With EAP the AAA server can look at the realm from the user credential (IMSI) in authentication request and appropriately provide the service context in retail-service-id, for the ESM host corresponding to the UE.
For open SSID, the decision can be made by the AAA server based on the SSID, as learned by any of the methods described in Authentication.
The SSID is passed to the AAA server in initial MAC based authentication on DHCP DISCOVER. The retail-service-id can be returned in access-accept. This assumes the AP broadcasts unique SSID per retail provider and inserts it in Option82 as a DHCP relay-agent. As an alternative to SSID in option-82, the AP can insert a unique dot1Q tag per retail provider, before tunneling the Ethernet frame, using single GRE tunnel per AP to the WLAN-GW. 7750 supports configuring a map of dot1Q tags to retail-service-id. Therefore, the determination of the retail provider for the subscriber can be made in the data plane when DHCP is received, and the subscriber state can be created and processed in the right service context.
The following output displays a wholesale configuration example.
config>service>ies>
config>service>vprn>
subscriber-interface <ip-int-name>
group-interface <ip-int-name> wlangw
wlan-gw
[no] router (base | <vprn-id>) # tunnel service context
[no] wlan-gw-group <group-id>
....snip
vlan-tag-ranges # Precedence for retail-service-id:
# RADIUS, vlan-retail-service-map, default-retail-svc
[no] vlan start <start-tag> end <end-tag> retail-svc-id <svc-id>
[no] default-retail-svc-id
exit
exit
exit