IP Subscriber Session Initiation

ISG can be configured to allow one or more of the following events to signal the start of an IP session or IP subnet session on an interface:

• DHCP DISCOVER packet— If the following conditions are met, an IP session is created after ISG receives a DHCP DISCOVER packet:
  
  • ISG serves as a DHCP relay or a server for new IP address assignments.
    
  • Subscribers are configured for DHCP.
    
  • The DHCP DISCOVER packet is the first DHCP request received from the subscriber.
    Source IP address is unclassified— For routed IP subscribers, a new IP session is triggered when an IP packet with an unclassified source IP address (an IP session does not yet exist for that IP address) is received.
• Unclassified source MAC address— For Layer 2-connected IP subscribers, a new IP session is triggered when an IP packet with an unclassified source MAC address (which means that an IP session does not yet exist for that MAC address) is received.
  
• RADIUS Access-Request packet— For routed or Layer 2-connected access, a new IP session is triggered by the appearance of a RADIUS Access-Request packet when ISG is serving as a RADIUS proxy.