. Eldad Perahia, Cisco Systems
Home Scenario #1 • Initial State • No 802.11 network. • New State • Consumer adds 802.11n/h BB Gateway and 802.11n clients • AP Behavior • Scan all available channels to find the cleanest ones (The neighbors may operate WLANs) • Operate in 802.11n/h mode (do not communicate with any legacy equipment) • Client Behavior 1. Search for 802.11n access points. If they fail to find them search for legacy access points and operate in a fallback mode. Eldad Perahia, Cisco Systems
Home Scenario #2 • Initial State • 802.11a/h access point, 802.11g access point, dual-mode clients. • New State • Consumer adds 802.11n/h BB Gateway and 802.11n clients Eldad Perahia, Cisco Systems
Home Scenario #2 (Access Points) • 802.11n/h Access Points • Scan all channels to find the cleanest one(s). • Present scan results to the consumer along with suggested channels. • Three potential situations in which channel(s) are used and the modes are operated in: • 11n only operation (With the ability to move legacy equipment off the 802.11n channels) • Fallback mode (802.11g or 802.11a/h) • Dual – mode operation (802.11a/h or 802.11n/h on the same channel). Eldad Perahia, Cisco Systems
Home Scenario #2 (Clients) • 802.11n/h Clients • Search for 802.11n access points. If they fail to find them, search for legacy access points and operate in a fallback mode. • Legacy Dual-Mode Clients • Continue to operate as they had before the installation of the new 802.11n systems. • If the 802.11n access point moves them to another channel, do so. Eldad Perahia, Cisco Systems
Access Point Summary • Mandatory Behavior • Scan all available channels to find the cleanest channel(s) • Have the ability to fall back to 802.11 a/g • Have the ability to detect legacy clients and access points when operating in HT mode. • Highly Desirable Behavior • Have the ability to move legacy clients to another channel (Ent., Hot Spot, Home) • Desirable Behavior 1. Have the ability to communicate with both legacy and 802.11n clients on the same channel (Home & Hot Spot) Eldad Perahia, Cisco Systems
Client Summary • Mandatory Behavior • Scan all available channels to find an 802.11n access point. • If that fails, have the ability to fall back to 802.11 a/g. • Desirable Behavior 1. Share a channel/cell/access points with legacy clients (Home). Eldad Perahia, Cisco Systems