Figure: Data flow in determining subscriber profile and SLA profile describes the data flow while determining which subscriber profile and SLA profile to use for a specified subscriber host based on a snooped/relayed DHCP ACK for that subscriber host.
An incoming DHCP ACK (relayed or snooped) is processed by the script provisioned in the sub-ident-policy defined in the SAP on which the message arrived. This script outputs one or more of the following strings:
- sub-ident
- identifies the subscriber (always needed)
- sub-profile
- identifies the subscriber class (optional)
- sla-profile
- identifies the SLA Profile for this subscriber host (optional)
These strings are used for a lookup in one or more maps to find the names of the sub-profile and sla-profile to use. If none of the maps contained an entry for these strings, the names are determined based on a set of defaults.
Only when the names for both the sub-profile and sla-profile are known, the subscriber host can be instantiated. If even no default is found for either profile, the DHCP ACK is dropped and the host does not gain network access.